CN113148970A - Preparation method of high-purity lithium difluorophosphate - Google Patents
Preparation method of high-purity lithium difluorophosphate Download PDFInfo
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- CN113148970A CN113148970A CN202110269945.3A CN202110269945A CN113148970A CN 113148970 A CN113148970 A CN 113148970A CN 202110269945 A CN202110269945 A CN 202110269945A CN 113148970 A CN113148970 A CN 113148970A
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- C01B25/00—Phosphorus; Compounds thereof
- C01B25/16—Oxyacids of phosphorus; Salts thereof
- C01B25/26—Phosphates
- C01B25/455—Phosphates containing halogen
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Abstract
The invention discloses a preparation method of high-purity lithium difluorophosphate, which comprises the following steps: firstly, fusing phosphorus pentafluoride in a mailing solvent to obtain a first solution, and reacting the first solution with a hydrocarbyl disiloxane compound containing active oxygen to prepare a difluorophosphoric siloxane compound; and (II) dissolving the difluorophosphoric acid siloxane compound in an organic solvent, and reacting with a basic lithium salt to prepare the lithium difluorophosphate. The preparation method of the high-purity lithium difluorophosphate has the advantages of wide raw material source, simple operation method, high product production capacity and simple post-treatment, is suitable for large-scale production, particularly can effectively control moisture in the reaction process, reduces the generation of hydrolysis byproducts, and finally obtains the high-purity lithium difluorophosphate meeting the use requirements of electronic chemicals.
Description
Technical Field
The invention relates to the technical field of battery materials, in particular to a preparation method of high-purity lithium difluorophosphate.
Background
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
The lithium ion battery has the advantages of high specific capacity, long cycle life, small self-discharge, environmental friendliness and the like, is widely applied to the field of various mobile portable electronic products at present, and is considered to be an ideal matched power supply for developing great applications such as electric vehicles, photovoltaic engineering and the like. Currently, commercial lithium ion batteries can be cycled thousands of times, but their cycle life still needs to be further improved to effectively utilize the lithium ion battery technology. Therefore, the improvement of the cyclicity of the lithium ion battery is a hot problem which needs to be solved urgently in the global new energy field. Under the current technical conditions, the high and low temperature cycle performance of the lithium ion battery directly determines the endurance mileage and the service life of the electric automobile. Lithium difluorophosphate (LiPO) in the electrolyte system commonly used in lithium ion batteries at present2F2) The low-resistance interfacial film is formed on the surfaces of the anode and the cathode of the lithium ion battery as an additive, so that the side reaction between the electrode and the electrolyte is inhibited, and the cycle life of the battery is prolonged.
In the Sanyo electric machine patent (JPH1167270), Li is used2PO3F and LiPO2F2As a film forming additive, LiPO is used in Sony corporation (CN102983359) to remarkably improve the high temperature storage performance of lithium ion batteries2F2The high-temperature cyclic capacity and the high-temperature storage performance of the battery are improved by using the cyclic methylene carbonate; the patent of Mitsubishi chemical (CN102064345) is LiPO2F2The additive is used as an additive for improving the low-temperature performance of the battery. In Sony patent JP201336042 LiPO2F2The composite material is used in an overcharge-preventing additive system and is matched with other overcharge additives, so that not only can the redox reaction occur at a specific potential to protect a battery and improve the safety of the battery, but also the discharge capacity of the battery is more uniform.
The synthesis of difluorophosphate is more reported and patent WO2012004187a2 discloses a process for the preparation of lithium difluorophosphate which comprises subjecting LiP04 to a gas-solid reaction with HF at 140 ℃ to produce a mixture of lithium difluorophosphate and lithium monofluorophosphate and lithium fluoride, wherein the mixture is difficult to separate; japanese patent JP2012051752 discloses a method for producing lithium difluorophosphate by reacting difluorophosphoric acid with a metal chloride and crystallizing the difluorophosphoric acid to obtain difluorophosphate, and japanese patent JP2010155773 discloses a method for producing lithium difluorophosphate by reacting a halide such as an alkali metal with difluorophosphoric acid in the presence of hexafluorophosphate; JP2010155774 discloses the use of oxyacids of phosphorusOr anhydride and lithium hexafluorophosphate in the presence of hydrogen fluoride to prepare difluorophosphate, and the synthesis is carried out in Japanese patent JP2005219994 by reacting lithium hexafluorophosphate with silicon dioxide in carbonate/carboxylate solution, and the by-product is silicon tetrafluoride. Chinese patent CN103259040B discloses a method for preparing lithium difluorophosphate, which comprises the step of reacting lithium dichlorophosphate with tin fluoride RnSn to generate lithium difluoro , wherein the lithium dichlorophosphate is respectively reacted with LiOH and Li through phosphorus oxychloride3PO4、P2O5And LiC1, and has the problems that lithium dichlorophosphate contains impurities which are difficult to separate, a byproduct, namely lithium monochlorophosphate and the like, so that lithium difluorophosphate obtained by the reaction contains residual chlorine, heavy metal tin and other harmful impurities, and the electrochemical performance of the battery is irreversibly influenced. Meanwhile, the organic tin has a great toxic effect on human bodies and the environment, and is strictly limited by European Union.
