CN115000518A - Application of compound with sulfur ring phosphoryl ester structure as electrolyte high-voltage additive - Google Patents

Application of compound with sulfur ring phosphoryl ester structure as electrolyte high-voltage additive Download PDF

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CN115000518A
CN115000518A CN202210733130.0A CN202210733130A CN115000518A CN 115000518 A CN115000518 A CN 115000518A CN 202210733130 A CN202210733130 A CN 202210733130A CN 115000518 A CN115000518 A CN 115000518A
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additive
electrolyte
lithium
compound
voltage
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高田慧
盖建丽
陈涛
徐康杰
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Tianmu Lake Institute of Advanced Energy Storage Technologies Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0567—Liquid materials characterised by the additives
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • 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

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Abstract

The invention discloses application of a compound with a sulfur ring phosphoryl ester structure as an electrolyte high-voltage additive, a composite additive and a lithium battery high-voltage electrolyte, wherein the high-voltage additive is applied to the electrolyte of a lithium ion battery, so that a stable and compact inorganic CEI (ceramic electronic interface) film can be formed on a positive electrode, transition metal ions on the surface of a positive electrode material are stabilized, oxygen precipitation of the positive electrode material is inhibited, and oxidative decomposition of the electrolyte is reduced; the composite SEI film can be formed on the negative electrode and the auxiliary additive, so that the stability of the negative electrode SEI film is improved, the performance of the lithium battery under the high-voltage condition is improved, and the long high-temperature cycle life of the lithium battery is prolonged.

Description

Application of compound with sulfur ring phosphoryl ester structure as electrolyte high-voltage additive
Technical Field
The invention relates to the technical field of lithium batteries, in particular to application of a compound with a sulfur ring phosphoryl ester structure as an electrolyte high-voltage additive.
Background
Since commercialization in the 90's of the 20 th century, lithium batteries have been widely used because of their advantages of high energy density, high charge and discharge efficiency, small self-discharge, long service life, and environmental friendliness. The method is applied to the fields of consumer electronics, aerospace, military, electric tools, electric automobiles and the like. With skillIn the development of the technology, people have higher and higher requirements on the energy density of lithium ion batteries in the consumer field and the power battery field, and the improvement of the working voltage of the lithium battery becomes one of the technologies for improving the energy density of the lithium battery. Various high voltage positive electrode materials have been developed, such as high voltage lithium cobaltate, high voltage nickel manganese materials, and olivine structured LiMPO 4 And the like.
However, in the research of high voltage lithium batteries, it has been found that, as the voltage of the lithium battery increases, the conventional electrolyte not only undergoes oxidative decomposition by itself, but also undergoes chemical reaction with the positive electrode material, resulting in degradation of battery performance and severely shortening of battery service life. Therefore, the development of electrolyte matching with high voltage lithium battery becomes key.
Disclosure of Invention
In order to solve the technical problems, the invention provides a compound with a sulfur ring phosphoryl ester structure as an electrolyte high-voltage additive, wherein the high-voltage additive can improve the stability of a CEI (cellulose-activated carbon) membrane on the surface of a battery anode material and improve the service performance of a lithium battery.
The technical scheme adopted for realizing the purpose of the invention is as follows:
on one hand, the invention provides application of a compound with a sulfur ring phosphoryl ester structure as an electrolyte high-voltage additive.
Specifically, the structural formula of the compound with the structure of the thiocyclophosphoryl ester is as follows:
Figure BDA0003714642340000011
wherein, R1, R2, R3 and R4 can be selected from one of hydrogen, alkyl with 1-6 carbon atoms, alkenyl, alkynyl or cycloalkyl with 6-12 carbon atoms, cycloalkenyl, aryl and halogenated derivatives thereof, the halogenation in the halogenated derivatives of the alkyl, the alkenyl, the alkynyl and the aryl is partial substitution or full substitution, and the halogen in the halogenation part is one or more of fluorine, chlorine and bromine.
Further, R1 and R2 are preferably one of hydrogen, alkyl with 1-2 carbon atoms, alkenyl, alkynyl or fluorinated alkyl, and R3 and R4 are preferably hydrogen, alkyl with 1-2 carbon atoms or alkenyl.
Further, R1 and R2 are preferably one of hydrogen, methyl, ethane, vinyl, ethynyl or trifluoromethyl, R3 is preferably one of hydrogen, methyl or vinyl, and R4 is preferably hydrogen or methyl.
