JP2022507458A - A process for removing the reactive solvent from lithium bis (fluorosulfonyl) imide (LIFSI) using an organic solvent that is stable to the anode of lithium ion and lithium metal batteries. - Google Patents

Abstract

A method for producing high-purity LiFSI salts and intermediate products using one, the other or both of the reactive solvent removal / substitution method and the LiFSI purification method. In some embodiments, the reactive solvent removal / replacement method comprises using a non-reactive anhydrous organic solvent to remove and / or replace one or more reactive solvents in the crude LiFSI. In some embodiments, the LiFSI purification method comprises using an anhydrous organic solvent to remove impurities such as synthetic impurities from the crude LiFSI. In some embodiments, crude LiFSI can be produced using an aqueous neutralization process. LiFSI salts and products produced using the methods of the present disclosure are also described, as well as the use of such salts and products and electrochemical devices containing such salts and products.

Description

Related Application Data This application was filed on September 13, 2019, and was filed on September 13, 2019, "PURIFIED LITHIUM BIS (FLUOROSULFONYL) IMIDE (LiFSI) PRODUCTS, METHODS OF PURIFYING CRUDE LiFSI, AND USES OF PURIFSI It is a partial continuation application of Application No. 16 / 570,262, which is incorporated herein by reference in its entirety. The application also asserts the priority interests of the following applications, each of which is incorporated herein by reference in its entirety.
Filed on August 6, 2019, "PROCESS FOR PRODUCTING ULTRAPURE LITHIUM BIS (FLUOROSULFONYL) IMIDE (LiFSI) FOR LITHIUM METAL ANODE BATTERIES, Japanese Patent No. 7, Japanese Patent No. 7, APPLICATIONS, U.S.A.
Filed on August 6, 2019, "PROCESS FOR REMOVING SOLVENT FROM LITHIUM BIS (FLUOROSULFONYL) IMIDE (LIFSI) USING ORGANIC SOLVENTS THAT ALPHA 62 / 883,178;
US Provisional Patent Application No. 62 / 840,949, filed April 30, 2019, entitled "PROCESS FOR REMOVING PROTIC SOLVENTS FROM LITHIUM BIS (FLUORO-SULFONYL) IMIDE (LiFSI)";
US Provisional Patent Application No. 62 / 768,447, filed November 16, 2018, entitled "PROCESS FOR THE PURIFICANION OF LITHIUM BIS (FLUOROSULFONYL) IMIDE (LiFSI)".

The present invention generally relates to the field of lithium sulfoneimide salts for electrolytes for lithium-based electrochemical devices. In particular, the present invention relates to a process for removing a reactive solvent from a lithium bis (fluorosulfonyl) imide (LiFSI) using a lithium ion and an organic solvent stable to the anode of a lithium metal battery.

Lithium bis (fluorosulfonyl) imide (LiFSI) has been reported as a conductive salt in lithium-based batteries due to its desirable physicochemical and electrochemical properties. LiFSI has a melting point of 143 ° C and is thermally stable up to 200 ° C. LiFSI exhibits much better stability to hydrolysis compared to lithium hexafluorophosphate (LiPF ₆ ), which is a commonly used salt for lithium ion battery electrolytes. LiFSI is a lithium due to its unique properties such as excellent solubility, ionic conductivity comparable to LiPF ₆ -based electrolytes, cost effectiveness, environmental friendliness, and good solid electrolyte interface (SEI) forming properties. It is attracting great interest as an electrolyte / additive for ion batteries. The purity level of LiFSI used in the battery electrolyte may be important for the operation and cycle life of the battery using the LiFSI-based electrolyte. However, many commercial processes for synthesizing LiFSI produce by-products that remain in the crude LiFSI produced by the synthesis process. The main synthetic impurities in LiFSI are lithium fluoride (LiF), lithium chloride (LiCl), lithium sulfate (Li ₂ SO ₄ ), lithium fluorosulfonate (LiFSO ₃ ), and acid-type impurities such as hydrogen fluoride (LiF). HF). These impurities must be removed or reduced to various acceptable levels before using the LiFSI salt in the battery. However, it can be difficult to remove them.

Some processes for removing impurities such as the above synthetic impurities from crude LiFSI utilize one or more solvents that are reactive with the lithium metal, such as alcohol (s) and water. do. In addition, the crude LiFSI may contain water by means other than the solvent. Thus, even if such LiFSI is purified to a point where the level of targeted synthetic impurities is low enough not to interfere with the function of the electrochemical device when the purified LiFSI is placed in the electrolyte of the device. Purified LiFSI may still not be suitable for use in secondary lithium metal batteries. This is because the purified LiFSI contains a residue of the reactive solvent used to remove target impurities and / or water that may otherwise be present, and the reactive solvent residue and / or water of the device. This is because it reacts with the lithium metal of the anode, thereby destroying the integrity of the lithium metal and the ability of the anode to function properly. Over time, even relatively small amounts of the reactive solvent (s) in the LiFSI salt used to produce the electrolyte will affect the performance and cycle life of the secondary lithium metal battery. It can have a big impact.

There is a need for ultra-high purity LiFSI salts with very low levels of synthetic impurities as well as very low levels of reactive solvents.

In one embodiment, the present disclosure relates to a method for producing a reduced-reactive-solvent lithium bis (fluorosulfonyl) imide (LiFSI) product. The method provides a first crude LiFSI containing LiFSI and one or more reactive solvents, the first crude LiFSI under inert conditions with at least one first anhydrous organic solvent. Contacting is to produce a solution containing the first crude LiFSI and one or more reactive solvents, wherein the solubility of LiFSI in at least one first anhydrous organic solvent is less than 25 ° C. LiFSI is at least about 35%, subjecting the solution to vacuum to remove at least one first anhydrous organic solvent and one or more reactive solvents to obtain a solid mass. Treating the solid mass with at least one second anhydrous organic solvent that is insoluble to produce a combination with an insoluble moiety, isolating the insoluble moiety in an inert atmosphere, at least one insoluble moiety. Reactive solvent-reduced LiFSI product by flushing with a dry inert gas to remove traces of at least one second anhydrous organic solvent and subjecting the flushed insoluble moiety to a pressure of less than about 100 Torr. Including getting.

For purposes of illustrating the invention, the drawings show aspects of one or more embodiments of the invention. However, it should be understood that the invention is not limited to the exact arrangement and means shown in the drawings.

It is a flow chart which shows the multipath method which reduces the reactive solvent in lithium bis (fluorosulfonyl) imide (LiFSI) by the aspect of this disclosure.

It is a high level figure which shows the electrochemical device made by the aspect of this disclosure.

It is a flow chart which shows the multipath method for purifying LiFSI by the aspect of this disclosure.

It is a graph of the discharge capacity vs. the number of cycles of a non-aqueous electrolyte using a LiFSI salt synthesized according to the present disclosure (upper line) and a similar non-aqueous electrolyte using a commercially available LiFSI salt (lower line).

It is a graph of the capacity retention rate vs. the number of cycles of a non-aqueous electrolyte using a LiFSI salt synthesized according to the present disclosure (upper line) and a similar non-aqueous electrolyte using a commercially available LiFSI salt (lower line). ..

In some embodiments, the present disclosure relates to a method of removing one or more reactive solvents from a crude lithium bis (fluorosulfonyl) imide (LiFSI). As used herein and in the context of the accompanying patent claims, the use of the term "reactive" to modify "solvents" or "solvents", etc., unless otherwise stated. It is assumed that the solvent (s) is reactive with a lithium metal in a lithium-based battery, for example, a lithium metal in the anode of a lithium metal battery. As will be appreciated by those skilled in the art, "reactivity" in this context refers to the magnitude of the reduction potential of a lithium metal with respect to a solvent (s). The reactive solvent has a reactive proton having a relatively high reduction potential with respect to a lithium metal having a relatively low reduction potential. Examples of the reactive solvent include a protonic solvent such as water and a reactive organic solvent such as alcohol. Conversely, as used herein and in the appended claims, the term "non-reactive" to modify "solvents" or "solvents" and the like, unless otherwise stated. The use of is meant that the solvent (s) is non-reactive with the lithium metal. Also, reactive solvents (s) are not effective in passivating lithium metals, whereas non-reactive solvents (s) are non-reactive with lithium metals. There is or effectively passivates to the lithium metal, i.e. dynamically stabilizes the electrolyte / lithium anode system. Examples of non-reactive solvents include dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, fluorine-containing carbonate and glycol ether.

As used herein and in the appended claims, the term "crude" and similar terms when referring to LiFSI result from or are present at least LiFSI and the synthesis and / or purification of LiFSI. A synthetic product comprising one or more reactive solvents, such as a reactive solvent, is shown. The presence of reactive solvent (s) in LiFSI salts used in electrolytes for lithium-ion batteries and lithium metal batteries adversely affects cycle performance such as battery discharge capacity and capacity retention. May affect. Therefore, it is desirable to remove as much of the reactive solvent (s) present in the LiFSI salt as possible. Such reactive solvents may also be referred to as "solvent residues" or "solvent residues" as used herein and in the appended claims. The crude LiFSI may contain additional impurities, such as the impurities described below in Section II.

As used herein and in the appended claims, the term "anhydrous" refers to about 1% by weight or less of water, typically about 0.5% by weight or less of water, often about 0.1%. It refers to having water of less than or equal to weight, more often less than or less than about 0.01% by weight, and most often less than or less than about 0.001% by weight. Within this definition, the term "substantially anhydrous" refers to water of about 0.1% by weight or less, typically about 0.01% by weight or less, often about 0.001% by weight or less. Refers to having.

Throughout this disclosure, the term "about", when used with the corresponding number, is ± 20% of the number, typically ± 10% of the number, often ± 5% of the number, and most often ± of the number. Refers to 2%. In some embodiments, the term "about" can mean the number itself.

When describing a chemical reaction, such as any of the synthetic and purification reactions described herein and / or addressed within the appended claims, "treat," "contact," and "react." The term is used interchangeably and refers to the addition or mixing of two or more reagents under conditions sufficient to produce the indicated and / or desired product (s). .. It should be appreciated that the reactions shown and / or producing the desired product do not necessarily result directly from the combination of reagents added initially (s). That is, there may be one or more intermediates that are produced in the mixture and ultimately result in the formation of the indicated and / or desired product.

On a commercial scale, crude LiFSI usually contains one or more reactive solvent residues such as methanol, ethanol or water from the solvent source from which LiFSI is synthesized or purified. These reactive solvent residues are known to be very strongly solvated with alkali metal salts and are difficult to remove by suction under vacuum without heating to high temperatures. However, LiFSI is unstable to heating at high temperatures in the presence of reactive solvents, and high heat causes defluorination of LiFSI, which is a strong acid known to be corrosive, hydrogen fluoride. (HF) is generated. The following scheme shows the defluorination of LiFSI containing a protonic solvent during heating.

All protic solvents also tend to undergo proton reduction to produce hydrogen gas, which are generally used only for reduction electrochemical using electrodes such as mercury or carbon, which are kinetically slow in proton reduction. To. The protonic solvent also reacts with the lithium metal present in the lithium-based battery, and in particular, reacts with the lithium metal anode of the lithium metal battery to generate hydrogen gas according to the following scheme.

Although the above details relate to LiFSI, crude lithium bis (trifluoromethanesulfonyl) imides (LiTFSI), especially crude LiTFSI manufactured using commercial scale processes, have the same or similar problems with reactive solvents. Note that it exists. As a result, general methodologies for reducing the amount of each of the one or more reactive solvents described herein for crude LiFSI are also relevant to crude LiTFSI.

In another aspect, the disclosure comprises LiFSI and one or more reactive solvents used for the synthesis and / or purification of relatively low levels of one or more reactive solvents, such as crude LiFSI. Reduced-reactive-solvent with respect to LiFSI products. Examples of reactive solvents that may be present in crude LiFSI or LiTFSI include, among others, water, methanol, ethanol and propanol, alone or in various combinations with each other. As described in more detail below, such reactive solvent-reduced LiFSI products may be a single passthrough of one of the disclosed basic processes, or one or more of the disclosed basic processes. It can be produced using the reactive solvent reduction method of the present disclosure, which is capable of producing a reactive solvent-reduced LiFSI product in multiple pass-throughs.

In yet a further aspect, the present disclosure relates to the use of the LiFSI salt products of the present disclosure. For example, the LiFSI salt products of the present disclosure are used to produce an electrolyte that can be used in any suitable electrochemical device such as a battery or supercapacitor, in particular a secondary lithium ion battery and a secondary lithium metal battery. be able to.

In some embodiments, the methods disclosed herein are used to remove (s) reactive solvents and / or (s) reactive solvents (s). Substitution with a non-reactive solvent may be sufficient for a particular use of LiFSI (or LiTFSI), but in other cases LiFSI generation in which the reactive solvent removal / replacement methods of the present disclosure can be used otherwise. It may be beneficial to apply to LiFSI products of higher purity than the product. The two routes that provide such high-purity LiFSI specifically addressed below are a method of removing non-solvent impurities from the crude LiFSI and a method of synthesizing the crude LiFSI using an aqueous neutralization process. As a result, as described below, additional embodiments of the present disclosure include various combinations of these methods and processes, as well as two or more of the methods disclosed herein, their accompanying intermediates and final production. These include objects as well as their use, which are described shortly below.

In some additional embodiments, the present disclosure relates to a method of purifying crude LiFSI to remove any one or more of various non-solvent impurities from crude LiFSI. As used in the context of non-solvent impurity removal and in the appended claims, the term "crude LiFSI" and similar terms refer to at least LiFSI and one or more non-solvent impurities resulting from the synthesis of LiFSI. The synthetic product containing non-solvent impurities is shown. In the following and attached claims, this type of impurity is referred to as a "synthetic impurity". Each of the targeted impurities that is removed to some extent or to some extent using the disclosed method is referred to as "targeted impurities" as used herein and in the appended claims. In one example, the target impurity may be a synthetic impurity that is a by-product of the synthesis of LiFSI as described above.

この例では、Ｌｉ_２ＳＯ_４、ＦＳＯ_３Ｌｉ、ＬｉＦ、およびＬｉＣｌは、粗ＬｉＦＳＩから除去されることが望ましい標的不純物（ここでは、合成不純物）である。いくつかの実施形態では、本開示の精製方法は、Ｌｉ_２ＳＯ_４、ＦＳＯ_３Ｌｉ、ＬｉＦ、およびＬｉＣｌのうちの１種または複数などの１種または複数の合成不純物、および／または開示された方法による除去に適した分子構造および特性を有する任意の他の不純物を除去し、その各々は本開示の用語では「標的不純物」である。 On a commercial scale, crude LiFSI is generally hydrogen containing various concentrations of synthetic impurities such as hydrogen fluoride (HF), fluorosulfuric acid (FSO ₃ H), hydrogen chloride (HCl), and sulfuric acid (H ₂ SO ₄ ). It is obtained by neutralizing bis (fluorosulfonyl) imide (HFSI) with lithium carbonate (Li ₂ CO ₃ ) or lithium hydroxide (LiOH). As an example, using LiOH-based synthesis, impurities such as HFSI and HF, FSO ₃ H, HCl, and H ₂ SO ₄ are added to the corresponding Li salts by the following scheme during this process to produce crude LiFSI. The conversion produces LiFSI, Li ₂ SO ₄ , FSO ₃ Li, LiF, and Li Cl, respectively.

In this example, Li ₂ SO ₄ , FSO ₃ Li, LiF, and LiCl are target impurities (here, synthetic impurities) that should be removed from the crude LiFSI. In some embodiments, the purification methods of the present disclosure are one or more synthetic impurities, such as one or more of Li ₂ SO ₄ , FSO ₃ Li, LiF, and Li Cl, and / or disclosed. It removes any other impurities with molecular structure and properties suitable for removal by method, each of which is a "target impurity" in the terms of the present disclosure.

In another aspect, the present disclosure discloses LiFSI and relatively low levels of one or more target impurities, such as one or more synthetic impurities, such as the Li ₂ SO ₄ , FSO ₃ Li, LiF, and LiCl described above. With respect to purified LiFSI products containing. As described in more detail below, such purified LiFSI products may be a single passthrough of one of the disclosed basic processes, or one or more of the disclosed basic processes. It can be produced using the purification methods of the present disclosure which can produce purified LiFSI products in pass-through.

In yet a further aspect, the present disclosure relates to the use of the LiFSI salt products of the present disclosure. For example, the LiFSI salt products of the present disclosure can be used to produce electrolytes that can be used in any suitable electrochemical device such as batteries or supercapacitors.

In yet another aspect, the present disclosure relates to a method of synthesizing LiFSI using an aqueous neutralization method following removal of impurities. As described in more detail below, one exemplary LiFSI synthesis method neutralizes hydrogen bis (fluorosulfonyl) imide (HFSI) (eg, purified HFSI) with one or more lithium bases in deionized water. To obtain an aqueous solution of LiFSI and one or more synthetic impurities. Additional steps may include removing at least a portion of the deionized water to obtain crude LiFSI and then purifying the crude LiFSI to remove at least a portion of one or more synthetic impurities.

Also in a further aspect, the present disclosure relates to performing any one of the various combinations of the various methods disclosed herein. For example, the overall process is to synthesize LiFSI using the aqueous neutralization synthesis method of the present disclosure, followed by this synthesis using the synthesized LiFSI to purify the non-reactive solvent of the present disclosure. It can include the process, the reactive solvent reduction / substitution methods of the present disclosure, or any combination of the two. If both additional methods are used, especially if either reactive solvent is used in the non-reactive solvent purification process, it is generally preferred to carry out the reactive solvent reduction / substitution method last. As another example, the overall process begins with an already synthesized crude LiFSI, such as a commercially supplied crude LiFSI synthesized by conventional methods, followed by the non-reactive solvent purification process or book of the present disclosure. It may include performing one, the other or both of the reactive solvent reduction / substitution methods disclosed.

In yet a further aspect, the present disclosure is either a purified LiFSI product containing LiFSI produced using any one of the combinations of methods described in the preceding paragraph, or any of the combinations described in the preceding paragraph. With respect to electrolytes produced using purified LiFSI salts produced using one of them, and the use of such electrolytes.

Details of the aforementioned and other aspects of the present disclosure will be described below.

I. Removal / replacement of reactive solvent (s)

This section covers methods of removing and / or substituting reactive solvents in lithium sulfoneimide salts, the reactive solvent-reduced lithium sulfoneimide salts produced thereby, and the use of such reactive solvent-reduced lithium sulfoneimide salts. Handle.

I. A. An exemplary method of removing / replacing the reactive solvent (s) in the crude LiFSI.

As mentioned above, the crude LiFSI can include, for example, one or more reactive solvents as residues from the synthesis and / or purification of LiFSI. The reactive solvent removal methods of the present disclosure can be used to reduce the amount, including the complete removal of one or more reactive solvents in the crude LiFSI. The removal of the reactive solvent (s) used one or more non-reactive solvents, and at least a portion of the non-reactive solvents (s) completed the reactive solvent removal method. In some embodiments, this method may also be considered as a solvent replacement method, as it remains behind, and the undesired reactive solvent (s) may be a reactive solvent (s). It is replaced with a non-reactive solvent (s) that does not adversely affect the battery performance of (s). As described below, in some embodiments, the residual non-reactive solvent (s) is often in the range of about 3000 ppm or less, eg, about 100 ppm to about 3000 ppm.

In some embodiments, the reactive solvent removal method comprises contacting the crude LiFSI with at least one first anhydrous organic solvent under inert conditions to contain the crude LiFSI and one or more reactive solvents. Includes producing a solution. In general, this step involves replacing the ion-bound coordination-reactive solvent molecule with the desired non-reactive molecule. In some embodiments, the solubility of LiFSI in at least one first anhydrous organic solvent is at least about 35% to about 65% at room temperature. In some embodiments, contacting the crude LiFSI with at least one first anhydrous organic solvent keeps the crude LiFSI in the range of about 35% to about 65% by weight based on the total weight of the solution. It involves contacting with an amount of at least one first anhydrous organic solvent.

Inactive conditions during contact of LiFSI with at least one first anhydrous organic solvent include, among other things, the use of argon gas and / or nitrogen gas, and / or other inert dry (ie, anhydrous) gas. , Can be produced using any suitable technique. The purification method can be carried out at any suitable pressure, such as 1 atmosphere.

Examples of anhydrous organic solvents in which each of at least one first anhydrous organic solvent can be selected are dimethylcarbonate (DMC), diethylcarbonate (DEC), ethylmethylcarbonate (EMC), propylmethylcarbonate. Organic carbonates such as (PMC), ethylene carbonate (EC), fluoroethylene carbonate (FEC), and transbutylene carbonate, nitriles such as acetonitrile, malononitrile, and adiponitrile, methyl acetate, ethyl acetate, propyl acetate, and acetic acid. Examples include, but are not limited to, alkyl acetates such as butyl and alkyl propionates such as methyl propionate (MP) and ethyl propionate (EP). For example, when removing one or more reactive solvents using one or more non-reactive organic solvents to produce LiFSI salts for lithium ion batteries or lithium metal batteries, at least one. It is desirable that each anhydrous organic solvent selected for the first anhydrous organic solvent be non-reactive with lithium metal. Examples of such non-reactive anhydrous organic solvents include DMC, DEC, EMC, fluoroethylene carbonate, difluoroethylene carbonate, and trifluoromethyl ethyl carbonate.

After contacting the crude LiFSI or LiTFSI with at least one first anhydrous organic solvent, the solution is subjected to vacuum to present at least one first anhydrous organic solvent and one or more reactive solvents, eg. One or more of the possible ones, especially water, methanol or ethanol, are removed to give a solid mass. In some embodiments, the vacuum pressure may be less than about 100 Torr, less than about 10 Torr, or less than about 1 Torr, less than about 0.1 Torr, or less than about 0.01 Torr. In some embodiments, the vacuum is performed at a controlled temperature, such as a temperature in the range of about 25 ° C to about 40 ° C.

The solid mass can then be treated with at least 100% by weight of one or more second anhydrous organic solvents in which the LiFSI in the solid mass is insoluble to produce a combination with an insoluble moiety. This treatment can remove any coordination solvent or solvate solvent. Examples of anhydrous organic solvents in which each of the one or more second anhydrous organic solvents may be selected include dichloromethane, dichloroethane, chloroform, pentane, hexane, heptane, octane, nonane, decane, undecane, and dodecane. However, it is not always limited to these.

The insoluble moiety is isolated from the combination in the inert atmosphere provided by the dry inert gas, such as argon, nitrogen, another dry inert gas, or any combination thereof. The insoluble moiety can be isolated by any suitable method such as filtration performed using any suitable method such as one or more filters, centrifugation, specific gravity separation, hydrocyclone and the like. One of ordinary skill in the art will understand suitable filtration techniques for use in any particular embodiment of the protonic solvent reduction methods of the present disclosure.

The insoluble moiety can be flushed with at least one inert gas (eg, a dry inert gas, i.e. less than 1 ppm of water) to remove trace amounts of at least one second anhydrous organic solvent. Examples of the inert gas in which each of the at least one dry inert gas can be selected includes argon and nitrogen.

The flushed insoluble moiety can be subjected to a pressure of less than about 100 Torr to give a LiFSI product with reduced protonic solvent or a LiTFSI product with reduced protonic solvent. In some embodiments, the pressure may be less than about 10 Torr, or less than about 1 Torr, less than about 0.1 Torr, or less than about 0.01 Torr. In one example, the pressure in vacuum is less than about 0.01 Torr. In some embodiments, the vacuum is performed at a controlled temperature, such as a temperature below about 40 ° C (eg, in the range of about 20 ° C to about 40 ° C). The resulting reactive solvent-reduced LiFSI product is typically a white, free-flowing powder.

The dried reactive solvent-reduced LiFSI product is a dry polytetrafluoroethylene (PTFE) container or a dry inert container such as a nickel alloy that is inert to free fluoride to suppress the decomposition of LiFSI during storage. In addition, it can be stored in an inert gas such as argon at a low temperature such as about 25 ° C. or lower.

In a general example where DMC is used as at least one first anhydrous organic solvent and dichloromethane is used as at least one second anhydrous organic solvent, the typical process is particularly water. Crude LiFSI with various levels of one or more reactive solvents such as methanol and / or ethanol is contacted with about 30% to about 50% by weight anhydrous dimethylcarbonate in which LiFSI is soluble. In this example, the crude LiFSI is contacted with the DMC and then under vacuum (eg, less than about 0.01 Torr) with a reactive solvent (s) such as water, methanol, and / or ethanol. Remove. Removal of DMC results in a solid mass. This method further comprises treating the resulting solid mass with anhydrous dichloromethane in which LiFSI is insoluble to obtain an insoluble moiety and a combination of anhydrous dichloromethane and any other insoluble component (s). It may be included. Insoluble moieties (eg, powdered LiFSI) can be obtained by filtration and trace amounts of dichloromethane can be removed by flushing with dry Ar and / or dry _N2 . The flushed LiFSI can then be subjected to vacuum (eg, less than 0.01 Torr) at a temperature below about 40 ° C. to give a dry reactive solvent-reduced LiFSI product, in this case a free solvent-free LiFSI product. can. Reactive solvent-reduced LiFSI products may be free of free solvent, but in practice LiFSI products are typically at least some reactive and / or non-reactive coordinated with LiFSI. Contains solvent. The LiFSI product, which does not contain a dry protonic solvent, may be stored in a PTFE container under inert conditions, for example, at a temperature of less than about 25 ° C.

The amount of reactive solvent (s) in the crude LiFSI from which the reactive solvent (s) is removed using any one of the above methods and the reactive solvent in the desired LiFSI product. It may be necessary to carry out a multipass method to sequentially reduce the amount of one or more reactive solvents in each pass, depending on the desired maximum amount (s). Such a multipath method is initially in crude LiFSI and then each of one or more reactive solvents that may still remain in the resulting reactive solvent-reduced LiFSI product. Any one or more of the above methods can be continuously utilized to continuously reduce the level of. An exemplary multipath-reactive solvent reduction method 100 of the present disclosure is shown in FIG.

Referring to FIG. 1, in block 105, crude LiFSI containing one or more reactive solvents present at a particular level (s) is provided. In block 110, the reactive solvent content of the crude LiFSI is reduced using any one of the above methods. The end result of reactive solvent reduction in block 110 is a reactive solvent reduced LiFSI product with reduced levels of each reactive solvent. In the optional block 115, the level of each of one or more of the reactive solvents in the reactive solvent reduced LiFSI product is measured using appropriate measurement procedures. In the optional block 120, each of the measured levels is compared to the maximum desired level of the reactive solvent (s) that are allowed to be present in the reactive solvent reduced LiFSI product. In the optional block 125, it is determined whether one or more of the measured levels exceeds the corresponding desired maximum level. If not exceeded, i.e., if each measured level is below the corresponding desired maximum level, the reactive solvent reduced LiFSI product meets the specifications for the desired reactive solvent reduction level, further reducing the reactive solvent. do not need. Therefore, the multipath reactive solvent reduction method 100 can be terminated at block 130.

However, in block 125, if any one or more of the measured levels exceeds the corresponding desired maximum level (s), the reactivity treated with the previous pass-through reactive solvent reduction in block 110. The solvent-reduced LiFSI product can be processed in block 110 via loop 135. In this reactive solvent reduction pass-through in block 110, the anhydrous organic solvent (s) used for solution formation and / or washing of the crystallized LiFSI is used in the previous pass-through reactive solvent reduction in block 110. It may be the same as or different from the original. At the end of the reactive solvent reduction in block 110, one or more measurements of the reactive solvent level (s) and one of the measured levels (s) in the optional blocks 115 and 120. Alternatively, the method 100 can be terminated at block 130 by comparison with multiple corresponding desired maximum levels, or LiFSI in the reactive solvent-reduced LiFSI product of the latest pass is again via loop 135. It can be determined whether it should be subjected to reactive solvent reduction.

A non-limiting and exemplary example in which a multipath-reactive solvent reduction method may be useful is a lithium-based electrolyte such as LiFSI for lithium-based batteries. Crude LiFSI typically has a reactive solvent such as methanol, ethanol, and / or propanol from the LiFSI crystallization process. These reactive solvents can be present in excess of 3000 ppm. However, such levels of the reactive solvent are detrimental to the lithium metal battery as the reactive solvent reacts with the lithium metal to produce hydrogen gas and lithium alkoxide. As a result, it is desirable to keep the level of the reactive solvent in the LiFSI-based electrolyte for lithium metal batteries low, for example, less than about 200 ppm, less than about 100 ppm, less than about 50 ppm, or less than about 10 ppm. For crude LiFSI used to synthesize the LiFSI salt used in the electrolyte, it is such low to use the multipath purification methods of the present disclosure, such as the multipath reactive solvent reduction method 100 shown in FIG. It can be a useful method of achieving reactive solvent levels.

