CN112758904B - Preparation method of lithium difluorophosphate - Google Patents

Preparation method of lithium difluorophosphate Download PDF

Info

Publication number
CN112758904B
CN112758904B CN201911159657.1A CN201911159657A CN112758904B CN 112758904 B CN112758904 B CN 112758904B CN 201911159657 A CN201911159657 A CN 201911159657A CN 112758904 B CN112758904 B CN 112758904B
Authority
CN
China
Prior art keywords
lithium difluorophosphate
fluorine
gas
reaction
lithium
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201911159657.1A
Other languages
Chinese (zh)
Other versions
CN112758904A (en
Inventor
李世江
薛旭金
杨明霞
于贺华
张照坡
于洋
刘海霞
耿梦湍
张扬
李迪
周苏
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Duofudo New Material Co ltd
Original Assignee
Duofudo New Material Co ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Duofudo New Material Co ltd filed Critical Duofudo New Material Co ltd
Priority to CN201911159657.1A priority Critical patent/CN112758904B/en
Publication of CN112758904A publication Critical patent/CN112758904A/en
Application granted granted Critical
Publication of CN112758904B publication Critical patent/CN112758904B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • C01B25/10—Halides or oxyhalides of phosphorus
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
    • C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/80—Compositional purity
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Secondary Cells (AREA)

Abstract

The invention relates to the technical field of lithium ion battery additives, in particular to a preparation method of lithium difluorophosphate. The preparation method specifically comprises the steps of reacting lithium phosphate with fluorine-containing reaction gas, and purifying to obtain the lithium phosphate. The preparation method of the lithium difluorophosphate adopts the fluorine-containing reaction gas and the lithium phosphate to synthesize the lithium difluorophosphate through fluorination, has few byproducts, high utilization rate of raw materials, direct solid-gas reaction, simple treatment after reaction, almost zero discharge of three wastes in the production process, green and environment-friendly preparation process, can obviously shorten the preparation period of the lithium difluorophosphate and reduce the preparation cost.

