CN116902997A - Preparation method for co-production of lithium difluorophosphate and lithium hexafluorophosphate - Google Patents

Preparation method for co-production of lithium difluorophosphate and lithium hexafluorophosphate Download PDF

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CN116902997A
CN116902997A CN202310679775.5A CN202310679775A CN116902997A CN 116902997 A CN116902997 A CN 116902997A CN 202310679775 A CN202310679775 A CN 202310679775A CN 116902997 A CN116902997 A CN 116902997A
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lithium
difluorophosphate
hexafluorophosphate
solution
lithium hexafluorophosphate
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王笃涛
王昊
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Dongying Lingshi Technology Consulting Co ltd
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D15/00—Lithium compounds
    • C01D15/005—Lithium hexafluorophosphate
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B25/00—Phosphorus; Compounds thereof
    • C01B25/16—Oxyacids of phosphorus; Salts thereof
    • C01B25/26—Phosphates
    • C01B25/455—Phosphates containing halogen
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0567—Liquid materials characterised by the additives
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
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    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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    • Y02E60/10—Energy storage using batteries

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Abstract

The application provides a preparation method for co-producing lithium hexafluorophosphate by lithium difluorophosphate, which comprises the following steps: 1) Dissolving lithium phosphate in a carbonate solvent to obtain a lithium phosphate solution, and regulating the temperature of the solution to 5-10 ℃; 2) Introducing phosphorus pentafluoride gas into the lithium phosphate solution to gradually react to generate lithium difluorophosphate and lithium fluoride, and continuously reacting the lithium fluoride with phosphorus pentafluoride to generate lithium hexafluorophosphate, wherein the molar ratio of the lithium phosphate to the phosphorus pentafluoride is 1: 2+/-0.1 to obtain lithium difluorophosphate and lithium hexafluorophosphate solution, wherein the lithium hexafluorophosphate is dissolved in carbonate solution to form lithium hexafluorophosphate solution, the lithium difluorophosphate is slightly dissolved in carbonate and precipitated in a crystal form to form turbid liquid; 3) Separating the lithium hexafluorophosphate solution from the lithium difluorophosphate turbid liquid, drying the crystalline lithium difluorophosphate to obtain a finished product, and directly entering the electrolyte system after the concentration of the liquid-phase lithium hexafluorophosphate is regulated.

Description

Preparation method for co-production of lithium difluorophosphate and lithium hexafluorophosphate
Technical Field
The application belongs to the technical field of chemical product preparation, and particularly relates to a preparation method for co-producing lithium difluorophosphate and lithium hexafluorophosphate.
Background
As a prior application patent: CN202211453030.9A method for preparing lithium difluorophosphate and lithium hexafluorophosphate is a part of the priority patent of the application.
Lithium hexafluorophosphate, liPF6, CAS:21324-40-3, which is mainly used as electrolyte of lithium ion battery electrolyte, and lithium hexafluorophosphate is the most advantageous in terms of conductivity, safety and environmental protection in organic solvents, and becomes the lithium salt electrolyte with the widest application range at present.
Lithium difluorophosphate, liPO2F2, CAS:24389-25-1, which is mainly used as an electrolyte additive of lithium ion batteries and is used for improving the cycle life and the performance of the lithium ion batteries.
At present, for the preparation of lithium hexafluorophosphate, the common method is that lithium fluoride is dissolved in anhydrous hydrogen fluoride, phosphorus pentafluoride gas is introduced, after synthesis, crystallization, drying and the like are carried out, the operation risk of solvent anhydrous hydrogen fluoride is high, the process extraction is troublesome, and the problems of energy consumption, material consumption and the like are wasted when the solvent anhydrous hydrogen fluoride is used for electrolyte after crystallization into solid. There are data that mention is made of the preparation of lithium hexafluorophosphate by the reaction of lithium carbonate and phosphorus pentafluoride, in which system the carbonate (CO 32-) will be replaced, the phosphorus of phosphorus pentafluoride is introduced into the system in the form of pentavalent (p5+) and the reaction to form lithium hexafluorophosphate lacks the presence of negative fluorine (F-) and thus the route is not viable, whereas the use of lithium phosphate as a starting material, the reaction of lithium phosphate with phosphorus pentafluoride first to form lithium difluorophosphate and lithium fluoride, the lithium fluoride providing negative fluorine (F-) to continue to react with phosphorus pentafluoride to form lithium hexafluorophosphate, conforming to the synthesis mechanism of lithium hexafluorophosphate.