Specifically, the adding amount of the compound with the structure of the thiocyclophosphoryl ester is 0.05-5 wt% of the total mass of the electrolyte.
On the other hand, the invention also provides a composite additive, wherein the composite additive is a combination of the compound with the structure of the thiocyclophosphatyl ester and a compound additive, the compound additive is an auxiliary additive A and/or an auxiliary additive B, the auxiliary additive A is one or more of lithium tetrafluoroborate, lithium bis (oxalato) borate and lithium difluoro (oxalato) borate, and lithium difluoro (oxalato) borate is preferred, and lithium difluoro (LiDFOB) borate is preferred; the auxiliary additive B is one or more of vinylene carbonate, vinyl ethylene carbonate, vinyl ethyl acetate, ethylene sulfite, propylene sulfite, ethylene sulfate, 1, 3-propane sultone, propenyl-1, 3-propane sultone, 1, 4-butane sultone, methyl methane disulfonate, hexamethyldisilazane, magnesium trifluoromethanesulfonate, tris (pentafluorophenyl) boron, tris (trimethylsilane) phosphate and tris (trimethylsilane) phosphite, and is preferably Vinylene Carbonate (VC), and the addition amount of the compound additive is 0.5-5 wt% of the total mass of the electrolyte.
Further, the ratio of the compound with the structure of the thiocyclophosphoryl ester to the compound additive is 1:1-5, preferably 1:1-3, more preferably 1: (2. + -. 0.5).
The electrolyte also comprises lithium salt and an organic solvent; further, the lithium salt can be selected from one or more of lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium perchlorate, lithium difluorophosphate, lithium bis (trifluoromethyl) sulfonyl imide and lithium bis (fluoro) sulfonyl imide, and is preferably lithium hexafluorophosphate; further, the organic solvent may be selected from any one or more of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, 1, 4-butyrolactone, methyl formate, ethyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, ethyl butyrate and halogenated derivatives thereof, and preferably, ethylene carbonate, fluoroethylene carbonate, diethyl carbonate and propyl propionate are mixed.
Further, the auxiliary additive can be selected from one or more of vinylene carbonate, vinyl ethylene carbonate, vinyl ethyl acetate, ethylene sulfite, propylene sulfite, vinyl sulfate, 1, 3-propane sultone, propenyl-1, 3-propane sultone, 1, 4-butane sultone, methyl methylene methane disulfonate, hexamethyldisilazane, magnesium imine trifluoromethanesulfonate, tris (pentafluorophenyl) boron, tris (trimethylsilane) phosphate, tris (trimethylsilane) phosphite, preferably one or more of vinylene carbonate, vinyl ethylene carbonate, vinyl ethyl acetate, ethylene sulfite, propylene sulfite, and vinyl sulfate, more preferably vinylene carbonate, and the lithium salt is added in an amount of 0.5 wt% to 20 wt% of the total mass of the electrolyte, the adding amount of the organic solvent is 70-90 wt% of the total mass of the electrolyte.
On the other hand, the invention also provides a high-voltage electrolyte of a lithium battery, which comprises the lithium salt, an organic solvent, a high-voltage additive and a compound additive, wherein the high-voltage additive is the compound with the thiophosphoryl ester structure, and the addition amount of the high-voltage additive is 0.05-5 wt% of the total mass of the electrolyte.
Compared with the prior art, the invention has the beneficial effects that:
the invention takes the compound with the structure of the sulfur ring phosphoryl ester as the high-voltage additive in the electrolyte, which not only can form a stable and compact inorganic CEI film on the anode, stabilize the transition metal ions on the surface of the anode material, inhibit the oxygen precipitation of the anode material and reduce the oxidative decomposition of the electrolyte; the composite SEI film can be formed on the negative electrode and the auxiliary additive, so that the stability of the negative electrode SEI film is improved, the performance of the lithium battery under a high-voltage condition is improved, and the long high-temperature cycle life of the lithium battery is prolonged.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
Example 1
The present invention will be described in detail with reference to examples.
A high voltage additive having the formula:
Figure BDA0003714642340000031
Figure BDA0003714642340000041
Figure BDA0003714642340000051
example 1: preparation of lithium batteries
(1) Selecting lithium cobaltate suitable for high voltage as a positive electrode material, and preparing the positive electrode material LiCoO 2 Mixing CNTs and PVDF uniformly according to the ratio of 97.5:1:1.5, coating the mixture on an aluminum foil current collector, drying the aluminum foil current collector through an oven, rolling the aluminum foil current collector on a roller press, and compacting the aluminum foil current collector to obtain the aluminum foil current collector with the density of 4.0g/cm 3 And obtaining the required positive plate.