It should be noted that the above background description is only for the sake of clarity and complete description of the technical solutions of the present invention and for the understanding of those skilled in the art. Such solutions are not considered to be known to the person skilled in the art merely because they have been set forth in the background section of the invention.
Disclosure of Invention
The invention aims to provide a preparation method of high-purity lithium difluorophosphate.
In order to solve the technical problems, the invention provides a preparation method of high-purity lithium difluorophosphate, which comprises the following steps:
firstly, fusing phosphorus pentafluoride in a mailing solvent to obtain a first solution, and reacting the first solution with a hydrocarbyl disiloxane compound containing active oxygen to prepare a difluorophosphoric siloxane compound; and (II) dissolving the difluorophosphoric acid siloxane compound in an organic solvent, and reacting with a basic lithium salt to prepare the lithium difluorophosphate.
Preferably, the general formula of the hydrocarbyl disiloxane compound containing active oxygen is represented by the following formula (2):
wherein each of X1 to X6 independently represents a hydrocarbon group or a cyclic structure which may have a substituent.
Preferably, the molar ratio of the phosphorus pentafluoride to the hydrocarbyl disiloxane compound and the basic lithium salt is 1:2.0: 1-1: 2.5: 1.
Preferably, the reaction condition of the step (one) is 25-60 ℃, the reaction lasts for 5-12h, and in the step (two), the temperature is raised to 20-100 ℃, and the reaction lasts for 2-24 h.
Preferably, the basic lithium salt is Li2CO3、Li2O, LiOH or a mixture of several of them.
Preferably, the organic solvent is one or a combination of ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, vinylene carbonate, propylene carbonate, methyl carbonate and 1-fluoroethylene carbonate.
Preferably, the organic solvent is a mixture of ethylene carbonate, dimethyl carbonate, ethyl methyl carbonate and vinylene carbonate.
By means of the technical scheme, the invention has the following beneficial effects:
the preparation method of the high-purity lithium difluorophosphate has the advantages of wide raw material source, simple operation method, high product production capacity and simple post-treatment, is suitable for large-scale production, particularly can effectively control moisture in the reaction process, reduces the generation of hydrolysis byproducts, and finally obtains the high-purity lithium difluorophosphate meeting the use requirements of electronic chemicals.
Detailed Description
The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1:
in a dry reaction kettle, introducing 19.40g (0.153mol) of phosphorus pentafluoride gas into 50g (0.308mol) of hexamethyldisiloxane and 150g of dry ethyl methyl carbonate at normal temperature, stirring, reacting for 10 hours at 25 ℃, adding 4.59g (0.153mol) of LiOH into the reaction kettle, raising the temperature to 50 ℃, reacting for 10 hours, then decompressing and evaporating the solvent, redissolving the obtained solid by tetrahydrofuran, recrystallizing at-25 to 0 ℃, generating a crystalline product in the solution, filtering to remove a mother liquor, collecting the crystalline solid, and drying in vacuum at 90 ℃ to obtain 15.78g of lithium difluorophosphate white solid with the purity of 99.0%.
Example 2:
in a dry reaction vessel, 19.40g (0.153mol) of phosphorus pentafluoride gas was introduced into 50g (0.308mol) of hexamethyldisiloxane and 150g of dry ethylmethyl carbonate at normal temperature, stirred, reacted at 25 ℃ for 10 hours, and then 4.59g (0.153mol) of Li was added to the reaction vessel2O, raising the temperature to 50 ℃, reacting for 15h, then decompressing and evaporating the solvent, re-dissolving the obtained solid with tetrahydrofuran, and reacting at-25 DEG C
Recrystallizing at 0 deg.C to obtain crystalline product, filtering to remove mother liquor, collecting crystalline solid, and vacuum drying at 90 deg.C to obtain 15.20g lithium difluorophosphate white solid with purity of 99.0%.
The above-mentioned embodiments are merely preferred embodiments for fully illustrating the present invention, and the scope of the present invention is not limited thereto. The equivalent substitution or change made by the technical personnel in the technical field on the basis of the invention is all within the protection scope of the invention. The protection scope of the invention is subject to the claims.
Claims (7)
1. The preparation method of high-purity lithium difluorophosphate is characterized by comprising the following steps:
firstly, fusing phosphorus pentafluoride in a mailing solvent to obtain a first solution, and reacting the first solution with a hydrocarbyl disiloxane compound containing active oxygen to prepare a difluorophosphoric siloxane compound; and (II) dissolving the difluorophosphoric acid siloxane compound in an organic solvent, and reacting with a basic lithium salt to prepare the lithium difluorophosphate.
