CN117886330A - Method for reducing content of monosubstituted difluorophosphate lithium trifluoroborate in mixture - Google Patents
Method for reducing content of monosubstituted difluorophosphate lithium trifluoroborate in mixture Download PDFInfo
- Publication number
- CN117886330A CN117886330A CN202211220899.9A CN202211220899A CN117886330A CN 117886330 A CN117886330 A CN 117886330A CN 202211220899 A CN202211220899 A CN 202211220899A CN 117886330 A CN117886330 A CN 117886330A
- Authority
- CN
- China
- Prior art keywords
- lithium
- difluorophosphate
- trifluoroborate
- mixture
- disubstituted
- 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.)
- Pending
Links
- -1 monosubstituted difluorophosphate lithium trifluoroborate Chemical class 0.000 title claims abstract description 147
- 239000000203 mixture Substances 0.000 title claims abstract description 99
- 238000000034 method Methods 0.000 title claims abstract description 30
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 claims abstract description 32
- 239000012141 concentrate Substances 0.000 claims abstract description 15
- 239000003960 organic solvent Substances 0.000 claims abstract description 13
- 239000013078 crystal Substances 0.000 claims abstract description 11
- QPFMBZIOSGYJDE-UHFFFAOYSA-N 1,1,2,2-tetrachloroethane Chemical compound ClC(Cl)C(Cl)Cl QPFMBZIOSGYJDE-UHFFFAOYSA-N 0.000 claims abstract description 10
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims abstract description 9
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 claims abstract description 8
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 claims abstract description 6
- 238000001914 filtration Methods 0.000 claims abstract description 5
- BZLVMXJERCGZMT-UHFFFAOYSA-N Methyl tert-butyl ether Chemical compound COC(C)(C)C BZLVMXJERCGZMT-UHFFFAOYSA-N 0.000 claims abstract description 4
- DKPFZGUDAPQIHT-UHFFFAOYSA-N Butyl acetate Natural products CCCCOC(C)=O DKPFZGUDAPQIHT-UHFFFAOYSA-N 0.000 claims abstract description 3
- FUZZWVXGSFPDMH-UHFFFAOYSA-N hexanoic acid Chemical compound CCCCCC(O)=O FUZZWVXGSFPDMH-UHFFFAOYSA-N 0.000 claims abstract description 3
- 238000006243 chemical reaction Methods 0.000 claims description 32
- WTEOIRVLGSZEPR-UHFFFAOYSA-N boron trifluoride Chemical compound FB(F)F WTEOIRVLGSZEPR-UHFFFAOYSA-N 0.000 claims description 26
- 229910001496 lithium tetrafluoroborate Inorganic materials 0.000 claims description 17
- 229910015900 BF3 Inorganic materials 0.000 claims description 13
- IGILRSKEFZLPKG-UHFFFAOYSA-M lithium;difluorophosphinate Chemical compound [Li+].[O-]P(F)(F)=O IGILRSKEFZLPKG-UHFFFAOYSA-M 0.000 claims description 13
- 229910003002 lithium salt Inorganic materials 0.000 claims description 12
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 claims description 11
- 239000007810 chemical reaction solvent Substances 0.000 claims description 11
- 239000003792 electrolyte Substances 0.000 claims description 11
- 229910052731 fluorine Inorganic materials 0.000 claims description 11
- 239000011737 fluorine Substances 0.000 claims description 11
- 229910052744 lithium Inorganic materials 0.000 claims description 9
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims description 6
- 229910001416 lithium ion Inorganic materials 0.000 claims description 6
- 159000000002 lithium salts Chemical class 0.000 claims description 5
- 239000002994 raw material Substances 0.000 claims description 5
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 4
- 238000001704 evaporation Methods 0.000 claims description 3
- 238000004821 distillation Methods 0.000 claims description 2
- 238000005292 vacuum distillation Methods 0.000 claims description 2
- 230000001276 controlling effect Effects 0.000 abstract description 2
- 230000001105 regulatory effect Effects 0.000 abstract description 2
- 238000001228 spectrum Methods 0.000 description 48
- 238000002425 crystallisation Methods 0.000 description 25
- 230000008025 crystallization Effects 0.000 description 22
- 238000001514 detection method Methods 0.000 description 12
- 239000000047 product Substances 0.000 description 11
- 230000000052 comparative effect Effects 0.000 description 10
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 9
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 8
- 239000007789 gas Substances 0.000 description 7
- WEVYAHXRMPXWCK-UHFFFAOYSA-N Acetonitrile Chemical compound CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 description 6
- 238000003756 stirring Methods 0.000 description 6
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical group [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 5
- KZMGYPLQYOPHEL-UHFFFAOYSA-N Boron trifluoride etherate Chemical compound FB(F)F.CCOCC KZMGYPLQYOPHEL-UHFFFAOYSA-N 0.000 description 4
- 229910052796 boron Inorganic materials 0.000 description 4
- 238000003860 storage Methods 0.000 description 4