(2) Selecting artificial graphite as a negative electrode material, and mixing graphite, CMC, a conductive agent and a binder according to a ratio of 95: 1.2: 1.8:
2 to obtain the negative pole piece, wherein the compaction density of the pole piece is 1.6g/cm 3 。
(3) Selecting a PE film coated with ceramic as an isolating film (9+3+3) um, and manufacturing a pole piece into a small soft package battery of 1.5Ah by a lamination method for testing high-voltage electrolyte.
Example 2: lithium battery performance test
The charging and discharging voltage window of the lithium battery is 3.0-4.45V; the cycle test of the battery is that the room temperature is 25 ℃ and the high temperature is 45 ℃, and the charge and discharge current of the cycle is 0.5C.
Example 3:
in argon atmosphere, the environmental index is H 2 O≤0.5ppm，O 2 In a glove box with the mass ratio of EC/FEC/DEC/PP being equal to or less than 2.0ppm, organic solvents EC, FEC, DEC and PP are mixed according to the mass ratio of EC/FEC/DEC/PP being 25/5/50/20, then lithium hexafluorophosphate is added for dissolution, electrolyte with the concentration of lithium hexafluorophosphate being 1.1M is prepared, then 1% of auxiliary additive VC is added, then 1% of high-voltage additive A is added, and electrolyte I is prepared.
Example 4:
in argon atmosphere, the environmental index is H 2 O≤0.5ppm，O 2 In a glove box with the mass ratio of less than or equal to 2.0ppm, mixing organic solvents of Ethylene Carbonate (EC), fluoroethylene carbonate (FEC), diethyl carbonate (DEC) and Propyl Propionate (PP) according to the mass ratio of EC/FEC/DEC/PP of 25/5/50/20, adding lithium hexafluorophosphate for dissolution to prepare an electrolyte with the concentration of lithium hexafluorophosphate of 1.1M, adding 1% of an auxiliary additive VC, and then adding 1% of a high-voltage additive B to prepare an electrolyte II.
Example 5:
in argon atmosphere, the environmental index is H 2 O≤0.5ppm，O 2 In a glove box with the mass ratio of EC/FEC/DEC/PP being equal to or less than 2.0ppm, organic solvents EC, FEC, DEC and PP are mixed according to the mass ratio of EC/FEC/DEC/PP being 25/5/50/20, then lithium hexafluorophosphate is added for dissolution, electrolyte with the concentration of lithium hexafluorophosphate being 1.1M is prepared, then 1% of auxiliary additive VC is added, then 1% of high-voltage additive C is added, and electrolyte III is prepared.
Example 6:
in argon atmosphere, the environmental index is H 2 O≤0.5ppm，O 2 In a glove box with the mass ratio of EC/FEC/DEC/PP being equal to or less than 2.0ppm, organic solvents EC, FEC, DEC and PP are mixed according to the mass ratio of EC/FEC/DEC/PP being 25/5/50/20, then lithium hexafluorophosphate is added for dissolution, electrolyte with the concentration of lithium hexafluorophosphate being 1.1M is prepared, then 1% of auxiliary additive VC is added, then 1% of high-voltage additive D is added, and electrolyte IV is prepared.
Example 7:
in an argon atmosphere, the environmental index is H 2 O≤0.5ppm，O 2 In a glove box with the mass ratio of EC/FEC/DEC/PP being equal to or less than 2.0ppm, organic solvents EC, FEC, DEC and PP are mixed according to the mass ratio of EC/FEC/DEC/PP being 25/5/50/20, then lithium hexafluorophosphate is added for dissolution, electrolyte with the concentration of lithium hexafluorophosphate being 1.1M is prepared, then 1% of auxiliary additive VC is added, then 1% of high-voltage additive E is added, and electrolyte V is prepared.
Example 8:
in an argon atmosphere, the environmental index is H 2 O≤0.5ppm，O 2 In a glove box with the mass ratio of EC/FEC/DEC/PP being less than or equal to 2.0ppm, mixing organic solvents EC, FEC, DEC and PP according to the mass ratio of EC/FEC/DEC/PP being 25/5/50/20, then adding lithium hexafluorophosphate for dissolution, preparing electrolyte with the concentration of lithium hexafluorophosphate being 1.1M, then adding 1% of auxiliary additive VC, then adding 1% of high voltage additive F, and preparing electrolyte VI.