The application relates to a method for preparing lithium hexafluorophosphate by using phosphorus oxide as a raw material, which is based on the principle that phosphorus oxide is used for preparing phosphorus pentafluoride and then reacted with fluorine-containing lithium salt to prepare fluorine-containing phosphate.
Disclosure of Invention
The main purpose of the application is to provide a preparation method for co-producing lithium hexafluorophosphate by lithium difluorophosphate, which has simple raw materials, can simultaneously produce two lithium salts, and can also control the addition amount of phosphorus pentafluoride to produce lithium difluorophosphate and lithium fluoride.
The application adopts the following technical scheme: the preparation method for co-producing lithium hexafluorophosphate by using lithium difluorophosphate comprises the following steps:
1) Dissolving lithium phosphate in carbonic ester to obtain lithium phosphate solution, and regulating the temperature of the solution to 5-10 ℃;
2) Introducing phosphorus pentafluoride gas into the lithium phosphate solution to gradually react to generate lithium difluorophosphate and lithium fluoride, and continuously reacting the lithium fluoride with phosphorus pentafluoride to generate lithium hexafluorophosphate, wherein the molar ratio of the lithium phosphate to the phosphorus pentafluoride is 1: 2+/-0.1 to obtain the lithium difluorophosphate and the lithium hexafluorophosphate. Dissolving lithium hexafluorophosphate in a carbonate solution to form a lithium hexafluorophosphate solution, slightly dissolving lithium difluorophosphate in the carbonate, and separating out the lithium difluorophosphate in a crystal form to form a turbid liquid;
3) Carrying out solid-liquid separation on the reacted lithium hexafluorophosphate and lithium difluorophosphate solution to obtain lithium difluorophosphate crystals and lithium hexafluorophosphate solution; the liquid phase lithium hexafluorophosphate can directly enter an electrolyte system after the concentration is regulated;
4) Drying the lithium difluorophosphate crystal to obtain a lithium difluorophosphate product;
5) The concentration of the liquid phase lithium hexafluorophosphate was adjusted to 40.+ -. 0.1%.
As a further preferable example, in the step 1), the solvent is dimethyl carbonate, methylethyl carbonate, diethyl carbonate, or the like.
As a further preferred aspect, in step 1), the concentration of lithium phosphate in the solution is 20 to 25% (Wt%).
As a further preference, in step 2), the phosphorus pentafluoride is fed at a rate of from 10 to 15L/min.
As a further preferred aspect, in step 4), the solid-liquid separation is a centrifugal separation.
The beneficial effects of the application are as follows: compared with the traditional lithium fluoride serving as a raw material for preparing lithium hexafluorophosphate, the lithium hexafluorophosphate has the advantages of low raw material cost, capability of producing byproduct lithium difluorophosphate and higher production benefit.
As an optimized option, trifluoromethanesulfonyl carbonate can be added into the solvent, and the preparation method comprises the following steps:
the preparation method comprises the steps of:
according to weight portions, 42 to 60 portions of 1-aminopropyl-3-methylimidazole bis (trifluoromethanesulfonyl) imide salt, 50 to 100 portions of allyl diglycol dicarbonate, 200 to 600 portions of DMF and 2 to 6 portions of ethylenediamine are stirred for 30 to 80 minutes at 50 to 60 ℃, and DMF is removed by distillation, thus obtaining the trifluoromethanesulfonyl carbonate;
the addition amount is 0.5-3% of the solvent mass percent.