- SLCLABDXYGNNOO-UHFFFAOYSA-N dimethyl carbonate;trifluoroborane Chemical compound FB(F)F.COC(=O)OC SLCLABDXYGNNOO-UHFFFAOYSA-N 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000002390 rotary evaporation Methods 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- BTBUEUYNUDRHOZ-UHFFFAOYSA-N Borate Chemical compound [O-]B([O-])[O-] BTBUEUYNUDRHOZ-UHFFFAOYSA-N 0.000 description 1
- 102100028667 C-type lectin domain family 4 member A Human genes 0.000 description 1
- 101000766908 Homo sapiens C-type lectin domain family 4 member A Proteins 0.000 description 1
- 229910013075 LiBF Inorganic materials 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000001351 cycling effect Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- DGTVXEHQMSJRPE-UHFFFAOYSA-M difluorophosphinate Chemical compound [O-]P(F)(F)=O DGTVXEHQMSJRPE-UHFFFAOYSA-M 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
Classifications
-
- 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 method for reducing the content of single-substituted difluorophosphate lithium trifluoroborate in a mixture, which comprises the following steps: (1) obtaining a mixture concentrate; (2) Adding an organic solvent into the mixture concentrated solution, preserving heat for 0.5-144 h at the temperature of-60-20 ℃, separating out crystals, and filtering to obtain a disubstituted difluoro phosphate lithium trifluoroborate solution; the organic solvent is at least one selected from dichloromethane, chloroform, tetrachloroethane, isopropanol, methyl tertiary butyl ether, butyl acetate and toluene. The invention has the advantages of simple operation, capability of freely regulating and controlling the contents of the disubstituted difluorophosphate lithium trifluoroborate and the monosubstituted difluorophosphate lithium trifluoroborate in the product, and the like.
Description
Technical Field
The invention relates to the field of electrolyte, in particular to a method for reducing monosubstituted difluorophosphate lithium trifluoroborate in a mixture.
Background
The lithium salt electrolyte has a vital effect on the battery, directly influences the electrochemical performance of the battery, particularly has a certain modification effect on positive and negative interfaces by additives such as lithium difluorophosphate, lithium difluorooxalato borate and the like, and can effectively improve the high-temperature storage and the cycling stability of the battery. Development of effective novel salt products is an important direction of electrolyte research.
Patent CN102414902a discloses a novel fluorine-containing lithium salt compound and an electrolyte containing the novel fluorine-containing lithium salt, but as known from the [ 0071 ] section of the specification thereof [ 0077 ], the patent can only obtain a single-substituted novel fluorine-containing lithium salt compound (e.g., liBF 3 (PO 2 F 2 ) Peaks corresponding to the-85.6 ppm (1 f, d, j=961.3 Hz) position) and disubstituted novel fluorine-containing lithium salt compounds (e.g. LiBF 2 (PO 2 F 2 ) 2 The mixture corresponding to the peak at the-83.1 ppm (1 f, d, j=961.3 Hz) position does not give a single-substance disubstituted novel fluorine-containing lithium salt compound, and the patent does not disclose how to give a single-substance disubstituted novel fluorine-containing lithium salt compound. Indeed, the process of this patent is repeated throughout, and the final product obtained is indeed a mixture of mono-and di-substituted new fluorine-containing lithium salt compounds, the content of which is much higher than that of di-substituted new fluorine-containing lithium salt compounds.
The boron atom exists in the form of electron deficiency in the above-mentioned lithium difluorophosphate trifluoroborate so as to coordinate with oxygen having a strong electronegativity in the difluorophosphate to improve the solubility. However, the compatibility of boron atoms to a graphite negative electrode interface is poor, and the monosubstituted difluorophosphate lithium trifluoroborate has better low-impedance performance, but the problems of poor high-temperature storage gas production and long-cycle performance of the battery are caused by the excessively high boron content. Therefore, the disubstituted difluorophosphate lithium trifluoroborate has relatively low boron content, and has the advantages of excellent low-impedance performance, high-temperature gas storage and production, long cycle performance and the like.
Therefore, in order to achieve the best effect of the battery performance, the content of the monosubstituted product in the lithium difluorophosphate lithium trifluoroborate is reduced, and the lithium difluorophosphate lithium trifluoroborate has practical application value.
Disclosure of Invention
In order to solve the technical problems, the invention provides a method which is simple to operate and can reduce the content of single-substituted difluorophosphate lithium trifluoroborate in the mixture.