Example 9:
in argon atmosphere, the environmental index is H 2 O≤0.5ppm，O 2 In a glove box with the mass ratio of EC/FEC/DEC/PP being equal to or less than 2.0ppm, mixing organic solvents EC, FEC, DEC and PP according to the mass ratio of EC/FEC/DEC/PP being 25/5/50/20, then adding lithium hexafluorophosphate for dissolution, preparing electrolyte with the concentration of lithium hexafluorophosphate being 1.1M, then adding 1% of auxiliary additive VC, and then adding 0.5% of high-voltage additive E, thus preparing the electrolyte VII.
Example 10:
in an argon atmosphere, the environmental index is H 2 O≤0.5ppm，O 2 In a glove box with the mass ratio of less than or equal to 2.0ppm, organic solvents EC, FEC, DEC and PP are mixed according to the mass ratio of EC/FEC/DEC/PP which is 25/5/50/20, and then lithium hexafluorophosphate is added for carrying outDissolving, preparing electrolyte with lithium hexafluorophosphate concentration of 1.1M, then adding 1% of auxiliary additive VC, and then respectively adding 1% of high-voltage additives E and F to prepare electrolyte VIII.
Example 11:
in argon atmosphere, the environmental index is H 2 O≤0.5ppm，O 2 In a glove box with the mass ratio of EC/FEC/DEC/PP being equal to or less than 2.0ppm, organic solvents EC, FEC, DEC and PP are mixed according to the mass ratio of EC/FEC/DEC/PP being 25/5/50/20, then lithium hexafluorophosphate is added for dissolution, electrolyte with the concentration of lithium hexafluorophosphate being 1.1M is prepared, then 1% of auxiliary additive LiDFOB is added, and then 1% of high voltage additive E is added, thus preparing electrolyte IX.
Example 12:
in argon atmosphere, the environmental index is H 2 O≤0.5ppm，O 2 In a glove box with the mass ratio of EC/FEC/DEC/PP being equal to or less than 2.0ppm, organic solvents EC, FEC, DEC and PP are mixed according to the mass ratio of EC/FEC/DEC/PP being 25/5/50/20, then lithium hexafluorophosphate is added for dissolution, electrolyte with the concentration of lithium hexafluorophosphate being 1.1M is prepared, then 2% of auxiliary additive LiDFOB is added, and then 1% of high voltage additive E is added, thus preparing the electrolyte X.
Example 13:
in argon atmosphere, the environmental index is H 2 O≤0.5ppm，O 2 In a glove box with the mass ratio of EC/FEC/DEC/PP being equal to or less than 2.0ppm, organic solvents EC, FEC, DEC and PP are mixed according to the mass ratio of EC/FEC/DEC/PP being 25/5/50/20, then lithium hexafluorophosphate is added for dissolution, electrolyte with the concentration of lithium hexafluorophosphate being 1.1M is prepared, then 1% of auxiliary additives VC and LiDFOB are respectively added, and then 1% of high voltage additive E is added, thus preparing the electrolyte XI.
Comparative example 1:
in argon atmosphere, the environmental index is H 2 O≤0.5ppm，O 2 In a glove box with the mass ratio EC/FEC/DEC of 2.0ppm or less, organic solvents EC, FEC, and DEC were mixed at 25/5/70, and then lithium hexafluorophosphate was added to dissolve the mixture, to prepare an electrolyte solution with the concentration of lithium hexafluorophosphate of 1M, and then 1% of an auxiliary additive VC was added to prepare a comparative electrolyte solution 1.
Comparative example 2:
in a glove box with the environmental indexes of H2O ≤ 0.5ppm and O2 ≤ 2.0ppm under an argon atmosphere, organic solvents EC, FEC, and DEC were mixed at a mass ratio of EC/FEC/DEC of 25/5/70, and then lithium hexafluorophosphate was added to dissolve the organic solvents, thereby preparing an electrolyte solution with a lithium hexafluorophosphate concentration of 1M, and then 1% of an auxiliary additive VC and LiDFOB were added, respectively, to prepare a comparative electrolyte solution 2.
