CN112467211A - Electrolyte additive, electrolyte and silicon-carbon negative electrode lithium ion battery - Google Patents
Electrolyte additive, electrolyte and silicon-carbon negative electrode lithium ion battery Download PDFInfo
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- CN112467211A CN112467211A CN201910864682.3A CN201910864682A CN112467211A CN 112467211 A CN112467211 A CN 112467211A CN 201910864682 A CN201910864682 A CN 201910864682A CN 112467211 A CN112467211 A CN 112467211A
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- H01—ELECTRIC ELEMENTS
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- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
- H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
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Abstract
The invention belongs to the technical field of lithium batteries, and relates to an electrolyte additive and electrolyte of a silicon-carbon negative electrode lithium ion battery and the silicon-carbon negative electrode lithium ion battery. Wherein, an electrolyte additive, its characterized in that, this electrolyte additive includes: fluorine-containing silyl sulfimide compounds and fluoroethylene carbonate; the structural formula of the fluorine-containing silyl sulfimide compound is shown as a general formula I), wherein R1、R2And R3Each independently selected from C1‑C6An alkyl group; r4And R5Each independently selected from fluorine, alkyl, alkoxy, C substituted by fluorine1‑C12Any one of linear or branched alkyl, and R4And/or R5Being fluorine atoms or C substituted by fluorine1‑C12Linear or branched alkyl. The electrolyte additive provided by the invention can effectively improve lithium ionsThe battery has electrochemical properties such as cycle performance, rate performance, storage performance and the like under high-temperature and low-temperature conditions.
Description
Technical Field
The invention belongs to the technical field of lithium ion batteries, and particularly relates to an electrolyte additive and electrolyte of a silicon-carbon negative electrode lithium ion battery and the silicon-carbon negative electrode lithium ion battery.
Background
The new energy automobile industry in China is vigorously developed under the drive of markets and policies. The power battery, especially the lithium ion battery, has wide market prospect. With the urgent pursuit of the endurance mileage and the safety of the power automobile, higher requirements are put forward on the energy density and the working environment of the lithium ion battery.
To meet the market demand for high energy and high density of lithium ion batteries, nano silicon or SiOxThe silicon-carbon cathode prepared by the carbon material composite technology is a feasible route, and the energy and the density of the lithium ion battery can be greatly improved.
At present, a large amount of Fluoro Ethylene Carbonate (FEC) is usually used as an additive of the electrolyte of the lithium ion battery having a silicon-carbon negative electrode. The fluoroethylene carbonate can be reduced under a lower reduction potential, so that a compact Solid Electrolyte Interface (SEI) film with low resistance is formed on the surface of the negative electrode, and the cycle stability, the normal temperature capacity and the high temperature stability of the lithium ion battery under the same multiplying power are improved.
However, lithium hexafluorophosphate is easily decomposed in a high temperature environment to generate lewis acid, and further, the decomposition of fluoroethylene carbonate is accelerated to generate hydrofluoric acid, so that a vicious cycle is formed, and the stability of the lithium ion battery is affected.
Research shows that the combination of fluoroethylene carbonate and vinylene carbonate can improve the cycle life and high-temperature resistance of the battery, but the lithium ion battery has higher impedance when discharged in a low-temperature environment.
In view of this, it is desirable to provide an electrolyte additive and an electrolyte which have high and low temperature performances of a silicon-carbon negative electrode lithium ion battery, so as to improve the electrochemical performance of the silicon-carbon negative electrode lithium ion battery under high and low temperature conditions, and further expand the application range of the lithium ion battery.
Disclosure of Invention
The invention aims to provide an electrolyte additive and an electrolyte of a silicon-carbon cathode lithium ion battery and the silicon-carbon cathode lithium ion battery, which are used for solving the technical problem that the existing silicon-carbon cathode lithium ion battery cannot consider both high and low temperature performances.
In order to achieve the above object, a first aspect of the present invention provides an electrolyte additive. The electrolyte additive comprises: fluorine-containing silyl sulfimide compounds and fluoroethylene carbonate;
the structural formula of the fluorine-containing silyl sulfimide compound is shown as a general formula I),
wherein R is1、R2And R3Each independently selected from C1-C6An alkyl group; r4And R5Each independently selected from fluorine atom, alkyl, alkoxy, C substituted by fluorine1-C12Any one of linear or branched alkyl, and R4And R5At least one of which is a fluorine atom or C substituted by fluorine1-C12Linear or branched alkyl.
In a preferred embodiment of the present invention, R is1The R is2And said R3Each independently selected from C1-C2An alkyl group; the R is4And said R5Each independently selected from fluorine atom, alkyl, alkoxy, C substituted by fluorine1-C3Any one of linear or branched alkyl, and said R4And said R5At least one of which is a fluorine atom or C substituted by fluorine1-C3Linear or branched alkyl.