The invention aims at realizing the following technical scheme:
a method of reducing the content of lithium monosubstituted difluorophosphate trifluoroborate in a mixture, said method comprising the steps of:
(1) Obtaining a mixture concentrate;
(2) Adding an organic solvent into the mixture concentrated solution, preserving heat for 0.5-144 h at the temperature of-60-20 ℃, separating out crystals, and filtering to obtain a disubstituted difluoro phosphate lithium trifluoroborate solution;
the organic solvent is at least one selected from dichloromethane, chloroform, tetrachloroethane, isopropanol, methyl tertiary butyl ether, butyl acetate and toluene.
In step (1), the reaction solvent in the mixture is removed by atmospheric distillation or vacuum distillation to obtain a mixture concentrate. Because the mixture concentrate is in a solvated state, the mixture concentrate contains a reaction solvent, specifically, the mixture concentrate has a reaction solvent content of at least 40 wt.% or less, preferably at least 36 wt.% or less, more preferably at least 30 wt.% or less, and most preferably at least 20 wt.% or less.
The invention adopts a crystallization method to realize the conversion from the single-substituted difluorophosphate lithium trifluoroborate to the double-substituted difluorophosphate lithium trifluoroborate, thereby reducing the content of the single-substituted difluorophosphate lithium trifluoroborate in the mixture. LiBF4 crystals are precipitated at the same time when the lithium monosubstituted difluorophosphate trifluoroborate is converted into the lithium disubstituted difluorophosphate trifluoroborate.
The method can adopt single crystallization or multiple crystallization, and the content of the single-substituted difluorophosphate lithium trifluoroborate in the monomer crystallization mixture is higher than that of the single-substituted difluorophosphate lithium trifluoroborate in the mixture after multiple crystallization, so that the single-substituted difluorophosphate lithium trifluoroborate can be lower and even disappear along with the increase of crystallization times.
The disubstituted difluorophosphate lithium trifluoroborate solution obtained by the steps (1) and (2) is single crystallization; after the step (2) is carried out to obtain the disubstituted difluorophosphate lithium trifluoroborate solution, the step (1) and the step (2) are continuously repeated once, namely, secondary crystallization is carried out; and (3) after the disubstituted difluorophosphate lithium trifluoroborate solution is obtained in the step (2), continuously repeating the step (1) and the step (2) for two or more times, namely, performing multiple crystallization.
In the step (2) of the method according to the present invention, the organic solvent is preferably at least one selected from the group consisting of methylene chloride, chloroform and tetrachloroethane, and more preferably methylene chloride.
In step (2) of the method of the present invention, the volume of the organic solvent is 0.2 to 10 times, preferably 0.5 to 5 times, more preferably 1 to 2 times the volume of the mixture concentrate.
In the step (2) of the method, crystals are preferably separated out after heat preservation for 3-36 hours at the temperature of minus 30-0 ℃ and then filtered; more preferably, the temperature is kept at-20 to 0 ℃ for 2 to 24 hours to precipitate crystals, and then the crystals are filtered. The difference of crystallization time can be used for regulating and controlling the precipitation proportion of LiBF4, the precipitation time is increased at any time, the precipitated LiBF4 is increased, and the content of the single-substituted difluorophosphate lithium trifluoroborate in the mixture is reduced.
The mixture of the invention can be a mixture of monosubstituted difluorophosphate lithium trifluoroborate and disubstituted difluorophosphate lithium trifluoroborate which are prepared by taking lithium difluorophosphate and boron trifluoride/boron trifluoride complex as raw materials. The reaction formula is as follows:
in the reaction process, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, acetonitrile, diethyl ether and the like are adopted as reaction solvents, a certain amount of lithium difluorophosphate (purity is 99%) is added into a reaction bottle, and stirring is started to uniformly mix the system; the same molar amount of boron trifluoride gas or boron trifluoride dimethyl carbonate complex or boron trifluoride diethyl etherate complex is introduced into the reaction flask and stirred to react thoroughly.
In a specific operation mode, 1mol of lithium difluorophosphate (purity 99%) is added into a reaction bottle, dimethyl carbonate is used as a solvent, and stirring is started to uniformly mix the system; then, 1mol of boron trifluoride gas was introduced into the reaction flask, and the mixture was reacted at 25℃for 24 hours.
The mixture of the invention can also be a mixture of single-substituted difluorophosphate lithium trifluoroborate and lithium tetrafluoroborate, which is prepared by taking lithium difluorophosphate and boron trifluoride/boron trifluoride complex as raw materials and lithium tetrafluoroborate as a reaction accelerator. The reaction formula is as follows:
in the reaction process, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, acetonitrile, diethyl ether and the like are adopted as reaction solvents, a certain amount of lithium difluorophosphate and lithium tetrafluoroborate are added into a reaction bottle, the molar charging ratio of the lithium difluorophosphate to a reaction accelerator LiBF4 is 1 (0.02-3), and stirring is started to uniformly mix the system; the same molar amount of boron trifluoride gas or boron trifluoride dimethyl carbonate complex or boron trifluoride diethyl etherate complex as that of lithium difluorophosphate is introduced into the reaction flask, and the reaction is sufficiently carried out with stirring.