2. The process according to claim 1, wherein the active oxygen-containing hydrocarbyl disiloxane compound has a general formula of a compound represented by the following formula (2):
in the formula (I), the compound is shown in the specification,
each independently is a hydrocarbon group or a cyclic structure optionally having a substituent.
3. The preparation method according to claim 1, wherein the molar ratio of the phosphorus pentafluoride to the hydrocarbyl disiloxane compound to the basic lithium salt is 1:2.0:1 to 1:2.5: 1.
4. The preparation method according to claim 1, wherein the reaction conditions in the step (one) are 25-60 ℃ and the reaction is carried out for 5-12h, and in the step (two), the temperature is raised to 20-100 ℃ and the reaction is continued for 2-24 h.
5. The method according to claim 1, wherein the basic lithium salt is Li2CO3、Li2O, LiOH or a mixture of several of them.
6. The preparation method of claim 1, wherein the organic solvent is one or more of ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, vinylene carbonate, propylene carbonate, methyl carbonate and 1-fluoroethylene carbonate.
7. The method according to claim 6, wherein the organic solvent is a mixture of ethylene carbonate, dimethyl carbonate, ethyl methyl carbonate and vinylene carbonate.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115477297A (en) * | 2022-10-18 | 2022-12-16 | 山东海科创新研究院有限公司 | Preparation method of lithium difluorophosphate and product obtained by preparation method |
Citations (7)
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|---|---|---|---|---|
| WO2008023744A1 (en) * | 2006-08-22 | 2008-02-28 | Mitsubishi Chemical Corporation | Lithium difluorophosphate, electrolytic solution containing lithium difluorophosphate, process for producing lithium difluorophosphate, process for producing nonaqueous electrolytic solution, nonaqueous electrolytic solution, and nonaqueous-electrolytic-solution secondary cell employing the same |
| US20110111288A1 (en) * | 2008-12-02 | 2011-05-12 | Stella Chemifa Corporation | Production process of difluorophosphate, nonaqueous electrolytic solution and nonaqueous electrolytic secondary battery |
| US20130129595A1 (en) * | 2010-08-04 | 2013-05-23 | Solvay Sa | Manufacture of LiPO2F2 from POF3 or PF5 |
| CN105236380A (en) * | 2015-09-28 | 2016-01-13 | 广州天赐高新材料股份有限公司 | Preparation method of high purity difluorophosphate |
| CN105731412A (en) * | 2015-12-29 | 2016-07-06 | 中国科学院宁波材料技术与工程研究所 | Preparation method of difluorophosphate |
| CN111224164A (en) * | 2019-12-13 | 2020-06-02 | 九江天赐高新材料有限公司 | Preparation method of lithium difluorophosphate |
| CN113636534A (en) * | 2021-06-08 | 2021-11-12 | 森田新能源材料（张家港）有限公司 | Preparation method of lithium difluorophosphate |
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Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2008023744A1 (en) * | 2006-08-22 | 2008-02-28 | Mitsubishi Chemical Corporation | Lithium difluorophosphate, electrolytic solution containing lithium difluorophosphate, process for producing lithium difluorophosphate, process for producing nonaqueous electrolytic solution, nonaqueous electrolytic solution, and nonaqueous-electrolytic-solution secondary cell employing the same |
| US20110111288A1 (en) * | 2008-12-02 | 2011-05-12 | Stella Chemifa Corporation | Production process of difluorophosphate, nonaqueous electrolytic solution and nonaqueous electrolytic secondary battery |
| US20130129595A1 (en) * | 2010-08-04 | 2013-05-23 | Solvay Sa | Manufacture of LiPO2F2 from POF3 or PF5 |
| CN105236380A (en) * | 2015-09-28 | 2016-01-13 | 广州天赐高新材料股份有限公司 | Preparation method of high purity difluorophosphate |
| CN105731412A (en) * | 2015-12-29 | 2016-07-06 | 中国科学院宁波材料技术与工程研究所 | Preparation method of difluorophosphate |
| CN111224164A (en) * | 2019-12-13 | 2020-06-02 | 九江天赐高新材料有限公司 | Preparation method of lithium difluorophosphate |
| CN113636534A (en) * | 2021-06-08 | 2021-11-12 | 森田新能源材料（张家港）有限公司 | Preparation method of lithium difluorophosphate |
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| 李亚楠: "二氟磷酸锂的制备方法及其研究进展", 《河南化工》, vol. 35, no. 08, 31 August 2018 (2018-08-31), pages 8 - 11 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115477297A (en) * | 2022-10-18 | 2022-12-16 | 山东海科创新研究院有限公司 | Preparation method of lithium difluorophosphate and product obtained by preparation method |
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Application publication date: 20210723 |