As a non-limiting but exemplary example, the multipass reactive solvent reduction method 100 is used to start with crude LiFSI containing 3000 ppm alcohol as a synthetic impurity (target reactivity) in the LiFSI product. The reactive solvent content (in the form of alcohol) can be reduced to less than 1 ppm. At block 105, the desired amount of crude LiFSI is provided. In block 110, the crude LiFSI is purified, i.e., using either the method described above or exemplified below, the amount of undesired alcohol is reduced.

In the optional block 115, the level of alcohol in the reactive solvent-reduced LiFSI product is measured to be 1000 ppm. In the optional block 120, a measured level of 1000 ppm is compared to a requirement of less than 100 ppm. In the optional block 125, the reactive solvent-reduced LiFSI product reduces the reactive solvent level in the initial crude LiFSI via loop 135 in block 110, as 1000 ppm is greater than the requirement of less than 100 ppm. It is processed using the same or different reactive solvent reduction process as that used to. In this second pass, the starting alcohol level is 1000 ppm and the final impurity level in the double-reactive solvent-reduced LiFSI product is 500 ppm as measured in optional block 115. After comparing this 500 ppm level with the requirement of less than 100 ppm in the optional block 120, the double-reactive solvent-reduced LiFSI product in the optional block 125 is previously in block 110 via loop 135. It is determined that the treatment needs to be retreated with the same or different reactive solvent reduction method as that used in either of the two passes.

In this third pass, the starting alcohol level is 500 ppm and the final impurity level in the triplicate solvent-reduced LiFSI product is less than 100 ppm, as measured by optional block 115. After comparing this level of less than 100 ppm with the requirement of less than 100 ppm in the optional block 120, the triple-reactive solvent-reduced LiFSI product is blocked by the multipath-reactive solvent reduction method 100 in the optional block 125. It is determined that the requirement is satisfied so that the process can be completed at 130.

I. B. example

The above methods are further described by the following examples, but it will be appreciated that these examples are included solely for illustrative purposes and are not intended to limit the scope of the present disclosure. Unless otherwise stated, all chemicals used in these examples were of high purity and were obtained from reliable commercial sources. Strict precautions were taken to remove water from the process and the reaction was carried out using a well-ventilated hood.

I. B. 1. 1. Example 1

Removal of Methanol from LiFSI Using DMC and dichloromethane: LiFSI (200 g) containing 4000 ppm methanol and 50 ppm water was sampled in a 250 mL dry flask under a nitrogen atmosphere and cooled to 10 ° C. using a water bath. .. Anhydrous DMC (140 g (about 41% by weight)) was added little by little with stirring to obtain a clear solution. The mixture was stirred at room temperature for 0.5 hours. The clear solution was concentrated under reduced pressure below 0.01 Torr to give a solid, which was treated with anhydrous dichloromethane (150 g) under argon. The combination was stirred at room temperature for 1 hour and the desired insoluble LiFSI product was isolated by filtration. Traces of dichloromethane were removed by flushing with dry Ar / N ₂ gas. The isolated LiFSI was dried in vacuo (less than 0.1 Torr) at 35 ° C. to give a reactive solvent-reduced LiFSI product containing 0 ppm methanol and 15.0 ppm water in 90% yield.

I. B. 2. 2. Example 2

Removal of Ethanol from LiFSI Using DMC and dichloromethane: LiFSI (178 g) containing 2900 ppm ethanol and 15 ppm water was sampled in a 250 mL dry flask under a nitrogen atmosphere and cooled to 10 ° C. using a water bath. .. Anhydrous DMC (140 g (about 44% by weight)) was added little by little with stirring to obtain a clear solution. The mixture was stirred at room temperature for 0.5 hours. The clear solution was concentrated under reduced pressure below 0.01 Torr to give a solid, which was treated with anhydrous dichloromethane (150 g) under argon. The combination was stirred at room temperature for 1 hour and the desired insoluble LiFSI product was isolated by filtration. Traces of dichloromethane were removed by flushing with dry Ar / N ₂ gas. The isolated LiFSI was dried in vacuo (less than 0.1 Torr) at 35 ° C. to give a reactive solvent-reduced LiFSI product containing 0 ppm ethanol and 4 ppm water in 90% yield.

I. B. 3. 3. Example 3

Removal of Isopropanol from LiFSI Using DMC and dichloromethane: LiFSI (350 g) containing 2000 ppm isopropanol and 30 ppm water was sampled in a 250 mL dry flask under a nitrogen atmosphere and cooled to 10 ° C. using a water bath. .. Anhydrous DMC (200 g (about 36% by weight)) was added little by little with stirring to obtain a clear solution. The mixture was stirred at room temperature for 0.5 hours. The clear solution was concentrated under reduced pressure below 0.01 Torr to give a solid, which was treated with anhydrous dichloromethane (350 g) under argon. The combination was stirred at room temperature for 1 hour and the desired insoluble LiFSI product was isolated by filtration. Traces of dichloromethane were removed by flushing with dry Ar / N ₂ gas. The isolated LiFSI was dried in vacuo (less than 0.1 Torr) at 35 ° C. to give a reactive solvent-reduced LiFSI product containing 0 ppm isopropanol and 4 ppm water in 92% yield.

I. C. Exemplary Reactive Solvent Reduced LiFSI Products

Using either of the single-pass reactive solvent reduction methods disclosed above or the reactive solvent reduction methods described above, such as any of the multi-pass methods 100 of FIG. 1, the resulting purified LiFSI product is reactive. The target reactivity level of the solvent (s) can be very low. For example, in some embodiments particularly suitable for use in lithium metal batteries, they remain in the final ultra-purity LiFSI salt product (ie, after completion of the reactive solvent reduction disclosed herein). The amount of the reactive solvent (s) is preferably less than about 100 ppm, more preferably less than about 50 ppm, most preferably less than about 25 ppm. In some embodiments, the non-reactive solvent remaining in the final ultra-purity LiFSI salt product does not adversely affect battery performance more than the reactive solvent, but in such embodiments it is final. The amount of non-reactive solvent (s) remaining in the ultra-purity LiFSI salt product is typically less than about 3000 ppm, more typically less than about 1000 ppm. If purification is performed using only non-reactive solvents for all purification steps, the final ultra-purity LiFSI salt product will typically be at least about 100 ppm non-reactive solvent (s). However, typically, it has a reactive solvent (s) of about 100 ppm or less. The level of the reactive solvent (s) in the crude LiFSI prior to the reduction of the reactive solvent according to the present disclosure may be about 500 ppm or more, about 1000 ppm or more, or about 2000 ppm or more. In one example where DMC is used in a reactive solvent removal / replacement method, the purified LiFSI of the present disclosure has about 0.2% to about 0.3% DMC and less than 100 ppm water as a reactive solvent.

I. D. Example of use of reactive solvent-reduced LiFSI salt product

As mentioned above, reactive solvent-reduced LiFSI salt products can be used to produce reactive solvent-reduced LiFSI-based electrolytes, among other things, for electrochemical devices. Here, the reactive solvent reduction of the reactive solvent reduced electrolyte results from the fact that the reactive solvent reduced LiFSI salt product was treated by any one or more of the methods disclosed herein. Such reactive solvent reducing electrolytes are the reactive solvent reducing solvent LiFSI salt products (salts) of the present disclosure in one or more solvents, one or more diluents, and / or one or more additives. It can be produced using any of a variety of methods, such as mixing with, and solvents, diluents, and additives may be known in the art.

If the electrochemical device is a lithium-based device such as a secondary lithium-ion battery or a secondary lithium metal battery, the reactive solvent (s) will generate an electrolyte so that it does not affect the performance of the battery. It is desirable to minimize the amount of reactive solvent (s) in the LiFSI salt used in. For example, the more reactive solvent in the LiFSI salt, the greater the adverse effect of the reactive solvent on cycle performance such as discharge capacity and capacity retention. Therefore, in the case of lithium-based secondary batteries, it is desirable to remove as much reactive solvent (s) as possible from the LiFSI salt used in the electrolyte of such batteries. Typically, as described above, this involves the use of one or more non-reactive solvents in the reactive solvent reduction process disclosed herein. Therefore, the majority of the reactive solvent in the initial crude LiFSI is removed and / or replaced with the non-reactive solvent (s) used in the corresponding reactive solvent reduction process. In some embodiments, the reactive solvent-reduced LiFSI product produced using the techniques disclosed herein is referred to as the "IC exemplary protonic solvent-reduced LiFSI product" described above. It can have reactive and / or non-reactive solvent levels as shown in the title section.

I. D. 1. 1. Preparation of LiFSI salt for use in electrolytes for lithium-based electrochemical devices

As mentioned above, an important step in preparing electrolytes for use in lithium-based electrochemical devices such as secondary lithium batteries with lithium metal anodes is from LiFSI salts containing such residues. For example, removing as much reactive solvent residue as possible from the process of synthesizing and / or purifying the LiFSI salt (s). In some embodiments, the removal process comprises a substitution embodiment in which one or more reactive solvents such as one or more alcohols and water are at least partially replaced by one or more non-reactive solvents. Can include. As described above, it is present in the LiFSI salt by removing and / or substituting the reactive solvent residue (s) in the LiFSI salt prior to forming the electrolyte for lithium-based electrochemical devices. Due to the fact that there is much less (and in some cases non-existent) reactive solvent in the device that reacts with the lithium metal, better performance and / or improved cycle life of the electrochemical device is brought about. It should be noted that the non-reactive solvent (s) used in the substitution / removal process can be selected on the basis of its benefit to lithium-based electrochemical devices. For example, the non-reactive solvent selected may be of a type that can be used as a solvent in which the LiFSI salt is dissolved so as to give the electrolyte the desired concentration. In this case, the reactive solvent removal / replacement method of the present disclosure may be used to remove the reactive solvent (s) and potentially replace the reactive solvent with a small amount of final solvent, as well as the final electrolyte. Will be beneficial to you. Alternatively, the non-reactive solvent (s) selected for the reactive solvent removal / substitution process, apart from any major salt dissolution function, is a solid electrolyte interface (SEI), especially on a lithium metal anode. It may be a desirable additive added to be particularly beneficial to the electrochemical device, such as an additive to promote layer formation.

The method of preparing LiFSI salts for use in lithium-based electrochemical devices removes and / or replaces such solvent residues prior to using LiFSI salts to prepare electrolytes for lithium-based devices. It involves providing a LiFSI salt containing one or more reactive solvent residues that, if not, would be detrimental to the function of the lithium-based device. Providing LiFSI salts may include purchasing LiFSI salts from commercial suppliers of such salts, or synthesizing and / or purifying crude LiFSI salts in-house. The Reactive Solvent Residue-Containing LiFSI Salt is then exemplified by removing, for example, "IA crude LiFSI from the reactive solvent (s) by any of the methods disclosed herein. Methods "can be processed by the methods described above in the section entitled". The method of preparing a LiFSI salt for use in a lithium-based electrochemical device may include selecting one or more non-reactive solvents for use in a reactive solvent removal / substitution method. Note that "removal / replacement" and forward slashes or diagonal lines at similar positions, as is generally understood, mean "and / or", i.e. one, the other, or both. In some embodiments, at least one of the non-reactive solvents selected is not only non-reactive with lithium metals, but also has positive benefits such as promoting SEI layer growth like electrolyte additives. Selected based on the offer. LiFSI salts can be used to produce electrolytes for lithium-based electrochemical devices when subjected to reactive solvent removal / substitution treatments.

I. D. 2. 2. An exemplary electrochemical device utilizing the LiFSI salt produced using the methods of the present disclosure.

FIG. 2 shows an electrochemical device 200 made according to the aspects of the present disclosure. Those skilled in the art will readily appreciate that the electrochemical device 200 may be, for example, a battery or a supercapacitor. In addition, those skilled in the art show that FIG. 2 shows only some basic functional components of the electrochemical device 200, which is typically a realization of an electrochemical device such as a secondary battery or supercapacitor. It will be easy to understand that it is embodied using either a wound structure or a laminated structure. In addition, those skilled in the art will appreciate that the electrochemical device 200 is not shown in FIG. 2 for ease of illustration, among others, electrical terminals, seals (s), heat shield layers (s). , And / or will be understood to include other components such as vents (s).

In this example, the electrochemical device 200 includes spaced positive and negative electrodes 204, 208, and a pair of corresponding current collectors 204A, 208A, respectively. The porous dielectric separator 212 is arranged between the positive electrode and the negative electrodes 204 and 208 to electrically separate the positive electrode and the negative electrode, and the ions of the reactive solvent-reducing LiFSI-based electrolyte 216 produced by the present disclosure are placed therein. Allows to flow. One, the other, or both of the porous dielectric separator 212 and / or the positive electrode and the negative electrode 204, 208 is impregnated with the protic and aprotic solvent-reduced LiFSI-based electrolyte or the LiTFSI-based electrolyte 216, depending on whether or not they are porous. ing. In FIG. 2, both the positive electrode and the negative electrodes 204, 208 are shown to be porous by showing the reactive solvent-reduced LiFSI-based electrolyte 216 extending internally. As described above, the advantage of using the reactive solvent-reduced LiFSI-based electrolyte of the present disclosure for the reactive solvent-reduced LiFSI-based electrolyte 216 is that the reactive solvent may be present in the LiFSI-based electrolyte such as a synthetic or purified protonic solvent. (One or more) can be reduced to acceptable levels for use in the electrochemical device 200 (eg, meeting the specifications for one or more protonic solvent levels). Examples of reactive solvent-reduced LiFSI products (salts) and low-level examples of reactive solvents (s) that can be used to produce the reactive solvent-reduced LiFSI-based electrolyte 216 are described above. ing. The electrochemical device 200 includes collectors 204A, 208A, positive and negative electrodes 204, 208, a porous dielectric separator 212, and a container 220 containing a protonic solvent-reduced LiFSI-based electrolyte or LiTFSI-based electrolyte 216.

As will be appreciated by those skilled in the art, depending on the type and design of the electrochemical device, each of the positive and negative electrodes 204, 208 will be suitable for alkali metal ions and other components in the purified LiFSI-based electrolyte 216. Including materials. Each of the current collectors 204A, 208A can be made of any suitable conductive material such as copper or aluminum or any combination thereof. The porous dielectric separator 212 can be made of any suitable porous dielectric material, in particular, such as a porous polymer. Various battery and supercapacitor structures that can be used to build the electrochemical device 200 of FIG. 2 are known in the art. When any of such known structures are used, the novelty of the electrochemical device 200 is a high-purity reactive solvent-reduced LiFSI system that was not achieved by conventional methods of producing LiFSI salts and corresponding electrolytes. It is in the electrolyte 216.

In one example, the electrochemical device 200 can be made as follows. The reactive solvent reduction LiFSI-based electrolyte 216 can be produced starting from the crude LiFSI, which can then be made using any one or more of the reactive solvent reduction methods described herein. Purification is performed to produce reactive solvent-reduced LiFSI products with suitable low levels of one or more target reactive solvents. The reactive solvent-reduced LiFSI product is then used, for example, to improve the performance of the electrochemical device 200, for example, one or more solvents, one or more diluents, and / or one or more additions. By adding the agent, the reactive solvent-reduced LiFSI-based electrolyte 216 can be produced. The reactive solvent-reduced LiFSI-based electrolyte 216 can then be added to the electrochemical device 200 and then the container 220 can be sealed.

II. Removal of non-solvent impurities from crude lithium sulfone imide salt

This section deals with methods of removing non-solvent impurities from crude lithium sulfoneimide salts, the purified lithium sulfoneimide salts produced thereby, and the use of such purified lithium sulfoneimide salts.

II. A. An exemplary method for purifying crude LiFSI

Although several processes for producing LiFSI are known, each of the known methods for synthesizing LiFSI on a commercial scale produces crude LiFSI containing various levels of impurities such as synthetic impurities. .. For example, as mentioned above, LiFSI is often produced commercially using crude HFSI that reacts with Li ₂ CO ₃ or LiOH, and crude HFSI is an impurity in the crude LiFSI so synthesized. Contains various synthetic impurities that produce.

For example, one method of synthesizing HFSI uses urea (NH ₂ CONH ₂ ) and fluorosulfuric acid (FSO ₃ H). Disadvantages of this process are the low yield of HFSI and the isolated HFSI with a large excess of fluorosulfonic acid as an impurity. The boiling point of fluorosulfonic acid (bp) (bp165.5 ° C.) and b. Of HFSI. p. (B. p. 170 ° C.) are very close to each other and it is very difficult to separate them from each other by simple fractional distillation [1]. Attempts have been made to remove fluorosulfuric acid by treating a mixture of HFSI and fluorosulfuric acid with sodium chloride. In this case, sodium chloride selectively reacts with fluorosulfuric acid to produce sodium salts and HCl by-products. This process has the disadvantages that the yield of purified HFSI is low and that the HFSI product is contaminated with some chloride impurities (HCl and NaCl) as impurities.

Another method of synthesizing HFSI for use in LiFSI synthesis involves fluorinating the bis (chlorosulfonyl) imide (HCSI) with arsenic trifluoride (AsF ₃ ). In this reaction, HCSI is treated with AsF ₃ . Arsenic trifluoride is toxic and has a high vapor pressure, making it particularly difficult to handle on an industrial scale. A typical reaction uses a ratio of HCSI to AsF ₃ of 1: 8.6. The HFSI produced by this method was also found to be contaminated with AsF ₃ and AsCl ₃ synthetic impurities, which were found to be good sources of chloride and fluoride impurities [2].

HFSI for use in LiFSI synthesis can also be prepared by fluorinating HCSI with antimony trifluoride (SbF ₃ ). The antimony trichloride by-product of this reaction has high solubility in HFSI, is essentially sublimable, and is very difficult to separate from the desired product. The product of this reaction is typically contaminated with antimony trichloride, which is a good source of chloride impurities [3].

Yet another method for producing HFSI for use in LiFSI synthesis involves reacting HCSI with excess anhydrous HF at elevated temperatures [4]. The yield of this reaction is up to 60% and the product is contaminated with the fluorosulfonic acid produced from the decomposition of HCSI. Since the boiling point is close to the boiling point of HFSI, this by-product is difficult to remove. This reaction of fluorinating HSCI using anhydrous HF achieved yields of> 95% [5], but the product was still a synthetic impurity with fluorosulfuric acid, hydrogen fluoride, hydrogen chloride, and sulfuric acid. It is contaminated.

It has been reported that reaction of HCSI with bismuth trifluoride (BiF ₃ ) produces HFSI in a cleaner reaction product. Since BiCl ₃ is not sublimable in this reaction, the formed BiCl ₃ by-product can be easily separated from HFSI by fractional distillation [6]. However, the product has some chloride, fluoride, and fluorosulfonic acid as synthetic impurities.

Another method of synthesizing HFSI is to react potassium bis (fluorosulfonyl) imide (KFSI) with perchloric acid [7]. In this process, the by-product potassium perchlorate is considered explosive. Also, the isolated HFSI is contaminated with high levels of potassium cations and some chloride impurities present in KFSI.

Hydrogen bis (fluorosulfonic acid), also known as imidebis (sulfuric acid) difluoride having the formula FSO ₂ NH-O ₂ F, has a melting point (mp) of 17 ° C. and b. p. Is a colorless liquid having a density of 1.892 g / cm ³ at 170 ° C. It dissolves very well in water and many organic solvents. Hydrolysis in water is relatively slow, resulting in the formation of HF, H ₂ SO ₄ , and amidosulfate (H ₃ NSO ₃ ). HFSI is a strong acid and pKa is 1.28 [8].

Produced using the purification methods of the present disclosure using targeted impurities such as synthetic impurities and / or other impurities present in crude LiFSI, eg, one or more of the synthetic methods described above. The crude LiFSI synthesized can be removed using the crude HFSI. In some embodiments, the purification method contacts the crude LiFSI with at least one first anhydrous organic solvent under inert conditions to produce a solution containing the crude LiFSI and one or more target impurities. Including doing. In some embodiments, the solubility of LiFSI in at least one first anhydrous organic solvent is at least about 60% at room temperature, typically in the range of about 60% to about 90%, and one or more. The solubility of each of the plurality of target impurities is typically less than about 20 parts per million (ppm) at room temperature, often less than about 13 ppm, for example. In some embodiments, contact of the crude LiFSI with at least one first anhydrous organic solvent is carried out using a minimum amount of at least one first anhydrous organic solvent. The "minimum amount" in the context of at least one first anhydrous organic solvent means that the at least one first anhydrous organic solvent is provided in an amount that substantially no longer continues to dissolve LiFSI. means. In some embodiments, the minimum amount of at least one anhydrous inorganic solvent is in the range of about 50% by weight to about 75% by weight of the solution.

In some embodiments, the contact of the crude LiFSI with at least one first anhydrous organic solvent is carried out at a temperature below the temperature in the range of about 15 ° C to about 25 ° C. Dissolution of the crude LiFSI in at least one anhydrous organic solvent is an exothermic reaction. As a result, in some embodiments, the temperature of the solution can be controlled using any suitable temperature control device such as a cooler, thermostat, circulator or the like. In some embodiments, the temperature of the solution is controlled to maintain the temperature of the solution below about 25 ° C. when contacting the crude LiFSI with at least one anhydrous organic solvent. At least one to achieve a minimum amount of at least one first anhydrous organic solvent and / or to control the temperature of the solution during contact of the crude LiFSI with at least one first anhydrous organic solvent. Anhydrous organic solvents of the species can be added continuously or continuously at precisely controlled rates or in precisely controlled amounts using appropriate feeders or feeders.

Inactive conditions during contact of LiFSI with at least one first anhydrous organic solvent include, among other things, the use of argon gas and / or nitrogen gas, and / or other inert dry (ie, anhydrous) gas. , Can be produced using any suitable technique. The purification method can be carried out at any suitable pressure, such as 1 atmosphere.

Examples of anhydrous organic solvents in which each of at least one first anhydrous organic solvent can be selected include dimethylcarbonate (DMC), diethylcarbonate (DEC), ethylmethylcarbonate (EMC), and propylmethylcarbonate. (PMC), Ethyl Carbonate (EC), Fluoroethylene Carbonate (FEC), Transbutylene Carbonate, acetonitrile, Marononitrile, Adiponitrile, Methyl Acetate, Ethyl Acetate, Propyl Acetate, Butyl Acetate, Methyl Propionate (MP), Propion Examples include, but are not limited to, ethyl acetate (EP), methanol, ethanol, propanol and isopropanol.

After contacting the crude LiFSI with at least one first anhydrous organic solvent, at least one second anhydrous organic solvent is added to the solution to precipitate the at least one target impurity. The at least one second anhydrous organic solvent is substantially insoluble in LiFSI and one or more target impurities in at least one second anhydrous organic solvent (as mentioned above, the target impurities exceed 20 ppm). It is generally desirable that it should not be soluble). In some embodiments, the minimum amount of at least one second anhydrous organic solvent is added. The "minimum amount" in the context of at least one second anhydrous organic solvent is that at least one second anhydrous organic solvent substantially continues to precipitate one or more target impurities from the solution. Means that it is provided in no quantity. In some embodiments, the minimum amount of at least one anhydrous inorganic solvent ranges from more than 0% by weight to less than 10% by weight of the solution. The at least one second anhydrous organic solvent can be added under the same temperature, pressure and inert conditions as present during contact between the crude LiFSI and the at least one first anhydrous organic solvent.

Examples of anhydrous organic solvents in which each of at least one second anhydrous organic solvent can be selected include dichloromethane, dichloroethane, chloroform, pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, etc. Not necessarily limited to these.

After adding at least one second anhydrous organic solvent, the insoluble portion of each of the one or more target impurities is separated from the solution, for example by filtration or cannulating, and a filtrate containing LiFSI in the solution. Generate. Filtration can be performed using any suitable method, such as using one or more filters, centrifugation, gravity separation, hydrocyclone, and the like. One of ordinary skill in the art will understand suitable filtration techniques (s) for use in any particular embodiment of the purification methods of the present disclosure.

After the filtrate is obtained from filtration, the solvent in the filtrate is removed to give a solid mass consisting primarily of LiFSI and a somewhat reduced amount of one or more target impurities. The solvent removed is typically each of one or more first anhydrous organic solvents and one or more second anhydrous organic solvents from the previous treatment. The solvent can be removed using any suitable technique, for example under suitable temperature and reduced pressure conditions. For example, removing the solvent may be performed at a pressure of about 0.5 Torr or less or about 0.1 Torr or less. The temperature at the time of removal may be, for example, about 25 ° C. to about 40 ° C. or lower.

After obtaining the solid mass, the solid mass is contacted with at least one third anhydrous organic solvent in which LiFSI is substantially insoluble and solvated with the third solvent by one or more target impurities. , More one or more target impurities can be further removed. Another advantage is to remove any ppm levels of HF formed during the process, especially by aspirating the solvent at reduced pressure and slightly above room temperature. In some embodiments, the amount of at least one third anhydrous organic solvent used to contact the solid mass may be at least 50% by weight by weight of the solid mass. Examples of anhydrous organic solvents in which each of at least one third anhydrous organic solvent can be selected include dichloromethane, dichloroethane, chloroform, pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, etc. Not necessarily limited to these.

After contacting the solid mass with at least one third anhydrous organic solvent, LiFSI is isolated from at least one third anhydrous organic solvent and each of the reduced amounts of one or more target impurities. A purified LiFSI product containing the above is obtained. Isolation of LiFSI from at least one third anhydrous organic solvent uses any suitable technique, such as filtration of LiFSI in solid form and / or drying of solid LiFSI in vacuum, etc. Can be done. In some embodiments, the pressure in vacuum is less than about 0.1 Torr or less than about 0.01 Torr. The resulting purified LiFSI product is typically a white free-flowing powder.

The dried purified LiFSI product is placed in a dry polytetrafluoroethylene (PTFE) container or a dry inert container such as a nickel alloy that is inert to free fluoride to suppress the decomposition of LiFSI during storage. It can be stored in an inert gas such as argon at a low temperature such as 25 ° C. or lower.

Table I below shows examples of selection of each of the first, second and third anhydrous organic solvents for the LiFSI purification method of the present disclosure. As can be seen in the table, the selected first anhydrous organic solvent is dimethylcarbonate and the selected second and third anhydrous organic solvents are dichloromethane.

Based on Table I above, the solubility of LiFSI in dimethylcarbonate is greater than 90% and is insoluble in dichloromethane. On the other hand, the solubility of target impurities such as LiF, LiCl and Li ₂ SO ₄ in this example is less than 13 ppm in dimethylcarbonate under anhydrous conditions. Therefore, in this example of purifying crude LiFSI, anhydrous dimethylcarbonate and anhydrous dichloromethane solvents were selected to obtain the purified LiFSI product according to the present disclosure. According to the embodiment of the above method, the crude LiFSI containing the impurities reported in Table I above is mixed in dimethylcarbonate at a concentration of about 40% to about 75% at about 25 ° C. and stirred at room temperature. , Subsequently, about 2% to about 10% dichloromethane can be added to precipitate the target impurities. The target impurities can then be removed, for example by filtration, and the filtrate can be concentrated to dryness. The resulting solid can then be treated with anhydrous dichloromethane to remove any target HF impurities soluble in dichloromethane. However, LiFSI is insoluble in dichloromethane.

Purified LiFSI can be recovered by filtration and finally dried under reduced pressure (less than about 0.1 Torr in one example) and below about 40 ° C. to give a white free-flowing powder. In this example, the white powder was stored in an argon atmosphere in a PTFE container.

The concentration of the target impurity (s) in the crude LiFSI purified using any one of the above methods and the desired one or more of the target impurities in the desired purified LiFSI product. Depending on the maximum concentration, it may be necessary to perform a multi-pass method to sequentially reduce the amount of one or more target impurities in each pass. Such a multipath method is first in crude LiFSI and then continuous with each level of one or more target impurities that may still remain in the resulting purified LiFSI product. One or more of the above-mentioned methods can be continuously utilized in order to reduce the temperature. An exemplary multipath purification method 100 of the present disclosure is shown in FIG.