Table 1 shows the results of the electrical property tests of the electrolytes of examples 3 to 13 and comparative examples 1 and 2.
Table 1: summary of electrical property data for different electrolytes
Figure BDA0003714642340000081
From the comparative analysis of the experimental data in table 1, the following conclusions can be drawn:
comparing examples 3-8 with comparative example 1 respectively, it is seen that after the high-voltage additive disclosed by the invention is added into the electrolyte, the electrolyte performance parameters such as capacity retention rate of 300 cycles at 25 ℃ and capacity retention rate of 150 cycles at 45 ℃ are greatly improved compared with the electrolyte without the high-voltage additive, and the high-voltage additive disclosed by the invention is proved to be excellent in performance and the prepared high-voltage electrolyte is good in electrical performance.
From examples 3 to 8, it can be seen that the used high-voltage additives are A, B, C, D, E, F used alone respectively, and the auxiliary additives are all VC, and from the electrical property of the prepared electrolyte, the electrical property of the electrolyte ii obtained in example 4 is the best, the first effect of the electrolyte reaches 90.14%, the capacity retention rate reaches 86.4% after being cycled at 25 ℃ for 300 weeks, and the capacity retention rate reaches 84.8% after being cycled at 45 ℃ for 150 weeks, which verifies that R1 and R2 in the sulfur cyclic phosphoryl ester structural compound select an alkenyl group with 1-2 carbon atoms, and the electrical property of the electrolyte is good when R3 and R4 select hydrogen, which indicates that carbon-carbon double bonds play a key role in the electrolytic reaction of the lithium battery, stabilizes transition metal ions on the surface of the positive electrode material, inhibits oxygen precipitation of the positive electrode material, and reduces oxidative decomposition of the electrolyte.
The ratio of the compound with the structure of the thiocyclophosphoryl ester (namely, the high-voltage additive) to the compound additive can be 1:1-5, preferably 1:1-3, more preferably 1: (2 ± 0.5); as can be seen from comparison between example 7 and example 9, when the auxiliary additive VC and the high voltage additive E are used simultaneously, and the amounts of the auxiliary additive VC and the high voltage additive E are changed, it is found that the electrical property index of the electrolyte is better when the amount ratio of the VC to the high voltage additive E is 2: 1; similarly, it can be seen from example 11 and example 12 that the performance of the electrolyte when the LiDFOB and the high voltage additive E are used together at a ratio of 2:1 is better than that of the electrolyte when the LiDFOB and the high voltage additive E are added at a ratio of 1:1. It was verified that an electrolyte having more excellent electrical properties can be obtained by appropriately increasing the content of LiDFOB or VC.
It can be seen from the comparison between example 7 or example 8 and example 10 that when two high-voltage additives E, F are used simultaneously, compared with the electrolyte obtained by using the high-voltage additive E or F alone, the capacity retention rate of the electrolyte obtained by using the two high-voltage additives at 45 ℃ for 150 weeks is found to reach 84.2%, the retention rate is higher, the electrical property is better, and the fact that when the thiophosphoryl ester structural compound contains a dilute bond and a fluoroalkyl group at the same time is verified, the prepared electrolyte has better electrical property, which shows that the existence of a carbon-carbon double bond and fluorine at the same time plays a key role in the electrolytic reaction of the lithium battery.
Comparative example 2, example 7, example 11 and example 13 demonstrate that the electrical performance index of the electrolyte increases gradually when the high-voltage additive, the auxiliary additive LiDFOB alone or the auxiliary additive VC alone and the auxiliary additives LiDFOB and VC are added into the electrolyte, which shows that the electrical performance is better after the high-voltage additive is combined with the compound additive LiDFOB and/or VC.
Specifically, example 13 and comparative example 2 can verify that: the first effect, capacity retention ratio of 300 weeks at 25 ℃ and capacity retention ratio of 150 weeks at 45 ℃ of the electrolyte obtained by using the two additives VC or LiDFOB are all higher than the performance of the electrolyte without the high-voltage additive. Example 7 and example 11 verify that when the high-voltage additive E is used simultaneously and the auxiliary additive is used for VC and lidfeed, the first effect of the electrolyte obtained by using the lidfeed alone reaches 90.35%, the capacity retention ratio reaches 90.6% at 25 ℃ after 300 cycles, and the capacity retention ratio reaches 87.2% at 45 ℃ after 150 cycles, which are better than the electrical performance of the electrolyte using VC alone; examples 11 and 13 demonstrate that the electrolyte performance obtained using the two auxiliary additives VC and liddob was slightly better than the electrolyte performance of liddob alone at 45 ℃ for 150 cycles when the high voltage additive E was used together.