The lithium hexafluorophosphate solution can directly enter an electrolyte system, so that crystallization of lithium hexafluorophosphate and a process of redissolving the electrolyte are avoided, energy consumption, material consumption and manual consumption of low-temperature crystallization in a salifying process are reduced, and cost reduction and synergy in an industrial process are facilitated.
The trifluoro methane sulfonyl carbonate is used as an organic solvent in the reaction of co-producing lithium hexafluorophosphate from lithium difluorophosphate, and has the advantages of high efficiency, high purity and the like.
The trifluoromethyl fluorine atoms in the trifluoromethanesulfonyl carbonate are arranged in cis sequence and the fluorine atoms in the hexafluorophosphoric acid in the same sequence, so that the trifluoromethyl fluorine atoms and the hexafluorophosphoric acid have affinity, and simultaneously repel the remaining two fluorine atoms of the difluorophosphate substituted by oxygen atoms in trans arrangement, so that the solubility of lithium hexafluorophosphate can be improved, the solubility of lithium difluorophosphate is reduced, and the solubility of the lithium difluorophosphate is changed from slight solubility to insoluble. The solubility curves of lithium hexafluorophosphate and lithium difluorophosphate in the carbonate after addition of trifluoromethanesulfonyl carbonate are shown in fig. 2 and 3.
The trifluoromethanesulfonyl carbonate may be used as an electrolyte additive by mixing an organic carbonate solvent with lithium tetramethylguanidine trifluoromethanesulfonate to form a hybrid electrolyte. The battery of the electrolyte can reduce the impedance at low temperature, can improve the capacity retention rate at low temperature, and can improve the charge-discharge multiplying power in the aspect of charge-discharge performance.
The reaction equation of the present application is as follows:
(1)Li 3 PO 4 +PF 5 →2LiPO 2 F 2 +LiF
(2)LiF+PF 5 →LiPF 6
or alternatively
Li 3 PO 4 +2PF 5 →2LiPO 2 F 2 +LiPF 6
Drawings
Fig. 1 is a process flow diagram of the co-production of lithium difluorophosphate and lithium hexafluorophosphate.
Fig. 2 is the solubility of lithium hexafluorophosphate in carbonate solutions before and after addition of trifluoromethanesulfonyl carbonate.
Fig. 3 is the solubility of lithium difluorophosphate in a carbonate solution before and after addition of trifluoromethanesulfonyl carbonate.
FIG. 4 is the cell impedance at-10℃for example 8.
FIG. 5 shows the capacity retention at-20℃in example 8.
Fig. 6 is a discharge of example 8 showing a rate discharge performance.
Fig. 7 is a rate charging performance graph of example 8.
Detailed Description
In order to better understand the above technical solutions, the following detailed description of the technical solutions of the present application is provided by specific embodiments, and it should be understood that the specific features of the embodiments and the embodiments of the present application are detailed descriptions of the technical solutions of the present application, and not limiting the technical solutions of the present application, and the embodiments and the technical features of the embodiments of the present application may be combined with each other without conflict. It is to be understood that the term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.
The present application is described in more detail below by way of examples. These examples are merely illustrative of the best mode of the application and do not limit the scope of the application in any way.
Example 1
The preparation method for co-producing lithium hexafluorophosphate by using lithium difluorophosphate comprises the following steps:
1) 200g of lithium phosphate is dissolved in 800g of dimethyl carbonate to obtain a 20% lithium phosphate solution, and the temperature of the solution is regulated to 5 ℃;
2) Introducing 435.2g of phosphorus pentafluoride gas into the lithium phosphate solution at normal temperature, and reacting to obtain lithium difluorophosphate and lithium hexafluorophosphate, wherein the lithium difluorophosphate is separated out in a crystal form and suspended in a dimethyl carbonate solution, and the lithium hexafluorophosphate is dissolved in the dimethyl carbonate solution;
3) Centrifugally separating the solution to obtain lithium difluorophosphate crystals and lithium hexafluorophosphate solution;
4) Drying the lithium difluorophosphate crystal to obtain a finished lithium difluorophosphate (365.2 g);
5) The sample analysis yielded a total of 262g of lithium hexafluorophosphate. The separated lithium hexafluorophosphate solution was heated to evaporate 393.5g of dimethyl carbonate, and the concentration of the lithium hexafluorophosphate solution was adjusted to 40%.