Referring to FIG. 3, in block 305, crude LiFSI containing one or more target impurities present at a particular level (s) is provided. In block 310, crude LiFSI is purified using any one of the above methods. The end result of purification in block 310 is a purified LiFSI product with reduced levels of each target impurity. In optional block 315, the level of each of one or more of the target impurities in the purified LiFSI product is measured using appropriate measurement procedures. In optional block 320, each of the measured levels is compared to the maximum desired level of the corresponding target impurity that is allowed to be present in the purified LiFSI product. In the optional block 325, it is determined whether any one or more of the measured levels exceed the corresponding desired maximum level. If not exceeded, i.e., if each measured level is below the corresponding desired maximum level, the purified LiFSI product meets the desired impurity level specifications and does not require further purification. Therefore, the multipath purification method 300 can be terminated at block 330.

However, in block 325, if one or more of the measured levels exceeds the corresponding desired maximum level (s), the purified LiFSI production purified by the previous pass-through purification in block 310. The material can be purified via loop 335 in block 310. In this pass-through purification at block 310, the anhydrous organic solvent (s) used to generate the solution and / or wash the crystallized LiFSI were the same as those used in the previous pass-through purification at block 310. May be different. At the end of purification in block 310, in optional blocks 315 and 320, one or more measurements of the target impurity level (s), and one or more correspondences with the measured levels (s). Whether the method 300 can be terminated at block 330 by making one or more comparisons with the desired maximum level, or the LiFSI in the purified LiFSI product of the latest path is purified again via loop 335. It is possible to decide whether or not it should be offered to.

A non-limiting but exemplary example in which a multipath purification method may be useful is a lithium-based electrolyte such as LiFSI for lithium-based batteries. Crude LiFSI typically has around 350 ppm LiCl from chloride impurities, eg, HCl synthetic impurities in crude HFSI used to produce LiFSI. However, such chloride levels are corrosive to lithium metal batteries. As a result, it is desirable to keep the chloride level in the LiFSI-based electrolyte for lithium metal batteries low, for example less than about 10 ppm or less than 1 ppm. For crude LiFSI used to synthesize the LiFSI salt used in the electrolyte, using the multipath purification methods of the present disclosure, such as the multipath purification method 300 shown in FIG. 3, is such a low chloride level. Can be a useful way to achieve.

As a non-limiting but exemplary example, the multipath purification method 300 is used to start with crude LiFSI containing 200 ppm LiCl as a synthetic impurity and in the LiFSI product (in the form of the target impurity LiCl). ) The chlorine content can be reduced to less than 1 ppm. At block 305, the desired amount of crude HFSI is provided. In block 310, the crude LiFSI is purified using either the purification method described above or exemplified below.

In optional block 315, the level of LiCl (or chloride) in the purified LiFSI product is measured to be 100 ppm. In the optional block 320, a measured level of 300 ppm is compared to a requirement of less than 1 ppm. In the optional block 325, 100 ppm is greater than the requirement of less than 1 ppm, so the purified LiFSI product is the same as that used to purify the first crude LiFSI in block 310 via loop 335. Or it is processed using a different purification process. In this second pass, the starting target impurity level is 100 ppm and the final impurity level in the double purified LiFSI product is 20 ppm as measured in optional block 315. After comparing this 20 ppm level with the requirement of less than 1 ppm in optional block 320, the double purified LiFSI product in block 310 via loop 335 the previous two passes. It is determined that it needs to be purified again by the same or different purification method used in any of the above.

In this third pass, the starting target impurity level is 20 ppm and the final impurity level of the triple purified LiFSI product is less than 1 ppm as measured in optional block 315. After comparing this less than 1 ppm level with less than 1 ppm requirements in optional block 320, the triple-purified LiFSI product in optional block 325 may be terminated in block 330 by the multipath purification method 300. It is determined that the necessary conditions that can be met are satisfied.

II. B. example

The above methods are further described by the following examples, but it will be appreciated that these examples are included solely for illustrative purposes and are not intended to limit the scope of the present disclosure. Unless otherwise stated, all chemicals used in these examples were of high purity and were obtained from reliable commercial sources. Strict precautions were taken to remove water from the process and the reaction was carried out using a well-ventilated hood.

II. B. 1. 1. Example 1

Purification of LiFSI using ^dimethyl carbonate (DMC) and dichloromethane: Various levels of impurities in a 500 mL dry flask, here FSO _3- = 400 ppm ^{, Cl-} = 50 ppm ^, F- = 200 ppm, SO _4-2 . Crude LiFSI (250 g) containing = 200 ppm and water = 200 ppm was collected under a nitrogen atmosphere and cooled to 10 ° C. using a water bath. Anhydrous DMC (250 g (50% by weight)) was added little by little to the flask with stirring, followed by 20 g (4% by weight) of anhydrous dichloromethane. The mixture was stirred at room temperature for 1 hour. Insoluble impurities were removed from the mixture by filtration. The filtrate was concentrated under reduced pressure to give a solid, which was then treated with anhydrous dichloromethane (200 g) under argon. The mixture is stirred at room temperature for 1 hour, the desired insoluble LiFSI product is isolated by filtration and finally dried in vacuo (less than 0.1 Torr) at 35 ° C. to give the purified LiFSI product in 95% yield. rice field. In this example, the purified LiFSI product had the following impurities: FSO ₃ ⁻ = 100 ppm, Cl ⁻ = 10 ppm, F ⁻ = 50 ppm, ^SO _4-2 = 60 ppm, and water = 50 ppm.

II. B. 2. 2. Example 2

Purification of LiFSI using Ethyl Methyl Carbonate (EMC) and dichloromethane: Various levels of impurities in a 500 mL dry flask, here FSO ₃ ⁻ = 200 ppm, Cl ⁻ = 10 ppm, F ^{− =} 100 ppm, SO ₄₂ . Crude LiFSI (250 g) containing ⁻ = 100 ppm and water = 100 ppm was collected under a nitrogen atmosphere and cooled to 10 ° C. using a water bath. Anhydrous EMC (200 g (about 44% by weight)) was added little by little to the flask with stirring, followed by 25 g (about 5.6% by weight) of anhydrous dichloromethane. The mixture was stirred at room temperature for 1 hour. Insoluble impurities were removed by filtration. The filtrate was concentrated under reduced pressure to give a solid, which was then treated with anhydrous dichloromethane (250 g) under argon. The mixture is stirred at room temperature for 1 hour, the desired insoluble LiFSI product is isolated by filtration and finally dried in vacuo (less than 0.1 Torr) at 35 ° C. to give the purified LiFSI product in 92% yield. rice field. In this example, the purified LiFSI had the following impurities: FSO ₃ ⁻ = 40 ppm, Cl ⁻ = 1 ppm, F ⁻ = 10 ppm, ^{SO 4-2} ₌ 20 ppm, and water = 30 ppm.

II. B. 3. 3. Example 3

Purification of LiFSI using diethyl carbonate (DEC) and dichloromethane: Various levels of impurities in a 500 mL dry flask, here FSO _3- = 400 ppm ^{, Cl-} = 50 ppm ^{, F-} = 200 ppm, SO _4-2 . Crude LiFSI (250 g) containing = 200 ppm and water = 200 ppm was collected under a nitrogen atmosphere and cooled to 10 ° C. using a water bath. Anhydrous DEC (250 g (50% by weight)) was added little by little to the flask with stirring, followed by 20 g (4% by weight) of anhydrous dichloromethane. The mixture was stirred at room temperature for 1 hour. Insoluble impurities were removed from the mixture by filtration. The filtrate was concentrated under reduced pressure to give a solid, which was then treated with anhydrous dichloromethane (200 g) under argon. The mixture is stirred at room temperature for 1 hour, the desired insoluble LiFSI product is isolated by filtration and finally dried in vacuo (less than 0.1 Torr) at 35 ° C. to give the purified LiFSI product in 90% yield. rice field. In this example, the purified LiFSI product has the following impurities: FSO ₃ ⁻ = 80 ppm, Cl ⁻ = 5 ppm, F ⁻ = 30 ppm, ^SO _4-2 = 50 ppm, and water = 45 ppm.

II. B. 4. Example 4

Purification of LiFSI using dipropylcarbonate (DPC) and dichloromethane: Various levels of impurities in a 500 mL dry flask, here FSO _3- = 200 ppm ^{, Cl-} = 10 ppm ^, F- ⁼ 100 ppm, SO ₄₂ . Crude LiFSI (250 g) containing ⁻ = 100 ppm and water = 100 ppm was collected under a nitrogen atmosphere and cooled to 10 ° C. using a water bath. Dipropyl carbonate (200 g (about 44% by weight)) was added little by little to the flask with stirring, followed by 20 g (about 4.4% by weight) of dichloromethane. The mixture was stirred at room temperature for 1 hour. Insoluble impurities were removed from the mixture by filtration. The filtrate was concentrated under reduced pressure to give a solid, which was treated with anhydrous dichloromethane (250 g) under argon. The mixture is stirred at room temperature for 1 hour, the desired insoluble LiFSI product is isolated by filtration and finally dried in vacuo (less than 0.1 Torr) at 35 ° C. to give the purified LiFSI product in 90% yield. rice field. In this example, the purified LiFSI product had the following impurities: FSO ₃ ⁻ = 30 ppm, Cl ⁻ = 1 ppm, F ⁻ = 11 ppm, ^SO _4-2 = 15 ppm, and water = 30 ppm.

II. B. 5. Example 5

Purification of LiFSI using Methylpropyl Carbonate (MPC) and dichloromethane: Various levels of impurities in a 500 mL dry flask, here FSO ₃ ⁻ = 200 ppm, Cl ⁻ = 10 ppm, F ^{− =} 100 ppm, SO ₄₂ . Crude LiFSI (250 g) containing ⁻ = 100 ppm and water = 100 ppm was collected under a nitrogen atmosphere and cooled to 10 ° C. using a water bath. Methylpropylcarbonate anhydride (MPC) (200 g (about 44.4% by weight)) was added to the flask little by little with stirring, followed by 20 g (about 4.4% by weight) of dichloromethane. The mixture was stirred at room temperature for 1 hour. Insoluble impurities were removed by filtration. The filtrate was concentrated under reduced pressure to give a solid, which was treated with anhydrous dichloromethane (250 g) under argon. The mixture is stirred at room temperature for 1 hour, the desired insoluble LiFSI product is isolated by filtration and finally dried in vacuo (less than 0.1 Torr) at 35 ° C. to give the purified LiFSI product in 91% yield. rice field. In this example, the purified LiFSI product had the following impurities: FSO ₃ ⁻ = 32 ppm, Cl ⁻ = ² ppm, F ⁻ = 12 ppm, SO _4-2 = 22 ppm, and water = 35 ppm.

II. B. 6. Example 6

Purification of LiFSI using ^ethyl acetate and chloroform: various levels of impurities in a 500 mL dry flask, here FSO _3- = 200 ppm ^{, Cl-} = 10 ppm ^, F- = 100 ppm, SO _4-2 = 100 ppm, and. Crude LiFSI (250 g) containing 100 ppm of water was collected under a nitrogen atmosphere and cooled to 10 ° C. using a water bath. Acetic anhydride (150 g (37.5% by weight)) is added little by little to the flask with stirring, followed by 20 g (5% by weight) of anhydrous chloroform. The mixture was stirred at room temperature for 1 hour. Insoluble impurities were removed by filtration. The filtrate was concentrated under reduced pressure to give a solid, which was treated with anhydrous chloroform (250 g) under argon. The mixture is stirred at room temperature for 1 hour, the desired insoluble LiFSI product is isolated by filtration and finally dried in vacuo (less than 0.1 Torr) at 35 ° C. to give the purified LiFSI product in 88% yield. rice field. In this example, the purified LiFSI had the following impurities: FSO ₃ ⁻ = 40 ppm, Cl ⁻ = ² ppm, F ⁻ = 15 ppm, SO _4-2 = 20 ppm, and water = 40 ppm.

II. B. 7. Example 7

Purification of LiFSI using butyl acetate and dichloromethane: Various levels of impurities in a 500 mL dry flask, here FSO _3- = 200 ppm ^{, Cl-} = 10 ppm ^{, F-} = 100 ppm, SO _4-2 = 100 ppm, and. Crude LiFSI (200 g) containing water = 100 ppm was collected under a nitrogen atmosphere and cooled to 10 ° C. using a water bath. Acetic anhydride butyl acetate (150 g (about 43% by weight)) was added little by little to the flask with stirring, followed by addition of 30 g (about 8.6% by weight) of acetic anhydride. The mixture was stirred at room temperature for 1 hour. Insoluble impurities were removed by filtration. The filtrate was concentrated under reduced pressure to give a solid, which was treated with anhydrous dichloromethane (250 g) under argon. The mixture is stirred at room temperature for 1 hour, the desired insoluble LiFSI product is isolated by filtration and finally dried in vacuo (less than 0.1 Torr) at 35 ° C. to give the purified LiFSI product in 89% yield. rice field. In this example, the purified LiFSI product had the following impurities: FSO ₃ ⁻ = 38 ppm, Cl ⁻ = 1 ppm, F ⁻ = 15 ppm, ^SO _4-2 = 22 ppm, and water = 40 ppm.

II. B. 8. Example 8

Purification of LiFSI using acetonitrile and dichloromethane: Various levels of impurities in a 500 mL dry flask, here FSO _3- = 200 ppm ^{, Cl-} = 10 ppm ^{, F-} = 100 ppm, SO _4-2 = 100 ppm, and water. Crude LiFSI (200 g) containing = 100 ppm was collected under a nitrogen atmosphere and cooled to 10 ° C. in a water bath. Acetic anhydride butyl acetate (150 g (about 43% by weight)) was added little by little with stirring, followed by 30 g (about 8.6% by weight) of acetic anhydride. The mixture was stirred at room temperature for 1 hour. Insoluble impurities were removed by filtration. The filtrate was concentrated under reduced pressure to give a solid, which was treated with anhydrous dichloromethane (250 g) under argon. The mixture is stirred at room temperature for 1 hour, the desired insoluble LiFSI product is isolated by filtration and finally dried in vacuo (less than 0.1 Torr) at 35 ° C. to give the purified LiFSI product in 90% yield. rice field. In this example, the purified LiFSI had the following impurities: FSO ₃ ⁻ = 50 ppm, Cl ⁻ = 5 ppm, F ⁻ = 20 ppm, ^SO _4-2 = 22 ppm, and water = 38 ppm.

II. C. Exemplary Purified LiFSI Products

Purified LiFSI products obtained using any of the aforementioned purification methods, such as either the single-pass purification method disclosed above or the multipath method 300 of FIG. 3, were removed by the purification method as an exception. Can have low levels of target impurities. For example, the purified LiFSI products of the present disclosure in which at least one of the target impurities is LiCl can have LiCl (Cl ⁻ ) levels of 10 ppm or less or less than 1 ppm. As another example, the purified LiFSI products of the present disclosure containing at least one of the target impurities LiF (F ⁻ ), FSO ₃ Li (FSO ₃ ⁻ ), and LiCl (Cl ⁻ ) are F ⁻ of about 80 ppm or less. , FSO _3- of about 100 ppm or less, ^Cl- of less than about 100 ppm, F- of about 40 ppm or less, FSO _3- of about 250 ppm or less ^{, and Cl-} of about 20 ppm or less ^, or F- of about 200 ppm or less ^, about 100 ppm It can have the following FSO ₃ ^- and ^Cl- of about 30 ppm or less. In another example, starting from a crude LiFSI with an F- of about 200 ppm or more ^, an FSO _3- of about 200 ppm or more, ^{and / or a Cl- of} about 200 ppm or more, each of the above-mentioned levels of impurities and combinations thereof. Can be achieved. In yet another example, the purified ^LiFSI products of the present disclosure in which at least one of the target impurities is SO _4-2 can have SO _4-2 ^levels of about 280 ppm or less, or about 100 ppm or less. In a further example, each of the aforementioned SO _4-2 levels can be achieved starting with a crude ^LiFSI having an ^SO _4-2 of about 500 ppm or higher. A useful feature of the purification methods of the present disclosure is the ability to simultaneously remove different types of target impurities in each (or only) pass-through of the method.

II. D. Illustrative Use of Purified LiFSI Product

As mentioned above, purified LiFSI products can be used to produce purified LiFSI-based electrolytes, among other things, for electrochemical devices. Here, the purity of the purified electrolyte comes from the fact that the purified LiFSI product was purified by one or more of the methods disclosed herein. Such purified electrolytes may vary, such as mixing the purified LiFSI product (salt) of the present disclosure with one or more solvents, one or more diluents, and / or one or more additives. Can be produced using any of the above methods, and solvents, diluents, and additives may be known in the art.

Section I. D. As mentioned above in 2, FIG. 2 shows an electrochemical device 200 made according to the aspects of the present disclosure. In this example, the purified LiFSI-based electrolyte 216A produced in the present disclosure may be used instead of the reactive solvent-reduced LiFSI-based electrolyte 216 described above. As mentioned above, for the purified LiFSI-based electrolyte 216A, the advantage of using the purified LiFSI-based electrolyte of the present disclosure purified to remove non-solvent impurities is that impurities that may be present in the LiFSI-based electrolyte such as synthetic impurities can be removed. , To a level acceptable for use in the electrochemical device 200 (eg, satisfying one or more impurity level specifications). Examples of purified LiFSI products (salts) and examples of their various impurities at low levels that can be used to produce the purified LiFSI-based electrolyte 216A are described above.

In one example, the purified LiFSI-based electrolyte 216A can be produced starting from crude LiFSI, which is then purified using any one or more of the purification methods described herein. , Produces purified LiFSI products with suitable low levels of one or more target impurities. In another example, the crude HFSI can be first synthesized, for example by any of the above synthesis methods, and the crude HFSI can be used to synthesize the crude LiFSI. The crude LiFSI can be purified using one or more of the purification methods described herein to produce a purified LiFSI product (salt). The purified LiFSI product is then used to add, for example, one or more solvents, one or more diluents, and / or one or more additives that improve the performance of the electrochemical device 200. By doing so, the purified LiFSI-based electrolyte 216A can be produced. The purified LiFSI-based electrolyte 216A can then be added to the electrochemical device 200 and then the container 220 can be sealed.

III. Synthesis of LiFSI using an aqueous neutralization process

This section deals with methods of synthesizing LiFSI using an aqueous neutralization process, the LiFSI salts produced thereby, and the use of such LiFSI salts.

III. A. Exemplary Aqueous Neutralization Synthesis Methods

In the present disclosure, the LiFSI product (eg, salt) is initially purified hydrogen bis (fluorosulfonyl) imide (HFSI), one such as lithium carbonate (Li ₂ CO ₃ ) or lithium hydroxide (LiOH) or It can be obtained by neutralizing with a plurality of lithium bases, and can be carried out in deionized water to obtain an aqueous solution of LiFSI. Insoluble impurities such as Li ₂ SO ₄ , LiCl, LiF, and LiFSO ₃ described above can be removed by filtration. Water can be removed, for example, in vacuum. Purified HFSI for use in this process is, for example, filed September 13, 2019, which is incorporated herein by reference with reference to the teaching of purification of HFSI, "Purified Hydrogen Bis (fluorosulfonyl) imide (HFSI) Products). , Methods of Purifying Crystal HFSI, and Uses of Purified HFSI Products (purified hydrogen bis (fluorosulfonyl) imide (HFSI) product, method for purifying crude HFSI, and use of purified HFSI product). As described in / 570,131, it can be obtained by any suitable method such as purifying HFSI by crystallization. Experimental examples of synthesizing LiFSI using aqueous neutralization and their corresponding resulting impurity levels are described in Section III. C. 1, III. C. 4, and III. C. 6 Examples 1, 4, and 6 are described below.

III. B. Exemplary purification of LiFSI salt produced using aqueous neutralization

Section III above. Purify the crude LiFSI product produced using the aqueous neutralization process of A to remove one or more target impurities, such as any synthetic impurities remaining after removing water from the synthetic LiFSI product. be able to. In addition or alternatively, Section III. The crude LiFSI product produced using the aqueous neutralization process of A can be purified to remove and / or replace the reactive solvent (s) such as water present in the LiFSI product. can. This section briefly describes an example of purification of crude LiFSI produced using an aqueous neutralization process.

III. B. 1. 1. Removal of non-reactive solvent impurities

Section II. As mentioned above in A, Section III. The crude LiFSI containing the crude LiFSI product produced using the aqueous neutralization process described in A can be purified to remove the target impurities. Such target impurities can remain in any synthetic salt that may remain after filtration of such insoluble salts and removal of water, eg, Section III. A may include Li ₂ SO ₄ , LiCl, LiF and LiFSO ₃ described above. As an example, after removing water from the aqueous neutralization process, the resulting LiFSI product (where "crude LiFSI" for the context of purification according to Section II.A above) is referred to Section II. It can be subjected to the above-mentioned purification in A. The resulting purified LiFSI product has reduced levels of targeted impurities (s). Experimental examples of such purification and corresponding target impurity levels are described in III. C. 2, III. C. 5 and III. C. Section 7, Examples 2, 5 and 7 are described below. When preparing an electrolyte using purified LiFSI products, the solvent (s) used in the purification process is one or more of the solvents (s) used in the final electrolyte. Note that there may be more than one. In this way, the solvent (s) remaining from the purification process becomes part of the final electrolyte solvent (s).

III. B. 2. 2. Removal / replacement of reactive solvent (s)

Section I. As mentioned above in A, Section III. The crude LiFSI containing the crude LiFSI product produced using the aqueous neutralization process described in A can be purified to remove / replace one or more reactive solvents. Such reactive solvents are described in Section III. It may contain any residual water that was not removed in the water removal step described above in A. In addition, one or more reactive solvents targeted for removal and / or replacement with one or more non-reactive solvents are described in Section III. B. 1 and II. A. As described in, may be present after purification to remove non-reactive solvent impurities. As an example, after removing water from the aqueous neutralization process, the resulting LiFSI product (where "crude LiFSI" for the context of purification by Section I.A. above) is referred to Section I. A. Can be used for the purification described in 1. As another example, Section III. Purification of LiFSI synthesized by the aqueous neutralization process of A (see Section III.B.1 above) followed by the resulting purified LiFSI product (where, in the context of purification by Section I.A. above). Section I. It can be subjected to the above-mentioned purification in A. In either case, the resulting purified LiFSI product will have reduced levels of the targeted reactive solvent (s). Experimental examples of such purification and corresponding target impurity levels are described in Section III. C. It is described below in Example 3 of 3. When preparing an electrolyte using purified LiFSI products, the solvent (s) used in the reactive solvent removal / substitution process is that of the solvent (s) used in the final electrolyte. Note that one or more of them may be used. In this way, the solvent (s) remaining from the removal / replacement process becomes part of the final electrolyte solvent (s).

The crude LiFSI thus obtained can be purified to remove one or more target impurities such as synthetic impurities and / or other impurities present in the crude LiFSI. In some embodiments, crude LiFSI is mixed with a minimum amount of one or more first anhydrous organic solvents in which LiFSI is soluble (eg, from about 50% to about 70% by weight) to Li ₂ . Impurities such as SO ₄ , LiCl, LiF, and LiFSO ₃ can be further insoluble. Anhydrous organic solvents that can be used for this purpose include dimethylcarbonate (DMC), diethylcarbonate (DEC), ethylmethylcarbonate (EMC), propylmethylcarbonate (PMC), and ethylenecarbonate (EC). , Fluoroethylene carbonate (FEC), transbutylene carbonate, acetonitrile, malononitrile, adiponitrile, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate (MP) and ethyl propionate (EP).

To the solution is added one or more second anhydrous organic solvents insoluble in LiFSI (eg, in an amount of about 2% to 10% by weight). Organic solvents that can be used for this include dichloromethane, dichloroethane, chloroform, pentane, hexane, heptane, octane, nonane, decane, undecane and dodecane.

In some embodiments, the impurities remain precipitated after the addition of one or more second anhydrous organic solvents and can be removed by filtration. The filtrate can be recovered and the solvent (s) removed from it to give a solid. In some examples, the solvent (s) is removed in vacuum (eg, less than about 0.1 Torr) at a controlled temperature (eg, less than about 40 ° C.) to give a solid. The resulting solid can then be treated with at least one third anhydrous organic solvent insoluble in LiFSI. Examples of the organic solvent that can be used for this include dichloromethane, dichloroethane, chloroform, pentane, hexane, heptane, octane, nonane, decane, undecane, and dodecane. The precipitated LiFSI salt product can then be isolated by filtration in an inert environment (eg, argon gas) and dried, for example, in vacuum (eg, less than about 0.1 Torr) at less than about 40 ° C. can.

For illustration purposes, Table II below provides detailed examples of impurities and their solubility in dimethylcarbonate and dichloromethane.

As seen in Table II above, the solubility of LiFSI in dimethylcarbonate is greater than 90% and is insoluble in dichloromethane. On the other hand, the solubility of impurities such as LiF, LiCl and Li ₂ SO ₄ is less than 13 ppm in dimethyl carbonate under anhydrous conditions.

Based on these soluble / insoluble properties, dimethylcarbonate and dichloromethane solvents are selected, in one example, for the process of purifying the crude LiFSI produced using the aqueous neutralization process described above. In this example, crude LiFSI containing the impurities reported in Table II above is mixed in dimethylcarbonate at a concentration of 50% to 75% at about 25 ° C. (here room temperature), stirred at room temperature, followed by About 2% by weight to about 10% by weight of dichloromethane was added to precipitate impurities. Impurities were removed by filtration and the filtrate was concentrated to dryness. The resulting dry solid was treated with anhydrous dichloromethane to remove HF impurities where LiFSI was insoluble in dichloromethane while soluble in dichloromethane.

The ultra-purity LiFSI salt product was recovered by filtration and finally dried under reduced pressure (eg, less than about 0.1 Torr) and at a temperature of less than about 40 ° C. to give a white free-flowing powder. This can optionally be stored in a dry polytetrafluoroethylene (PTFE) container.

In view of the above, in some embodiments, the present disclosure describes a process of producing an ultra-high purity lithium bis (fluorosulfonyl) imide (LiFSI) for lithium metal anode battery applications. This process involves purifying hydrogen bis (fluorosulfonyl) imide (HFSI) in less than about 40% deionized water below about 25 ° C., lithium carbonate (Li ₂ CO ₃ ) or lithium hydroxide (LiOH). Includes base neutralization. Insoluble impurities such as Li ₂ SO ₄ , LiCl, LiF, and LiFSO ₃ can be removed by filtration. Water can be removed in vacuum (eg, less than about 0.1 Torr) at a suitable temperature, such as less than about 35 ° C.

The resulting crude LiFSI is mixed with a minimum amount (eg, 50% to 70% by weight) of an anhydrous organic solvent in which LiFSI is soluble (eg, dimethylcarbonate (DMC) or ethylmethylcarbonate (EMC)). Thus, impurities such as LiCl, LiF, Li ₂ SO4 and / or LiFSO ₃ can be further insoluble. In some embodiments, the temperature of the solution is maintained below about 25 ° C. The solution can then be filtered in an inert atmosphere to remove impurities.

This process can further include removing the organic solvent from the filtrate to give a solid mass and treating the solid with an organic solvent (eg, dichloromethane) in which lithium bis (fluorosulfonyl) imide is insoluble. The insoluble LiFSI can be isolated by filtering in an inert atmosphere and flushing a trace amount of organic solvent with dry argon and / or nitrogen gas. The resulting LiFSI is aspirated (eg, less than about 0.1 Torr) at a suitable temperature (eg, less than about 35 ° C.) for a suitable period (eg, at least 24 hours) to obtain an ultra-high purity anhydrous LiFSI salt product. It can be obtained as a white free-flowing powder, which can optionally be stored in a dry polytetrafluoroethylene (PTFE) container.

In some embodiments, LiFSI salt production synthesized by the disclosed aqueous neutralization method and purified to remove non-reactive solvent impurities and purified to remove / replace the reactive solvent (s). The material can be produced in an electrolyte solution and used in a lithium metal battery, i.e. a battery having a lithium metal anode. Section III below. C. As shown in Example 8 of 8, this "ultra-high purity" LiFSI salt product and the electrolyte produced using it are the stocks of Nippon Catalyst Co., Ltd. (Japan), Shanghai Capchem Co., Ltd. (China), and Shang Hai Shengzhan Chemifish. It showed much better cycle life compared to LiFSI from commercial sources such as the company (China) and Oakwood Products (USA).