In a specific operation mode, 1mol of lithium difluorophosphate (purity 99%) and 0.5mol of lithium tetrafluoroborate are added into a reaction bottle, dimethyl carbonate is used as a solvent, and stirring is started to uniformly mix the system; then, 1mol of boron trifluoride gas was introduced into the reaction flask, and the mixture was reacted at 25℃for 24 hours.
The method for reducing the content of the single-substituted difluorophosphate lithium trifluoroborate in the mixture further comprises the following steps:
and (3) evaporating the organic solvent to obtain a disubstituted difluorophosphate lithium trifluoroborate product.
The crystallization method can obviously reduce the content of the single-substituted difluorophosphate lithium trifluoroborate in the mixture.
In a specific embodiment, single crystallization is adopted to generate LiBF4, the LiBF4 can be precipitated in a crystal form, and when the molar ratio of the precipitated LiBF4 to the monosubstituted difluorophosphate lithium trifluoroborate in the mixture concentrate is (0.153-0.256): 1, the LiBF4 is filtered and removed, and then the organic solvent is distilled off, so that the product with the mass content of the disubstituted difluorophosphate lithium trifluoroborate of 50-70 wt% is obtained. The specific reaction equation is as follows:
in another specific embodiment, multiple crystallization is employed to produce LiBF4, which LiBF4 can be precipitated in crystalline form, when the molar ratio of precipitated LiBF4 to the monosubstituted difluorophosphate lithium trifluoroborate in the mixture concentrate is (0.256-0.5): and 1, filtering to remove LiBF4, and evaporating to remove the organic solvent to obtain a product with the mass content of 70-100 wt% of the disubstituted difluorophosphate lithium trifluoroborate.
The reaction solvent of the mixture is contained in the product of the disubstituted lithium difluorophosphate trifluoroborate, and the reaction solvent and the disubstituted lithium difluorophosphate trifluoroborate exist in a solvated state. Typically, the disubstituted difluorophosphate lithium trifluoroborate product comprises about 10 to 40 weight percent reaction solvent. For the convenience of calculation, the content of the disubstituted difluorophosphate lithium trifluoroborate is 100 weight percent of the content of the fluorine-containing lithium salt.
In a preferred embodiment, the lithium disubstituted difluorophosphate trifluoroborate product comprises at least 60 weight percent lithium disubstituted difluorophosphate trifluoroborate by multiple crystallization, wherein the lithium disubstituted difluorophosphate trifluoroborate product further comprises not more than 35 weight percent lithium monosubstituted difluorophosphate trifluoroborate and not more than 5 weight percent lithium trisubstituted difluorophosphate trifluoroborate. The disubstituted lithium difluorophosphate trifluoroborate product can comprise 80 weight percent of the disubstituted lithium difluorophosphate trifluoroborate, 90 weight percent of the disubstituted lithium difluorophosphate trifluoroborate, and even more than 99 weight percent of the disubstituted lithium difluorophosphate trifluoroborate.
The invention also provides a lithium ion battery electrolyte, in particular to the electrolyte which comprises the disubstituted difluoro phosphate lithium trifluoroborate product obtained by the method.
The invention also provides a lithium ion battery, in particular to the lithium ion battery comprising the electrolyte.
Compared with the prior art, the invention has the following beneficial effects:
the invention adopts a crystallization method to reduce the content of the monosubstituted difluorophosphate lithium trifluoroborate in the mixture, greatly improves the content of the disubstituted difluorophosphate lithium trifluoroborate, namely reduces the proportion of boron element in the mixture, and improves the compatibility with a graphite negative electrode interface when the mixture is used in electrolyte. Meanwhile, the high-temperature storage performance and long-cycle stability of the battery can be improved, particularly, the high-temperature gas production of the battery is inhibited, the constant-temperature cycle capacity retention is improved, and the increase of the internal resistance of the circulating DCIR is reduced.
Detailed Description
The invention will be further illustrated with reference to the following specific examples, without limiting the invention to these specific embodiments. It will be appreciated by those skilled in the art that the invention encompasses all alternatives, modifications and equivalents as may be included within the scope of the claims.
The mixture adopted in the embodiment of the invention is monosubstituted difluorophosphate lithium trifluoroborate and disubstituted difluorophosphate lithium trifluoroborate which are prepared by taking lithium difluorophosphate and boron trifluoride complex as raw materials, and the specific preparation method comprises the following steps: adding 1mol of lithium difluorophosphate (purity 99%) into a reaction bottle, taking 500g of dimethyl carbonate as a reaction solvent, and starting stirring to uniformly mix the system; then, 1mol of boron trifluoride dimethyl carbonate complex was added to the reaction flask and reacted at 25℃for 24 hours. A mixture containing lithium monosubstituted difluorophosphate trifluoroborate and lithium di-substituted difluorophosphate trifluoroborate is obtained. The mixture contained 33% by weight of lithium difluorophosphate trifluoroborate and 67% by weight of lithium monodifluorophosphate trifluoroborate.
