CN113716543B - Preparation method and application of lithium monofluorophosphate - Google Patents
Preparation method and application of lithium monofluorophosphate Download PDFInfo
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- SXWUDUINABFBMK-UHFFFAOYSA-L dilithium;fluoro-dioxido-oxo-$l^{5}-phosphane Chemical compound [Li+].[Li+].[O-]P([O-])(F)=O SXWUDUINABFBMK-UHFFFAOYSA-L 0.000 title claims abstract description 47
- 238000002360 preparation method Methods 0.000 title claims abstract description 32
- -1 lithium hexafluorophosphate Chemical compound 0.000 claims abstract description 29
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims abstract description 18
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 18
- 239000011574 phosphorus Substances 0.000 claims abstract description 18
- 238000005580 one pot reaction Methods 0.000 claims abstract description 15
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 claims abstract description 11
- 229910052808 lithium carbonate Inorganic materials 0.000 claims abstract description 11
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical group [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 25
- 239000002904 solvent Substances 0.000 claims description 20
- 238000000034 method Methods 0.000 claims description 19
- 239000003960 organic solvent Substances 0.000 claims description 16
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 claims description 14
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims description 9
- 239000000376 reactant Substances 0.000 claims description 9
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims description 8
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 claims description 7
- 238000007086 side reaction Methods 0.000 claims description 7
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 6
- XTHFKEDIFFGKHM-UHFFFAOYSA-N Dimethoxyethane Chemical compound COCCOC XTHFKEDIFFGKHM-UHFFFAOYSA-N 0.000 claims description 6
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 claims description 6
- VZGDMQKNWNREIO-UHFFFAOYSA-N tetrachloromethane Chemical compound ClC(Cl)(Cl)Cl VZGDMQKNWNREIO-UHFFFAOYSA-N 0.000 claims description 6
- DLYUQMMRRRQYAE-UHFFFAOYSA-N tetraphosphorus decaoxide Chemical compound O1P(O2)(=O)OP3(=O)OP1(=O)OP2(=O)O3 DLYUQMMRRRQYAE-UHFFFAOYSA-N 0.000 claims description 6
- UEZVMMHDMIWARA-UHFFFAOYSA-N Metaphosphoric acid Chemical compound OP(=O)=O UEZVMMHDMIWARA-UHFFFAOYSA-N 0.000 claims description 5
- 239000013078 crystal Substances 0.000 claims description 5
- 229920000137 polyphosphoric acid Polymers 0.000 claims description 5
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 claims description 4
- 150000002576 ketones Chemical class 0.000 claims description 4
- 235000011007 phosphoric acid Nutrition 0.000 claims description 4
- 125000004437 phosphorous atom Chemical group 0.000 claims description 4
- SCYULBFZEHDVBN-UHFFFAOYSA-N 1,1-Dichloroethane Chemical compound CC(Cl)Cl SCYULBFZEHDVBN-UHFFFAOYSA-N 0.000 claims description 3
- 230000035484 reaction time Effects 0.000 claims description 3
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 claims description 2
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 claims description 2
- POLCUAVZOMRGSN-UHFFFAOYSA-N dipropyl ether Chemical compound CCCOCCC POLCUAVZOMRGSN-UHFFFAOYSA-N 0.000 claims description 2
- 238000001556 precipitation Methods 0.000 claims description 2
- 239000002994 raw material Substances 0.000 abstract description 7
- 230000007797 corrosion Effects 0.000 abstract description 4
- 238000005260 corrosion Methods 0.000 abstract description 4
- 229910052744 lithium Inorganic materials 0.000 description 23
- 238000006243 chemical reaction Methods 0.000 description 20
- 239000000047 product Substances 0.000 description 10
- 238000012360 testing method Methods 0.000 description 10
- 239000003792 electrolyte Substances 0.000 description 9
- 239000000203 mixture Substances 0.000 description 9
- 229910052731 fluorine Inorganic materials 0.000 description 7
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 6
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 6
- 239000011737 fluorine Substances 0.000 description 6
- 229910001416 lithium ion Inorganic materials 0.000 description 6
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- YWEUIGNSBFLMFL-UHFFFAOYSA-N diphosphonate Chemical compound O=P(=O)OP(=O)=O YWEUIGNSBFLMFL-UHFFFAOYSA-N 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 239000000654 additive Substances 0.000 description 3
- 230000000996 additive effect Effects 0.000 description 3
- 238000000354 decomposition reaction Methods 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 238000001914 filtration Methods 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 239000012535 impurity Substances 0.000 description 3
- IGILRSKEFZLPKG-UHFFFAOYSA-M lithium;difluorophosphinate Chemical compound [Li+].[O-]P(F)(F)=O IGILRSKEFZLPKG-UHFFFAOYSA-M 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000007773 negative electrode material Substances 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- 239000002002 slurry Substances 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 239000012298 atmosphere Substances 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 239000007795 chemical reaction product Substances 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000011255 nonaqueous electrolyte Substances 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 239000013589 supplement Substances 0.000 description 2