In the present disclosure, the process for producing ultra-high purity LiFSI may be a continuous process from the start of neutralization to the end of production of ultra-high purity LiFSI product.

III. C. example

The embodiments of the present disclosure will be further described by the following examples, but it will be appreciated that these examples are included solely for illustrative purposes and are not intended to limit the scope of the present disclosure. Unless otherwise stated, all chemicals used were of high purity and were obtained from commercial sources. Strict precautions were taken to eliminate moisture during the process and the reaction was carried out in a well-ventilated hood.

III. C. 1. 1. Example 1

Neutralization of Purified HFSI with Lithium Carbonate in Deionized Water: In a 1000 mL flask, 1 mol of lithium carbonate (Li ₂ CO ₃ ) was mixed with 40 g of deionized water. The suspension is cooled in an ice water bath below 20 ° C. 2 mol of hydrogen bis (fluorosulfonyl) imide (HFSI) was taken in a dropping funnel and dropped into a stirred lithium carbonate suspension slurry. After the addition of HFSI was complete, the water bath was removed and the solution was stirred at room temperature for 0.5 hours. Insoluble impurities were removed by filtration. The resulting clear filtrate was concentrated in vacuum below 0.1 Torr and below 35 ° C. to give crude LiFSI in quantitative yield, which was used in Example 2 below.

III. C. 2. 2. Example 2

Treatment of crude LiFSI with dimethyl carbonate: The crude LiFSI obtained in Example 1 above was used in Example 2. The flask was placed in a nitrogen atmosphere and cooled to 10 ° C. using a water bath. Add anhydrous dimethyl carbonate (DMC) (300 g) little by little with stirring, followed by adding 50 g of anhydrous dichloromethane. The mixture was stirred at room temperature for 1 hour. Insoluble impurities were removed by filtration. The filtrate was concentrated under reduced pressure to give a solid, which was treated with anhydrous dichloromethane (200 g) under argon. The mixture was stirred at room temperature for 1 hour, the desired insoluble LiFSI product was isolated by filtration and finally dried in vacuo (<0.1 Torr) below 35 ° C. to give LiFSI in 95% yield. The obtained LiFSI product had impurities FSO ₃ ⁻ = 100 ppm, Cl ⁻ = 1 ppm, F ⁻ = 40 ^ppm , SO _4-2- = 40 ppm, and water = 50 ppm.

III. C. 3. 3. Example 3

Treatment of LiFSI with dimethyl carbonate: The LiFSI obtained in Example 2 was used in this Example 3. 200 g of LiFSI obtained in Example 2 above was placed in a glove box having a measured moisture value of less than 1 ppm and transferred to a 1 L dry flask. The flask was removed and cooled in a water bath below 15 ° C. LiFSI was mixed with 100 g of anhydrous dimethyl carbonate containing less than 5 ppm of water. Insoluble impurities were removed by filtration under argon and the filtrate was collected in a 1 L flask. The filtrate was concentrated under reduced pressure below 0.1 Torr to give a solid. The solid was treated with anhydrous dichloromethane (150 g) under argon and the solution was stirred at room temperature for 1 hour. The desired insoluble LiFSI product was isolated by filtration and dried in vacuo (<0.1 Torr) at 30 ° C. to give a white free fluid powder LiFSI in 95% yield. When the obtained LiFSI product was analyzed by ion chromatography, impurities F- = 1.3 ppm, ^Cl- = 0.18 ppm, and SO _4-2 = ^4.4 ppm were found. When analyzed by Karl Fischer, the water content was 1.3 ppm. Based on proton NMR, it has 0.2% dimethyl carbonate. Since dimethyl carbonate is non-reactive with lithium metals in electrochemical devices, it was used in the test electrolyte formulation. This salt electrolyte formulation was used in a lithium metal battery test.

III. C. 3. 3. i. Comparative example

Comparative example of LiFSI salt obtained from Capchem (China): By visual inspection, the color of the Capchem LiFSI salt was lower in white than the LiFSI obtained in this Example 3. The ^Capchem LiFSI salt had the following impurities: water = 15 ppm, F ⁻ = 1 ppm, Cl ⁻ = 1 ppm, and SO _4-2 = 5.98 ppm. Based on proton NMR, the Capchem LiFSI salt contains 0.3% ethanol, which is incompatible with lithium metals due to its reactivity. Ethanol reacts with the lithium metal by the following reaction to form an undesired by-product.
2Li + 2CH ₃ CH ₂ OH = 2CH ₃ CH ₂ OLi + H ₂

III. C. 4 Example 4

Neutralization of purified HFSI in water with dionized water using lithium hydroxide: In a 1 L flask, lithium hydroxide (LiOH) (2 mol) was dissolved in 40 g of deionized water. The suspension was cooled in an ice water bath below 20 ° C. 2 mol of HFSI was placed in a dropping funnel and added dropwise to the stirred lithium carbonate suspension slurry. After the addition of HFSI was complete, the water bath was removed and the solution was stirred at room temperature for 0.5 hours. Insoluble impurities were removed by filtration. The resulting clear filtrate was concentrated in vacuum below 0.1 Torr and below 35 ° C. to give crude LiFSI in quantitative yield, which was used in Example 5 below.

III. C. 5 example 5

Treatment of crude LiFSI with dimethyl carbonate (DMC): The crude LiFSI obtained in Example 4 above was used in Example 5. The flask was placed in a nitrogen atmosphere and cooled to 10 ° C. using a water bath. Anhydrous dimethylcarbonate (DMC) (300 g) was added little by little with stirring, followed by 50 g of anhydrous dichloromethane. The solution was stirred at room temperature for 1 hour. Insoluble impurities were removed by filtration. The filtrate was concentrated under reduced pressure to give a solid, which was treated with anhydrous dichloromethane (200 g) under argon. The mixture was stirred at room temperature for 1 hour, the desired insoluble LiFSI product was isolated by filtration and finally dried in vacuo (<0.1 Torr) below 35 ° C. to give LiFSI in 92% yield. The obtained purified LiFSI had impurities FSO ₃ ⁻ = 100 ppm, Cl ⁻ = 1 ppm, F ⁻ = 45 ppm, ^SO _4-2 = 35 ppm, and water = 60 ppm.

III. C. 6. Example 6

Neutralization of Purified HFSI with Lithium Carbonate in Dionized Water In a 1 L flask, 0.5 mol of lithium carbonate (Li ₂ CO ₃ ) was mixed with 20 g of deionized water. The suspension was cooled in an ice water bath below 20 ° C. 1 mol of HFSI was taken into a dropping funnel and dropped into a stirred lithium carbonate suspension slurry. After the addition of HFSI was complete, the water bath was removed and the solution was stirred at room temperature for 0.5 hours. Insoluble impurities were removed by filtration. The resulting clear filtrate was concentrated in vacuum below 0.1 Torr and below 35 ° C. to give crude LiFSI in quantitative yield, which was used in Example 7 below.

III. C. 7. Example 7

Treatment of Crude LiFSI with Ethyl Methyl Carbonate: The crude LiFSI obtained in Example 6 was used in this Example 7. The flask was cooled in a nitrogen atmosphere and cooled to 10 ° C. using a water bath. Ethylmethylcarbonate anhydrous (EMC) (100 g) was added in small portions with stirring, followed by 50 g of dichloromethane. The solution was stirred at room temperature for 1 hour. Insoluble impurities were removed by filtration. The filtrate was concentrated under reduced pressure to give a solid, which was treated with anhydrous dichloromethane (200 g) under argon. This was stirred at room temperature for 1 hour, the desired insoluble LiFSI product was isolated by filtration and finally dried in vacuo (less than 0.1 Torr) at 35 ° C. to give LiFSI in 90% yield. The purified LiFSI product had impurities FSO ₃ ⁻ = 100 ppm, Cl ⁻ = 0.5 ppm, F ⁻ = 20 ppm, ^SO _4-2 = 20 ppm, and water = 46 ppm.

III. C. 8. Example 8

Comparison of use and results of the ultra-high purity LiFSI of Example 7 above with commercially available LiFSI in lithium metal anode batteries: Battery grade electrochemically stable organic solvents (dimethylcarbonate, ethylmethylcarbonate, dimethoxymethane, Diethoxyethane, etc.) was used to produce the obtained LiFSI electrolytes of the present disclosure, and comparative studies were performed using various commercially available LiFSI salts and corresponding electrolytes under similar conditions.

The ultra-purity LiFSI product produced by the present disclosure provided the maximum number of cycles in a lithium metal anode battery when compared to LiFSI commercially available from Capchem, Nippon Shokubai, Chemfish and Oakwood. Examples of better performance of the ultra-purity LiFSI products of the present disclosure can be found in FIGS. 4A and 4B, respectively, where one of the electrolytes is the aqueous neutralization of Section III of the present disclosure. The ultra-purity LiFSI salt product produced using the synthetic method (upper line of each of FIGS. 4A and 4B, "SES LiFSI") is used and the other electrolyte is Capchem (FIG. 4A). And the discharge capacity for two non-aqueous electrolytes with the same concentration and the same chemicals, except that they were produced using LiFSI salts supplied from each lower line of FIG. 4B, "CapChem LiFSI"). The number of cycles and the capacity retention rate are shown.

The battery used in the experiment for which the graphs of FIGS. 4A and 4B were obtained was a pouch cell with a three-layer cathode and a four-layer anode. Each electrolyte was composed of 2.0 mol LiFSI in 1 liter of solvent mixture. Except for the source of LiFSI salt, all other battery design factors and test conditions were the same. Batteries were cycled under 0.2 C rate charge and 1.0 C rate discharge. As shown in FIGS. 4A and 4B, batteries with LiFSI from both sources delivered the same capacity in the initial cycle. However, batteries with electrolytes produced using the ultra-purity LiFSI salt of the present disclosure showed better capacity retention than batteries with Capchem LiFSI salt after about 100 cycles. This data shows the advantage of stability of ultra-purity LiFSI salt over Capchem LiSFI salt under long cycle conditions with lithium metal anode rechargeable battery.

III. D. Illustrative use of ultra-high purity LiFSI

As mentioned above, the ultra-purity LiFSI salt product produced by the process described above may be particularly beneficial for lithium metal batteries with lithium metal anodes. In this regard, the ultra-purity LiFSI product is used as the electrolyte if at least some of the solvent can remain in the ultra-purity LiFSI product and is reactive with the lithium metal. It is important to select a suitable anhydrous organic solvent for the treatment as it can interfere with the performance of lithium metal batteries. In fact, the residual solvent in the Capchem LiFSI salt such as ethanol reported in Example 3 above has very high performance of the Capchem LiFSI salt, as evidenced by Example 8 above (Sections III.C.8). This may be the reason why it was inferior to the performance of the purity LiFSI salt product. As mentioned in Example 3 above (Sections III.C.3), ethanol is reactive with the lithium metal present on / in the anode of the lithium metal battery.

Therefore, when producing the ultra-high purity LiFSI salt product for lithium metal batteries according to the present disclosure, the solvent selected must be a solvent known to be non-reactive with lithium metals. In this way, any solvent that can remain in the final dry solid ultra-purity LiFSI salt product (eg, by coordination with LiFSI or by other methods) is non-reactive with the lithium metal. It is property and therefore is unlikely to adversely affect the performance of lithium metal batteries in which ultra-high purity LiFSI salt products are used. As used herein and in the appended claims, the term "non-reactive" is used to modify "solvents" or "solvents" unless otherwise stated. If so, it is meant that the solvent (s) is non-reactive with the lithium metal. Conversely, unless otherwise stated, the term "reactive" as used herein and in the appended claims to modify "solvents" or "solvents" refers to solvents (solvents). It shall mean that one or more) is reactive with the lithium metal. As will be appreciated by those skilled in the art, "reactivity" in this context refers to the magnitude of the reduction potential of a lithium metal with respect to a solvent (s). Reactive solvents are also not effective in passivating lithium metals, but non-reactive solvents are either non-reactive with lithium metals or effectively passivated lithium metals. That is, it is stable in terms of speed.

In some embodiments particularly suitable for use in lithium metal batteries, during the final ultra-purity LiFSI salt product (ie, after complete treatment of the process and / or purification disclosed herein). The amount of residual reactive solvent is preferably less than about 500 ppm, more preferably less than about 100 ppm, most preferably less than about 50 ppm. In some embodiments, depending on the entire cathode-electrolyte-anode system utilized, the non-reactive solvent remaining in the final LiFSI salt product adversely affects battery performance over the removed reactive solvent. May not be given. In such embodiments, the amount of non-reactive solvent (s) remaining in the final LiFSI salt product is preferably less than about 3000 ppm, more preferably less than about 2000 ppm, most preferably less than about 500 ppm. be. In some embodiments, the non-reactive solvent (s) used also, depending on the entire cathode-electrolyte-anode system utilized, can improve and / or ionize SEI formation within the electrolyte. Battery performance is the non-reactive solvent that remains in the final LiFSI salt product, such as when deliberately selected to provide one or more benefits to the cathode-electrolyte-anode system, such as improved properties. May be beneficial to. In some embodiments, additional amounts of the non-reactive solvent (s) used during purification and / or removal / replacement of the reactive solvent are added as needed to produce the final electrolyte. can do. In embodiments where the non-reactive solvent (s) used to treat LiFSI is beneficial to battery performance, the amount of non-reactive solvent remaining may be greater than 2000 ppm or greater than 3000 ppm. .. When purification is performed using only non-reactive solvents for all purification steps, the final LiFSI salt product typically has at least about 100 ppm of non-reactive solvent (s). It typically has about 100 ppm or less of the reactive solvent (s). Examples of non-reactive solvents that may be suitable to remain in the LiFSI salt after removal / substitution of the reactive solvent (s) according to the present disclosure include hexane, hydrocarbons, toluene, xylene, aromatic solvents, esters. And nitriles.

Section I. D. As mentioned above in 2, FIG. 2 shows an electrochemical device 200 made according to the aspects of the present disclosure. In this example, the ultra-high purity LiFSI-based electrolyte 216B produced by Section III may be used instead of the reactive solvent-reduced LiFSI-based electrolyte 216 described above. As mentioned above, the advantage of using the ultra-high purity LiFSI-based electrolyte of the present disclosure for the purified LiFSI-based electrolyte 216B is that it contains impurities that may be present in the LiFSI-based electrolyte, such as synthetic impurities and reactive solvents (s). , To a level acceptable for use in the electrochemical device 200 (eg, satisfying one or more impurity level specifications). Examples of ultra-high purity LiFSI products (salts) that can be used to produce the purified LiFSI-based electrolyte 216B and examples of their various impurities at low levels are described above. The ultra-purity LiFSI product is then used, for example, to improve the performance of the electrochemical device 200, for example, one or more solvents, one or more diluents, and / or one or more additives. Can be added to produce an ultra-high purity LiFSI-based electrolyte 216B. The ultra-high purity LiFSI-based electrolyte 216B can then be added to the electrochemical device 200 and then the container 220 can be sealed.

Given the desire to remove many reactive solvents (s) from the final ultra-purity LiFSI salt product in lithium metal battery applications, the purification methods disclosed herein are to purify. It can be enhanced by the selection of one or more solvents known to be non-reactive to the lithium metal for the appropriate step (s) of the method used to carry out.

In some embodiments, the present disclosure relates to a method for producing a reactive solvent-reduced lithium bis (fluorosulfonyl) imide (LiFSI) product, wherein the method comprises LiFSI and one or more reactive solvents. To provide one crude LiFSI, under inert conditions, contact the first crude LiFSI with at least one first anhydrous organic solvent to provide the first crude LiFSI and one or more reactive solvents. The solubility of LiFSI in at least one first anhydrous organic solvent is at least about 35% below 25 ° C., and the solution is subjected to vacuum to produce at least one. The first anhydrous organic solvent and one or more reactive solvents are removed to obtain a solid mass, and the solid mass is treated with at least one second anhydrous organic solvent insoluble in LiFSI to be insoluble. Producing a moiety-bearing combination, isolating the insoluble moiety in an inert atmosphere, flushing the insoluble moiety with at least one dry inert gas to create a trace amount of at least one second anhydrous organic solvent. Includes removing the flushed insoluble moiety to a pressure of less than about 100 Torr to obtain a reactive solvent-reduced LiFSI product.

In one or more embodiments of the method, providing a first crude LiFSI provides a LiFSI and a second crude LiFSI containing one or more target impurities, under inert conditions. The second crude LiFSI is contacted with at least one third anhydrous organic solvent to produce a solution containing LiFSI and one or more target impurities, wherein at least one first at room temperature. LiFSI is soluble in 3 anhydrous organic solvents and each of the one or more target impurities is substantially insoluble, and at least one fourth anhydrous organic solvent is added to the solution. Precipitating at least one target impurity, wherein each of LiFSI and one or more target impurities is substantially insoluble in at least one fourth anhydrous organic solvent, one or more. Filtering each insoluble portion of the target impurity from the solution to form a filtrate, removing the solvent from the filtrate to obtain a solid mass, the solid mass, at least one in which LiFSI is substantially insoluble. It involves contacting with a fifth anhydrous organic solvent and isolating LiFSI from at least one fifth anhydrous organic solvent to obtain a first crude LiFSI.

In one or more embodiments of the method, the second crude LiFSI has a solubility of at least about 50% at room temperature with respect to at least one third anhydrous organic solvent and is one or more targets. Each of the impurities has a solubility of less than about 20 parts per million (ppm) at room temperature with respect to at least one third anhydrous organic solvent.

In one or more embodiments of the method, contacting the second crude LiFSI with at least one third anhydrous organic solvent causes the second crude LiFSI to have a minimum amount of at least one third. Includes contact with anhydrous organic solvent.

In one or more embodiments of the method, the minimum amount of at least one third anhydrous organic solvent is from about 40% to about 75% by weight of the solution.

In one or more embodiments of the method, adding at least one fourth anhydrous organic solvent to the solution is an amount of at least one fourth anhydrous organic solvent in an amount of about 10% by weight or less of the solution. Including adding in.

In one or more embodiments of the method, contact of the second crude LiFSI with at least one third anhydrous organic solvent is carried out at a temperature of less than about 25 ° C.

In one or more embodiments of the method, the temperature of the solution is controlled during contact between the second crude LiFSI and at least one third anhydrous organic solvent so that the temperature is within about 2 ° C. of the target temperature. Including maintaining in.

In one or more embodiments of the method, filtration is performed in an inert atmosphere.

In one or more embodiments of the method, the inert atmosphere comprises argon gas.

In one or more embodiments of the method, removing the solvent is done in vacuum.

In one or more embodiments of the method, removing the solvent is performed at a pressure of about 0.1 Torr or less.

In one or more embodiments of the method, removal of the solvent is carried out at a temperature below about 40 ° C.

In one or more embodiments of the method, isolating LiFSI comprises filtering the solid form of LiFSI from at least one fifth anhydrous organic solvent.

In one or more embodiments of the method, isolating LiFSI comprises drying the solid LiFSI in vacuo.

In one or more embodiments of the method, drying the solid LiFSI in vacuum comprises drying the solid LiFSI at a pressure of about 0.1 Torr or less.

In one or more embodiments of the method, the one or more target impurities are lithium chloride (LiCl), lithium fluoride (LiF), lithium sulfate (Li ₂ SO ₄ ), lithium fluorosulfate (LiSO ₃ ). Includes one or more target impurities from the group consisting of, hydrogen fluoride (HF), and fluorosulfuric acid (FSO _3H ).

In one or more embodiments of the method, one or more target impurities contain lithium sulphate (Li ₂ SO ₄ ), and filtering each insoluble portion of one or more target impurities is Li. ₂ Includes simultaneous filtration of insoluble moieties of _SO4 .

In one or more embodiments of the method, the at least one third anhydrous organic solvent is dimethylcarbonate (DMC), diethylcarbonate (DEC), ethylmethylcarbonate (EMC), propylmethylcarbonate. (PMC), Ethyl Carbonate (EC), Fluoroethylene Carbonate (FEC), Transbutylene Carbonate, acetonitrile, Marononitrile, Adiponitrile, Methyl Acetate, Ethyl Acetate, Propyl Acetate, Butyl Acetate, Methyl Propionate (MP), Propion It contains at least one solvent selected from the group consisting of ethyl acetate (EP), methanol, ethanol, propanol and isopropanol.

In one or more embodiments of the method, contacting the second crude LiFSI with at least one third anhydrous organic solvent brings the second crude LiFSI to about 50% by weight to about 75% by weight of the solution. It comprises contacting with at least one third anhydrous organic solvent in an amount by weight%.

In one or more embodiments of the method, adding at least one fourth anhydrous organic solvent to the solution is an amount of at least one fourth anhydrous organic solvent in an amount of about 10% by weight or less of the solution. Including adding in.

In one or more embodiments of the method, the at least one fourth anhydrous organic solvent is selected from the group consisting of dichloromethane, dichloroethane, chloroform, pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane. Contains at least one solvent to be used.

In one or more embodiments of the method, adding at least one fourth anhydrous organic solvent to the solution is an amount of at least one fourth anhydrous organic solvent in an amount of about 10% by weight or less of the solution. Including adding in.

In one or more embodiments of the method, at least one fifth anhydrous organic solvent is selected from the group consisting of dichloromethane, dichloroethane, chloroform, pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane. Contains at least one solvent to be used.

In one or more embodiments of the method, the at least one fourth anhydrous organic solvent is selected from the group consisting of dichloromethane, dichloroethane, chloroform, pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane. Contains at least one solvent to be used.

In one or more embodiments of the method, at least one fifth anhydrous organic solvent is selected from the group consisting of dichloromethane, dichloroethane, chloroform, pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane. Contains at least one solvent to be used.

In one or more embodiments of the method, placing the first crude LiFSI in a dry atmosphere in a container that does not substantially react with free fluorine, and storing the container at a temperature below about 25 ° C. Further included.

In one or more embodiments of the method, the one or more target impurities are by-products of the process of synthesizing LiFSI in the second crude LiFSI.

In one or more embodiments of the method, the first crude LiFSI comprises 10 parts per million (ppm) or less of LiCl.

In one or more embodiments of the method, the first crude LiFSI contains less than 1 ppm LiCl.

In one or more embodiments of the method, the first crude LiFSI contains about 500 parts per million (ppm) or less FSO ₃ Li, about 100 ppm or less LiCl, and about 150 ppm or less LiF. ..

In one or more embodiments of the method, providing a second crude LiFSI comprises synthesizing a second crude LiFSI using an aqueous neutralization process.

In one or more embodiments of the method, providing the first crude LiFSI comprises synthesizing the first crude LiFSI using an aqueous neutralization process.

In one or more embodiments of the method, the reactive solvent-reduced LiFSI product is a salt of an electrolyte for a lithium metal battery, the method selecting each of at least one first anhydrous organic solvent. Further, it includes improving the performance of the lithium ion battery.

One or more embodiments of the method further include selecting each of at least one second anhydrous organic solvent to improve the performance of the lithium ion battery.

In one or more embodiments of the method, the reactive solvent-reduced LiFSI product is a salt of the electrolyte containing an additive solvent and at least one of the first anhydrous solvents is an additive. Same as solvent.

In some embodiments, the present disclosure relates to a method of making an electrochemical device, wherein the method treats a lithium bis (fluorosulfonyl) imide (LiFSI) salt using any of the methods listed herein. Provided an electrochemical device structure comprising producing a purified LiFSI salt, compounding an electrolyte using the purified LiFSI salt, a positive electrode, a negative electrode separated from the positive electrode, and a volume extending between the positive electrode and the negative electrode. And if an electrolyte is present, it involves allowing ions in the electrolyte to move between the positive and negative electrodes, and adding the electrolyte to the volume.

In one or more embodiments of the method, the electrochemical device is an electrochemical cell, and the electrochemical device structure further comprises a separator disposed within the volume.

In one or more embodiments of the method, the electrochemical battery is a lithium ion battery.

In one or more embodiments of the method, the electrochemical battery is a lithium metal battery.

In one or more embodiments of the method, the electrochemical device is a supercapacitor.

In some embodiments, the present disclosure comprises a positive electrode, a negative electrode separated from the positive electrode, a porous dielectric separator located between the positive electrode and the negative electrode, and at least the electrolyte contained within the porous dielectric separator. It relates to an electrochemical device produced using a LiFSI salt produced using any one of the methods described herein.

In one or more embodiments of the electrochemical device, the electrochemical device is a lithium battery.

In one or more embodiments of the electrochemical device, the electrochemical device is a lithium metal secondary battery.

In one or more embodiments of the electrochemical device, the electrochemical device is a supercapacitor.

The above is a detailed description of an exemplary embodiment of the invention. The terms "at least one of X, Y and Z" and "one of X, Y, and Z, unless expressly specified or otherwise indicated in this specification and the claims attached herein. A conjunctive language, such as used in one or more, means that each item in the conjunctive list is any number except all other items in the list, or any or all others in the conjunctive list. It should be noted that it can be present in any number in combination with the item of, and is interpreted to mean that each may be present in any number. Applying this general rule, the conjunctive phrase in the above example where the conjunctive list consists of X, Y, and Z is one or more of X, one or more of Y, of Z. One or more of, one or more of X and one or more of Y, one or more of Y and one or more of Z, one or more of X And one or more of Z, and one or more of X, one or more of Y and one or more of Z, respectively.

Various modifications and additions can be made without departing from the spirit and scope of the present invention. Each feature of the various embodiments described above can be combined with the features of other described embodiments as needed to provide a combination of numerous features in the relevant novel embodiments. Further, although the above describes some separate embodiments, those described herein are merely exemplary of the application of the principles of the invention. Further, certain methods herein can be illustrated and / or described as being performed in a particular order, the order of which is highly diverse within one of ordinary skill in the art to achieve aspects of the present disclosure. Is. Therefore, this description is intended to be construed as an example only and is not intended to limit the scope of the invention.

An exemplary embodiment is disclosed above and shown in the accompanying drawings. It will be appreciated by those skilled in the art that various modifications, omissions, and additions may be made to those specifically disclosed herein without departing from the spirit and scope of the invention. There will be.

Related Application Data This application was filed on September 13, 2019, and was filed on September 13, 2019, "PURIFIED LITHIUM BIS (FLUOROSULFONYL) IMIDE (LiFSI) PRODUCTS, METHODS OF PURIFYING CRUDE LiFSI, AND USES OF PURIFSI It is a partial continuation application of Application No. 16 / 570,262, which is incorporated herein by reference in its entirety. The application also asserts the priority interests of the following applications, each of which is incorporated herein by reference in its entirety.
Filed on August 6, 2019, "PROCESS FOR PRODUCTING ULTRAPURE LITHIUM BIS (FLUOROSULFONYL) IMIDE (LiFSI) FOR LITHIUM METAL ANODE BATTERIES, Japanese Patent No. 7, Japanese Patent No. 7, APPLICATIONS, U.S.A.
Filed on August 6, 2019, "PROCESS FOR REMOVING SOLVENT FROM LITHIUM BIS (FLUOROSULFONYL) IMIDE (LIFSI) USING ORGANIC SOLVENTS THAT ALPHA 62 / 883,178;
US Provisional Patent Application No. 62 / 840,949, filed April 30, 2019, entitled "PROCESS FOR REMOVING PROTIC SOLVENTS FROM LITHIUM BIS (FLUORO-SULFONYL) IMIDE (LiFSI)";
US Provisional Patent Application No. 62 / 768,447, filed November 16, 2018, entitled "PROCESS FOR THE PURIFICANION OF LITHIUM BIS (FLUOROSULFONYL) IMIDE (LiFSI)".

The present invention generally relates to the field of lithium sulfoneimide salts for electrolytes for lithium-based electrochemical devices. In particular, the present invention relates to a process for removing a reactive solvent from a lithium bis (fluorosulfonyl) imide (LiFSI) using a lithium ion and an organic solvent stable to the anode of a lithium metal battery.