Example 1
The embodiment provides a method for reducing the content of single-substituted difluorophosphate lithium trifluoroborate in a mixture, which specifically comprises the following steps:
s1, performing rotary evaporation on the mixture in a drying room with a dew point of-40 ℃ by using a rotary evaporator to obtain a mixture concentrated solution (the content of the dimethyl carbonate is about 15 wt%).
S2, adding dichloromethane into the mixture concentrate according to the volume ratio of 1:1, preserving heat for 24 hours at the temperature of minus 20 ℃, precipitating crystals, and filtering to obtain a disubstituted difluoro phosphate lithium trifluoroborate solution, which is marked as composition 1.
The nuclear magnetic F-spectrum is shown below by NMR detection:
substituted difluorophosphate lithium trifluoroborate: delta = -88.87ppm (d, J = 958.8 Hz), delta = -154.54 ppm(s)
Disubstituted difluorophosphate lithium trifluoroborate: delta= -88.62ppm (d, j= 963.5 Hz), delta= -147.90 ppm(s)
The nuclear magnetic P-spectrum is shown below:
substituted difluorophosphate lithium trifluoroborate: delta = -29.08ppm (t, J = 958.8 Hz)
Disubstituted difluorophosphate lithium trifluoroborate: delta= -30.47ppm (t, j= 963.5 Hz)
The nuclear magnetic P spectrum peak area is integrated, and the composition 1 contains 61.6wt% of disubstituted difluorophosphate lithium trifluoroborate and 38.4wt% of monosubstituted difluorophosphate lithium trifluoroborate. And the F spectrum is used for carrying out area integral conversion, so that the results are uniform, and the calculation reliability is high.
Example 2
The operation of this embodiment is identical to that of embodiment 1, except that: the mixture is subjected to three crystallization, specifically: after primary crystallization to obtain a disubstituted difluorophosphate lithium trifluoroborate solution, repeating the steps S1 and S2 to perform secondary crystallization; and (3) after secondary crystallization to obtain a disubstituted difluorophosphate lithium trifluoroborate solution, repeating the steps S1 and S2 to perform third crystallization, and recording the obtained disubstituted difluorophosphate lithium trifluoroborate solution as a composition 2.
The nuclear magnetic F-spectrum is shown below by NMR detection:
substituted difluorophosphate lithium trifluoroborate: delta = -88.87ppm (d, J = 958.8 Hz), delta = -154.54 ppm(s)
Disubstituted difluorophosphate lithium trifluoroborate: delta= -88.62ppm (d, j= 963.5 Hz), delta= -147.90 ppm(s)
Trisubstituted difluorophosphate lithium trifluoroborate: delta= -88.08ppm (d, j= 972.8 Hz), delta= -143.46 ppm(s)
The nuclear magnetic P-spectrum is shown below:
substituted difluorophosphate lithium trifluoroborate: delta = -29.37ppm (t, J = 958.8 Hz)
Disubstituted difluorophosphate lithium trifluoroborate: delta= -30.47ppm (t, j= 963.5 Hz)
Trisubstituted difluorophosphate lithium trifluoroborate: delta = -31.83ppm (t, J = 972.8 Hz)
The peak area of the nuclear magnetic P spectrum is integrated, and the composition 2 contains 89.2 weight percent of disubstituted difluorophosphate lithium trifluoroborate, 8.7 weight percent of monosubstituted difluorophosphate lithium trifluoroborate and 2.1 weight percent of trisubstituted difluorophosphate lithium trifluoroborate. And the F spectrum is used for carrying out area integral conversion, so that the results are uniform, and the calculation reliability is high.
Example 3
The operation of this embodiment is identical to that of embodiment 1, except that: in the step S2, the crystallization temperature is increased to 5 ℃, and other conditions are unchanged, and the obtained disubstituted difluorophosphate lithium trifluoroborate solution is named as a composition 3.
Nuclear magnetic P-spectrum and F-spectrum were obtained by NMR detection. The nuclear magnetic P spectrum peak area is integrated, and the composition 3 contains 53.8 weight percent of disubstituted difluorophosphate lithium trifluoroborate and 46.2 weight percent of monosubstituted difluorophosphate lithium trifluoroborate. And the F spectrum is used for carrying out area integral conversion, so that the results are uniform, and the calculation reliability is high.
Example 4
The operation of this embodiment is identical to that of embodiment 1, except that: in the step S2, methyl tertiary butyl ether is adopted to replace dichloromethane, other conditions are unchanged, and the obtained disubstituted difluorophosphate lithium trifluoroborate solution is named as a composition 4.