- 230000001988 toxicity Effects 0.000 description 2
- 231100000419 toxicity Toxicity 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 238000005303 weighing Methods 0.000 description 2
- 239000002000 Electrolyte additive Substances 0.000 description 1
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 1
- 229910000733 Li alloy Inorganic materials 0.000 description 1
- 229910013870 LiPF 6 Inorganic materials 0.000 description 1
- 238000002479 acid--base titration Methods 0.000 description 1
- 239000006183 anode active material Substances 0.000 description 1
- 239000012300 argon atmosphere Substances 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 239000003518 caustics Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000002001 electrolyte material Substances 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 229910000040 hydrogen fluoride Inorganic materials 0.000 description 1
- 238000002354 inductively-coupled plasma atomic emission spectroscopy Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 238000009830 intercalation Methods 0.000 description 1
- 230000002687 intercalation Effects 0.000 description 1
- 239000013067 intermediate product Substances 0.000 description 1
- 238000004255 ion exchange chromatography Methods 0.000 description 1
- VUZPPFZMUPKLLV-UHFFFAOYSA-N methane;hydrate Chemical compound C.O VUZPPFZMUPKLLV-UHFFFAOYSA-N 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 239000007774 positive electrode material Substances 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000001577 simple distillation Methods 0.000 description 1
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
- C01B25/16—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
- H01M10/052—Li-accumulators
-
- 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
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- 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
-
- 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
Abstract
The invention discloses a preparation method and application of lithium monofluorophosphate. A preparation method of lithium monofluorophosphate comprises the step of carrying out one-pot reaction on lithium hexafluorophosphate, lithium carbonate and a phosphorus source. According to the preparation method of lithium monofluorophosphate, the preparation raw materials are optimized, so that one-pot reaction can be realized, and the preparation process is simplified; meanwhile, the preparation raw materials with serious corrosiveness are abandoned, so that the corrosion of the preparation process to equipment is relieved.
Description
Technical Field
The invention belongs to the technical field of lithium battery raw materials, and particularly relates to a preparation method of lithium monofluorophosphate.
Background
The rapid development of the fields of new energy automobiles and the like brings higher requirements to lithium ion batteries and key materials thereof. Lithium hexafluorophosphate is an electrolyte material which is most widely used at present due to excellent chemical and electrochemical properties, but has poor thermal stability, high sensitivity to moisture and easy decomposition to generate corrosive substances, so that side reactions such as electrolyte decomposition and the like can be generated in the working process of a lithium battery taking lithium hexafluorophosphate as an electrolyte salt, the performances such as cycle, high-temperature storage and the like of the battery can be influenced, and further the application of the lithium battery under special conditions such as high temperature, low temperature and high multiplying power and the like is limited. Therefore, the development of electrolyte salt capable of improving the electrochemical and chemical stability of the lithium battery as an additive to assist and improve the performance of lithium hexafluorophosphate, thereby improving the performance of the lithium battery, becomes an important research direction at the present stage.
Lithium monofluorophosphate, molecular formula Li 2 PO 3 F, as a lithium battery additive, the comprehensive performance of the lithium battery can be obviously improved, and the specific performance is that: at least one of lithium monofluorophosphate and lithium difluorophosphate is used as an additive in an organic solvent (electrolyte), so that the obtained nonaqueous electrolyte can form a film on the surface of a positive electrode and a negative electrode of a lithium battery, further inhibit the electrolyte from decomposing caused by the contact of the nonaqueous electrolyte with a positive electrode active material or a negative electrode active material, inhibit self-discharge, improve the preservation performance and remarkably improve the high-temperature storage performance of the lithium ion battery.