Lithium bis (fluorosulfonyl) imide (LiFSI) has been reported as a conductive salt in lithium-based batteries due to its desirable physicochemical and electrochemical properties. LiFSI has a melting point of 143 ° C and is thermally stable up to 200 ° C. LiFSI exhibits much better stability to hydrolysis compared to lithium hexafluorophosphate (LiPF ₆ ), which is a commonly used salt for lithium ion battery electrolytes. LiFSI is a lithium due to its unique properties such as excellent solubility, ionic conductivity comparable to LiPF ₆ -based electrolytes, cost effectiveness, environmental friendliness, and good solid electrolyte interface (SEI) forming properties. It is attracting great interest as an electrolyte / additive for ion batteries. The purity level of LiFSI used in the battery electrolyte may be important for the operation and cycle life of the battery using the LiFSI-based electrolyte. However, many commercial processes for synthesizing LiFSI produce by-products that remain in the crude LiFSI produced by the synthesis process. The main synthetic impurities in LiFSI are lithium fluoride (LiF), lithium chloride (LiCl), lithium sulfate (Li ₂ SO ₄ ), lithium fluorosulfonate (LiFSO ₃ ), and acid-type impurities such as hydrogen fluoride (LiF). HF). These impurities must be removed or reduced to various acceptable levels before using the LiFSI salt in the battery. However, it can be difficult to remove them.

Some processes for removing impurities such as the above synthetic impurities from crude LiFSI utilize one or more solvents that are reactive with the lithium metal, such as alcohol (s) and water. do. In addition, the crude LiFSI may contain water by means other than the solvent. Thus, even if such LiFSI is purified to a point where the level of targeted synthetic impurities is low enough not to interfere with the function of the electrochemical device when the purified LiFSI is placed in the electrolyte of the device. Purified LiFSI may still not be suitable for use in secondary lithium metal batteries. This is because the purified LiFSI contains a residue of the reactive solvent used to remove target impurities and / or water that may otherwise be present, and the reactive solvent residue and / or water of the device. This is because it reacts with the lithium metal of the anode, thereby destroying the integrity of the lithium metal and the ability of the anode to function properly. Over time, even relatively small amounts of the reactive solvent (s) in the LiFSI salt used to produce the electrolyte will affect the performance and cycle life of the secondary lithium metal battery. It can have a big impact.

There is a need for ultra-high purity LiFSI salts with very low levels of synthetic impurities as well as very low levels of reactive solvents.

In one embodiment, the present disclosure relates to a method for producing a reduced-reactive-solvent lithium bis (fluorosulfonyl) imide (LiFSI) product. The method provides a first crude LiFSI containing LiFSI and one or more reactive solvents, the first crude LiFSI under inert conditions with at least one first anhydrous organic solvent. Contacting is to produce a solution containing the first crude LiFSI and one or more reactive solvents, wherein the solubility of LiFSI in at least one first anhydrous organic solvent is less than 25 ° C. LiFSI is at least about 35%, subjecting the solution to vacuum to remove at least one first anhydrous organic solvent and one or more reactive solvents to obtain a solid mass. Treating the solid mass with at least one second anhydrous organic solvent that is insoluble to produce a combination with an insoluble moiety, isolating the insoluble moiety in an inert atmosphere, at least one insoluble moiety. Reactive solvent-reduced LiFSI product by flushing with a dry inert gas to remove traces of at least one second anhydrous organic solvent and subjecting the flushed insoluble moiety to a pressure of less than about 100 Torr. Including getting.

For purposes of illustrating the invention, the drawings show aspects of one or more embodiments of the invention. However, it should be understood that the invention is not limited to the exact arrangement and means shown in the drawings.

It is a flow chart which shows the multipath method which reduces the reactive solvent in lithium bis (fluorosulfonyl) imide (LiFSI) by the aspect of this disclosure.

It is a high level figure which shows the electrochemical device made by the aspect of this disclosure.

It is a flow chart which shows the multipath method for purifying LiFSI by the aspect of this disclosure.

It is a graph of the discharge capacity vs. the number of cycles of a non-aqueous electrolyte using a LiFSI salt synthesized according to the present disclosure (upper line) and a similar non-aqueous electrolyte using a commercially available LiFSI salt (lower line).

It is a graph of the capacity retention rate vs. the number of cycles of a non-aqueous electrolyte using a LiFSI salt synthesized according to the present disclosure (upper line) and a similar non-aqueous electrolyte using a commercially available LiFSI salt (lower line). ..

In some embodiments, the present disclosure relates to a method of removing one or more reactive solvents from a crude lithium bis (fluorosulfonyl) imide (LiFSI). As used herein and in the context of the accompanying patent claims, the use of the term "reactive" to modify "solvents" or "solvents", etc., unless otherwise stated. It is assumed that the solvent (s) is reactive with a lithium metal in a lithium-based battery, for example, a lithium metal in the anode of a lithium metal battery. As will be appreciated by those skilled in the art, "reactivity" in this context refers to the magnitude of the reduction potential of a lithium metal with respect to a solvent (s). The reactive solvent has a reactive proton having a relatively high reduction potential with respect to a lithium metal having a relatively low reduction potential. Examples of the reactive solvent include a protonic solvent such as water and a reactive organic solvent such as alcohol. Conversely, as used herein and in the appended claims, the term "non-reactive" to modify "solvents" or "solvents" and the like, unless otherwise stated. The use of is meant that the solvent (s) is non-reactive with the lithium metal. Also, reactive solvents (s) are not effective in passivating lithium metals, whereas non-reactive solvents (s) are non-reactive with lithium metals. There is or effectively passivates to the lithium metal, i.e. dynamically stabilizes the electrolyte / lithium anode system. Examples of non-reactive solvents include dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, fluorine-containing carbonate and glycol ether.

As used herein and in the appended claims, the term "crude" and similar terms when referring to LiFSI result from or are present at least LiFSI and the synthesis and / or purification of LiFSI. A synthetic product comprising one or more reactive solvents, such as a reactive solvent, is shown. The presence of reactive solvent (s) in LiFSI salts used in electrolytes for lithium-ion batteries and lithium metal batteries adversely affects cycle performance such as battery discharge capacity and capacity retention. May affect. Therefore, it is desirable to remove as much of the reactive solvent (s) present in the LiFSI salt as possible. Such reactive solvents may also be referred to as "solvent residues" or "solvent residues" as used herein and in the appended claims. The crude LiFSI may contain additional impurities, such as the impurities described below in Section II.

As used herein and in the appended claims, the term "anhydrous" refers to about 1% by weight or less of water, typically about 0.5% by weight or less of water, often about 0.1%. It refers to having water of less than or equal to weight, more often less than or less than about 0.01% by weight, and most often less than or less than about 0.001% by weight. Within this definition, the term "substantially anhydrous" refers to water of about 0.1% by weight or less, typically about 0.01% by weight or less, often about 0.001% by weight or less. Refers to having.

Throughout this disclosure, the term "about", when used with the corresponding number, is ± 20% of the number, typically ± 10% of the number, often ± 5% of the number, and most often ± of the number. Refers to 2%. In some embodiments, the term "about" can mean the number itself.

When describing a chemical reaction, such as any of the synthetic and purification reactions described herein and / or addressed within the appended claims, "treat," "contact," and "react." The term is used interchangeably and refers to the addition or mixing of two or more reagents under conditions sufficient to produce the indicated and / or desired product (s). .. It should be appreciated that the reactions shown and / or producing the desired product do not necessarily result directly from the combination of reagents added initially (s). That is, there may be one or more intermediates that are produced in the mixture and ultimately result in the formation of the indicated and / or desired product.

On a commercial scale, crude LiFSI usually contains one or more reactive solvent residues such as methanol, ethanol or water from the solvent source from which LiFSI is synthesized or purified. These reactive solvent residues are known to be very strongly solvated with alkali metal salts and are difficult to remove by suction under vacuum without heating to high temperatures. However, LiFSI is unstable to heating at high temperatures in the presence of reactive solvents, and high heat causes defluorination of LiFSI, which is a strong acid known to be corrosive, hydrogen fluoride. (HF) is generated. The following scheme shows the defluorination of LiFSI containing a protonic solvent during heating.

All protic solvents also tend to undergo proton reduction to produce hydrogen gas, which are generally used only for reduction electrochemical using electrodes such as mercury or carbon, which are kinetically slow in proton reduction. To. The protonic solvent also reacts with the lithium metal present in the lithium-based battery and, in particular, reacts with the lithium metal anode of the lithium -metal battery to produce hydrogen gas according to the following scheme.

Although the above details relate to LiFSI, crude lithium bis (trifluoromethanesulfonyl) imides (LiTFSI), especially crude LiTFSI manufactured using commercial scale processes, have the same or similar problems with reactive solvents. Note that it exists. As a result, general methodologies for reducing the amount of each of the one or more reactive solvents described herein for crude LiFSI are also relevant to crude LiTFSI.

In another aspect, the disclosure comprises LiFSI and one or more reactive solvents used for the synthesis and / or purification of relatively low levels of one or more reactive solvents, such as crude LiFSI. Reduced-reactive-solvent with respect to LiFSI products. Examples of reactive solvents that may be present in crude LiFSI or LiTFSI include, among others, water, methanol, ethanol and propanol, alone or in various combinations with each other. As described in more detail below, such reactive solvent-reduced LiFSI products may be a single passthrough of one of the disclosed basic processes, or one or more of the disclosed basic processes. It can be produced using the reactive solvent reduction method of the present disclosure, which is capable of producing a reactive solvent-reduced LiFSI product in multiple pass-throughs.

In yet a further aspect, the present disclosure relates to the use of the LiFSI salt products of the present disclosure. For example, the LiFSI salt products of the present disclosure are used to produce an electrolyte that can be used in any suitable electrochemical device such as a battery or supercapacitor, in particular a secondary lithium ion battery and a secondary lithium metal battery. be able to.

In some embodiments, the methods disclosed herein are used to remove (s) reactive solvents and / or (s) reactive solvents (s). Substitution with a non-reactive solvent may be sufficient for a particular use of LiFSI (or LiTFSI), but in other cases LiFSI generation in which the reactive solvent removal / replacement methods of the present disclosure can be used otherwise. It may be beneficial to apply to LiFSI products of higher purity than the product. The two routes that provide such high-purity LiFSI specifically addressed below are a method of removing non-solvent impurities from the crude LiFSI and a method of synthesizing the crude LiFSI using an aqueous neutralization process. As a result, as described below, additional embodiments of the present disclosure include various combinations of these methods and processes, as well as two or more of the methods disclosed herein, their accompanying intermediates and final production. These include objects as well as their use, which are described shortly below.

In some additional embodiments, the present disclosure relates to a method of purifying crude LiFSI to remove any one or more of various non-solvent impurities from crude LiFSI. As used in the context of non-solvent impurity removal and in the appended claims, the term "crude LiFSI" and similar terms refer to at least LiFSI and one or more non-solvent impurities resulting from the synthesis of LiFSI. The synthetic product containing non-solvent impurities is shown. In the following and attached claims, this type of impurity is referred to as a "synthetic impurity". Each of the targeted impurities that is removed to some extent or to some extent using the disclosed method is referred to as "targeted impurities" as used herein and in the appended claims. In one example, the target impurity may be a synthetic impurity that is a by-product of the synthesis of LiFSI as described above.

この例では、Ｌｉ_２ＳＯ_４、ＦＳＯ_３Ｌｉ、ＬｉＦ、およびＬｉＣｌは、粗ＬｉＦＳＩから除去されることが望ましい標的不純物（ここでは、合成不純物）である。いくつかの実施形態では、本開示の精製方法は、Ｌｉ_２ＳＯ_４、ＦＳＯ_３Ｌｉ、ＬｉＦ、およびＬｉＣｌのうちの１種または複数などの１種または複数の合成不純物、および／または開示された方法による除去に適した分子構造および特性を有する任意の他の不純物を除去し、その各々は本開示の用語では「標的不純物」である。 On a commercial scale, crude LiFSI is generally hydrogen containing various concentrations of synthetic impurities such as hydrogen fluoride (HF), fluorosulfuric acid (FSO ₃ H), hydrogen chloride (HCl), and sulfuric acid (H ₂ SO ₄ ). It is obtained by neutralizing bis (fluorosulfonyl) imide (HFSI) with lithium carbonate (Li ₂ CO ₃ ) or lithium hydroxide (LiOH). As an example, using LiOH-based synthesis, impurities such as HFSI and HF, FSO ₃ H, HCl, and H ₂ SO ₄ can be added to the corresponding Li salts by the following scheme during this process to produce crude LiFSI. The conversion produces LiFSI, Li ₂ SO ₄ , FSO ₃ Li, LiF, and Li Cl, respectively.

In this example, Li ₂ SO ₄ , FSO ₃ Li, LiF, and LiCl are target impurities (here, synthetic impurities) that should be removed from the crude LiFSI. In some embodiments, the purification methods of the present disclosure are one or more synthetic impurities, such as one or more of Li ₂ SO ₄ , FSO ₃ Li, LiF, and Li Cl, and / or disclosed. It removes any other impurities with molecular structure and properties suitable for removal by method, each of which is a "target impurity" in the terms of the present disclosure.

In another aspect, the present disclosure discloses LiFSI and relatively low levels of one or more target impurities, such as one or more synthetic impurities, such as the Li ₂ SO ₄ , FSO ₃ Li, LiF, and LiCl described above. With respect to purified LiFSI products containing. As described in more detail below, such purified LiFSI products may be a single passthrough of one of the disclosed basic processes, or one or more of the disclosed basic processes. It can be produced using the purification methods of the present disclosure which can produce purified LiFSI products in pass-through.

In yet a further aspect, the present disclosure relates to the use of the LiFSI salt products of the present disclosure. For example, the LiFSI salt products of the present disclosure can be used to produce electrolytes that can be used in any suitable electrochemical device such as batteries or supercapacitors.

In yet another aspect, the present disclosure relates to a method of synthesizing LiFSI using an aqueous neutralization method following removal of impurities. As described in more detail below, one exemplary LiFSI synthesis method neutralizes hydrogen bis (fluorosulfonyl) imide (HFSI) (eg, purified HFSI) with one or more lithium bases in deionized water. To obtain an aqueous solution of LiFSI and one or more synthetic impurities. Additional steps may include removing at least a portion of the deionized water to obtain crude LiFSI and then purifying the crude LiFSI to remove at least a portion of one or more synthetic impurities.

Also in a further aspect, the present disclosure relates to performing any one of the various combinations of the various methods disclosed herein. For example, the overall process is to synthesize LiFSI using the aqueous neutralization synthesis method of the present disclosure, followed by this synthesis using the synthesized LiFSI to purify the non-reactive solvent of the present disclosure. It can include the process, the reactive solvent reduction / substitution methods of the present disclosure, or any combination of the two. If both additional methods are used, especially if either reactive solvent is used in the non-reactive solvent purification process, it is generally preferred to carry out the reactive solvent reduction / substitution method last. As another example, the overall process begins with an already synthesized crude LiFSI, such as a commercially supplied crude LiFSI synthesized by conventional methods, followed by the non-reactive solvent purification process or book of the present disclosure. It may include performing one, the other or both of the reactive solvent reduction / substitution methods disclosed.

In yet a further aspect, the present disclosure is either a purified LiFSI product containing LiFSI produced using any one of the combinations of methods described in the preceding paragraph, or any of the combinations described in the preceding paragraph. With respect to electrolytes produced using purified LiFSI salts produced using one of them, and the use of such electrolytes.

Details of the aforementioned and other aspects of the present disclosure will be described below.

I. Removal / replacement of reactive solvent (s)

This section covers methods of removing and / or substituting reactive solvents in lithium sulfoneimide salts, the reactive solvent-reduced lithium sulfoneimide salts produced thereby, and the use of such reactive solvent-reduced lithium sulfoneimide salts. Handle.

I. A. An exemplary method of removing / replacing the reactive solvent (s) in the crude LiFSI.

As mentioned above, the crude LiFSI can include, for example, one or more reactive solvents as residues from the synthesis and / or purification of LiFSI. The reactive solvent removal methods of the present disclosure can be used to reduce the amount, including the complete removal of one or more reactive solvents in the crude LiFSI. The removal of the reactive solvent (s) used one or more non-reactive solvents, and at least a portion of the non-reactive solvents (s) completed the reactive solvent removal method. In some embodiments, this method may also be considered as a solvent replacement method, as it remains behind, and the undesired reactive solvent (s) may be a reactive solvent (s). It is replaced with a non-reactive solvent (s) that does not adversely affect the battery performance of (s). As described below, in some embodiments, the residual non-reactive solvent (s) is often in the range of about 3000 ppm or less, eg, about 100 ppm to about 3000 ppm.

In some embodiments, the reactive solvent removal method comprises contacting the crude LiFSI with at least one first anhydrous organic solvent under inert conditions to contain the crude LiFSI and one or more reactive solvents. Includes producing a solution. In general, this step involves replacing the ion-bound coordination-reactive solvent molecule with the desired non-reactive molecule. In some embodiments, the solubility of LiFSI in at least one first anhydrous organic solvent is at least about 35% to about 65% at room temperature. In some embodiments, contacting the crude LiFSI with at least one first anhydrous organic solvent keeps the crude LiFSI in the range of about 35% to about 65% by weight based on the total weight of the solution. It involves contacting with an amount of at least one first anhydrous organic solvent.

Inactive conditions during contact of LiFSI with at least one first anhydrous organic solvent include, among other things, the use of argon gas and / or nitrogen gas, and / or other inert dry (ie, anhydrous) gas. , Can be produced using any suitable technique. The purification method can be carried out at any suitable pressure, such as 1 atmosphere.

Examples of anhydrous organic solvents in which each of at least one first anhydrous organic solvent can be selected are dimethylcarbonate (DMC), diethylcarbonate (DEC), ethylmethylcarbonate (EMC), propylmethylcarbonate. Organic carbonates such as (PMC), ethylene carbonate (EC), fluoroethylene carbonate (FEC), and transbutylene carbonate, nitriles such as acetonitrile, malononitrile, and adiponitrile, methyl acetate, ethyl acetate, propyl acetate, and acetic acid. Examples include, but are not limited to, alkyl acetates such as butyl and alkyl propionates such as methyl propionate (MP) and ethyl propionate (EP). For example, when removing one or more reactive solvents using one or more non-reactive organic solvents to produce LiFSI salts for lithium ion batteries or lithium metal batteries, at least one. It is desirable that each anhydrous organic solvent selected for the first anhydrous organic solvent be non-reactive with lithium metal. Examples of such non-reactive anhydrous organic solvents include DMC, DEC, EMC, fluoroethylene carbonate, difluoroethylene carbonate, and trifluoromethyl ethyl carbonate.

After contacting the crude LiFSI or LiTFSI with at least one first anhydrous organic solvent, the solution is subjected to vacuum to present at least one first anhydrous organic solvent and one or more reactive solvents, eg. One or more of the possible ones, especially water, methanol or ethanol, are removed to give a solid mass. In some embodiments, the vacuum pressure may be less than about 100 Torr, less than about 10 Torr, or less than about 1 Torr, less than about 0.1 Torr, or less than about 0.01 Torr. In some embodiments, the vacuum is performed at a controlled temperature, such as a temperature in the range of about 25 ° C to about 40 ° C.

The solid mass can then be treated with at least 100% by weight of one or more second anhydrous organic solvents in which the LiFSI in the solid mass is insoluble to produce a combination with an insoluble moiety. This treatment can remove any coordination solvent or solvate solvent. Examples of anhydrous organic solvents in which each of the one or more second anhydrous organic solvents may be selected include dichloromethane, dichloroethane, chloroform, pentane, hexane, heptane, octane, nonane, decane, undecane, and dodecane. However, it is not always limited to these.

The insoluble moiety is isolated from the combination in the inert atmosphere provided by the dry inert gas, such as argon, nitrogen, another dry inert gas, or any combination thereof. The insoluble moiety can be isolated by any suitable method such as filtration performed using any suitable method such as one or more filters, centrifugation, specific gravity separation, hydrocyclone and the like. One of ordinary skill in the art will understand suitable filtration techniques for use in any particular embodiment of the protonic solvent reduction methods of the present disclosure.

The insoluble moiety can be flushed with at least one inert gas (eg, a dry inert gas, i.e. less than 1 ppm of water) to remove trace amounts of at least one second anhydrous organic solvent. Examples of the inert gas in which each of the at least one dry inert gas can be selected includes argon and nitrogen.

The flushed insoluble moiety can be subjected to a pressure of less than about 100 Torr to give a LiFSI product with reduced protonic solvent or a LiTFSI product with reduced protonic solvent. In some embodiments, the pressure may be less than about 10 Torr, or less than about 1 Torr, less than about 0.1 Torr, or less than about 0.01 Torr. In one example, the pressure in vacuum is less than about 0.01 Torr. In some embodiments, the vacuum is performed at a controlled temperature, such as a temperature below about 40 ° C (eg, in the range of about 20 ° C to about 40 ° C). The resulting reactive solvent-reduced LiFSI product is typically a white, free-flowing powder.

The dried reactive solvent-reduced LiFSI product is a dry polytetrafluoroethylene (PTFE) container or a dry inert container such as a nickel alloy that is inert to free fluoride to suppress the decomposition of LiFSI during storage. In addition, it can be stored in an inert gas such as argon at a low temperature such as about 25 ° C. or lower.

In a general example where DMC is used as at least one first anhydrous organic solvent and dichloromethane is used as at least one second anhydrous organic solvent, the typical process is particularly water. Crude LiFSI with various levels of one or more reactive solvents such as methanol and / or ethanol is contacted with about 30% to about 50% by weight anhydrous dimethylcarbonate in which LiFSI is soluble. In this example, the crude LiFSI is contacted with the DMC and then under vacuum (eg, less than about 0.01 Torr) with a reactive solvent (s) such as water, methanol, and / or ethanol. Remove. Removal of DMC results in a solid mass. This method further comprises treating the resulting solid mass with anhydrous dichloromethane in which LiFSI is insoluble to obtain an insoluble moiety and a combination of anhydrous dichloromethane and any other insoluble component (s). It may be included. Insoluble moieties (eg, powdered LiFSI) can be obtained by filtration and trace amounts of dichloromethane can be removed by flushing with dry Ar and / or dry _N2 . The flushed LiFSI can then be subjected to vacuum (eg, less than 0.01 Torr) at a temperature below about 40 ° C. to give a dry reactive solvent-reduced LiFSI product, in this case a free solvent-free LiFSI product. can. Reactive solvent-reduced LiFSI products may be free of free solvent, but in practice LiFSI products are typically at least some reactive and / or non-reactive coordinated with LiFSI. Contains solvent. The LiFSI product, which does not contain a dry protonic solvent, may be stored in a PTFE container under inert conditions, for example, at a temperature of less than about 25 ° C.

The amount of reactive solvent (s) in the crude LiFSI from which the reactive solvent (s) is removed using any one of the above methods and the reactive solvent in the desired LiFSI product. It may be necessary to carry out a multipass method to sequentially reduce the amount of one or more reactive solvents in each pass, depending on the desired maximum amount (s). Such a multipath method is initially in crude LiFSI and then each of one or more reactive solvents that may still remain in the resulting reactive solvent-reduced LiFSI product. Any one or more of the above methods can be continuously utilized to continuously reduce the level of. An exemplary multipath-reactive solvent reduction method 100 of the present disclosure is shown in FIG.

Referring to FIG. 1, in block 105, crude LiFSI containing one or more reactive solvents present at a particular level (s) is provided. In block 110, the reactive solvent content of the crude LiFSI is reduced using any one of the above methods. The end result of reactive solvent reduction in block 110 is a reactive solvent reduced LiFSI product with reduced levels of each reactive solvent. In the optional block 115, the level of each of one or more of the reactive solvents in the reactive solvent reduced LiFSI product is measured using appropriate measurement procedures. In the optional block 120, each of the measured levels is compared to the maximum desired level of the reactive solvent (s) that are allowed to be present in the reactive solvent reduced LiFSI product. In the optional block 125, it is determined whether one or more of the measured levels exceeds the corresponding desired maximum level. If not exceeded, i.e., if each measured level is below the corresponding desired maximum level, the reactive solvent reduced LiFSI product meets the specifications for the desired reactive solvent reduction level, further reducing the reactive solvent. do not need. Therefore, the multipath reactive solvent reduction method 100 can be terminated at block 130.

However, in block 125, if any one or more of the measured levels exceeds the corresponding desired maximum level (s), the reactivity treated with the previous pass-through reactive solvent reduction in block 110. The solvent-reduced LiFSI product can be processed in block 110 via loop 135. In this reactive solvent reduction pass-through in block 110, the anhydrous organic solvent (s) used for solution formation and / or washing of the crystallized LiFSI is used in the previous pass-through reactive solvent reduction in block 110. It may be the same as or different from the original. At the end of the reactive solvent reduction in block 110, one or more measurements of the reactive solvent level (s) and one of the measured levels (s) in the optional blocks 115 and 120. Alternatively, the method 100 can be terminated at block 130 by comparison with multiple corresponding desired maximum levels, or LiFSI in the reactive solvent-reduced LiFSI product of the latest pass is again via loop 135. It can be determined whether it should be subjected to reactive solvent reduction.

A non-limiting and exemplary example in which a multipath-reactive solvent reduction method may be useful is a lithium-based electrolyte such as LiFSI for lithium-based batteries. Crude LiFSI typically has a reactive solvent such as methanol, ethanol, and / or propanol from the LiFSI crystallization process. These reactive solvents can be present in excess of 3000 ppm. However, such levels of the reactive solvent are detrimental to the lithium metal battery as the reactive solvent reacts with the lithium metal to produce hydrogen gas and lithium alkoxide. As a result, it is desirable to keep the level of the reactive solvent in the LiFSI-based electrolyte for lithium metal batteries low, for example, less than about 200 ppm, less than about 100 ppm, less than about 50 ppm, or less than about 10 ppm. For crude LiFSI used to synthesize the LiFSI salt used in the electrolyte, it is such low to use the multipath purification methods of the present disclosure, such as the multipath reactive solvent reduction method 100 shown in FIG. It can be a useful method of achieving reactive solvent levels.

As a non-limiting but exemplary example, the multipass reactive solvent reduction method 100 is used to start with a crude LiFSI containing 3000 ppm alcohol as the reactive solvent (target reaction) in the LiFSI product. The reactive solvent content (in the form of a sex alcohol) can be reduced to less than 1 ppm. At block 105, the desired amount of crude LiFSI is provided. In block 110, the crude LiFSI is purified, i.e., using either the method described above or exemplified below, the amount of undesired alcohol is reduced.

In the optional block 115, the level of alcohol in the reactive solvent-reduced LiFSI product is measured to be 1000 ppm. In the optional block 120, a measured level of 1000 ppm is compared to a requirement of less than 100 ppm. In the optional block 125, the reactive solvent-reduced LiFSI product reduces the reactive solvent level in the initial crude LiFSI via loop 135 in block 110, as 1000 ppm is greater than the requirement of less than 100 ppm. It is processed using the same or different reactive solvent reduction process as that used to. In this second pass, the starting alcohol level is 1000 ppm and the final impurity level in the double-reactive solvent-reduced LiFSI product is 500 ppm as measured in optional block 115. After comparing this 500 ppm level with the requirement of less than 100 ppm in the optional block 120, the double-reactive solvent-reduced LiFSI product in the optional block 125 is previously in block 110 via loop 135. It is determined that the treatment needs to be retreated with the same or different reactive solvent reduction method as that used in either of the two passes.

In this third pass, the starting alcohol level is 500 ppm and the final alcohol level in the triplicate solvent-reduced LiFSI product is less than 100 ppm as measured in optional block 115. After comparing this level of less than 100 ppm with the requirement of less than 100 ppm in the optional block 120, the triple-reactive solvent-reduced LiFSI product is blocked by the multipath-reactive solvent reduction method 100 in the optional block 125. It is determined that the requirement is satisfied so that the process can be completed at 130.

I. B. example

The above methods are further described by the following examples, but it will be appreciated that these examples are included solely for illustrative purposes and are not intended to limit the scope of the present disclosure. Unless otherwise stated, all chemicals used in these examples were of high purity and were obtained from reliable commercial sources. Strict precautions were taken to remove water from the process and the reaction was carried out using a well-ventilated hood.

I. B. 1. 1. Example 1

Removal of Methanol from LiFSI Using DMC and dichloromethane: LiFSI (200 g) containing 4000 ppm methanol and 50 ppm water was sampled in a 250 mL dry flask under a nitrogen atmosphere and cooled to 10 ° C. using a water bath. .. Anhydrous DMC (140 g (about 41% by weight)) was added little by little with stirring to obtain a clear solution. The mixture was stirred at room temperature for 0.5 hours. The clear solution was concentrated under reduced pressure below 0.01 Torr to give a solid, which was treated with anhydrous dichloromethane (150 g) under argon. The combination was stirred at room temperature for 1 hour and the desired insoluble LiFSI product was isolated by filtration. Traces of dichloromethane were removed by flushing with dry Ar / N ₂ gas. The isolated LiFSI was dried in vacuo (less than 0.1 Torr) at 35 ° C. to give a reactive solvent-reduced LiFSI product containing 0 ppm methanol and 15.0 ppm water in 90% yield.