Example 2
The preparation method for co-producing lithium hexafluorophosphate by using lithium difluorophosphate comprises the following steps:
1) 260g of lithium phosphate was dissolved in 921.8g of ethyl methyl carbonate to obtain a 22% lithium phosphate solution, the temperature of which was adjusted to 8 ℃;
2) Introducing 565.8g of phosphorus pentafluoride gas into the lithium phosphate solution at normal temperature, and reacting to obtain lithium difluorophosphate and lithium hexafluorophosphate, wherein the lithium difluorophosphate is separated out in a crystal form and suspended in the methyl ethyl carbonate solution, and the lithium hexafluorophosphate is dissolved in the methyl ethyl carbonate solution;
3) Centrifugally separating the solution to obtain lithium difluorophosphate crystals and lithium hexafluorophosphate solution;
4) Drying the lithium difluorophosphate crystal to obtain a finished product of lithium difluorophosphate (474.8 g);
5) Sampling analysis yielded 340.3g of lithium hexafluorophosphate in total. The separated lithium hexafluorophosphate solution was heated to evaporate 413.5g of ethyl methyl carbonate, and the concentration of the lithium hexafluorophosphate solution was adjusted to 40.1%.
Example 3
The preparation method for co-producing lithium hexafluorophosphate by using lithium difluorophosphate comprises the following steps:
1) 320g of lithium phosphate was dissolved in 1041.7g of diethyl carbonate to obtain a 23.5% lithium phosphate solution, and the temperature of the solution was adjusted to 10 ℃;
2) Introducing 696.4g of phosphorus pentafluoride gas into the lithium phosphate solution at normal temperature, and reacting to obtain lithium difluorophosphate and lithium hexafluorophosphate, wherein the lithium difluorophosphate is separated out in a crystal form and suspended in a diethyl carbonate solution, and the lithium hexafluorophosphate is dissolved in the diethyl carbonate solution;
3) Centrifugally separating the solution to obtain lithium difluorophosphate crystals and lithium hexafluorophosphate solution;
4) Drying the lithium difluorophosphate crystal to obtain a finished product of lithium difluorophosphate (584.1 g);
5) Sampling analysis yielded 419.1g of lithium hexafluorophosphate in total. The separated lithium hexafluorophosphate solution was heated to evaporate 410.4g of diethyl carbonate, and the concentration of the lithium hexafluorophosphate solution was adjusted to 39.9%.
Example 4
The preparation method for co-producing lithium hexafluorophosphate by using lithium difluorophosphate comprises the following steps:
1) 390g of lithium phosphate is dissolved in 1170g of dimethyl carbonate to obtain a 25% lithium phosphate solution, and the temperature of the solution is adjusted to 9 ℃;
2) Introducing 848.7g of phosphorus pentafluoride gas into the lithium phosphate solution at normal temperature, and reacting to obtain lithium difluorophosphate and lithium hexafluorophosphate, wherein the lithium difluorophosphate is separated out in a crystal form and suspended in a dimethyl carbonate solution, and the lithium hexafluorophosphate is dissolved in the dimethyl carbonate solution;
3) Centrifugally separating the solution to obtain lithium difluorophosphate crystals and lithium hexafluorophosphate solution;
4) Drying the lithium difluorophosphate crystal to obtain a finished product of lithium difluorophosphate (712.0 g);
5) Sampling analysis yielded a total of 511.0g of lithium hexafluorophosphate. The separated lithium hexafluorophosphate solution was heated to evaporate 403.5g of dimethyl carbonate, and the concentration of the lithium hexafluorophosphate solution was adjusted to 40.0%.