Nuclear magnetic P-spectrum and F-spectrum were obtained by NMR detection. The nuclear magnetic P spectrum peak area is integrated, and the composition 4 contains 43.8 weight percent of disubstituted difluorophosphate lithium trifluoroborate and 56.2 weight percent of monosubstituted difluorophosphate lithium trifluoroborate. And the F spectrum is used for carrying out area integral conversion, so that the results are uniform, and the calculation reliability is high.
Example 5
The operation of this embodiment is identical to that of embodiment 1, except that: in the step S2, tetrachloroethane is adopted to replace dichloromethane, and other conditions are unchanged, and the obtained disubstituted difluorophosphate lithium trifluoroborate solution is named as a composition 5.
Nuclear magnetic P-spectrum and F-spectrum were obtained by NMR detection. The nuclear magnetic P spectrum peak area is integrated, and 58.7 weight percent of disubstituted difluorophosphate lithium trifluoroborate and 41.3 weight percent of monosubstituted difluorophosphate lithium trifluoroborate are contained in the composition 5. And the F spectrum is used for carrying out area integral conversion, so that the results are uniform, and the calculation reliability is high.
Example 6
The operation of this embodiment is identical to that of embodiment 1, except that: in the step S2, methylene dichloride is added into the mixture concentrated solution according to the volume ratio of 1:10, and other conditions are unchanged, and the obtained disubstituted difluorophosphate lithium trifluoroborate solution is named as a composition 6.
Nuclear magnetic P-spectrum and F-spectrum were obtained by NMR detection. The nuclear magnetic P spectrum peak area is integrated, and the composition 6 contains 66.4 weight percent of disubstituted difluorophosphate lithium trifluoroborate and 43.6 weight percent of monosubstituted difluorophosphate lithium trifluoroborate. And the F spectrum is used for carrying out area integral conversion, so that the results are uniform, and the calculation reliability is high.
Example 7
The operation of this embodiment is identical to that of embodiment 1, except that: the mixture is subjected to six crystallization, specifically: after the primary crystallization to obtain the disubstituted difluorophosphate lithium trifluoroborate solution, repeating the steps S1 and S2 for five times, and carrying out six crystallization operations altogether, wherein the obtained disubstituted difluorophosphate lithium trifluoroborate solution is denoted as a composition 7.
Nuclear magnetic P-spectrum and F-spectrum were obtained by NMR detection. The peak area of the nuclear magnetic P spectrum is integrated, and the composition 7 contains 95.6wt% of disubstituted difluorophosphate lithium trifluoroborate, 1.2wt% of monosubstituted difluorophosphate lithium trifluoroborate and 3.2wt% of trisubstituted difluorophosphate lithium trifluoroborate. And the F spectrum is used for carrying out area integral conversion, so that the results are uniform, and the calculation reliability is high.
Comparative example 1
The comparative example provides a method for reducing the content of single-substituted difluorophosphate lithium trifluoroborate in a mixture, which specifically comprises the following steps:
s1, performing rotary evaporation on the mixture in a drying room with a dew point of-40 ℃ by using a rotary evaporator to obtain a mixture concentrated solution (the content of the dimethyl carbonate is about 15 wt%).
S2, adding dimethyl carbonate into the mixture concentrate according to the volume ratio of 1:1, and preserving the temperature at-20 ℃ for 24 hours, wherein no crystal is found to be separated out, and obtaining a disubstituted difluoro phosphate lithium trifluoroborate solution, which is marked as a composition D1.
Nuclear magnetic P-spectrum and F-spectrum were obtained by NMR detection. The nuclear magnetic P spectrum peak area is integrated, and the composition D1 is converted to contain 33 weight percent of disubstituted difluorophosphate lithium trifluoroborate and 67 weight percent of monosubstituted difluorophosphate lithium trifluoroborate. And the F spectrum is used for carrying out area integral conversion, so that the results are uniform, and the calculation reliability is high.
Comparative example 2
The operation of this comparative example is the same as in example 1, except that: in the step S2, ethanol is adopted to replace dichloromethane, and other conditions are unchanged, so that the obtained disubstituted difluorophosphate lithium trifluoroborate solution is named as a composition D2.
Nuclear magnetic P-spectrum and F-spectrum were obtained by NMR detection. The nuclear magnetic P spectrum peak area is integrated, and the composition D2 contains 35.2 weight percent of disubstituted difluorophosphate lithium trifluoroborate and 64.8 weight percent of monosubstituted difluorophosphate lithium trifluoroborate. And the F spectrum is used for carrying out area integral conversion, so that the results are uniform, and the calculation reliability is high.