I. B. 2. 2. Example 2

Removal of Ethanol from LiFSI Using DMC and dichloromethane: LiFSI (178 g) containing 2900 ppm ethanol and 15 ppm water was sampled in a 250 mL dry flask under a nitrogen atmosphere and cooled to 10 ° C. using a water bath. .. Anhydrous DMC (140 g (about 44% by weight)) was added little by little with stirring to obtain a clear solution. The mixture was stirred at room temperature for 0.5 hours. The clear solution was concentrated under reduced pressure below 0.01 Torr to give a solid, which was treated with anhydrous dichloromethane (150 g) under argon. The combination was stirred at room temperature for 1 hour and the desired insoluble LiFSI product was isolated by filtration. Traces of dichloromethane were removed by flushing with dry Ar / N ₂ gas. The isolated LiFSI was dried in vacuo (less than 0.1 Torr) at 35 ° C. to give a reactive solvent-reduced LiFSI product containing 0 ppm ethanol and 4 ppm water in 90% yield.

I. B. 3. 3. Example 3

Removal of Isopropanol from LiFSI Using DMC and dichloromethane: LiFSI (350 g) containing 2000 ppm isopropanol and 30 ppm water was sampled in a 250 mL dry flask under a nitrogen atmosphere and cooled to 10 ° C. using a water bath. .. Anhydrous DMC (200 g (about 36% by weight)) was added little by little with stirring to obtain a clear solution. The mixture was stirred at room temperature for 0.5 hours. The clear solution was concentrated under reduced pressure below 0.01 Torr to give a solid, which was treated with anhydrous dichloromethane (350 g) under argon. The combination was stirred at room temperature for 1 hour and the desired insoluble LiFSI product was isolated by filtration. Traces of dichloromethane were removed by flushing with dry Ar / N ₂ gas. The isolated LiFSI was dried in vacuo (less than 0.1 Torr) at 35 ° C. to give a reactive solvent-reduced LiFSI product containing 0 ppm isopropanol and 4 ppm water in 92% yield.

I. C. Exemplary Reactive Solvent Reduced LiFSI Products

Using either of the single-pass reactive solvent reduction methods disclosed above or the reactive solvent reduction methods described above, such as any of the multi-pass methods 100 of FIG. 1, the resulting purified LiFSI product is reactive. The target reactivity level of the solvent (s) can be very low. For example, in some embodiments particularly suitable for use in lithium metal batteries, they remain in the final ultra-purity LiFSI salt product (ie, after completion of the reactive solvent reduction disclosed herein). The amount of the reactive solvent (s) is preferably less than about 100 ppm, more preferably less than about 50 ppm, most preferably less than about 25 ppm. In some embodiments, the non-reactive solvent remaining in the final ultra-purity LiFSI salt product does not adversely affect battery performance more than the reactive solvent, but in such embodiments it is final. The amount of non-reactive solvent (s) remaining in the ultra-purity LiFSI salt product is typically less than about 3000 ppm, more typically less than about 1000 ppm. If purification is performed using only non-reactive solvents for all purification steps, the final ultra-purity LiFSI salt product will typically be at least about 100 ppm non-reactive solvent (s). However, typically, it has a reactive solvent (s) of about 100 ppm or less. The level of the reactive solvent (s) in the crude LiFSI prior to the reduction of the reactive solvent according to the present disclosure may be about 500 ppm or more, about 1000 ppm or more, or about 2000 ppm or more. In one example where DMC is used in a reactive solvent removal / replacement method, the purified LiFSI of the present disclosure has about 0.2% to about 0.3% DMC and less than 100 ppm water as a reactive solvent.

I. D. Example of use of reactive solvent-reduced LiFSI salt product

As mentioned above, reactive solvent-reduced LiFSI salt products can be used to produce reactive solvent-reduced LiFSI-based electrolytes, among other things, for electrochemical devices. Here, the reactive solvent reduction of the reactive solvent reduced electrolyte results from the fact that the reactive solvent reduced LiFSI salt product was treated by any one or more of the methods disclosed herein. Such reactive solvent reducing electrolytes are the reactive solvent reducing solvent LiFSI salt products (salts) of the present disclosure in one or more solvents, one or more diluents, and / or one or more additives. It can be produced using any of a variety of methods, such as mixing with, and solvents, diluents, and additives may be known in the art.

If the electrochemical device is a lithium-based device such as a secondary lithium-ion battery or a secondary lithium metal battery, the reactive solvent (s) will generate an electrolyte so that it does not affect the performance of the battery. It is desirable to minimize the amount of reactive solvent (s) in the LiFSI salt used in. For example, the more reactive solvent in the LiFSI salt, the greater the adverse effect of the reactive solvent on cycle performance such as discharge capacity and capacity retention. Therefore, in the case of lithium-based secondary batteries, it is desirable to remove as much reactive solvent (s) as possible from the LiFSI salt used in the electrolyte of such batteries. Typically, as described above, this involves the use of one or more non-reactive solvents in the reactive solvent reduction process disclosed herein. Therefore, the majority of the reactive solvent in the initial crude LiFSI is removed and / or replaced with the non-reactive solvent (s) used in the corresponding reactive solvent reduction process. In some embodiments, the reactive solvent-reduced LiFSI product produced using the techniques disclosed herein is referred to as the "IC exemplary reactive solvent-reduced LiFSI product" described above. It can have reactive and / or non-reactive solvent levels as shown in the title section.

I. D. 1. 1. Preparation of LiFSI salt for use in electrolytes for lithium-based electrochemical devices

As mentioned above, an important step in preparing electrolytes for use in lithium-based electrochemical devices such as secondary lithium batteries with lithium metal anodes is from LiFSI salts containing such residues. For example, removing as much reactive solvent residue as possible from the process of synthesizing and / or purifying the LiFSI salt (s). In some embodiments, the removal process comprises a substitution embodiment in which one or more reactive solvents such as one or more alcohols and water are at least partially replaced by one or more non-reactive solvents. Can include. As described above, it is present in the LiFSI salt by removing and / or substituting the reactive solvent residue (s) in the LiFSI salt prior to forming the electrolyte for lithium-based electrochemical devices. Due to the fact that there is much less (and in some cases non-existent) reactive solvent in the device that reacts with the lithium metal, better performance and / or improved cycle life of the electrochemical device is brought about. It should be noted that the non-reactive solvent (s) used in the substitution / removal process can be selected on the basis of its benefit to lithium-based electrochemical devices. For example, the non-reactive solvent selected may be of a type that can be used as a solvent in which the LiFSI salt is dissolved so as to give the electrolyte the desired concentration. In this case, the reactive solvent removal / replacement method of the present disclosure may be used to remove the reactive solvent (s) and potentially replace the reactive solvent with a small amount of final solvent as well as the final electrolyte. Will be beneficial to you. Alternatively, the non-reactive solvent (s) selected for the reactive solvent removal / substitution process, apart from any major salt dissolution function, is a solid electrolyte interface (SEI), especially on a lithium metal anode. It may be a desirable additive added to be particularly beneficial to the electrochemical device, such as an additive to promote layer formation.

The method of preparing LiFSI salts for use in lithium-based electrochemical devices removes and / or replaces such solvent residues prior to using LiFSI salts to prepare electrolytes for lithium-based devices. It involves providing a LiFSI salt containing one or more reactive solvent residues that, if not, would be detrimental to the function of the lithium-based device. Providing LiFSI salts may include purchasing LiFSI salts from commercial suppliers of such salts, or synthesizing and / or purifying crude LiFSI salts in-house. The Reactive Solvent Residue-Containing LiFSI Salt is then exemplified by removing, for example, "IA crude LiFSI from the reactive solvent (s) by any of the methods disclosed herein. Methods "can be processed by the methods described above in the section entitled". The method of preparing a LiFSI salt for use in a lithium-based electrochemical device may include selecting one or more non-reactive solvents for use in a reactive solvent removal / substitution method. Note that "removal / replacement" and forward slashes or diagonal lines at similar positions, as is generally understood, mean "and / or", i.e. one, the other, or both. In some embodiments, at least one of the non-reactive solvents selected is not only non-reactive with lithium metals, but also has positive benefits such as promoting SEI layer growth like electrolyte additives. Selected based on the offer. LiFSI salts can be used to produce electrolytes for lithium-based electrochemical devices when subjected to reactive solvent removal / substitution treatments.

I. D. 2. 2. An exemplary electrochemical device utilizing the LiFSI salt produced using the methods of the present disclosure.

FIG. 2 shows an electrochemical device 200 made according to the aspects of the present disclosure. Those skilled in the art will readily appreciate that the electrochemical device 200 may be, for example, a battery or a supercapacitor. In addition, those skilled in the art show that FIG. 2 shows only some basic functional components of the electrochemical device 200, which is typically a realization of an electrochemical device such as a secondary battery or supercapacitor. It will be easy to understand that it is embodied using either a wound structure or a laminated structure. In addition, those skilled in the art will appreciate that the electrochemical device 200 is not shown in FIG. 2 for ease of illustration, among others, electrical terminals, seals (s), heat shield layers (s). , And / or will be understood to include other components such as vents (s).

In this example, the electrochemical device 200 includes spaced positive and negative electrodes 204, 208, and a pair of corresponding current collectors 204A, 208A, respectively. The porous dielectric separator 212 is arranged between the positive electrode and the negative electrodes 204 and 208 to electrically separate the positive electrode and the negative electrode, and the ions of the reactive solvent-reducing LiFSI-based electrolyte 216 produced by the present disclosure are placed therein. Allows to flow. One, the other, or both of the porous dielectric separator 212 and / or the positive electrode and the negative electrode 204, 208 is impregnated with the protic and aprotic solvent-reduced LiFSI-based electrolyte or the LiTFSI-based electrolyte 216, depending on whether or not they are porous. ing. In FIG. 2, both the positive electrode and the negative electrodes 204, 208 are shown to be porous by showing the reactive solvent-reduced LiFSI-based electrolyte 216 extending internally. As described above, the advantage of using the reactive solvent-reduced LiFSI-based electrolyte of the present disclosure for the reactive solvent-reduced LiFSI-based electrolyte 216 is that the reactive solvent may be present in the LiFSI-based electrolyte such as a synthetic or purified protonic solvent. (One or more) can be reduced to acceptable levels for use in the electrochemical device 200 (eg, meeting the specifications for one or more protonic solvent levels). Examples of reactive solvent-reduced LiFSI products (salts) and low-level examples of reactive solvents (s) that can be used to produce the reactive solvent-reduced LiFSI-based electrolyte 216 are described above. ing. The electrochemical device 200 includes collectors 204A, 208A, positive and negative electrodes 204, 208, a porous dielectric separator 212, and a container 220 containing a protonic solvent-reduced LiFSI-based electrolyte or LiTFSI-based electrolyte 216.

As will be appreciated by those skilled in the art, depending on the type and design of the electrochemical device, each of the positive and negative electrodes 204, 208 will be suitable for alkali metal ions and other components in the purified LiFSI-based electrolyte 216. Including materials. Each of the current collectors 204A, 208A can be made of any suitable conductive material such as copper or aluminum or any combination thereof. The porous dielectric separator 212 can be made of any suitable porous dielectric material, in particular, such as a porous polymer. Various battery and supercapacitor structures that can be used to build the electrochemical device 200 of FIG. 2 are known in the art. When any of such known structures are used, the novelty of the electrochemical device 200 is a high-purity reactive solvent-reduced LiFSI system that was not achieved by conventional methods of producing LiFSI salts and corresponding electrolytes. It is in the electrolyte 216.

In one example, the electrochemical device 200 can be made as follows. The reactive solvent reduction LiFSI-based electrolyte 216 can be produced starting from the crude LiFSI, which can then be made using any one or more of the reactive solvent reduction methods described herein. Purification is performed to produce reactive solvent-reduced LiFSI products with suitable low levels of one or more target reactive solvents. The reactive solvent-reduced LiFSI product is then used, for example, to improve the performance of the electrochemical device 200, for example, one or more solvents, one or more diluents, and / or one or more additions. By adding the agent, the reactive solvent-reduced LiFSI-based electrolyte 216 can be produced. The reactive solvent-reduced LiFSI-based electrolyte 216 can then be added to the electrochemical device 200 and then the container 220 can be sealed.

II. Removal of non-solvent impurities from crude lithium sulfone imide salt

This section deals with methods of removing non-solvent impurities from crude lithium sulfoneimide salts, the purified lithium sulfoneimide salts produced thereby, and the use of such purified lithium sulfoneimide salts.

II. A. An exemplary method for purifying crude LiFSI

Although several processes for producing LiFSI are known, each of the known methods for synthesizing LiFSI on a commercial scale produces crude LiFSI containing various levels of impurities such as synthetic impurities. .. For example, as mentioned above, LiFSI is often produced commercially using crude HFSI that reacts with Li ₂ CO ₃ or LiOH, and crude HFSI is an impurity in the crude LiFSI so synthesized. Contains various synthetic impurities that produce.

For example, one method of synthesizing HFSI uses urea (NH ₂ CONH ₂ ) and fluorosulfuric acid (FSO ₃ H). Disadvantages of this process are the low yield of HFSI and the isolated HFSI with a large excess of fluorosulfonic acid as an impurity. Boiling point of fluorosulfonic acid (bp) (bp 165.5 ° C.) and b. Of HFSI. p. (B. p. 170 ° C.) are very close to each other and it is very difficult to separate them from each other by simple fractional distillation [1]. Attempts have been made to remove fluorosulfuric acid by treating a mixture of HFSI and fluorosulfuric acid with sodium chloride. In this case, sodium chloride selectively reacts with fluorosulfuric acid to produce sodium salts and HCl by-products. This process has the disadvantages that the yield of purified HFSI is low and that the HFSI product is contaminated with some chloride impurities (HCl and NaCl) as impurities.

Another method of synthesizing HFSI for use in LiFSI synthesis involves fluorinating the bis (chlorosulfonyl) imide (HCSI) with arsenic trifluoride (AsF ₃ ). In this reaction, HCSI is treated with AsF ₃ . Arsenic trifluoride is toxic and has a high vapor pressure, making it particularly difficult to handle on an industrial scale. A typical reaction uses a ratio of HCSI to AsF ₃ of 1: 8.6. The HFSI produced by this method was also found to be contaminated with AsF ₃ and AsCl ₃ synthetic impurities, which were found to be good sources of chloride and fluoride impurities [2].

HFSI for use in LiFSI synthesis can also be prepared by fluorinating HCSI with antimony trifluoride (SbF ₃ ). The antimony trichloride by-product of this reaction has high solubility in HFSI, is essentially sublimable, and is very difficult to separate from the desired product. The product of this reaction is typically contaminated with antimony trichloride, which is a good source of chloride impurities [3].

Yet another method for producing HFSI for use in LiFSI synthesis involves reacting HCSI with excess anhydrous HF at elevated temperatures [4]. The yield of this reaction is up to 60% and the product is contaminated with the fluorosulfonic acid produced from the decomposition of HCSI. Since the boiling point is close to the boiling point of HFSI, this by-product is difficult to remove. This reaction of fluorinating HSCI using anhydrous HF achieved yields of> 95% [5], but the product was still a synthetic impurity with fluorosulfuric acid, hydrogen fluoride, hydrogen chloride, and sulfuric acid. It is contaminated.

It has been reported that reaction of HCSI with bismuth trifluoride (BiF ₃ ) produces HFSI in a cleaner reaction product. Since BiCl ₃ is not sublimable in this reaction, the formed BiCl ₃ by-product can be easily separated from HFSI by fractional distillation [6]. However, the product has some chloride, fluoride, and fluorosulfonic acid as synthetic impurities.

Another method of synthesizing HFSI is to react potassium bis (fluorosulfonyl) imide (KFSI) with perchloric acid [7]. In this process, the by-product potassium perchlorate is considered explosive. Also, the isolated HFSI is contaminated with high levels of potassium cations and some chloride impurities present in KFSI.

Hydrogen bis (fluorosulfonic acid), also known as imidebis (sulfuric acid) difluoride having the formula FSO ₂ NH-O ₂ F, has a melting point (mp) of 17 ° C. and b. p. Is a colorless liquid having a density of 1.892 g / cm ³ at 170 ° C. It dissolves very well in water and many organic solvents. Hydrolysis in water is relatively slow, resulting in the formation of HF, H ₂ SO ₄ , and amidosulfate (H ₃ NSO ₃ ). HFSI is a strong acid and pKa is 1.28 [8].

Produced using the purification methods of the present disclosure using targeted impurities such as synthetic impurities and / or other impurities present in the crude LiFSI, eg, one or more of the synthetic methods described above. The crude LiFSI synthesized can be removed using the crude HFSI. In some embodiments, the purification method contacts the crude LiFSI with at least one first anhydrous organic solvent under inert conditions to produce a solution containing the crude LiFSI and one or more target impurities. Including doing. In some embodiments, the solubility of LiFSI in at least one first anhydrous organic solvent is at least about 60% at room temperature, typically in the range of about 60% to about 90%, and one or more. The solubility of each of the plurality of target impurities is typically less than about 20 parts per million (ppm) at room temperature, often less than about 13 ppm, for example. In some embodiments, contact of the crude LiFSI with at least one first anhydrous organic solvent is carried out using a minimum amount of at least one first anhydrous organic solvent. The "minimum amount" in the context of at least one first anhydrous organic solvent means that the at least one first anhydrous organic solvent is provided in an amount that substantially no longer continues to dissolve LiFSI. means. In some embodiments, the minimum amount of at least one anhydrous organic solvent ranges from about 50% by weight to about 75% by weight of the solution.

In some embodiments, the contact of the crude LiFSI with at least one first anhydrous organic solvent is carried out at a temperature below the temperature in the range of about 15 ° C to about 25 ° C. Dissolution of the crude LiFSI in at least one anhydrous organic solvent is an exothermic reaction. As a result, in some embodiments, the temperature of the solution can be controlled using any suitable temperature control device such as a cooler, thermostat, circulator or the like. In some embodiments, the temperature of the solution is controlled to maintain the temperature of the solution below about 25 ° C. when contacting the crude LiFSI with at least one anhydrous organic solvent. At least one to achieve a minimum amount of at least one first anhydrous organic solvent and / or to control the temperature of the solution during contact of the crude LiFSI with at least one first anhydrous organic solvent. Anhydrous organic solvents of the species can be added continuously or continuously at precisely controlled rates or in precisely controlled amounts using appropriate feeders or feeders.

Inactive conditions during contact of LiFSI with at least one first anhydrous organic solvent include, among other things, the use of argon gas and / or nitrogen gas, and / or other inert dry (ie, anhydrous) gas. , Can be produced using any suitable technique. The purification method can be carried out at any suitable pressure, such as 1 atmosphere.

Examples of anhydrous organic solvents in which each of at least one first anhydrous organic solvent can be selected include dimethylcarbonate (DMC), diethylcarbonate (DEC), ethylmethylcarbonate (EMC), and propylmethylcarbonate. (PMC), Ethyl Carbonate (EC), Fluoroethylene Carbonate (FEC), Transbutylene Carbonate, acetonitrile, Marononitrile, Adiponitrile, Methyl Acetate, Ethyl Acetate, Propyl Acetate, Butyl Acetate, Methyl Propionate (MP), Propion Examples include, but are not limited to, ethyl acetate (EP), methanol, ethanol, propanol and isopropanol.

After contacting the crude LiFSI with at least one first anhydrous organic solvent, at least one second anhydrous organic solvent is added to the solution to precipitate the at least one target impurity. The at least one second anhydrous organic solvent is substantially insoluble in LiFSI and one or more target impurities in at least one second anhydrous organic solvent (as mentioned above, the target impurities exceed 20 ppm). It is generally desirable that it should not be soluble). In some embodiments, the minimum amount of at least one second anhydrous organic solvent is added. The "minimum amount" in the context of at least one second anhydrous organic solvent is that at least one second anhydrous organic solvent substantially continues to precipitate one or more target impurities from the solution. Means that it is provided in no quantity. In some embodiments, the minimum amount of at least one anhydrous organic solvent ranges from more than 0% by weight to less than 10% by weight of the solution. The at least one second anhydrous organic solvent can be added under the same temperature, pressure and inert conditions as present during contact between the crude LiFSI and the at least one first anhydrous organic solvent.

Examples of anhydrous organic solvents in which each of at least one second anhydrous organic solvent can be selected include dichloromethane, dichloroethane, chloroform, pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, etc. Not necessarily limited to these.

After adding at least one second anhydrous organic solvent, the insoluble portion of each of the one or more target impurities is separated from the solution, for example by filtration or cannulating, and a filtrate containing LiFSI in the solution. Generate. Filtration can be performed using any suitable method, such as using one or more filters, centrifugation, gravity separation, hydrocyclone, and the like. One of ordinary skill in the art will understand suitable filtration techniques (s) for use in any particular embodiment of the purification methods of the present disclosure.

After the filtrate is obtained from filtration, the solvent in the filtrate is removed to give a solid mass consisting primarily of LiFSI and a somewhat reduced amount of one or more target impurities. The solvent removed is typically each of one or more first anhydrous organic solvents and one or more second anhydrous organic solvents from the previous treatment. The solvent can be removed using any suitable technique, for example under suitable temperature and reduced pressure conditions. For example, removing the solvent may be performed at a pressure of about 0.5 Torr or less or about 0.1 Torr or less. The temperature at the time of removal may be, for example, about 25 ° C. to about 40 ° C. or lower.

After obtaining the solid mass, the solid mass is contacted with at least one third anhydrous organic solvent in which LiFSI is substantially insoluble and solvated with the third solvent by one or more target impurities. , More one or more target impurities can be further removed. Another advantage is to remove any ppm levels of HF formed during the process, especially by aspirating the solvent at reduced pressure and slightly above room temperature. In some embodiments, the amount of at least one third anhydrous organic solvent used to contact the solid mass may be at least 50% by weight by weight of the solid mass. Examples of anhydrous organic solvents in which each of at least one third anhydrous organic solvent can be selected include dichloromethane, dichloroethane, chloroform, pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, etc. Not necessarily limited to these.

After contacting the solid mass with at least one third anhydrous organic solvent, LiFSI is isolated from at least one third anhydrous organic solvent and each of the reduced amounts of one or more target impurities. A purified LiFSI product containing the above is obtained. Isolation of LiFSI from at least one third anhydrous organic solvent uses any suitable technique, such as filtration of LiFSI in solid form and / or drying of solid LiFSI in vacuum, etc. Can be done. In some embodiments, the pressure in vacuum is less than about 0.1 Torr or less than about 0.01 Torr. The resulting purified LiFSI product is typically a white free-flowing powder.

The dried purified LiFSI product is placed in a dry polytetrafluoroethylene (PTFE) container or a dry inert container such as a nickel alloy that is inert to free fluoride to suppress the decomposition of LiFSI during storage. It can be stored in an inert gas such as argon at a low temperature such as 25 ° C. or lower.

Table I below shows examples of selection of each of the first, second and third anhydrous organic solvents for the LiFSI purification method of the present disclosure. As can be seen in the table, the selected first anhydrous organic solvent is dimethylcarbonate and the selected second and third anhydrous organic solvents are dichloromethane.

Based on Table I above, the solubility of LiFSI in dimethylcarbonate is greater than 90% and is insoluble in dichloromethane. On the other hand, the solubility of target impurities such as LiF, LiCl and Li ₂ SO ₄ in this example is less than 13 ppm in dimethylcarbonate under anhydrous conditions. Therefore, in this example of purifying crude LiFSI, anhydrous dimethylcarbonate and anhydrous dichloromethane solvents were selected to obtain the purified LiFSI product according to the present disclosure. According to the embodiment of the above method, the crude LiFSI containing the impurities reported in Table I above is mixed in dimethylcarbonate at a concentration of about 40% to about 75% at about 25 ° C. and stirred at room temperature. , Subsequently, about 2% to about 10% dichloromethane can be added to precipitate the target impurities. The target impurities can then be removed, for example by filtration, and the filtrate can be concentrated to dryness. The resulting solid can then be treated with anhydrous dichloromethane to remove any target HF impurities soluble in dichloromethane. However, LiFSI is insoluble in dichloromethane.

Purified LiFSI can be recovered by filtration and finally dried under reduced pressure (less than about 0.1 Torr in one example) and below about 40 ° C. to give a white free-flowing powder. In this example, the white powder was stored in an argon atmosphere in a PTFE container.

The concentration of the target impurity (s) in the crude LiFSI purified using any one of the above methods and the desired one or more of the target impurities in the desired purified LiFSI product. Depending on the maximum concentration, it may be necessary to perform a multi-pass method to sequentially reduce the amount of one or more target impurities in each pass. Such a multipath method is first in crude LiFSI and then continuous with each level of one or more target impurities that may still remain in the resulting purified LiFSI product. One or more of the above-mentioned methods can be continuously utilized in order to reduce the temperature. An exemplary multipath purification method 100 of the present disclosure is shown in FIG.

Referring to FIG. 3, in block 305, crude LiFSI containing one or more target impurities present at a particular level (s) is provided. In block 310, crude LiFSI is purified using any one of the above methods. The end result of purification in block 310 is a purified LiFSI product with reduced levels of each target impurity. In optional block 315, the level of each of one or more of the target impurities in the purified LiFSI product is measured using appropriate measurement procedures. In optional block 320, each of the measured levels is compared to the maximum desired level of the corresponding target impurity that is allowed to be present in the purified LiFSI product. In the optional block 325, it is determined whether any one or more of the measured levels exceed the corresponding desired maximum level. If not exceeded, i.e., if each measured level is below the corresponding desired maximum level, the purified LiFSI product meets the desired impurity level specifications and does not require further purification. Therefore, the multipath purification method 300 can be terminated at block 330.

However, in block 325, if one or more of the measured levels exceeds the corresponding desired maximum level (s), the purified LiFSI production purified by the previous pass-through purification in block 310. The material can be purified via loop 335 in block 310. In this pass-through purification at block 310, the anhydrous organic solvent (s) used to generate the solution and / or wash the crystallized LiFSI were the same as those used in the previous pass-through purification at block 310. May be different. At the end of purification in block 310, in optional blocks 315 and 320, one or more measurements of the target impurity level (s), and one or more correspondences with the measured levels (s). Whether the method 300 can be terminated at block 330 by making one or more comparisons with the desired maximum level, or the LiFSI in the purified LiFSI product of the latest path is purified again via loop 335. It is possible to decide whether or not it should be offered to.

A non-limiting but exemplary example in which a multipath purification method may be useful is a lithium-based electrolyte such as LiFSI for lithium-based batteries. Crude LiFSI typically has around 350 ppm LiCl from chloride impurities, eg, HCl synthetic impurities in crude HFSI used to produce LiFSI. However, such chloride levels are corrosive to lithium metal batteries. As a result, it is desirable to keep the chloride level in the LiFSI-based electrolyte for lithium metal batteries low, for example less than about 10 ppm or less than 1 ppm. For crude LiFSI used to synthesize the LiFSI salt used in the electrolyte, using the multipath purification methods of the present disclosure, such as the multipath purification method 300 shown in FIG. 3, is such a low chloride level. Can be a useful way to achieve.

As a non-limiting but exemplary example, the multipath purification method 300 is used to start with crude LiFSI containing 200 ppm LiCl as a synthetic impurity and in the LiFSI product (in the form of the target impurity LiCl). ) The chlorine content can be reduced to less than 1 ppm. At block 305, the desired amount of crude HFSI is provided. In block 310, the crude LiFSI is purified using either the purification method described above or exemplified below.

In optional block 315, the level of LiCl (or chloride) in the purified LiFSI product is measured to be 100 ppm. In the optional block 320, a measured level of 300 ppm is compared to a requirement of less than 1 ppm. In the optional block 325, 100 ppm is greater than the requirement of less than 1 ppm, so the purified LiFSI product is the same as that used to purify the first crude LiFSI in block 310 via loop 335. Or it is processed using a different purification process. In this second pass, the starting target impurity level is 100 ppm and the final impurity level in the double purified LiFSI product is 20 ppm as measured in optional block 315. After comparing this 20 ppm level with the requirement of less than 1 ppm in optional block 320, the double purified LiFSI product in block 310 via loop 335 the previous two passes. It is determined that it needs to be purified again by the same or different purification method used in any of the above.