Example 5
In the technical scheme of example 1, trifluoromethanesulfonyl carbonate is added into the solvent, and the preparation method comprises the following steps:
42 parts of 1-aminopropyl-3-methylimidazole bis (trifluoromethanesulfonyl) imide salt, 50 parts of allyl diglycol dicarbonate, 200 parts of DMF and 2 parts of ethylenediamine are stirred at 50 ℃ for 30 minutes, and DMF is distilled off to obtain trifluoromethanesulfonyl carbonate;
the addition amount is 0.5 percent of the mass percent of the solvent.
The procedure is as in example 1.
Sampling analysis yielded 262.2g of lithium hexafluorophosphate, 372.1g of lithium hexafluorophosphate altogether.
Example 6
In the technical scheme of example 2, trifluoromethanesulfonyl carbonate is added into the solvent, and the preparation method comprises the following steps:
the preparation method comprises the steps of:
48 parts of 1-aminopropyl-3-methylimidazole bis (trifluoromethanesulfonyl) imide salt, 70 parts of allyl diglycol dicarbonate, 300 parts of DMF and 4 parts of ethylenediamine are stirred at 58 ℃ for 50 minutes, and DMF is distilled off to obtain trifluoromethanesulfonyl carbonate;
the addition amount is 0.8 percent of the mass percent of the solvent.
The procedure is as in example 2.
Sampling analysis yielded a total of 340.9g lithium hexafluorophosphate, 483.9g lithium hexafluorophosphate.
Example 7
In the technical scheme of example 4, trifluoromethanesulfonyl carbonate is added into the solvent, and the preparation method comprises the following steps:
according to parts by weight, 60 parts of 1-aminopropyl-3-methylimidazole bis (trifluoromethanesulfonyl) imine salt, 100 parts of allyl diglycol dicarbonate, 600 parts of DMF and 6 parts of ethylenediamine are stirred at 60 ℃ for 80 minutes, and DMF is distilled off to obtain trifluoromethanesulfonyl carbonate;
the addition amount is 3% of the mass percent of the solvent.
The procedure is as in example 4.
Sampling analysis yielded a total of 419.6g lithium hexafluorophosphate, 595.8g lithium hexafluorophosphate.
Example 8
To test the low temperature resistance, capacity retention at low temperature and change in charge and discharge performance of the battery by adding lithium trifluoromethane sulfonate to form a hybrid electrolyte, the impedance of the battery is tested after adding trifluoromethane sulfonyl carbonate into a 4.4V NCM 622/natural graphite battery system, the test data at-10 ℃ are shown in Table 8-1, and the test curve is shown in figure 4. The results show that the cell impedance is lower than the base electrolyte.
Table 8-1 base electrolyte and cell impedance data after addition of trifluoromethanesulfonyl carbonate:
in the 4.4V NCM 622/natural graphite cell system, the capacity retention rate was tested after adding trifluoromethanesulfonyl carbonate, the test data at-20℃are shown in Table 8-2, and the test curves are shown in FIG. 5. The results showed that the capacity retention was higher than the base electrolyte.
Table 8-2 base electrolyte and capacity retention after addition of trifluoromethanesulfonyl carbonate:
in a 4.4V NCM 622/natural graphite battery system, after adding trifluoromethanesulfonyl carbonate, the rate charge-discharge performance is tested, the test data are shown in tables 8-3, and the test curves are shown in figures 6 and 7. The results show that the rate charge-discharge performance is higher than that of the base electrolyte.
Table 8-3 base electrolyte and rate charge and discharge performance after addition of trifluoromethanesulfonyl carbonate:
in the above examples, lithium phosphate was taken as an example, and the starting material may be replaced with sodium phosphate to prepare sodium hexafluorophosphate and sodium difluorophosphate, which are also suitable for the present patent.