However, the process for preparing lithium monofluorophosphate at the present stage is complex, has serious corrosion to equipment, and is difficult to realize batch and high-quality production.
Disclosure of Invention
The present invention aims to solve at least one of the technical problems in the prior art described above. Therefore, the invention provides the preparation method of the lithium monofluorophosphate, and the preparation raw materials are optimized, so that one-pot reaction can be realized, and the preparation process is simplified; meanwhile, the preparation raw materials with serious corrosiveness are abandoned, so that the corrosion of the preparation process to equipment is relieved.
The invention also provides a lithium battery with the lithium monofluorophosphate obtained by the preparation method.
According to one aspect of the invention, a preparation method of lithium monofluorophosphate is provided, which takes lithium hexafluorophosphate, lithium carbonate and phosphorus source as raw materials and is prepared by one-pot reaction.
According to a preferred embodiment of the invention, there is at least the following advantageous effect:
(1) In the traditional preparation method of lithium monofluorophosphate, fluorine gas or hydrogen fluoride is generally adopted as a fluorine source, and the fluorine source has high reactivity, but in order to inhibit side reactions, strict environmental control is required for reaction conditions, so that the preparation cost is increased; meanwhile, the fluorine source has stronger toxicity and corrosiveness and has stronger harm to operators and preparation equipment; according to the invention, lithium hexafluorophosphate is used as a fluorine source, so that toxicity and corrosion hazard are reduced, meanwhile, phosphorus in the lithium hexafluorophosphate can supplement the phosphorus source, and lithium in the lithium hexafluorophosphate can supplement the lithium source, so that the yield of a reaction product is ensured.
(2) Because the selected preparation raw materials and products have different polarities and have different solubilities in specific solvents, the separation of residual reactants and lithium monofluorophosphate can be realized only by adjusting the solubility of the lithium monofluorophosphate in a mixture obtained after one-pot reaction, and the separation of intermediate products is not needed, so that the preparation process is simplified, and the purity of the obtained lithium monofluorophosphate is improved.
In some embodiments of the invention, the molar ratio of the lithium hexafluorophosphate to the lithium carbonate is (1.95-2.15): 11.
In some preferred embodiments of the invention, the molar ratio of the lithium hexafluorophosphate to the lithium carbonate is (2-2.1): 11.
In some embodiments of the invention, the molar ratio of lithium atoms in the lithium hexafluorophosphate to phosphorus atoms in the phosphorus source is (21.5-23.5): 10.
In some preferred embodiments of the present invention, the molar ratio of lithium atoms in the lithium hexafluorophosphate to phosphorus atoms in the phosphorus source is (22-23.1): 10.
In some embodiments of the invention, the lithium hexafluorophosphate is added in an amount of 1 to 1.07 times the theoretical reaction amount.
In some preferred embodiments of the present invention, the lithium hexafluorophosphate is added in an amount of 1 to 1.05 times the theoretical reaction amount.
The theoretical reaction amount is calculated according to the stoichiometric number of a reaction equation.
In some embodiments of the invention, the phosphorus source is selected from at least one of phosphorus pentoxide, metaphosphoric acid, orthophosphoric acid, and polyphosphoric acid.
When the phosphorus source is selected from phosphorus pentoxide, the reaction equation of the one-pot reaction is shown as formula (1):
5P 2 O 5 +11Li 2 CO 3 +2LiPF 6 →12Li 2 PO 3 F+11CO 2 ↑ (1)。
when the phosphorus source is selected from metaphosphoric acid, the reaction equation of the one-pot reaction is shown in formula (2):
10HPO 3 +11Li 2 CO 3 +2LiPF 6 →12Li 2 PO 3 F+5H 2 O+11CO 2 ↑ (2)。
when the phosphorus source is selected from orthophosphoric acid, the reaction equation of the one-pot reaction is shown as formula (3):
10H 3 PO 4 +11Li 2 CO 3 +2LiPF 6 →12Li 2 PO 3 F+15H 2 O+11CO 2 ↑ (3)。
when the phosphorus source is selected from polyphosphoric acid, the one-pot reaction has a reaction equation shown in formula (4):
5H 6 P 4 O 13 +22Li 2 CO 3 +4LiPF 6 →24Li 2 PO 3 F+15H 2 O+22CO 2 ↑ (4)。
from the reaction formulae (1) to (4), it is known that when the phosphorus source is selected from at least one of phosphorus pentoxide, metaphosphoric acid, orthophosphoric acid and polyphosphoric acid, the resultant reaction product includes only carbon dioxide and water in addition to the lithium monofluorophosphate, the carbon dioxide being evolved from the system during the reaction, and the water being removable by simple distillation; therefore, the preparation method is simple in impurity removal, and the purity of the obtained product is high.