Comparative example 3
The operation of this comparative example is the same as in example 1, except that: in the step S2, diethyl ether is adopted to replace dichloromethane, and other conditions are unchanged, so that the obtained disubstituted difluorophosphate lithium trifluoroborate solution is recorded as a composition D3.
Nuclear magnetic P-spectrum and F-spectrum were obtained by NMR detection. The nuclear magnetic P spectrum peak area is integrated, and the composition D3 contains 31.7wt% of disubstituted difluorophosphate lithium trifluoroborate and 68.3wt% of monosubstituted difluorophosphate lithium trifluoroborate. And the F spectrum is used for carrying out area integral conversion, so that the results are uniform, and the calculation reliability is high.
Comparative example 4
The operation of this comparative example is the same as in example 1, except that: in the step S2, the crystallization temperature is raised to 25 ℃, and other conditions are unchanged, and the obtained disubstituted difluorophosphate lithium trifluoroborate solution is named as a composition D4.
Nuclear magnetic P-spectrum and F-spectrum were obtained by NMR detection. The nuclear magnetic P spectrum peak area is integrated, and the composition D4 contains 38.8 weight percent of disubstituted difluorophosphate lithium trifluoroborate and 61.2 weight percent of monosubstituted difluorophosphate lithium trifluoroborate. And the F spectrum is used for carrying out area integral conversion, so that the results are uniform, and the calculation reliability is high.
Comparative example 5
The operation of this comparative example is the same as in example 1, except that: in step S1, the mixture was subjected to rotary evaporation using a rotary evaporator to obtain a mixture concentrate (reaction solvent content: about 50%). The resulting solution of lithium difluorophosphate trifluoroborate was identified as composition D5, with the other conditions unchanged.
Nuclear magnetic P-spectrum and F-spectrum were obtained by NMR detection. The nuclear magnetic P spectrum peak area is integrated, and the composition D5 contains 41.3 weight percent of disubstituted difluorophosphate lithium trifluoroborate and 58.7 weight percent of monosubstituted difluorophosphate lithium trifluoroborate. And the F spectrum is used for carrying out area integral conversion, so that the results are uniform, and the calculation reliability is high.
Claims (13)
1. A method for reducing the content of lithium monosubstituted difluorophosphate trifluoroborate in a mixture, comprising the steps of: the method comprises the following steps:
(1) Obtaining a mixture concentrate;
(2) Adding an organic solvent into the mixture concentrated solution, preserving heat for 0.5-144 hours at the temperature of-60-20 ℃, separating out crystals, and filtering to obtain a disubstituted difluorophosphate lithium trifluoroborate solution;
the organic solvent is at least one selected from dichloromethane, chloroform, tetrachloroethane, isopropanol, methyl tertiary butyl ether, butyl acetate or toluene.
2. The method for reducing the content of the single-substituted difluorophosphate lithium trifluoroborate in the mixture as claimed in claim 1, wherein: in the step (1), the reaction solvent is removed by atmospheric distillation or vacuum distillation to obtain a mixture concentrate.
3. The method for reducing the content of the single-substituted difluorophosphate lithium trifluoroborate in the mixture as claimed in claim 1, wherein: and (3) continuously repeating the step (1) and the step (2) once after the disubstituted difluorophosphate lithium trifluoroborate solution is obtained in the step (2).
4. The method for reducing the content of the single-substituted difluorophosphate lithium trifluoroborate in the mixture as claimed in claim 1, wherein: and (3) continuously repeating the step (1) and the step (2) for two or more times after the disubstituted difluorophosphate lithium trifluoroborate solution is obtained in the step (2).
5. The method for reducing the content of the single-substituted difluorophosphate lithium trifluoroborate in the mixture as claimed in claim 1, wherein: the volume of the organic solvent is 0.2-10 times of the volume of the mixture concentrate.
6. The method for reducing the content of the single-substituted difluorophosphate lithium trifluoroborate in the mixture as claimed in claim 1, wherein: the mixture is a mixture of monosubstituted difluoro phosphate lithium trifluoroborate and disubstituted difluoro phosphate lithium trifluoroborate prepared by taking lithium difluorophosphate and boron trifluoride/boron trifluoride complex as raw materials.
7. The method for reducing the content of the single-substituted difluorophosphate lithium trifluoroborate in the mixture as claimed in claim 1, wherein: the mixture is prepared from lithium difluorophosphate and boron trifluoride/boron trifluoride complex serving as raw materials and lithium tetrafluoroborate serving as a reaction accelerator.
8. The method for reducing the content of the single-substituted difluorophosphate lithium trifluoroborate in the mixture as claimed in claim 1, wherein: in the step (2), the temperature is kept at-20 to 0 ℃ for 2 to 24 hours to precipitate crystals.