In this third pass, the starting target impurity level is 20 ppm and the final impurity level of the triple purified LiFSI product is less than 1 ppm as measured in optional block 315. After comparing this less than 1 ppm level with less than 1 ppm requirements in optional block 320, the triple-purified LiFSI product in optional block 325 may be terminated in block 330 by the multipath purification method 300. It is determined that the necessary conditions that can be met are satisfied.

II. B. example

The above methods are further described by the following examples, but it will be appreciated that these examples are included solely for illustrative purposes and are not intended to limit the scope of the present disclosure. Unless otherwise stated, all chemicals used in these examples were of high purity and were obtained from reliable commercial sources. Strict precautions were taken to remove water from the process and the reaction was carried out using a well-ventilated hood.

II. B. 1. 1. Example 1

Purification of LiFSI using ^dimethyl carbonate (DMC) and dichloromethane: Various levels of impurities in a 500 mL dry flask, here FSO _3- = 400 ppm ^{, Cl-} = 50 ppm ^, F- = 200 ppm, SO _4-2 . Crude LiFSI (250 g) containing = 200 ppm and water = 200 ppm was collected under a nitrogen atmosphere and cooled to 10 ° C. using a water bath. Anhydrous DMC (250 g (50% by weight)) was added little by little to the flask with stirring, followed by 20 g (4% by weight) of anhydrous dichloromethane. The mixture was stirred at room temperature for 1 hour. Insoluble impurities were removed from the mixture by filtration. The filtrate was concentrated under reduced pressure to give a solid, which was then treated with anhydrous dichloromethane (200 g) under argon. The mixture is stirred at room temperature for 1 hour, the desired insoluble LiFSI product is isolated by filtration and finally dried in vacuo (less than 0.1 Torr) at 35 ° C. to give the purified LiFSI product in 95% yield. rice field. In this example, the purified LiFSI product had the following impurities: FSO ₃ ⁻ = 100 ppm, Cl ⁻ = 10 ppm, F ⁻ = 50 ppm, ^SO _4-2 = 60 ppm, and water = 50 ppm.

II. B. 2. 2. Example 2

Purification of LiFSI using Ethyl Methyl Carbonate (EMC) and dichloromethane: Various levels of impurities in a 500 mL dry flask, here FSO ₃ ⁻ = 200 ppm, Cl ⁻ = 10 ppm, F ^{− =} 100 ppm, SO ₄₂ . Crude LiFSI (250 g) containing ⁻ = 100 ppm and water = 100 ppm was collected under a nitrogen atmosphere and cooled to 10 ° C. using a water bath. Anhydrous EMC (200 g (about 44% by weight)) was added little by little to the flask with stirring, followed by 25 g (about 5.6% by weight) of anhydrous dichloromethane. The mixture was stirred at room temperature for 1 hour. Insoluble impurities were removed by filtration. The filtrate was concentrated under reduced pressure to give a solid, which was then treated with anhydrous dichloromethane (250 g) under argon. The mixture is stirred at room temperature for 1 hour, the desired insoluble LiFSI product is isolated by filtration and finally dried in vacuo (less than 0.1 Torr) at 35 ° C. to give the purified LiFSI product in 92% yield. rice field. In this example, the purified LiFSI had the following impurities: FSO ₃ ⁻ = 40 ppm, Cl ⁻ = 1 ppm, F ⁻ = 10 ppm, ^{SO 4-2} ₌ 20 ppm, and water = 30 ppm.

II. B. 3. 3. Example 3

Purification of LiFSI using diethyl carbonate (DEC) and dichloromethane: Various levels of impurities in a 500 mL dry flask, here FSO _3- = 400 ppm ^{, Cl-} = 50 ppm ^{, F-} = 200 ppm, SO _4-2 . Crude LiFSI (250 g) containing = 200 ppm and water = 200 ppm was collected under a nitrogen atmosphere and cooled to 10 ° C. using a water bath. Anhydrous DEC (250 g (50% by weight)) was added little by little to the flask with stirring, followed by 20 g (4% by weight) of anhydrous dichloromethane. The mixture was stirred at room temperature for 1 hour. Insoluble impurities were removed from the mixture by filtration. The filtrate was concentrated under reduced pressure to give a solid, which was then treated with anhydrous dichloromethane (200 g) under argon. The mixture is stirred at room temperature for 1 hour, the desired insoluble LiFSI product is isolated by filtration and finally dried in vacuo (less than 0.1 Torr) at 35 ° C. to give the purified LiFSI product in 90% yield. rice field. In this example, the purified LiFSI product has the following impurities: FSO ₃ ⁻ = 80 ppm, Cl ⁻ = 5 ppm, F ⁻ = 30 ppm, ^SO _4-2 = 50 ppm, and water = 45 ppm.

II. B. 4. Example 4

Purification of LiFSI using dipropylcarbonate (DPC) and dichloromethane: Various levels of impurities in a 500 mL dry flask, here FSO _3- = 200 ppm ^{, Cl-} = 10 ppm ^, F- ⁼ 100 ppm, SO ₄₂ . Crude LiFSI (250 g) containing ⁻ = 100 ppm and water = 100 ppm was collected under a nitrogen atmosphere and cooled to 10 ° C. using a water bath. Dipropyl carbonate (200 g (about 44% by weight)) was added little by little to the flask with stirring, followed by 20 g (about 4.4% by weight) of dichloromethane. The mixture was stirred at room temperature for 1 hour. Insoluble impurities were removed from the mixture by filtration. The filtrate was concentrated under reduced pressure to give a solid, which was treated with anhydrous dichloromethane (250 g) under argon. The mixture is stirred at room temperature for 1 hour, the desired insoluble LiFSI product is isolated by filtration and finally dried in vacuo (less than 0.1 Torr) at 35 ° C. to give the purified LiFSI product in 90% yield. rice field. In this example, the purified LiFSI product had the following impurities: FSO ₃ ⁻ = 30 ppm, Cl ⁻ = 1 ppm, F ⁻ = 11 ppm, ^SO _4-2 = 15 ppm, and water = 30 ppm.

II. B. 5. Example 5

Purification of LiFSI using Methylpropyl Carbonate (MPC) and dichloromethane: Various levels of impurities in a 500 mL dry flask, here FSO ₃ ⁻ = 200 ppm, Cl ⁻ = 10 ppm, F ^{− =} 100 ppm, SO ₄₂ . Crude LiFSI (250 g) containing ⁻ = 100 ppm and water = 100 ppm was collected under a nitrogen atmosphere and cooled to 10 ° C. using a water bath. Methylpropylcarbonate anhydride (MPC) (200 g (about 44.4% by weight)) was added to the flask little by little with stirring, followed by 20 g (about 4.4% by weight) of dichloromethane. The mixture was stirred at room temperature for 1 hour. Insoluble impurities were removed by filtration. The filtrate was concentrated under reduced pressure to give a solid, which was treated with anhydrous dichloromethane (250 g) under argon. The mixture is stirred at room temperature for 1 hour, the desired insoluble LiFSI product is isolated by filtration and finally dried in vacuo (less than 0.1 Torr) at 35 ° C. to give the purified LiFSI product in 91% yield. rice field. In this example, the purified LiFSI product had the following impurities: FSO ₃ ⁻ = 32 ppm, Cl ⁻ = ² ppm, F ⁻ = 12 ppm, SO _4-2 = 22 ppm, and water = 35 ppm.

II. B. 6. Example 6

Purification of LiFSI using ^ethyl acetate and chloroform: various levels of impurities in a 500 mL dry flask, here FSO _3- = 200 ppm ^{, Cl-} = 10 ppm ^, F- = 100 ppm, SO _4-2 = 100 ppm, and. Crude LiFSI (250 g) containing 100 ppm of water was collected under a nitrogen atmosphere and cooled to 10 ° C. using a water bath. Acetic anhydride (150 g (37.5% by weight)) is added little by little to the flask with stirring, followed by 20 g (5% by weight) of anhydrous chloroform. The mixture was stirred at room temperature for 1 hour. Insoluble impurities were removed by filtration. The filtrate was concentrated under reduced pressure to give a solid, which was treated with anhydrous chloroform (250 g) under argon. The mixture is stirred at room temperature for 1 hour, the desired insoluble LiFSI product is isolated by filtration and finally dried in vacuo (less than 0.1 Torr) at 35 ° C. to give the purified LiFSI product in 88% yield. rice field. In this example, the purified LiFSI had the following impurities: FSO ₃ ⁻ = 40 ppm, Cl ⁻ = ² ppm, F ⁻ = 15 ppm, SO _4-2 = 20 ppm, and water = 40 ppm.

II. B. 7. Example 7

Purification of LiFSI using butyl acetate and dichloromethane: Various levels of impurities in a 500 mL dry flask, here FSO _3- = 200 ppm ^{, Cl-} = 10 ppm ^{, F-} = 100 ppm, SO _4-2 = 100 ppm, and. Crude LiFSI (200 g) containing water = 100 ppm was collected under a nitrogen atmosphere and cooled to 10 ° C. using a water bath. Acetic anhydride butyl acetate (150 g (about 43% by weight)) was added little by little to the flask with stirring, followed by addition of 30 g (about 8.6% by weight) of acetic anhydride. The mixture was stirred at room temperature for 1 hour. Insoluble impurities were removed by filtration. The filtrate was concentrated under reduced pressure to give a solid, which was treated with anhydrous dichloromethane (250 g) under argon. The mixture is stirred at room temperature for 1 hour, the desired insoluble LiFSI product is isolated by filtration and finally dried in vacuo (less than 0.1 Torr) at 35 ° C. to give the purified LiFSI product in 89% yield. rice field. In this example, the purified LiFSI product had the following impurities: FSO ₃ ⁻ = 38 ppm, Cl ⁻ = 1 ppm, F ⁻ = 15 ppm, ^SO _4-2 = 22 ppm, and water = 40 ppm.

II. B. 8. Example 8

Purification of LiFSI using acetonitrile and dichloromethane: Various levels of impurities in a 500 mL dry flask, here FSO _3- = 200 ppm ^{, Cl-} = 10 ppm ^{, F-} = 100 ppm, SO _4-2 = 100 ppm, and water. Crude LiFSI (200 g) containing = 100 ppm was collected under a nitrogen atmosphere and cooled to 10 ° C. in a water bath. Acetic anhydride butyl acetate (150 g (about 43% by weight)) was added little by little with stirring, followed by 30 g (about 8.6% by weight) of acetic anhydride. The mixture was stirred at room temperature for 1 hour. Insoluble impurities were removed by filtration. The filtrate was concentrated under reduced pressure to give a solid, which was treated with anhydrous dichloromethane (250 g) under argon. The mixture is stirred at room temperature for 1 hour, the desired insoluble LiFSI product is isolated by filtration and finally dried in vacuo (less than 0.1 Torr) at 35 ° C. to give the purified LiFSI product in 90% yield. rice field. In this example, the purified LiFSI had the following impurities: FSO ₃ ⁻ = 50 ppm, Cl ⁻ = 5 ppm, F ⁻ = 20 ppm, ^SO _4-2 = 22 ppm, and water = 38 ppm.

II. C. Exemplary Purified LiFSI Products

Purified LiFSI products obtained using any of the aforementioned purification methods, such as either the single-pass purification method disclosed above or the multipath method 300 of FIG. 3, were removed by the purification method as an exception. Can have low levels of target impurities. For example, the purified LiFSI products of the present disclosure in which at least one of the target impurities is LiCl can have LiCl (Cl ⁻ ) levels of 10 ppm or less or less than 1 ppm. As another example, the purified LiFSI products of the present disclosure containing at least one of the target impurities LiF (F ⁻ ), FSO ₃ Li (FSO ₃ ⁻ ), and LiCl (Cl ⁻ ) are F ⁻ of about 80 ppm or less. , FSO _3- of about 100 ppm or less, ^Cl- of less than about 100 ppm, F- of about 40 ppm or less, FSO _3- of about 250 ppm or less ^{, and Cl-} of about 20 ppm or less ^, or F- of about 200 ppm or less ^, about 100 ppm It can have the following FSO ₃ ^- and ^Cl- of about 30 ppm or less. In another example, starting from a crude LiFSI with an F- of about 200 ppm or more ^, an FSO _3- of about 200 ppm or more, ^{and / or a Cl- of} about 200 ppm or more, each of the above-mentioned levels of impurities and combinations thereof. Can be achieved. In yet another example, the purified ^LiFSI products of the present disclosure in which at least one of the target impurities is SO _4-2 can have SO _4-2 ^levels of about 280 ppm or less, or about 100 ppm or less. In a further example, each of the aforementioned SO _4-2 levels can be achieved starting with a crude ^LiFSI having an ^SO _4-2 of about 500 ppm or higher. A useful feature of the purification methods of the present disclosure is the ability to simultaneously remove different types of target impurities in each (or only) pass-through of the method.

II. D. Illustrative Use of Purified LiFSI Product

As mentioned above, purified LiFSI products can be used to produce purified LiFSI-based electrolytes, among other things, for electrochemical devices. Here, the purity of the purified electrolyte comes from the fact that the purified LiFSI product was purified by one or more of the methods disclosed herein. Such purified electrolytes may vary, such as mixing the purified LiFSI product (salt) of the present disclosure with one or more solvents, one or more diluents, and / or one or more additives. Can be produced using any of the above methods, and solvents, diluents, and additives may be known in the art.

Section I. D. As mentioned above in 2, FIG. 2 shows an electrochemical device 200 made according to the aspects of the present disclosure. In this example, the purified LiFSI-based electrolyte 216A produced in the present disclosure may be used instead of the reactive solvent-reduced LiFSI-based electrolyte 216 described above. As mentioned above, for the purified LiFSI-based electrolyte 216A, the advantage of using the purified LiFSI-based electrolyte of the present disclosure purified to remove non-solvent impurities is that impurities that may be present in the LiFSI-based electrolyte such as synthetic impurities can be removed. , To a level acceptable for use in the electrochemical device 200 (eg, satisfying one or more impurity level specifications). Examples of purified LiFSI products (salts) and examples of their various impurities at low levels that can be used to produce the purified LiFSI-based electrolyte 216A are described above.

In one example, the purified LiFSI-based electrolyte 216A can be produced starting from crude LiFSI, which is then purified using any one or more of the purification methods described herein. , Produces purified LiFSI products with suitable low levels of one or more target impurities. In another example, the crude HFSI can be first synthesized, for example by any of the above synthesis methods, and the crude HFSI can be used to synthesize the crude LiFSI. The crude LiFSI can be purified using one or more of the purification methods described herein to produce a purified LiFSI product (salt). The purified LiFSI product is then used to add, for example, one or more solvents, one or more diluents, and / or one or more additives that improve the performance of the electrochemical device 200. By doing so, the purified LiFSI-based electrolyte 216A can be produced. The purified LiFSI-based electrolyte 216A can then be added to the electrochemical device 200 and then the container 220 can be sealed.

III. Synthesis of LiFSI using an aqueous neutralization process

This section deals with methods of synthesizing LiFSI using an aqueous neutralization process, the LiFSI salts produced thereby, and the use of such LiFSI salts.

III. A. Exemplary Aqueous Neutralization Synthesis Methods

In the present disclosure, the LiFSI product (eg, salt) is first charged with purified hydrogen bis (fluorosulfonyl) imide (HFSI) in deionized water to obtain an aqueous solution of LiFSI (Li ₂ CO ₃ ). Alternatively, it can be obtained by neutralizing with one or more lithium bases such as lithium hydroxide (LiOH). Insoluble impurities such as Li ₂ SO ₄ , LiCl, LiF, and LiFSO ₃ described above can be removed by filtration. Water can be removed, for example, in vacuum. Purified HFSI for use in this process is, for example, filed September 13, 2019, which is incorporated herein by reference with reference to the teaching of purification of HFSI, "Purified Hydrogen Bis (fluorosulfonyl) imide (HFSI) Products). , Methods of Purifying Crystal HFSI, and Uses of Purified HFSI Products (purified hydrogen bis (fluorosulfonyl) imide (HFSI) product, method for purifying crude HFSI, and use of purified HFSI product). As described in / 570,131, it can be obtained by any suitable method such as purifying HFSI by crystallization. Experimental examples of synthesizing LiFSI using aqueous neutralization and their corresponding resulting impurity levels are described in Section III. C. 1, III. C. 4, and III. C. 6 Examples 1, 4, and 6 are described below.

III. B. Exemplary purification of LiFSI salt produced using aqueous neutralization

Section III above. Purify the crude LiFSI product produced using the aqueous neutralization process of A to remove one or more target impurities, such as any synthetic impurities remaining after removing water from the synthetic LiFSI product. be able to. In addition or alternatively, Section III. The crude LiFSI product produced using the aqueous neutralization process of A can be purified to remove and / or replace the reactive solvent (s) such as water present in the LiFSI product. can. This section briefly describes an example of purification of crude LiFSI produced using an aqueous neutralization process.

III. B. 1. 1. Removal of non-reactive solvent impurities

Section II. As mentioned above in A, Section III. The crude LiFSI containing the crude LiFSI product produced using the aqueous neutralization process described in A can be purified to remove the target impurities. Such target impurities can remain in any synthetic salt that may remain after filtration of such insoluble salts and removal of water, eg, Section III. A may include Li ₂ SO ₄ , LiCl, LiF and LiFSO ₃ described above. As an example, after removing water from the aqueous neutralization process, the resulting LiFSI product (where "crude LiFSI" for the context of purification according to Section II.A above) is referred to Section II. It can be subjected to the above-mentioned purification in A. The resulting purified LiFSI product has reduced levels of targeted impurities (s). Experimental examples of such purification and corresponding target impurity levels are described in III. C. 2, III. C. 5 and III. C. Section 7, Examples 2, 5 and 7 are described below. When preparing an electrolyte using purified LiFSI products, the solvent (s) used in the purification process is one or more of the solvents (s) used in the final electrolyte. Note that there may be more than one. In this way, the solvent (s) remaining from the purification process becomes part of the final electrolyte solvent (s).

III. B. 2. 2. Removal / replacement of reactive solvent (s)

Section I. As mentioned above in A, Section III. The crude LiFSI containing the crude LiFSI product produced using the aqueous neutralization process described in A can be purified to remove / replace one or more reactive solvents. Such reactive solvents are described in Section III. It may contain any residual water that was not removed in the water removal step described above in A. In addition, one or more reactive solvents targeted for removal and / or replacement with one or more non-reactive solvents are described in Section III. B. 1 and II. A. As described in, may be present after purification to remove non-reactive solvent impurities. As an example, after removing water from the aqueous neutralization process, the resulting LiFSI product (where "crude LiFSI" for the context of purification by Section I.A. above) is referred to Section I. A. Can be used for the purification described in 1. As another example, Section III. Purification of LiFSI synthesized by the aqueous neutralization process of A (see Section III.B.1 above) followed by the resulting purified LiFSI product (where, in the context of purification by Section I.A. above). Section I. It can be subjected to the above-mentioned purification in A. In either case, the resulting purified LiFSI product will have reduced levels of the targeted reactive solvent (s). Experimental examples of such purification and corresponding target impurity levels are described in Section III. C. It is described below in Example 3 of 3. When preparing an electrolyte using purified LiFSI products, the solvent (s) used in the reactive solvent removal / substitution process is that of the solvent (s) used in the final electrolyte. Note that one or more of them may be used. In this way, the solvent (s) remaining from the removal / replacement process becomes part of the final electrolyte solvent (s).

The crude LiFSI thus obtained can be purified to remove one or more target impurities such as synthetic impurities and / or other impurities present in the crude LiFSI. In some embodiments, crude LiFSI is mixed with a minimum amount of one or more first anhydrous organic solvents in which LiFSI is soluble (eg, from about 50% to about 70% by weight) to Li ₂ . Impurities such as SO ₄ , LiCl, LiF, and LiFSO ₃ can be further insoluble. Anhydrous organic solvents that can be used for this purpose include dimethylcarbonate (DMC), diethylcarbonate (DEC), ethylmethylcarbonate (EMC), propylmethylcarbonate (PMC), and ethylenecarbonate (EC). , Fluoroethylene carbonate (FEC), transbutylene carbonate, acetonitrile, malononitrile, adiponitrile, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate (MP) and ethyl propionate (EP).

To the solution is added one or more second anhydrous organic solvents insoluble in LiFSI (eg, in an amount of about 2% to 10% by weight). Organic solvents that can be used for this include dichloromethane, dichloroethane, chloroform, pentane, hexane, heptane, octane, nonane, decane, undecane and dodecane.

In some embodiments, the impurities remain precipitated after the addition of one or more second anhydrous organic solvents and can be removed by filtration. The filtrate can be recovered and the solvent (s) removed from it to give a solid. In some examples, the solvent (s) is removed in vacuum (eg, less than about 0.1 Torr) at a controlled temperature (eg, less than about 40 ° C.) to give a solid. The resulting solid can then be treated with at least one third anhydrous organic solvent insoluble in LiFSI. Examples of the organic solvent that can be used for this include dichloromethane, dichloroethane, chloroform, pentane, hexane, heptane, octane, nonane, decane, undecane, and dodecane. The precipitated LiFSI salt product can then be isolated by filtration in an inert environment (eg, argon gas) and dried, for example, in vacuum (eg, less than about 0.1 Torr) at less than about 40 ° C. can.

For illustration purposes, Table II below provides detailed examples of impurities and their solubility in dimethylcarbonate and dichloromethane.

As seen in Table II above, the solubility of LiFSI in dimethylcarbonate is greater than 90% and is insoluble in dichloromethane. On the other hand, the solubility of impurities such as LiF, LiCl and Li ₂ SO ₄ is less than 13 ppm in dimethyl carbonate under anhydrous conditions.

Based on these soluble / insoluble properties, dimethylcarbonate and dichloromethane solvents are selected, in one example, for the process of purifying the crude LiFSI produced using the aqueous neutralization process described above. In this example, crude LiFSI containing the impurities reported in Table II above is mixed in dimethylcarbonate at a concentration of 50% to 75% at about 25 ° C. (here room temperature), stirred at room temperature, followed by About 2% by weight to about 10% by weight of dichloromethane was added to precipitate impurities. Impurities were removed by filtration and the filtrate was concentrated to dryness. The resulting dry solid was treated with anhydrous dichloromethane to remove HF impurities where LiFSI was insoluble in dichloromethane while soluble in dichloromethane.

The ultra-purity LiFSI salt product was recovered by filtration and finally dried under reduced pressure (eg, less than about 0.1 Torr) and at a temperature of less than about 40 ° C. to give a white free-flowing powder. This can optionally be stored in a dry polytetrafluoroethylene (PTFE) container.

In view of the above, in some embodiments, the present disclosure describes a process of producing an ultra-high purity lithium bis (fluorosulfonyl) imide (LiFSI) for lithium metal anode battery applications. This process involves purifying hydrogen bis (fluorosulfonyl) imide (HFSI) in less than about 40% deionized water below about 25 ° C., lithium carbonate (Li ₂ CO ₃ ) or lithium hydroxide (LiOH). Includes base neutralization. Insoluble impurities such as Li ₂ SO ₄ , LiCl, LiF, and LiFSO ₃ can be removed by filtration. Water can be removed in vacuum (eg, less than about 0.1 Torr) at a suitable temperature, such as less than about 35 ° C.

The resulting crude LiFSI is mixed with a minimum amount (eg, 50% to 70% by weight) of an anhydrous organic solvent in which LiFSI is soluble (eg, dimethylcarbonate (DMC) or ethylmethylcarbonate (EMC)). Thus, impurities such as LiCl, LiF, Li ₂ SO4 and / or LiFSO ₃ can be further insoluble. In some embodiments, the temperature of the solution is maintained below about 25 ° C. The solution can then be filtered in an inert atmosphere to remove impurities.

This process can further include removing the organic solvent from the filtrate to give a solid mass and treating the solid with an organic solvent (eg, dichloromethane) in which lithium bis (fluorosulfonyl) imide is insoluble. The insoluble LiFSI can be isolated by filtering in an inert atmosphere and flushing a trace amount of organic solvent with dry argon and / or nitrogen gas. The resulting LiFSI is aspirated (eg, less than about 0.1 Torr) at a suitable temperature (eg, less than about 35 ° C.) for a suitable period (eg, at least 24 hours) to obtain an ultra-high purity anhydrous LiFSI salt product. It can be obtained as a white free-flowing powder, which can optionally be stored in a dry polytetrafluoroethylene (PTFE) container.

In some embodiments, LiFSI salt production synthesized by the disclosed aqueous neutralization method and purified to remove non-reactive solvent impurities and purified to remove / replace the reactive solvent (s). The material can be produced in an electrolyte solution and used in a lithium metal battery, i.e. a battery having a lithium metal anode. Section III below. C. As shown in Example 8 of 8, this "ultra-high purity" LiFSI salt product and the electrolyte produced using it are the stocks of Nippon Catalyst Co., Ltd. (Japan), Shanghai Capchem Co., Ltd. (China), and Shang Hai Shengzhan Chemifish. It showed much better cycle life compared to LiFSI from commercial sources such as the company (China) and Oakwood Products (USA).

In the present disclosure, the process for producing ultra-high purity LiFSI may be a continuous process from the start of neutralization to the end of production of ultra-high purity LiFSI product.

III. C. example

The embodiments of the present disclosure will be further described by the following examples, but it will be appreciated that these examples are included solely for illustrative purposes and are not intended to limit the scope of the present disclosure. Unless otherwise stated, all chemicals used were of high purity and were obtained from commercial sources. Strict precautions were taken to eliminate moisture during the process and the reaction was carried out in a well-ventilated hood.

III. C. 1. 1. Example 1

Neutralization of Purified HFSI with Lithium Carbonate in Deionized Water: In a 1000 mL flask, 1 mol of lithium carbonate (Li ₂ CO ₃ ) was mixed with 40 g of deionized water. The suspension is cooled in an ice water bath below 20 ° C. 2 mol of hydrogen bis (fluorosulfonyl) imide (HFSI) was taken in a dropping funnel and dropped into a stirred lithium carbonate suspension slurry. After the addition of HFSI was complete, the water bath was removed and the solution was stirred at room temperature for 0.5 hours. Insoluble impurities were removed by filtration. The resulting clear filtrate was concentrated in vacuum below 0.1 Torr and below 35 ° C. to give crude LiFSI in quantitative yield, which was used in Example 2 below.

III. C. 2. 2. Example 2

Treatment of crude LiFSI with dimethyl carbonate: The crude LiFSI obtained in Example 1 above was used in Example 2. The flask was placed in a nitrogen atmosphere and cooled to 10 ° C. using a water bath. Add anhydrous dimethyl carbonate (DMC) (300 g) little by little with stirring, followed by adding 50 g of anhydrous dichloromethane. The mixture was stirred at room temperature for 1 hour. Insoluble impurities were removed by filtration. The filtrate was concentrated under reduced pressure to give a solid, which was treated with anhydrous dichloromethane (200 g) under argon. The mixture was stirred at room temperature for 1 hour, the desired insoluble LiFSI product was isolated by filtration and finally dried in vacuo (<0.1 Torr) below 35 ° C. to give LiFSI in 95% yield. The obtained LiFSI product had impurities FSO ₃ ⁻ = 100 ppm, Cl ⁻ = 1 ppm, F ⁻ = 40 ^ppm , SO _4-2- = 40 ppm, and water = 50 ppm.

III. C. 3. 3. Example 3

Treatment of LiFSI with dimethyl carbonate: The LiFSI obtained in Example 2 was used in this Example 3. 200 g of LiFSI obtained in Example 2 above was placed in a glove box having a measured moisture value of less than 1 ppm and transferred to a 1 L dry flask. The flask was removed and cooled in a water bath below 15 ° C. LiFSI was mixed with 100 g of anhydrous dimethyl carbonate containing less than 5 ppm of water. Insoluble impurities were removed by filtration under argon and the filtrate was collected in a 1 L flask. The filtrate was concentrated under reduced pressure below 0.1 Torr to give a solid. The solid was treated with anhydrous dichloromethane (150 g) under argon and the solution was stirred at room temperature for 1 hour. The desired insoluble LiFSI product was isolated by filtration and dried in vacuo (<0.1 Torr) at 30 ° C. to give a white free fluid powder LiFSI in 95% yield. When the obtained LiFSI product was analyzed by ion chromatography, impurities F- = 1.3 ppm, ^Cl- = 0.18 ppm, and SO _4-2 = ^4.4 ppm were found. When analyzed by Karl Fischer, the water content was 1.3 ppm. Based on proton NMR, it has 0.2% dimethyl carbonate. Since dimethyl carbonate is non-reactive with lithium metals in electrochemical devices, it was used in the test electrolyte formulation. This salt electrolyte formulation was used in a lithium metal battery test.