In a more preferred embodiment of the present invention, R is1The R is2And said R3Each independently selected from C1-C2An alkyl group; the R is4And said R5Each independently selected from fluorine atom, C substituted by fluorine1-C3Linear or branched alkoxy, C substituted by fluorine1-C3Any one of linear or branched alkyl groups.
In a preferred embodiment of the invention, the formula I) is selected from the group consisting of the formula A1) General formula A2) General formula A3) And general formula A4) At least one of;
it will be understood by those skilled in the art that the electrolyte solution contains, in addition to the above-described fluorine-containing silylimide-based compound and the fluoroethylene carbonate, other film-forming additives including: at least one of 1, 3-propane sultone, vinyl sulfate, allyl sulfate, vinyl sulfite, tris (trimethylsilane) phosphate, and tris (trimethylsilane) borate.
Preferably, the other film forming additives include: 1, 3-propane sultone and/or vinyl sulfate. More preferably, the other film forming additives are 1, 3-propane sultone and vinyl sulfate.
The invention provides an electrolyte of a silicon-carbon cathode lithium ion battery in a second aspect. The electrolyte comprises the electrolyte additive, electrolyte lithium salt and a non-aqueous organic solvent.
The amount of the fluorine-containing silyl sulfimide compound and the fluoroethylene carbonate can be selected by those skilled in the art according to actual needs. In order to further improve the cycle stability and high-temperature stability of the lithium ion battery with the electrolyte, the mass fraction of the fluorine-containing silyl sulfimide compound in the electrolyte is 0.1-3.0%; the mass fraction of the fluoroethylene carbonate in the electrolyte is 7.0-10.0%. For the existing electrolyte, the mass fraction of fluoroethylene carbonate in the electrolyte is 8.0-12%, and the content of fluoroethylene carbonate in the electrolyte of the invention is lower than that in the existing electrolyte. Therefore, the electrolyte of the invention can relatively reduce the dosage of fluoroethylene carbonate in the electrolyte of the silicon-carbon cathode lithium ion battery.
In a preferred embodiment of the present invention, the other film-forming additive is present in the electrolyte in an amount of 0.5% to 5.0% by mass.
Preferably, the mass fraction of the 1, 3-propane sultone in the electrolyte is 0.4% -1.0%; the mass fraction of the vinyl sulfate in the electrolyte is 0.75-1.5%.
The electrolyte lithium salt in the electrolyte of the present invention is an electrolyte lithium salt commonly used in the art, and the present invention is not particularly limited thereto. Specifically, the electrolyte lithium salt includes: at least one of lithium hexafluorophosphate, lithium difluorobis (oxalato) phosphate, lithium tetrafluorooxalato phosphate, lithium difluorophosphate, lithium bis (oxalato) borate, lithium difluorooxalato borate, lithium tetrafluoroborate, lithium bis (fluorosulfonyl) imide and lithium bis (trifluoromethanesulfonyl) imide. Preferably, the electrolyte lithium salt includes: lithium hexafluorophosphate, and at least one of lithium difluorobis (oxalato) phosphate, lithium tetrafluorooxalato phosphate, lithium difluorophosphate, lithium bis (oxalato) borate, lithium difluorooxalato borate, lithium tetrafluoroborate, lithium bis (fluorosulfonyl) imide, and lithium bis (trifluoromethanesulfonyl) imide. Further preferably, the electrolyte lithium salt includes: lithium hexafluorophosphate and at least one of lithium difluorophosphate, lithium difluorosulfonimide and lithium difluorooxalato borate. More preferably, the electrolyte lithium salt is lithium hexafluorophosphate, lithium difluorophosphate, lithium difluorosulfonimide, and lithium difluorooxalato borate. Compared with the single use of LiPF in electrolyte6The electrolyte of the silicon-carbon negative electrode lithium ion battery is also added with lithium salt additives of lithium difluorophosphate, lithium difluorosulfonimide and lithium difluorooxalato borate with good film forming characteristicsOne of the lithium salts is less, and multiple film-forming lithium salts are combined for use, so that the high and low temperature performance, rate capability, cycle performance and safety performance of the silicon-carbon negative electrode lithium ion battery are further improved.
In the case where the electrolyte lithium salt in the electrolyte solution of the present invention contains lithium hexafluorophosphate, the mass fraction of the lithium hexafluorophosphate in the electrolyte solution is 12.5% to 15.0%; in addition to lithium hexafluorophosphate, at least one of lithium difluorobis (oxalato) phosphate, lithium tetrafluorooxalato phosphate, lithium difluorophosphate, lithium bis (oxalato) borate, lithium difluorooxalato borate, lithium tetrafluoroborate, lithium bis (fluorosulfonyl) imide and lithium bis (trifluoromethanesulfonyl) imide is present in the electrolyte in a mass fraction of 0.1% to 5.0%. In addition to the lithium hexafluorophosphate, at least one of lithium difluorophosphate, lithium bis-fluorosulfonylimide, and lithium difluorooxalato borate is present in the electrolyte in a mass fraction of 0.1% to 5.0%.