Description

Preparation method of lithium difluorophosphate
Technical Field
The invention relates to the technical field of lithium ion battery additives, in particular to a preparation method of lithium difluorophosphate.
Background
At present, the lithium ion power battery anode material mainly takes a lithium iron phosphate and nickel cobalt manganese ternary material as a main material, and the electrolyte mainly takes a liquid electrolyte system of lithium hexafluorophosphate compounded with a carbonate organic solvent. In a ternary positive electrode material system, proper amount of lithium difluorophosphate is added to reduce the internal resistance of the battery, and a protective film is formed on the positive electrode of the battery, so that the cycle performance of the battery is obviously improved; meanwhile, in a lithium iron phosphate anode system with high compaction density, lithium difluorophosphate is taken as an additive of the electrolyte, so that the high and low temperature cycle storage performance and the cycle stability of the battery can be obviously improved, and the lithium difluorophosphate anode is a novel lithium salt additive with great industrial value and receives wide attention. The industrial preparation of the lithium difluorophosphate is researched, the manufacturing cost of the lithium difluorophosphate is reduced, and the method plays an important role in popularizing the industrial application of the lithium difluorophosphate.
The existing lithium difluorophosphate preparation methods are numerous, for example, chinese patent application with publication number CN106829909a discloses a lithium difluorophosphate preparation method, which takes lithium hexafluorophosphate and tris (trimethylsilane) borate or tris (trimethylsilane) borate as raw materials to prepare lithium difluorophosphate, on one hand, by-products are generated, and the product is easily coated, which affects the product quality; on the other hand, the cost of raw materials is high, which causes high production cost of products.
The Chinese patent application with publication number CN108689395A discloses a preparation method of lithium difluorophosphate, which takes a lithium hexafluorophosphate complex and lithium carbonate as raw materials to prepare lithium difluorophosphate, and on one hand, the method can cause a complexing agent of the lithium hexafluorophosphate complex to be dissociated out, which can cause the reduction of product yield and increase the raw material cost of the product; on the other hand, the product is also coated with impurities, the quality of the product is influenced, and the reaction time is longer.
The Chinese patent application with publication number CN108640096A discloses a method for preparing difluorophosphoric acid and lithium difluorophosphate, which takes dichlorophosphoric acid, a fluorination reagent and a lithium source substance as raw materials to prepare lithium difluorophosphate, and on one hand, the method can generate side reaction, the utilization rate of the raw materials is low, and the requirement on equipment is high; on the other hand, the produced industrial wastewater is more and is not beneficial to environmental protection.
Chinese patent application with publication number CN104445133A discloses a preparation method of lithium difluorophosphate, which comprises the steps of reacting pyrophosphate with fluorine gas to generate mixed gas, introducing the obtained mixed gas into anhydrous hydrogen fluoride solution of lithium fluoride for reaction, and crystallizing, filtering and drying a product after the reaction is finished to obtain a lithium difluorophosphate product. However, this method produces a large amount of by-product harmful gases, such as CoF produced when cobalt pyrophosphate is used as a raw material 2 And OF 2 The raw material utilization rate is low, two-step reaction is needed, the process flow is complex and is not easy to control.
Disclosure of Invention
The invention aims to provide a preparation method of lithium difluorophosphate, so as to solve the problems of low lithium difluorophosphate yield, low preparation efficiency and high preparation cost of the existing preparation method.
In order to realize the purpose, the technical scheme of the preparation method of lithium difluorophosphate is as follows:
a preparation method of lithium difluorophosphate is specifically characterized in that lithium phosphate is reacted with fluorine-containing reaction gas, and the reaction gas is purified to obtain the lithium difluorophosphate, wherein the fluorine-containing reaction gas consists of 20-100% of fluorine gas and 0-80% of inert gas.
The invention adopts fluorine-containing reaction gas and lithium phosphate to synthesize lithium difluorophosphate by fluorination, and byproducts are inert gas, lithium fluoride and oxygen, so that the method can be recycled, the reaction yield is high and can reach 78.5%, and the product purity is more than 99.95%. The preparation method of the invention has direct solid-gas contact reaction, and lithium phosphate is pretreated into powder state in order to increase the solid-gas contact area and make the reaction more sufficient. The preparation method has simple treatment after reaction, almost zero discharge of three wastes, and green and environment-friendly preparation process.
The inert gas may be any gas which does not react with the substance in the reaction system, and is selected from, for example, nitrogen, helium and argon, which are commonly used. From the viewpoint of production cost, nitrogen gas is preferred.
The reaction product contains a large amount of lithium difluorophosphate and lithium fluoride as a byproduct, and the lithium difluorophosphate can be obtained by conventional purification steps, such as recrystallization from an organic solvent and drying.
The organic solvent is selected from organic solvents having good solubility for lithium difluorophosphate, and preferably, the organic solvent is one of ester solvents, ether solvents and alcohol solvents. Further preferably, the ester solvent is ethyl acetate, the ether solvent is methyl tert-butyl ether, and the alcohol solvent is ethanol.
The step of recrystallization is to concentrate the mixed solution of the organic solvent and the reaction product to the volume of 1/5-1/3 of the original volume, then to cool and crystallize, and then to separate solid and liquid to obtain the lithium difluorophosphate crystal. The cooling temperature is preferably-10 to-30 ℃.
In order to ensure that the partial pressure of fluorine gas in mixed gas in a reactor is proper to reduce the occurrence of side reaction, excessive fluorine-containing reaction gas is introduced into lithium phosphate, the volume of the fluorine gas in the fluorine-containing reaction gas accounts for 20-100%, the volume of the fluorine-containing reaction gas introduced per minute is 10-500 times of the mass of lithium difluorophosphate, the volume of the fluorine-containing reaction gas is calculated by mL, and the mass of the lithium difluorophosphate is calculated by g.
Preferably, the flow rate of the fluorine-containing reaction gas is 200 to 1000mL/min.