III. C. 3. 3. i. Comparative example

Comparative example of LiFSI salt obtained from Capchem (China): By visual inspection, the color of the Capchem LiFSI salt was lower in white than the LiFSI obtained in this Example 3. The ^Capchem LiFSI salt had the following impurities: water = 15 ppm, F ⁻ = 1 ppm, Cl ⁻ = 1 ppm, and SO _4-2 = 5.98 ppm. Based on proton NMR, the Capchem LiFSI salt contains 0.3% ethanol, which is incompatible with lithium metals due to its reactivity. Ethanol reacts with the lithium metal by the following reaction to form an undesired by-product.
2Li + 2CH ₃ CH ₂ OH = 2CH ₃ CH ₂ OLi + H ₂

III. C. 4 Example 4

Neutralization of purified HFSI in water with dionized water using lithium hydroxide: In a 1 L flask, lithium hydroxide (LiOH) (2 mol) was dissolved in 40 g of deionized water. The suspension was cooled in an ice water bath below 20 ° C. 2 mol of HFSI was placed in a dropping funnel and added dropwise to the stirred lithium carbonate suspension slurry. After the addition of HFSI was complete, the water bath was removed and the solution was stirred at room temperature for 0.5 hours. Insoluble impurities were removed by filtration. The resulting clear filtrate was concentrated in vacuum below 0.1 Torr and below 35 ° C. to give crude LiFSI in quantitative yield, which was used in Example 5 below.

III. C. 5 example 5

Treatment of crude LiFSI with dimethyl carbonate (DMC): The crude LiFSI obtained in Example 4 above was used in Example 5. The flask was placed in a nitrogen atmosphere and cooled to 10 ° C. using a water bath. Anhydrous dimethylcarbonate (DMC) (300 g) was added little by little with stirring, followed by 50 g of anhydrous dichloromethane. The solution was stirred at room temperature for 1 hour. Insoluble impurities were removed by filtration. The filtrate was concentrated under reduced pressure to give a solid, which was treated with anhydrous dichloromethane (200 g) under argon. The mixture was stirred at room temperature for 1 hour, the desired insoluble LiFSI product was isolated by filtration and finally dried in vacuo (<0.1 Torr) below 35 ° C. to give LiFSI in 92% yield. The obtained purified LiFSI had impurities FSO ₃ ⁻ = 100 ppm, Cl ⁻ = 1 ppm, F ⁻ = 45 ppm, ^SO _4-2 = 35 ppm, and water = 60 ppm.

III. C. 6. Example 6

Neutralization of Purified HFSI with Lithium Carbonate in Dionized Water In a 1 L flask, 0.5 mol of lithium carbonate (Li ₂ CO ₃ ) was mixed with 20 g of deionized water. The suspension was cooled in an ice water bath below 20 ° C. 1 mol of HFSI was taken into a dropping funnel and dropped into a stirred lithium carbonate suspension slurry. After the addition of HFSI was complete, the water bath was removed and the solution was stirred at room temperature for 0.5 hours. Insoluble impurities were removed by filtration. The resulting clear filtrate was concentrated in vacuum below 0.1 Torr and below 35 ° C. to give crude LiFSI in quantitative yield, which was used in Example 7 below.

III. C. 7. Example 7

Treatment of Crude LiFSI with Ethyl Methyl Carbonate: The crude LiFSI obtained in Example 6 was used in this Example 7. The flask was cooled in a nitrogen atmosphere and cooled to 10 ° C. using a water bath. Ethylmethylcarbonate anhydrous (EMC) (100 g) was added in small portions with stirring, followed by 50 g of dichloromethane. The solution was stirred at room temperature for 1 hour. Insoluble impurities were removed by filtration. The filtrate was concentrated under reduced pressure to give a solid, which was treated with anhydrous dichloromethane (200 g) under argon. This was stirred at room temperature for 1 hour, the desired insoluble LiFSI product was isolated by filtration and finally dried in vacuo (less than 0.1 Torr) at 35 ° C. to give LiFSI in 90% yield. The purified LiFSI product had impurities FSO ₃ ⁻ = 100 ppm, Cl ⁻ = 0.5 ppm, F ⁻ = 20 ppm, ^SO _4-2 = 20 ppm, and water = 46 ppm.

III. C. 8. Example 8

Comparison of use and results of the ultra-high purity LiFSI of Example 7 above with commercially available LiFSI in lithium metal anode batteries: Battery grade electrochemically stable organic solvents (dimethylcarbonate, ethylmethylcarbonate, dimethoxymethane, Diethoxyethane, etc.) was used to produce the obtained LiFSI electrolytes of the present disclosure, and comparative studies were performed using various commercially available LiFSI salts and corresponding electrolytes under similar conditions.

The ultra-purity LiFSI product produced by the present disclosure provided the maximum number of cycles in a lithium metal anode battery when compared to LiFSI commercially available from Capchem, Nippon Shokubai, Chemfish and Oakwood. Examples of better performance of the ultra-purity LiFSI products of the present disclosure can be found in FIGS. 4A and 4B, respectively, where one of the electrolytes is the aqueous neutralization of Section III of the present disclosure. The ultra-purity LiFSI salt product produced using the synthetic method (upper line of each of FIGS. 4A and 4B, "SES LiFSI") is used and the other electrolyte is Capchem (FIG. 4A). And the discharge capacity for two non-aqueous electrolytes with the same concentration and the same chemicals, except that they were produced using LiFSI salts supplied from each lower line of FIG. 4B, "CapChem LiFSI"). The number of cycles and the capacity retention rate are shown.

The battery used in the experiment for which the graphs of FIGS. 4A and 4B were obtained was a pouch cell with a three-layer cathode and a four-layer anode. Each electrolyte was composed of 2.0 mol LiFSI in 1 liter of solvent mixture. Except for the source of LiFSI salt, all other battery design factors and test conditions were the same. Batteries were cycled under 0.2 C rate charge and 1.0 C rate discharge. As shown in FIGS. 4A and 4B, batteries with LiFSI from both sources delivered the same capacity in the initial cycle. However, batteries with electrolytes produced using the ultra-purity LiFSI salt of the present disclosure showed better capacity retention than batteries with Capchem LiFSI salt after about 100 cycles. This data shows the advantage of stability of ultra-purity LiFSI salt over Capchem LiSFI salt under long cycle conditions with lithium metal anode rechargeable battery.

III. D. Illustrative use of ultra-high purity LiFSI

As mentioned above, the ultra-purity LiFSI salt product produced by the process described above may be particularly beneficial for lithium metal batteries with lithium metal anodes. In this regard, the ultra-purity LiFSI product is used as the electrolyte if at least some of the solvent can remain in the ultra-purity LiFSI product and is reactive with the lithium metal. It is important to select a suitable anhydrous organic solvent for the treatment as it can interfere with the performance of lithium metal batteries. In fact, the residual solvent in the Capchem LiFSI salt such as ethanol reported in Example 3 above has very high performance of the Capchem LiFSI salt, as evidenced by Example 8 above (Sections III.C.8). This may be the reason why it was inferior to the performance of the purity LiFSI salt product. As mentioned in Example 3 above (Sections III.C.3), ethanol is reactive with the lithium metal present on / in the anode of the lithium metal battery.

Therefore, when producing the ultra-high purity LiFSI salt product for lithium metal batteries according to the present disclosure, the solvent selected must be a solvent known to be non-reactive with lithium metals. In this way, any solvent that can remain in the final dry solid ultra-purity LiFSI salt product (eg, by coordination with LiFSI or by other methods) is non-reactive with the lithium metal. It is property and therefore is unlikely to adversely affect the performance of lithium metal batteries in which ultra-high purity LiFSI salt products are used. As used herein and in the appended claims, the term "non-reactive" is used to modify "solvents" or "solvents" unless otherwise stated. If so, it is meant that the solvent (s) is non-reactive with the lithium metal. Conversely, unless otherwise stated, the term "reactive" as used herein and in the appended claims to modify "solvents" or "solvents" refers to solvents (solvents). It shall mean that one or more) is reactive with the lithium metal. As will be appreciated by those skilled in the art, "reactivity" in this context refers to the magnitude of the reduction potential of a lithium metal with respect to a solvent (s). Reactive solvents are also not effective in passivating lithium metals, but non-reactive solvents are either non-reactive with lithium metals or effectively passivated lithium metals. That is, it is stable in terms of speed.

In some embodiments particularly suitable for use in lithium metal batteries, during the final ultra-purity LiFSI salt product (ie, after complete treatment of the process and / or purification disclosed herein). The amount of residual reactive solvent is preferably less than about 500 ppm, more preferably less than about 100 ppm, most preferably less than about 50 ppm. In some embodiments, depending on the entire cathode-electrolyte-anode system utilized, the non-reactive solvent remaining in the final LiFSI salt product adversely affects battery performance over the removed reactive solvent. May not be given. In such embodiments, the amount of non-reactive solvent (s) remaining in the final LiFSI salt product is preferably less than about 3000 ppm, more preferably less than about 2000 ppm, most preferably less than about 500 ppm. be. In some embodiments, the non-reactive solvent (s) used also, depending on the entire cathode-electrolyte-anode system utilized, can improve and / or ionize SEI formation within the electrolyte. Battery performance is the non-reactive solvent that remains in the final LiFSI salt product, such as when deliberately selected to provide one or more benefits to the cathode-electrolyte-anode system, such as improved properties. May be beneficial to. In some embodiments, additional amounts of the non-reactive solvent (s) used during purification and / or removal / replacement of the reactive solvent are added as needed to produce the final electrolyte. can do. In embodiments where the non-reactive solvent (s) used to treat LiFSI is beneficial to battery performance, the amount of non-reactive solvent remaining may be greater than 2000 ppm or greater than 3000 ppm. .. When purification is performed using only non-reactive solvents for all purification steps, the final LiFSI salt product typically has at least about 100 ppm of non-reactive solvent (s). It typically has about 100 ppm or less of the reactive solvent (s). Examples of non-reactive solvents that may be suitable to remain in the LiFSI salt after removal / substitution of the reactive solvent (s) according to the present disclosure include hexane, hydrocarbons, toluene, xylene, aromatic solvents, esters. And nitriles.

Section I. D. As mentioned above in 2, FIG. 2 shows an electrochemical device 200 made according to the aspects of the present disclosure. In this example, the ultra-high purity LiFSI-based electrolyte 216B produced by Section III may be used instead of the reactive solvent-reduced LiFSI-based electrolyte 216 described above. As mentioned above, the advantage of using the ultra-high purity LiFSI-based electrolyte of the present disclosure for the purified LiFSI-based electrolyte 216B is that it contains impurities that may be present in the LiFSI-based electrolyte, such as synthetic impurities and reactive solvents (s). , To a level acceptable for use in the electrochemical device 200 (eg, satisfying one or more impurity level specifications). Examples of ultra-high purity LiFSI products (salts) that can be used to produce the purified LiFSI-based electrolyte 216B and examples of their various impurities at low levels are described above. The ultra-purity LiFSI product is then used, for example, to improve the performance of the electrochemical device 200, for example, one or more solvents, one or more diluents, and / or one or more additives. Can be added to produce an ultra-high purity LiFSI-based electrolyte 216B. The ultra-high purity LiFSI-based electrolyte 216B can then be added to the electrochemical device 200 and then the container 220 can be sealed.

Given the desire to remove many reactive solvents (s) from the final ultra-purity LiFSI salt product in lithium metal battery applications, the purification methods disclosed herein are to purify. It can be enhanced by the selection of one or more solvents known to be non-reactive to the lithium metal for the appropriate step (s) of the method used to carry out.

In some embodiments, the present disclosure relates to a method for producing a reactive solvent-reduced lithium bis (fluorosulfonyl) imide (LiFSI) product, wherein the method comprises LiFSI and one or more reactive solvents. To provide one crude LiFSI, under inert conditions, contact the first crude LiFSI with at least one first anhydrous organic solvent to provide the first crude LiFSI and one or more reactive solvents. The solubility of LiFSI in at least one first anhydrous organic solvent is at least about 35% below 25 ° C., and the solution is subjected to vacuum to produce at least one. The first anhydrous organic solvent and one or more reactive solvents are removed to obtain a solid mass, and the solid mass is treated with at least one second anhydrous organic solvent insoluble in LiFSI to be insoluble. Producing a moiety-bearing combination, isolating the insoluble moiety in an inert atmosphere, flushing the insoluble moiety with at least one dry inert gas to create a trace amount of at least one second anhydrous organic solvent. Includes removing the flushed insoluble moiety to a pressure of less than about 100 Torr to obtain a reactive solvent-reduced LiFSI product.

In one or more embodiments of the method, providing a first crude LiFSI provides a LiFSI and a second crude LiFSI containing one or more target impurities, under inert conditions. The second crude LiFSI is contacted with at least one third anhydrous organic solvent to produce a solution containing LiFSI and one or more target impurities, wherein at least one first at room temperature. LiFSI is soluble in 3 anhydrous organic solvents and each of the one or more target impurities is substantially insoluble, and at least one fourth anhydrous organic solvent is added to the solution. Precipitating at least one target impurity, wherein each of LiFSI and one or more target impurities is substantially insoluble in at least one fourth anhydrous organic solvent, one or more. Filtering each insoluble portion of the target impurity from the solution to form a filtrate, removing the solvent from the filtrate to obtain a solid mass, the solid mass, at least one in which LiFSI is substantially insoluble. It involves contacting with a fifth anhydrous organic solvent and isolating LiFSI from at least one fifth anhydrous organic solvent to obtain a first crude LiFSI.

In one or more embodiments of the method, the second crude LiFSI has a solubility of at least about 50% at room temperature with respect to at least one third anhydrous organic solvent and is one or more targets. Each of the impurities has a solubility of less than about 20 parts per million (ppm) at room temperature with respect to at least one third anhydrous organic solvent.

In one or more embodiments of the method, contacting the second crude LiFSI with at least one third anhydrous organic solvent causes the second crude LiFSI to have a minimum amount of at least one third. Includes contact with anhydrous organic solvent.

In one or more embodiments of the method, the minimum amount of at least one third anhydrous organic solvent is from about 40% to about 75% by weight of the solution.

In one or more embodiments of the method, adding at least one fourth anhydrous organic solvent to the solution is an amount of at least one fourth anhydrous organic solvent in an amount of about 10% by weight or less of the solution. Including adding in.

In one or more embodiments of the method, contact of the second crude LiFSI with at least one third anhydrous organic solvent is carried out at a temperature of less than about 25 ° C.

In one or more embodiments of the method, the temperature of the solution is controlled during contact between the second crude LiFSI and at least one third anhydrous organic solvent so that the temperature is within about 2 ° C. of the target temperature. Including maintaining in.

In one or more embodiments of the method, filtration is performed in an inert atmosphere.

In one or more embodiments of the method, the inert atmosphere comprises argon gas.

In one or more embodiments of the method, removing the solvent is done in vacuum.

In one or more embodiments of the method, removing the solvent is performed at a pressure of about 0.1 Torr or less.

In one or more embodiments of the method, removal of the solvent is carried out at a temperature below about 40 ° C.

In one or more embodiments of the method, isolating LiFSI comprises filtering the solid form of LiFSI from at least one fifth anhydrous organic solvent.

In one or more embodiments of the method, isolating LiFSI comprises drying the solid LiFSI in vacuo.

In one or more embodiments of the method, drying the solid LiFSI in vacuum comprises drying the solid LiFSI at a pressure of about 0.1 Torr or less.

In one or more embodiments of the method, the one or more target impurities are lithium chloride (LiCl), lithium fluoride (LiF), lithium sulfate (Li ₂ SO ₄ ), lithium fluorosulfate ( FSO ₃ Li ). ), Hydrogen fluoride (HF), and one or more target impurities from the group consisting of fluorosulfuric acid (FSO _3H ).

In one or more embodiments of the method, one or more target impurities contain lithium sulphate (Li ₂ SO ₄ ), and filtering each insoluble portion of one or more target impurities is Li. ₂ Includes simultaneous filtration of insoluble moieties of _SO4 .

In one or more embodiments of the method, the at least one third anhydrous organic solvent is dimethylcarbonate (DMC), diethylcarbonate (DEC), ethylmethylcarbonate (EMC), propylmethylcarbonate. (PMC), Ethyl Carbonate (EC), Fluoroethylene Carbonate (FEC), Transbutylene Carbonate, acetonitrile, Marononitrile, Adiponitrile, Methyl Acetate, Ethyl Acetate, Propyl Acetate, Butyl Acetate, Methyl Propionate (MP), Propion It contains at least one solvent selected from the group consisting of ethyl acetate (EP), methanol, ethanol, propanol and isopropanol.

In one or more embodiments of the method, contacting the second crude LiFSI with at least one third anhydrous organic solvent brings the second crude LiFSI to about 50% by weight to about 75% by weight of the solution. It comprises contacting with at least one third anhydrous organic solvent in an amount by weight%.

In one or more embodiments of the method, adding at least one fourth anhydrous organic solvent to the solution is an amount of at least one fourth anhydrous organic solvent in an amount of about 10% by weight or less of the solution. Including adding in.

In one or more embodiments of the method, the at least one fourth anhydrous organic solvent is selected from the group consisting of dichloromethane, dichloroethane, chloroform, pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane. Contains at least one solvent to be used.

In one or more embodiments of the method, adding at least one fourth anhydrous organic solvent to the solution is an amount of at least one fourth anhydrous organic solvent in an amount of about 10% by weight or less of the solution. Including adding in.

In one or more embodiments of the method, at least one fifth anhydrous organic solvent is selected from the group consisting of dichloromethane, dichloroethane, chloroform, pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane. Contains at least one solvent to be used.

In one or more embodiments of the method, the at least one fourth anhydrous organic solvent is selected from the group consisting of dichloromethane, dichloroethane, chloroform, pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane. Contains at least one solvent to be used.

In one or more embodiments of the method, at least one fifth anhydrous organic solvent is selected from the group consisting of dichloromethane, dichloroethane, chloroform, pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane. Contains at least one solvent to be used.

In one or more embodiments of the method, placing the first crude LiFSI in a dry atmosphere in a container that does not substantially react with free fluorine, and storing the container at a temperature below about 25 ° C. Further included.

In one or more embodiments of the method, the one or more target impurities are by-products of the process of synthesizing LiFSI in the second crude LiFSI.

In one or more embodiments of the method, the first crude LiFSI comprises 10 parts per million (ppm) or less of LiCl.

In one or more embodiments of the method, the first crude LiFSI contains less than 1 ppm LiCl.

In one or more embodiments of the method, the first crude LiFSI contains about 500 parts per million (ppm) or less FSO ₃ Li, about 100 ppm or less LiCl, and about 150 ppm or less LiF. ..

In one or more embodiments of the method, providing a second crude LiFSI comprises synthesizing a second crude LiFSI using an aqueous neutralization process.

In one or more embodiments of the method, providing the first crude LiFSI comprises synthesizing the first crude LiFSI using an aqueous neutralization process.

In one or more embodiments of the method, the reactive solvent-reduced LiFSI product is a salt of an electrolyte for a lithium metal battery, the method selecting each of at least one first anhydrous organic solvent. Further, it includes improving the performance of the lithium ion battery.

One or more embodiments of the method further include selecting each of at least one second anhydrous organic solvent to improve the performance of the lithium ion battery.

In one or more embodiments of the method, the reactive solvent-reduced LiFSI product is a salt of the electrolyte containing an additive solvent and at least one of the first anhydrous solvents is an additive. Same as solvent.

In some embodiments, the present disclosure relates to a method of making an electrochemical device, wherein the method treats a lithium bis (fluorosulfonyl) imide (LiFSI) salt using any of the methods listed herein. Provided an electrochemical device structure comprising producing a purified LiFSI salt, compounding an electrolyte using the purified LiFSI salt, a positive electrode, a negative electrode separated from the positive electrode, and a volume extending between the positive electrode and the negative electrode. And if an electrolyte is present, it involves allowing ions in the electrolyte to move between the positive and negative electrodes, and adding the electrolyte to the volume.

In one or more embodiments of the method, the electrochemical device is an electrochemical cell and the electrochemical device structure further comprises a separator disposed within the volume.

In one or more embodiments of the method, the electrochemical battery is a lithium ion battery.

In one or more embodiments of the method, the electrochemical battery is a lithium metal battery.

In one or more embodiments of the method, the electrochemical device is a supercapacitor.

In some embodiments, the present disclosure comprises a positive electrode, a negative electrode separated from the positive electrode, a porous dielectric separator located between the positive electrode and the negative electrode, and at least the electrolyte contained within the porous dielectric separator. It relates to an electrochemical device produced using a LiFSI salt produced using any one of the methods described herein.

In one or more embodiments of the electrochemical device, the electrochemical device is a lithium battery.

In one or more embodiments of the electrochemical device, the electrochemical device is a lithium metal secondary battery.

In one or more embodiments of the electrochemical device, the electrochemical device is a supercapacitor.

The above is a detailed description of an exemplary embodiment of the invention. The terms "at least one of X, Y and Z" and "one of X, Y, and Z, unless expressly specified or otherwise indicated in this specification and the claims attached herein. A conjunctive language, such as used in one or more, means that each item in the conjunctive list is any number except all other items in the list, or any or all others in the conjunctive list. It should be noted that it can be present in any number in combination with the item of, and is interpreted to mean that each may be present in any number. Applying this general rule, the conjunctive phrase in the above example where the conjunctive list consists of X, Y, and Z is one or more of X, one or more of Y, of Z. One or more of, one or more of X and one or more of Y, one or more of Y and one or more of Z, one or more of X And one or more of Z, and one or more of X, one or more of Y and one or more of Z, respectively.

Various modifications and additions can be made without departing from the spirit and scope of the present invention. Each feature of the various embodiments described above can be combined with the features of other described embodiments as needed to provide a combination of numerous features in the relevant novel embodiments. Further, although the above describes some separate embodiments, those described herein are merely exemplary of the application of the principles of the invention. Further, certain methods herein can be illustrated and / or described as being performed in a particular order, the order of which is highly diverse within one of ordinary skill in the art to achieve aspects of the present disclosure. Is. Therefore, this description is intended to be construed as an example only and is not intended to limit the scope of the invention.

An exemplary embodiment is disclosed above and shown in the accompanying drawings. It will be appreciated by those skilled in the art that various modifications, omissions, and additions may be made to those specifically disclosed herein without departing from the spirit and scope of the invention. There will be.

Claims (30)

A method for producing a reactive solvent-reduced lithium bis (fluorosulfonyl) imide (LiFSI) product.
To provide a first crude LiFSI containing LiFSI and one or more reactive solvents.
Under inert conditions, the first crude LiFSI is contacted with at least one first anhydrous organic solvent to produce a solution containing the first crude LiFSI and the one or more reactive solvents. That is, the solubility of the LiFSI in the at least one first anhydrous organic solvent is at least about 35% below 25 ° C.
The solution is evacuated to remove the at least one anhydrous organic solvent and the one or more reactive solvents to obtain a solid mass.
The solid mass is treated with at least one second anhydrous organic solvent in which the LiFSI is insoluble to produce a combination having an insoluble moiety.
Isolating the insoluble moiety in an inert atmosphere and
Flushing the insoluble moiety with at least one dry inert gas to remove trace amounts of the at least one second anhydrous organic solvent.
A method comprising subjecting the flushed insoluble moiety to a pressure of less than about 100 Torr to obtain the reactive solvent-reduced LiFSI product. Contacting the first crude LiFSI with at least one first anhydrous organic solvent causes the first crude LiFSI to be in the range of about 30% by weight to about 50% by weight with respect to the solution. The method of claim 1, comprising contacting with an amount of the at least one anhydrous organic solvent. The method of claim 2, wherein the at least one anhydrous organic solvent is selected from the group consisting of organic carbonates, nitriles, alkyl acetates and alkyl propionates. The at least one first anhydrous organic solvent is dimethylcarbonate (DMC), diethylcarbonate (DEC), ethylmethylcarbonate (EMC), propylmethylcarbonate (PMC), ethylenecarbonate (EC), and the like. Selected from the group consisting of fluoroethylene carbonate (FEC), transbutylene carbonate, acetonitrile, malononitrile, adiponitrile, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate (MP) and ethyl propionate (EP). The method according to claim 2. The method of claim 4, wherein the at least one anhydrous organic solvent comprises DMC. The method of claim 1, wherein the at least one anhydrous organic solvent is selected from the group consisting of organic carbonates, nitriles, alkyl acetates and alkyl propionates. Treatment of the solid mass with at least one second anhydrous organic solvent comprises the group consisting of dichloromethane, dichloroethane, chloroform, pentane, hexane, heptane, octane, nonane, decane, undecane, and dodecane. The method of claim 1, comprising treating with at least one second anhydrous organic solvent of choice. The method of claim 7, wherein the at least one second anhydrous organic solvent comprises dichloromethane. The at least one first anhydrous organic solvent is dimethylcarbonate (DMC), diethylcarbonate (DEC), ethylmethylcarbonate (EMC), propylmethylcarbonate (PMC), ethylenecarbonate (EC), and the like. Selected from the group consisting of fluoroethylene carbonate (FEC), transbutylene carbonate, acetonitrile, malononitrile, adiponitrile, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate (MP) and ethyl propionate (EP). The method according to claim 1. The method of claim 9, wherein the at least one anhydrous organic solvent comprises DMC. Treatment of the solid mass with at least one second anhydrous organic solvent comprises the group consisting of dichloromethane, dichloroethane, chloroform, pentane, hexane, heptane, octane, nonane, decane, undecane, and dodecane. 9. The method of claim 9, comprising treating with at least one second anhydrous organic solvent of choice. 11. The method of claim 11, wherein the at least one second anhydrous organic solvent comprises dichloromethane. 12. The method of claim 12, wherein the at least one anhydrous organic solvent comprises DMC. The method of claim 9, wherein the dry inert gas comprises at least one of argon and nitrogen. 9. The method of claim 9, wherein subjecting the solution to vacuum comprises subjecting the solution to a vacuum of less than about 1 Torr. 15. The method of claim 15, wherein subjecting the solution to vacuum comprises subjecting the solution to a vacuum of less than about 0.01 Torr. 11. The method of claim 11, wherein the temperature in vacuum is less than 35 ° C. Treatment of the solid mass with at least one second anhydrous organic solvent comprises the group consisting of dichloromethane, dichloroethane, chloroform, pentane, hexane, heptane, octane, nonane, decane, undecane, and dodecane. The method of claim 1, comprising treating with at least one second anhydrous organic solvent of choice. The method of claim 1, wherein isolating the insoluble moiety in an inert atmosphere comprises filtering the insoluble moiety from the combination. 15. The method of claim 15, wherein the inert atmosphere comprises a dry inert gas. The method of claim 1, wherein flushing the insoluble moiety with at least one dry inert gas comprises flushing the insoluble moiety with at least one of argon gas and nitrogen gas. The method of claim 1, wherein subjecting the flushed insoluble moiety to a pressure of less than about 100 Torr comprises subjecting the flushed insoluble moiety to a pressure of less than about 1 Torr. 18. The method of claim 18, wherein the pressure is less than about 0.01 Torr. Contacting the first crude LiFSI with at least one first anhydrous organic solvent causes the first crude LiFSI to be in the range of about 30% by weight to about 50% by weight with respect to the solution. The method of claim 1, comprising contacting with an amount of the at least one anhydrous organic solvent. 24. The method of claim 24, wherein subjecting the solution to vacuum comprises subjecting the solution to a vacuum of less than about 0.01 Torr at a temperature of less than about 35 ° C. 1. Method. The one or more reactive solvents in the first crude LiFSI contain an alcohol at a concentration of at least 2000 parts per million (ppm), and the alcohol in the reactive solvent reduced LiFSI product. The method of claim 1, wherein the amount is less than about 50 ppm. 26. The method of claim 26, wherein the alcohol has a concentration of at least about 3000 ppm. The one or more reactive solvents in the first crude LiFSI contain an initial concentration of water, and the water in the reactive solvent reduced LiFSI product is about 35% or less of the initial amount. , The method according to claim 1. 29. The method of claim 29, wherein the water in the reactive solvent-reduced LiFSI product is about 20% or less of the initial concentration.

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