In some embodiments of the invention, the one-pot reaction is at a temperature of 30 to 70 ℃.
In some embodiments of the invention, the one-pot reaction time is 1 to 10 hours.
In some preferred embodiments of the invention, the preparation method comprises the steps of:
s1, adding the lithium carbonate and a phosphorus source into an organic solvent in which the lithium hexafluorophosphate is dissolved to perform one-pot reaction;
s2, concentrating the product obtained in the step S1, and separating out crystals to obtain the product.
In some embodiments of the invention, in step S1, the weight ratio of the lithium hexafluorophosphate to the organic solvent is 1 (2-15).
In some embodiments of the invention, the weight ratio of the lithium hexafluorophosphate to the organic solvent is 1 (4-10).
In some embodiments of the present invention, in step S1, the organic solvent is selected from at least one of an ester solvent, an ether solvent, and a ketone solvent.
In some embodiments of the invention, the ester solvent is selected from at least one of dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and ethyl acetate.
In some embodiments of the invention, the ether solvent is selected from at least one of diethyl ether, propyl ether, and ethylene glycol dimethyl ether.
In some embodiments of the invention, the ketone solvent is selected from at least one of acetone and butanone.
In some embodiments of the invention, in step S2, the concentrating is one of atmospheric concentrating and vacuum concentrating.
In some embodiments of the invention, the reduced pressure concentration is at a temperature of 40 to 80 ℃.
In some embodiments of the invention, the reduced pressure concentration is at a pressure of-0.09 to-0.1 MPa.
In some embodiments of the invention, in step S2, the precipitating crystals comprises adding a poor solvent for the lithium monofluorophosphate to the resulting product after the concentrating.
The poor solvent is used for reducing the solubility of the lithium monofluorophosphate in the mixture (mainly the organic solvent used in the step S1), thereby realizing the precipitation of lithium monofluorophosphate crystals.
In some embodiments of the invention, the poor solvent is selected from at least one of dichloroethane, carbon tetrachloride and toluene.
In some embodiments of the invention, the poor solvent is added in an amount of 1 to 5 times the theoretical mass of the lithium monofluorophosphate.
The theoretical mass of the lithium monofluorophosphate means the yield of the lithium monofluorophosphate under the condition that reactants with small addition amount in the reaction formulas (1) to (4) are completely reacted and no side reaction exists; for example, in formula (1), when the molar ratio of the reactants is 6 moles of P 2 O 5 11 mol Li 2 CO 3 And 4 moles of LiPF 6 Then Li 2 CO 3 The reactant with small addition amount can theoretically generate 12mol of lithium monofluorophosphate after the reaction is completed, and the mass is 112g/mol multiplied by 12 mol=1344g; the addition mass of the poor solvent is 1 to 5 times that of 1344 g.
In some embodiments of the invention, the preparation process is carried out under an atmosphere of a shielding gas.
In some embodiments of the invention, the shielding gas is selected from at least one of nitrogen and an inert gas.
According to still another aspect of the present invention, there is provided a lithium battery including the lithium monofluorophosphate prepared by the preparation method.
The lithium battery according to a preferred embodiment of the present invention has at least the following advantageous effects:
the electrolyte in the lithium battery generally adopts lithium hexafluorophosphate as electrolyte salt, and side reactions such as electrolyte decomposition and the like can be generated in the use process of the lithium battery, and after the lithium monofluorophosphate prepared by the invention is added, a protective film can be formed on the positive and negative pole pieces, so that the side reactions are relieved; in addition, the purity of the electrolyte and the electrolyte additive has obvious influence on the electrochemical performance and the safety performance of the lithium battery, and the lithium monofluorophosphate obtained by the method has high purity and further inhibits the occurrence of side reactions in the lithium battery.
The lithium battery of the present invention includes at least one of a lithium metal battery and a lithium ion battery, unless otherwise specified.
The lithium metal battery comprises a negative electrode active material, a lithium battery and a lithium battery, wherein the negative electrode active material is an alloy of lithium metal and lithium and other materials; the lithium ion battery is characterized in that the anode active material is a material capable of containing lithium ions and supporting the removal and intercalation of the lithium ions.