In order to improve the reaction rate and further improve the preparation efficiency, the reaction temperature is 30-150 ℃.
In order to improve the reaction efficiency, the reaction time is 10-300 min.
Drawings
FIG. 1 is an XRD pattern of the reaction product of example 1 of the present invention.
Detailed Description
The following examples are provided to further illustrate the practice of the invention. In the following examples, lithium phosphate was purchased from a Luoyang reagent factory, the purity was 99%, and fluorine-containing reaction gas was prepared by itself.
Example 1
The preparation method of lithium difluorophosphate of the embodiment adopts the following steps:
adding 11.6g of lithium phosphate into a fluorination furnace, replacing with nitrogen, filling nitrogen until the pressure is 0.05MPa, setting the temperature of the fluorination furnace to be 30 ℃, starting to introduce mixed fluorine and nitrogen gas into the fluorination furnace when the temperature reaches a set value, controlling the flow rate to be 200mL/min, introducing the mixed fluorine and nitrogen gas for 300min, and cooling to room temperature after the reaction is finished, wherein the volume ratio of fluorine in the mixed fluorine and nitrogen gas is 20 percent of that of the mixed fluorine and nitrogen gas; then, the solid in the fluorination furnace was subjected to XRD by replacing it with nitrogen, and the results were as follows: all of lithium difluorophosphate and lithium fluoride; then using ethyl acetate to perform recrystallization, wherein the recrystallization steps are as follows: concentrating at 50 deg.C under-0.1 MPa for 2 hr, reducing the volume of the solution to 1/3 of the original volume, cooling to-20 deg.C, filtering to obtain crystal, and drying to obtain 8.48g lithium difluorophosphate with yield of 78.5% and purity of 99.97%.
The XRD patterns are shown in FIG. 1, the solid has a group of strong diffraction peaks at 21.623 degrees, 22.008 degrees, 27.216 degrees, 23.526 degrees, 34.187 degrees and 45.170 degrees, and no obvious diffraction peak is observed between 50 and 90 degrees.
Example 2
The preparation method of lithium difluorophosphate of the embodiment adopts the following steps:
adding 11.6g of lithium phosphate into a fluorination furnace, replacing with nitrogen, filling nitrogen until the pressure is 0.05MPa, setting the temperature of the fluorination furnace to 150 ℃, starting to introduce a fluorine-nitrogen mixed gas into the fluorination furnace when the temperature reaches a set value, controlling the flow rate to be 200mL/min, introducing the fluorine-nitrogen mixed gas for 60min, and cooling to room temperature after the reaction is finished, wherein the volume ratio of fluorine in the fluorine-nitrogen mixed gas is 40% of that of the fluorine-nitrogen mixed gas; then, the solid in the fluorination furnace was subjected to XRD by replacing it with nitrogen, and the results were as follows: all lithium difluorophosphate and lithium fluoride; then using ethanol for recrystallization, wherein the recrystallization steps are as follows: concentrating at 50 deg.C under-0.1 MPa for 3 hr, reducing the volume of the solution to 1/3 of the original volume, cooling to-30 deg.C, filtering to obtain crystal, and drying to obtain 8.5g lithium difluorophosphate with yield of 78.7% and purity of 99.96%.
Example 3
The preparation method of lithium difluorophosphate of the embodiment adopts the following steps:
adding 11.6g of lithium phosphate into a fluorination furnace, replacing with nitrogen, filling nitrogen until the pressure is 0.05MPa, setting the temperature of the fluorination furnace to be 30 ℃, starting to introduce mixed fluorine and nitrogen gas into the fluorination furnace when the temperature reaches a set value, controlling the flow rate to be 1000mL/min, introducing the mixed fluorine and nitrogen gas for 30min, and cooling to room temperature after the reaction is finished, wherein the volume ratio of fluorine in the mixed fluorine and nitrogen gas is 80% of that of the mixed fluorine and nitrogen gas; then, the solid in the fluorination furnace was subjected to XRD by replacing it with nitrogen, and the results were as follows: all of lithium difluorophosphate and lithium fluoride; then recrystallizing by using methyl tert-butyl ether, wherein the recrystallization steps are as follows: concentrating at 45 deg.C under-0.1 MPa for 1.5h, reducing the volume of the solution to 1/3 of the original volume, cooling to-15 deg.C, filtering to obtain crystal, and drying to obtain 8.47g lithium difluorophosphate with yield of 78.4% and purity of 99.98%.
Example 4
The preparation method of lithium difluorophosphate of the embodiment adopts the following steps:
adding 11.6g of lithium phosphate into a fluorination furnace, replacing with nitrogen, filling nitrogen until the pressure is 0.05MPa, setting the temperature of the fluorination furnace to be 150 ℃, starting to introduce a fluorine-nitrogen mixed gas into the fluorination furnace when the temperature reaches a set value, controlling the flow rate to be 1000mL/min, introducing the fluorine-nitrogen mixed gas for 10min, and cooling to room temperature after the reaction is finished, wherein the volume ratio of fluorine in the fluorine-nitrogen mixed gas is 100% of that of the fluorine-nitrogen mixed gas; then, the solid in the fluorination furnace was subjected to XRD by replacing it with nitrogen, and the results were as follows: all lithium difluorophosphate and lithium fluoride; then using ethyl acetate for recrystallization, wherein the recrystallization steps are as follows: concentrating at 50 deg.C under-0.1 MPa for 2 hr, reducing the volume of the solution to 1/3 of the original volume, cooling to-20 deg.C, filtering to obtain crystal, and drying to obtain 8.52g lithium difluorophosphate with yield of 78.9% and purity of 99.97%.
Example 5
The preparation method of lithium difluorophosphate of the embodiment adopts the following steps:
adding 11.6g of lithium phosphate into a fluorination furnace, replacing with nitrogen, filling nitrogen until the pressure is 0.05MPa, setting the temperature of the fluorination furnace to 70 ℃, starting to introduce a fluorine-nitrogen mixed gas into the fluorination furnace when the temperature reaches a set value, controlling the flow rate to be 300mL/min, introducing the fluorine-nitrogen mixed gas for 90min, and cooling to room temperature after the reaction is finished, wherein the volume ratio of fluorine in the fluorine-nitrogen mixed gas is 50% of that of the fluorine-nitrogen mixed gas; then, the solid in the fluorination furnace was subjected to XRD by replacing it with nitrogen, and the results were as follows: all lithium difluorophosphate and lithium fluoride; then using ethanol for recrystallization, wherein the recrystallization steps are as follows: under the conditions of 50 ℃ and-0.1 MPa pressure, the solution is concentrated for 3h, the volume of the solution is reduced to 1/3 of the original volume, and the solution is cooled to-30 ℃ to obtain 8.49g of lithium difluorophosphate, wherein the yield is 78.6 percent, and the purity is 99.96 percent.