9. A method for reducing the content of lithium monosubstituted difluorophosphate trifluoroborate in a mixture as claimed in any one of claims 1-8, wherein: the method further comprises the steps of:
(3) Evaporating the organic solvent to obtain the disubstituted difluorophosphate lithium trifluoroborate product.
10. The method for reducing the content of the lithium monosubstituted difluorophosphate trifluoroborate in the mixture as claimed in claim 9, wherein: the disubstituted lithium difluorophosphate trifluoroborate product contains at least 60 weight percent of the disubstituted lithium difluorophosphate trifluoroborate based on 100 weight percent total amount of the fluorine-containing lithium salt.
11. The method for reducing the content of the single-substituted difluorophosphate lithium trifluoroborate in the mixture as claimed in claim 10, wherein: the lithium disubstituted difluorophosphate trifluoroborate product contains not more than 35 weight percent of lithium monosubstituted difluorophosphate trifluoroborate and not more than 5 weight percent of lithium trisubstituted difluorophosphate trifluoroborate, based on 100 weight percent of the total amount of the fluorine-containing lithium salt.
12. The lithium ion battery electrolyte is characterized in that: the electrolyte comprises a disubstituted difluorophosphate lithium trifluoroborate product obtained by the method of any one of claims 9-11.
13. A lithium ion battery, characterized in that: the lithium ion battery comprises the electrolyte of claim 12.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211220899.9A CN117886330A (en) | 2022-10-08 | 2022-10-08 | Method for reducing content of monosubstituted difluorophosphate lithium trifluoroborate in mixture |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211220899.9A CN117886330A (en) | 2022-10-08 | 2022-10-08 | Method for reducing content of monosubstituted difluorophosphate lithium trifluoroborate in mixture |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117886330A true CN117886330A (en) | 2024-04-16 |
Family
ID=90649636
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211220899.9A Pending CN117886330A (en) | 2022-10-08 | 2022-10-08 | Method for reducing content of monosubstituted difluorophosphate lithium trifluoroborate in mixture |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117886330A (en) |
-
2022
- 2022-10-08 CN CN202211220899.9A patent/CN117886330A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5315971B2 (en) | Method for producing difluorobis (oxalato) lithium phosphate solution | |
| CN107226821B (en) | A kind of synthesis technology preparing difluorine oxalic acid boracic acid lithium with di-oxalate lithium borate | |
| KR102083080B1 (en) | The method for preparing lithium difluorophosphate using difluorophosphate ester | |
| CN108910919B (en) | Preparation method of electronic-grade lithium difluorobis (oxalate) phosphate | |
| CN101861323B (en) | Double (oxalic acid) lithium borates (LiBOB) being completely dissolved of crystallization | |
| KR20010072657A (en) | Lithium bisoxalatoborate, the production thereof and its use as a conducting salt | |
| CN109850926B (en) | Preparation method of lithium tetrafluoro oxalate phosphate and lithium difluorobis oxalate phosphate | |
| KR101887488B1 (en) | Manufactuiring method for crystallization of lithium difluorophosphate having high-purity and Non-aqueous electrolyte for secondary battery | |
| CN115340573B (en) | Preparation method of lithium difluorobis (oxalate) phosphate | |
| KR102300438B1 (en) | Manufacturing method for high-purity crystallization of lithium difluorophosphate with excellet solubility and Non-aqueous electrolyte for secondary battery | |
| CN109678694A (en) | A kind of preparation method of tetrafluoro oxalic acid lithium phosphate | |
| CN115340081A (en) | Method for synthesizing ammonium difluorophosphate | |
| JP3034202B2 (en) | Electrolyte for lithium battery, method for purifying the same, and lithium battery using the same | |
| CN113929711A (en) | Preparation method of lithium difluoroborate | |
| JP2020147558A (en) | Preparation method of high-purity lithium salt by mixture in predetermined ratio and applications of the lithium salt | |
| CN109627256A (en) | A kind of preparation method of the double borate boron difluorides of pentaerythrite | |
| CN113512052A (en) | Preparation process of lithium difluoroborate | |
| KR102219684B1 (en) | A method for preparing litium difluorophosphate | |
| CN117886330A (en) | Method for reducing content of monosubstituted difluorophosphate lithium trifluoroborate in mixture | |
| CN104230970B (en) | Preparation method of lithium difluorooxalatoborate electrolyte | |
| CN110627742A (en) | Preparation method and purification method of compound containing at least one cyclic ligand structure | |
| JP3555720B2 (en) | Addition compound of lithium hexafluorophosphate, method for producing the same, and electrolyte using the same | |
| CN110845524B (en) | Method for preparing specific lithium salt by using organic acyloxy silane | |
| CN117088390B (en) | Preparation method of hexafluorophosphate, electrolyte and secondary battery | |
| CN112830498A (en) | Lithium salt and preparation method thereof, lithium ion battery electrolyte additive, lithium ion battery electrolyte and lithium ion battery |
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 |