In the case where the electrolyte lithium salt in the electrolytic solution of the present invention contains lithium hexafluorophosphate, lithium difluorophosphate, lithium bis-fluorosulfonylimide, and lithium difluorooxalatoborate, the mass fractions of lithium hexafluorophosphate, lithium difluorophosphate, lithium bis-fluorosulfonylimide, and lithium difluorooxalatoborate in the electrolytic solution are 12.5%, 1.0%, 1.5%, and 0.4%, respectively.
The non-aqueous organic solvent in the electrolyte of the present invention may be a non-aqueous organic solvent commonly used in the art, and the present invention is not particularly limited thereto. Specifically, the non-aqueous organic solvent includes: a carbonate-based compound and/or a carboxylate-based compound.
In one embodiment of the present invention, the carbonate-based compound includes: cyclic carbonates and chain carbonates. Specifically, the cyclic carbonate includes: at least one of ethylene carbonate and propylene carbonate. Specifically, the chain carbonate includes: at least one of diethyl carbonate, methyl ethyl carbonate and dimethyl carbonate, specifically, the carboxylic ester compound includes: at least one of ethyl acetate and ethyl propionate.
In a preferred embodiment of the present invention, the non-aqueous organic solvent comprises: vinyl carbonate, ethyl methyl carbonate, and diethyl carbonate. More preferably, the non-aqueous organic solvent is ethylene carbonate, ethyl methyl carbonate, and diethyl carbonate.
The amount of the cyclic carbonate and the chain carbonate can be selected by those skilled in the art according to actual needs, and the invention is not particularly limited herein. In the present invention, the cyclic carbonate and the chain carbonate may be added in the following amounts: the mass fraction of the cyclic carbonate in the electrolyte is 20.0-40.0%; the mass fraction of the chain carbonate in the electrolyte is 35.0-65.0%.
The non-aqueous organic solvent comprises: in the case of ethylene carbonate, ethyl methyl carbonate, and diethyl carbonate, the mass ratio of ethylene carbonate, ethyl methyl carbonate, and dimethyl carbonate is 3:5:2 to 1:1: 1.
The invention provides a silicon-carbon cathode lithium ion battery. The lithium ion battery includes: the electrolyte comprises a positive pole piece, a silicon-carbon negative pole piece, a diaphragm positioned between the positive pole piece and the silicon-carbon negative pole piece, and the electrolyte.
The anode piece in the silicon-carbon cathode lithium ion battery preferably comprises the following components: an aluminum foil current collector and a positive plate; the silicon-carbon negative electrode piece preferably comprises: copper foil current collector and negative plate.
Specifically, the positive electrode sheet includes: a positive electrode active material, a first conductive agent, and a first binder.
Preferably, the positive electrode active material is LiNi1-x-yCoxMnyO2Wherein x is more than or equal to 0 and less than or equal to 0.5, y is more than or equal to 0 and less than or equal to 0.5, z is more than or equal to 0 and less than or equal to 0.5, and<x+y+z≤1。
specifically, the negative electrode tab includes: a negative electrode active material, a second conductive agent, and a second binder.
Preferably, the negative active material is nano silicon or SiOxAnd a silicon-carbon material compounded with graphite. More preferably, the silicon content in the silicon carbon material is 5% -30%.
In particular, the separator is made of polypropylene/polyethylene/polypropylene.
The invention does not specifically limit the positive active material, the first conductive agent, the first binder, the second conductive agent and the second binder, and the substances for preparing the positive pole piece and the negative pole piece of the lithium ion battery can be used for realizing the invention.
The fluorine-containing silyl sulfimide compound in the electrolyte additive provided by the invention has a functional group R1、R2、R3、R4And R5，R1、R2And R3Each independently selected from C1-C6An alkyl group; r4And R5Each independently selected from fluorine, alkyl, alkoxy, C substituted by fluorine1-C12Any one of linear or branched alkyl, and R4And/or R5Being fluorine atoms or C substituted by fluorine1-C12The alkyl of the straight chain or the branched chain ensures that an SEI film generated on the silicon-carbon cathode has good compactness and low-temperature ionic conductivity when the lithium ion battery is charged and discharged, and moreover, the fluorine-containing silyl sulfimide compound can effectively inhibit hydrofluoric acid generated by the decomposition of fluoroethylene carbonate under the high-temperature environment condition, and effectively improve the electrochemical properties of the lithium ion battery, such as cycle performance, rate capability, storage performance and the like under the high-temperature and low-temperature conditions, so that the silicon-carbon cathode lithium ion battery can give consideration to the high-temperature and low-temperature properties.