While preferred embodiments of the present application have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiments and all such alterations and modifications as fall within the scope of the application.
It will be apparent to those skilled in the art that various modifications and variations can be made to the present application without departing from the spirit or scope of the application. Thus, it is intended that the present application also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims (8)

1. The preparation method for co-producing lithium hexafluorophosphate by using lithium difluorophosphate comprises the following steps:
s1, dissolving lithium phosphate in carbonic ester to obtain a lithium phosphate solution, and regulating the temperature of the solution to 5-10 ℃;
s2, introducing phosphorus pentafluoride gas into the lithium phosphate solution to gradually react to generate lithium difluorophosphate and lithium fluoride, and continuously reacting the lithium fluoride with phosphorus pentafluoride to generate lithium hexafluorophosphate, wherein the molar ratio of the lithium phosphate to the phosphorus pentafluoride is 1: 2+/-0.1 to obtain the lithium difluorophosphate and the lithium hexafluorophosphate. Dissolving lithium hexafluorophosphate in a carbonate solution to form a lithium hexafluorophosphate solution, slightly dissolving lithium difluorophosphate in the carbonate, and separating out the lithium difluorophosphate in a crystal form to form a turbid liquid;
s3, carrying out solid-liquid separation on the reacted lithium hexafluorophosphate and lithium difluorophosphate solution to obtain lithium difluorophosphate crystals and lithium hexafluorophosphate solution; the liquid phase lithium hexafluorophosphate can directly enter an electrolyte system after the concentration is regulated;
s4, drying the lithium difluorophosphate crystal to obtain a lithium difluorophosphate product;
s5, adjusting the concentration of the liquid phase lithium hexafluorophosphate to 40+/-0.1%.
2. The method for producing lithium hexafluorophosphate according to claim 1, wherein: the solvent is carbonate solvent, including dimethyl carbonate, ethyl methyl carbonate and diethyl carbonate.
3. The method for producing lithium hexafluorophosphate according to claim 1, wherein: the raw material is lithium phosphate, but not limited to lithium ion batteries, but sodium phosphate can also be used for manufacturing sodium hexafluorophosphate and sodium difluorophosphate for sodium ion batteries.
4. The method for producing lithium hexafluorophosphate according to claim 1, wherein: the lithium phosphate and the phosphorus pentafluoride gas react to generate lithium difluorophosphate and lithium fluoride, and the lithium fluoride continues to react with the phosphorus pentafluoride to generate lithium hexafluorophosphate, so that the addition amount of the phosphorus pentafluoride can be controlled to only produce the lithium difluorophosphate and the lithium fluoride.
5. The method for producing lithium hexafluorophosphate according to claim 1, wherein: the concentration of lithium phosphate in the solution is 20-25% (Wt%).
6. The method for producing lithium hexafluorophosphate according to claim 1, wherein: the concentration of the lithium hexafluorophosphate solution is 40+/-0.1% (Wt%).
7. The method for preparing the lithium difluorophosphate co-production lithium hexafluorophosphate according to claim 1, which is characterized in that: the preparation method comprises the steps of:
according to the weight portions, 4 to 11 portions of 1-aminopropyl-3-methylimidazole bis (trifluoromethanesulfonyl) imide salt, 200 to 400 portions of allyl diglycol dicarbonate and 10 to 16 portions of triethylamine are stirred for 30 to 80 minutes at the temperature of 50 to 60 ℃ and DMF is distilled off to obtain the trifluoromethanesulfonyl carbonate.
8. The method for preparing the lithium difluorophosphate co-production lithium hexafluorophosphate according to claim 1, which is characterized in that: the addition amount is 0.5-3% of the solvent mass percent.
CN202310679775.5A 2022-11-21 2023-06-09 Preparation method for co-production of lithium difluorophosphate and lithium hexafluorophosphate Pending CN116902997A (en)

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