Claims (8)

1. A preparation method of lithium difluorophosphate is characterized in that powdery lithium phosphate is reacted with fluorine-containing reaction gas and purified to obtain the lithium difluorophosphate; the fluorine-containing reaction gas consists of 20-100% by volume of fluorine gas and 0-80% by volume of inert gas, wherein the proportion is volume percentage; the reaction is a gas-solid direct contact reaction, and the reaction temperature is 30-150 ℃; the volume of fluorine-containing gas introduced per minute in the reaction is 10-500 times of the mass of lithium difluorophosphate, the volume of the fluorine-containing reaction gas is calculated by mL, and the mass of the lithium difluorophosphate is calculated by g.
2. The method of claim 1, wherein the inert gas is one of nitrogen, helium, and argon.
3. The method for preparing lithium difluorophosphate as claimed in claim 1, wherein the purification is carried out by recrystallizing and drying the reaction product with an organic solvent.
4. The method for preparing lithium difluorophosphate according to claim 3, wherein the organic solvent is one of an ester solvent, an ether solvent and an alcohol solvent.
5. The method for preparing lithium difluorophosphate as claimed in claim 4, wherein the ester solvent is ethyl acetate, or the ether solvent is methyl tert-butyl ether, or the alcohol solvent is ethanol.
6. The method for preparing lithium difluorophosphate as claimed in claim 3, wherein the step of recrystallizing is carried out by concentrating the mixture of the organic solvent and the reaction product to a volume of 1/5 to 1/3 of the original volume, and then cooling to-10 to-30 ℃.
7. The method for producing lithium difluorophosphate as claimed in claim 1, wherein the flow rate of the fluorine-containing reaction gas is 200 to 1000mL/min.
8. The method for preparing lithium difluorophosphate of claim 1, wherein the reaction time is 10 to 300min.
CN201911159657.1A 2019-11-22 2019-11-22 Preparation method of lithium difluorophosphate Active CN112758904B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201911159657.1A CN112758904B (en) 2019-11-22 2019-11-22 Preparation method of lithium difluorophosphate

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201911159657.1A CN112758904B (en) 2019-11-22 2019-11-22 Preparation method of lithium difluorophosphate

Publications (2)

Publication Number Publication Date
CN112758904A CN112758904A (en) 2021-05-07
CN112758904B true CN112758904B (en) 2022-12-02

Family

ID=75692900

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201911159657.1A Active CN112758904B (en) 2019-11-22 2019-11-22 Preparation method of lithium difluorophosphate

Country Status (1)