Detailed Description
The conception and the technical effects produced by the present invention will be clearly and completely described in conjunction with the embodiments below to fully understand the objects, features and effects of the present invention. It is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments, and that other embodiments obtained by those skilled in the art without inventive effort are within the scope of the present invention based on the embodiments of the present invention.
Example 1
The lithium monofluorophosphate is prepared by the embodiment, and the specific process is as follows:
s1, weighing 50g of lithium hexafluorophosphate (about 0.329mol and about 1.005 times of theoretical addition amount) under a nitrogen atmosphere, adding into a closed container containing 500g of ethyl methyl carbonate, and stirring to prepare slurry;
then, 133.8g of lithium carbonate (about 1.8 mol) and 116.7g of phosphorus pentoxide (about 0.822mol, the least amount of the reactants added) were slowly added to the resulting mixture, and the reaction temperature was controlled at 70℃for 1 hour to obtain a mixture containing lithium monofluorophosphate;
s2, then, the temperature of the mixture obtained in the step S1 is increased to 80 ℃ for concentration, the concentration pressure is controlled to be minus 0.09MPa, and the organic solvent is distilled out to be about 2/3 of the added organic solvent; after concentration, 1080g of dichloroethane poor solvent is added to separate out solid, and 183g of lithium monofluorophosphate product is obtained after filtration and drying, and the yield is 82.8%.
The reaction equation occurring in this example and the theoretical yield of lithium monofluorophosphate are calculated as follows:
5P 2 O 5 +11Li 2 CO 3 +2LiPF 6 →12Li 2 PO 3 F+11CO 2 ↑；
5×142 12×112；
theoretical yield: 116.78g 221g;
yield = actual value x 100%/theoretical value = 183 x 100%/221 = 82.8%.
Example 2
The lithium monofluorophosphate is prepared by the embodiment, and the specific process is as follows:
s1, under the argon atmosphere, 80g of lithium hexafluorophosphate (about 0.526mol and about 1.05 times of the theoretical addition amount) is weighed, added into a closed container containing 480g of ethylene glycol dimethyl ether, and stirred to prepare slurry;
then, 204g of lithium carbonate (about 2.757mol, reactant with small addition amount) and 200.5g of metaphosphoric acid (about 2.506 mol) were slowly added to the obtained mixture, and the reaction temperature was controlled at 50 ℃ for 5 hours to obtain a reactant containing lithium monofluorophosphate;
s2, raising the temperature of the mixture obtained in the step S1 to 60 ℃ for concentration, controlling the concentration pressure to be-0.095 MPa, and evaporating the organic solvent to be about 2/3 of the added organic solvent; after concentration, 670g of toluene poor solvent is added to precipitate solid, and 286g of lithium monofluorophosphate product is obtained through filtration and drying, and the yield is 84.9%.
The reaction equation for the reaction in this example and the theoretical yield and yield of lithium difluorophosphate obtained are as follows:
10HPO 3 +11Li 2 CO 3 +2LiPF 6 →12Li 2 PO 3 F+5H 2 O+11CO 2 ↑
11×74 12×112；
theoretical yield: 204.04g 336.88g;
yield = actual x 100%/theoretical = 286 x 100%/336.88 = 84.9%.
Example 3
The lithium monofluorophosphate is prepared by the embodiment, and the specific process is as follows:
s1, weighing 100g of lithium hexafluorophosphate (about 0.6579mol, about 1.02 times of the theoretical addition amount) under helium atmosphere, adding into a closed container containing 400g of acetone, and stirring to prepare slurry;
then, 262.4g of lithium carbonate (about 3.546mol, a small amount of a reactant) and 272.4g of polyphosphoric acid (about 0.806 mol) were slowly added to the obtained mixture, the reaction temperature was controlled to 20 ℃ and the reaction time was controlled to 10 hours, to obtain a mixture containing lithium monofluorophosphate;
s2, concentrating at the temperature of 40 ℃, controlling the concentration pressure to be-0.01 MPa, and evaporating out the organic solvent to be about 2/3 of the added organic solvent; after concentration, 430g of carbon tetrachloride poor solvent is added to separate out solid, and 362g of lithium monofluorophosphate product is obtained through filtration and drying, and the yield is 83.55%.