In conclusion, compared with the electrolytes 1 and 2 without the high-voltage additive, the long high-temperature cycle life of the lithium battery is improved to a certain extent in a proper addition range after the high-voltage additive is used, and the electrical property is better after the high-voltage additive is combined with the compound additive.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (10)

1. The application of a compound with a sulfur-ring phosphoryl ester structure as an electrolyte high-voltage additive.
2. The use according to claim 1, wherein the compound of the structure of the thiocyclophosphoryl ester is of the general formula
Figure FDA0003714642330000011
Wherein, R1, R2, R3 and R4 are hydrogen, alkyl with 1-6 carbon atoms, alkenyl, alkynyl or one of cycloalkyl, cycloalkenyl, aryl with 6-12 carbon atoms and halogenated derivatives thereof, the halogenation in the halogenated derivatives of the alkyl, alkenyl, alkynyl and aryl is partial substitution or full substitution, and the halogenated halogen is one or more of fluorine, chlorine and bromine.
3. The method as claimed in claim 2, wherein R1 and R2 are hydrogen, C1-2 alkyl, alkenyl, alkynyl or fluorinated alkyl, and R3 and R4 are hydrogen, C1-2 alkyl and alkenyl.
4. The use of claim 3, wherein R1, R2 is one of hydrogen, methyl, ethane, vinyl, ethynyl, or trifluoromethyl, R3 is one of hydrogen, methyl, or vinyl, and R4 is hydrogen or methyl.
5. The use according to claim 1, wherein the compound is added in an amount of 0.05 to 5 wt% based on the total mass of the electrolyte.
6. The composite additive is characterized in that the composite additive is a combination of a compound with a thiophosphoryl ester structure and a compound additive, the compound additive is an auxiliary additive A and/or an auxiliary additive B, the auxiliary additive A is one or more of lithium tetrafluoroborate, lithium bis (oxalato) borate and lithium difluoro (oxalato) borate, and preferably lithium difluoro (oxalato) borate; the auxiliary additive B is one or more of vinylene carbonate, vinyl ethylene carbonate, vinyl ethyl acetate, ethylene sulfite, propylene sulfite, vinyl sulfate, 1, 3-propane sultone, propenyl-1, 3-propane sultone, 1, 4-butane sultone, methyl disulfonate, hexamethyldisilazane, magnesium trifluoromethanesulfonate, tris (pentafluorophenyl) boron, tris (trimethylsilane) phosphate and tris (trimethylsilane) phosphite, and is preferably vinylene carbonate.
7. The additive package according to claim 6, wherein the ratio of the compound of the structure of the thiocyclophosphoryl ester to the built-up additive is 1:1-5, preferably 1:1-3, more preferably 1: (2. + -. 0.5).
8. The composite additive according to claim 6, wherein the addition amount of the compound additive is 0.5 wt% to 5 wt% of the total mass of the electrolyte.
9. The composite additive according to claim 6, wherein the electrolyte further comprises a lithium salt and an organic solvent, the lithium salt is one or more of lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium perchlorate, lithium difluorophosphate, lithium bis (trifluoromethyl) sulfonyl imide and lithium bis (fluoro) sulfonyl imide, preferably lithium hexafluorophosphate, and the addition amount of the lithium salt is 0.5-20 wt% of the total mass of the electrolyte;
the organic solvent is any one or more of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, 1, 4-butyrolactone, methyl formate, ethyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, ethyl butyrate and halogenated derivatives thereof, preferably the mixture of four substances of ethylene carbonate, fluoroethylene carbonate, diethyl carbonate and propyl propionate, and the addition amount of the organic solvent is 70 wt% -90 wt% of the total mass of the electrolyte.
10. The high-voltage electrolyte of the lithium battery is characterized by comprising a lithium salt, an organic solvent, a high-voltage additive and a compound additive, wherein the high-voltage additive is a compound with a thiocyclophosphoryl ester structure, and the addition amount of the compound is 0.05-5 wt% of the total mass of the electrolyte.
CN202210733130.0A 2022-06-27 2022-06-27 Application of compound with sulfur ring phosphoryl ester structure as electrolyte high-voltage additive Pending CN115000518A (en)

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