Country Link
CN (1) CN112758904B (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115159494B (en) * 2022-09-01 2023-03-21 多氟多新材料股份有限公司 Preparation method of lithium difluorophosphate
CN115771888B (en) * 2023-01-05 2024-01-16 安阳工学院 Preparation method of high-purity lithium difluorophosphate

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108751234A (en) * 2018-06-29 2018-11-06 惠州市宙邦化工有限公司 A kind of method of purification of lithium fluoride

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4479223B2 (en) * 2002-11-12 2010-06-09 株式会社三徳 Method for producing fluorine-containing lithium compound
JP2013539448A (en) * 2010-07-08 2013-10-24 ソルヴェイ（ソシエテ アノニム） Production of LiPO2F2
WO2015028346A1 (en) * 2013-08-28 2015-03-05 Solvay Sa Production of metal difluorophosphates in an inorganic solvent
CN104692405A (en) * 2015-02-04 2015-06-10 多氟多化工股份有限公司 Preparation method of lithium tetrafluoroborate
CN105731399B (en) * 2016-04-29 2018-03-27 多氟多化工股份有限公司 A kind of preparation method of double fluorine sulfimide lithiums
CN205990244U (en) * 2016-08-30 2017-03-01 多氟多化工股份有限公司 A kind of fluorination stove and twin furnace fluorinated systems

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108751234A (en) * 2018-06-29 2018-11-06 惠州市宙邦化工有限公司 A kind of method of purification of lithium fluoride

Also Published As

Publication number Publication date
CN112758904A (en) 2021-05-07

Similar Documents

Publication Publication Date Title
CN108373142B (en) Preparation method of high-purity lithium bis (fluorosulfonyl) imide
CN111224164B (en) Preparation method of lithium difluorophosphate
CN113800485B (en) Preparation method of lithium bis (fluorosulfonyl) imide
CN112758904B (en) Preparation method of lithium difluorophosphate
KR101925044B1 (en) Manufactuiring method for crystallization of lithium difluorophosphate having high-purity and Non-aqueous electrolyte for secondary battery
CN112661791B (en) Preparation method of difluoro lithium bisoxalato phosphate
CN110718716B (en) Silicon-based negative electrode lithium ion battery electrolyte and preparation method thereof
CN114751431B (en) Preparation method of sodium salt for sodium battery
CN101570327A (en) Method for producing lithium hexafluorophosphate
KR102300438B1 (en) Manufacturing method for high-purity crystallization of lithium difluorophosphate with excellet solubility and Non-aqueous electrolyte for secondary battery
CN114634170A (en) Preparation method of lithium difluorophosphate
CN116239130B (en) Method for co-producing hexafluorophosphate and difluorophosphate by one-pot method
CN114560456A (en) Preparation method of lithium difluorophosphate
CN111690010A (en) Preparation method of lithium tetrafluoro oxalate phosphate and lithium difluorobis oxalate phosphate
CN111116429A (en) Method for synthesizing alkali metal trifluoromethanesulfonate
CN113912028B (en) Method for purifying difluoro sulfimide
CN113929711A (en) Preparation method of lithium difluoroborate
KR102693113B1 (en) Method for producing high purity lithium bis(fluorosulfonyl)imide
CN116143088A (en) Preparation method of difluoro-sulfonyl imide and difluoro-sulfonyl imide lithium
CN115321510A (en) Preparation method of lithium difluorophosphate
CN115259112A (en) Production method of bis-fluorosulfonyl imide and lithium salt thereof
CN114621289A (en) Preparation process and application of cyclic phosphate
CN115180610A (en) Method for preparing high-purity lithium difluorophosphate
KR102596526B1 (en) Manufactuiring method for crystallization of lithium difluorophosphate and Crystallization of lithium difluorophosphate
KR102596524B1 (en) Manufactuiring method for crystallization of lithium difluorophosphate and Crystallization of lithium difluorophosphate

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
CB02 Change of applicant information

Address after: 454191 Henan Province, Jiaozuo City Station area coke Rd

Applicant after: Duofudo New Material Co.,Ltd.

Address before: 454191, Feng County, Henan Province, Jiaozuo Feng Feng Chemical Industry Zone

Applicant before: DO-FLUORIDE CHEMICALS Co.,Ltd.

CB02 Change of applicant information
GR01 Patent grant
GR01 Patent grant