The reaction equation in this example and the theoretical yield and the yield of lithium monofluorophosphate are as follows:
5H 6 P 4 O 13 +22Li 2 CO 3 +4LiPF 6 →24Li 2 PO 3 F+15H 2 O+22CO 2 ↑；
5×338 24×112；
theoretical yield: 272.4 433.26;
yield = actual x 100%/theoretical = 362 x 100%/433.26 = 83.55%.
Test examples
This test example tests the purity of lithium monofluorophosphate prepared in the examples and comparative examples. Wherein:
the method for testing the metal cation content in lithium monofluorophosphate comprises the steps of adopting ICP-OES test;
the method for testing the moisture comprises the following steps: coulomb method;
the acidity testing method comprises the following steps: acid-base titration;
and testing the product types by adopting a fluorine spectrum and a phosphorus spectrum to judge whether other fluorine-phosphorus compound impurities are contained.
Purity was tested by ion chromatography.
The test results are shown in Table 1.
Table 1 test results of lithium monofluorophosphate obtained in examples 1 to 3.
The results obtained in Table 1 show that the product yield of the preparation method of lithium monofluorophosphate provided by the invention is more than or equal to 82.8%, and meanwhile, the purity of the lithium difluorophosphate obtained by the invention is higher as the content of impurities is known.
While the embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge of those skilled in the art. Furthermore, embodiments of the invention and features of the embodiments may be combined with each other without conflict.
Claims (15)
1. A method for preparing lithium monofluorophosphate, comprising the steps of:
s1, adding lithium carbonate and a phosphorus source into an organic solvent dissolved with lithium hexafluorophosphate to perform one-pot reaction; the reaction time of one pot is 1-10 h;
s2, concentrating the product obtained in the step S1, and separating out crystals to obtain the product;
the phosphorus source is selected from at least one of phosphorus pentoxide, metaphosphoric acid, orthophosphoric acid and polyphosphoric acid;
the molar ratio of the lithium hexafluorophosphate to the lithium carbonate is 1.95-2.15:11;
the molar ratio of lithium atoms in the lithium hexafluorophosphate to phosphorus atoms in the phosphorus source is 21.5-23.5:10;
the temperature of the one-pot reaction is 30-70 ℃.
2. The preparation method of claim 1, wherein the molar ratio of the lithium hexafluorophosphate to the lithium carbonate is 2-2.1:11.
3. The preparation method of claim 1, wherein the molar ratio of lithium atoms in the lithium hexafluorophosphate to phosphorus atoms in the phosphorus source is 22-23.1:10.
4. The preparation method according to claim 1, wherein in the step S1, the weight ratio of the lithium hexafluorophosphate to the organic solvent is 1:2-15.
5. The preparation method according to claim 1, wherein in the step S1, the weight ratio of the lithium hexafluorophosphate to the organic solvent is 1:4-10.
6. The method according to claim 1, wherein in step S1, the organic solvent is at least one selected from the group consisting of an ester solvent, an ether solvent and a ketone solvent.
7. The method according to claim 6, wherein the ester solvent is at least one selected from the group consisting of dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate and ethyl acetate.
8. The method according to claim 6, wherein the ether solvent is at least one selected from the group consisting of diethyl ether, propyl ether and ethylene glycol dimethyl ether.
9. The method according to claim 6, wherein the ketone solvent is at least one selected from the group consisting of acetone and butanone.
10. The method according to claim 1, wherein in step S2, the concentration is one of normal pressure concentration and reduced pressure concentration.
11. The process according to claim 10, wherein the reduced pressure concentration is carried out at a temperature of 40 to 80 ℃.
12. The method according to claim 10, wherein the reduced pressure concentration is carried out at a pressure of-0.09 to-0.1 MPa.
13. The method according to claim 1, wherein in step S2, the precipitation of crystals comprises adding a poor solvent for the lithium monofluorophosphate to the resultant product after the concentration.
14. The method of claim 13, wherein the poor solvent is selected from at least one of dichloroethane, carbon tetrachloride and toluene.
15. The preparation method of claim 13, wherein the addition amount of the poor solvent is 1-5 times the theoretical mass of the lithium monofluorophosphate; the theoretical mass of the lithium monofluorophosphate refers to the yield of the lithium monofluorophosphate under the condition that the reactant with a small addition amount is completely reacted and no side reaction exists.
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