The principle that the fluorine-containing silyl sulfimide compound shown as the general formula I) improves the high-low temperature performance of the silicon-carbon cathode lithium ion battery is that as shown as the formula II), a silicon nitrogen group, HF and H in the fluorine-containing silyl sulfimide compound2O reacts to generate sulfimide and fluorosilane/hydroxyl silane, thereby removing HF and H generated during charging and discharging of the silicon-carbon cathode lithium ion battery in high-temperature environment2And O, thereby effectively improving the high-temperature storage and high-temperature cycle performance of the silicon-carbon cathode lithium ion battery. And fluorine-containing silyl sulfimide compound having sulfonyl group and HF and H2O reaction, the reduced product is organic lithium salt containing sulfur,li is excellent in conductivity due to sulfur-containing organic lithium salt+Therefore, the electrolyte additive provided by the invention can obviously improve the low-temperature performance of the silicon-carbon cathode lithium ion battery.
The fluorine-containing silyl sulfimide compound, the fluoroethylene carbonate and other film forming additives in the electrolyte additive provided by the invention act synergistically, so that the electrolyte has excellent film forming property on the surface of a silicon-carbon negative electrode, and Li conduction of an SEI film is formed+The performance is excellent, the electrochemical performance of the silicon-carbon negative electrode lithium ion power battery at low temperature and high temperature is effectively improved, the silicon-carbon negative electrode lithium ion power battery can give consideration to high and low temperature performance, and the application range of the lithium ion battery is effectively expanded.
The electrolyte provided by the invention can improve the electrochemical performance of the silicon-carbon cathode lithium ion battery under high-temperature and low-temperature conditions.
The silicon-carbon cathode lithium ion battery provided by the invention has good electrochemical properties such as cycle performance, rate performance, storage performance and the like under high-temperature and low-temperature conditions, and can give consideration to high-temperature and low-temperature properties.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Drawings
The above and other objects, features and advantages of the present invention will become more apparent by describing in more detail exemplary embodiments thereof with reference to the attached drawings.
Fig. 1 shows EIS curves at-20 ℃ of the silicon-carbon negative electrode lithium ion batteries prepared in example 2, example 8, example 9 and comparative example 2.
Fig. 2 shows capacity retention rates of the silicon carbon negative electrode lithium ion batteries prepared in example 2, example 8, example 9 and comparative example 2 after storage at 55 ℃.
Fig. 3 shows the capacity recovery rates of the silicon carbon negative electrode lithium ion batteries prepared in example 2, example 8, example 9 and comparative example 2 after storage at 55 ℃.
Detailed Description
Preferred embodiments of the present invention will be described in more detail below. While the following describes preferred embodiments of the invention, it should be understood that the invention may be embodied in various forms and should not be construed as limited to the embodiments set forth herein.
Example 1
Preparing electrolyte: in a drying room with a dew point of-50 ℃, Ethylene Carbonate (EC), Ethyl Methyl Carbonate (EMC) and diethyl carbonate (DEC) are mixed according to the mass ratio of EC: EMC: DEC ═ 3:5:2 and then 12.5 wt% of lithium hexafluorophosphate (LiPF) based on the total weight of the electrolyte was slowly added thereto6) 1.0 wt% lithium difluorophosphate (LiPO) based on the total weight of the electrolyte2F2) And 1.5 wt% of lithium bis (fluorosulfonyl) imide (LiFSI) based on the total weight of the electrolyte, and finally 0.3 wt% of a fluorine-containing silyl sulfonyl imide compound represented by the general formula i (see table 1 for specific selection of the compound), 8.0 wt% of fluoroethylene carbonate (FEC), 0.5 wt% of 1, 3-Propane Sultone (PS), and 1.5 wt% of vinyl sulfate (DTD) based on the total weight of the electrolyte were added, and the mixture was uniformly stirred to obtain the electrolyte of the silicon-carbon negative electrode lithium ion battery of example 1.
Preparing a silicon-carbon lithium ion soft package battery: stacking the prepared positive pole piece, the diaphragm and the silicon-carbon negative pole piece in sequence, enabling the diaphragm to be positioned between the positive pole piece and the negative pole piece, and winding to obtain a bare cell; and (3) placing the bare cell into an outer package, injecting the prepared electrolyte into the dried battery, standing, forming and grading to finish the preparation of the silicon-carbon lithium ion soft package battery (the full battery material is a high nickel system of NCM 811/silicon-carbon 4.3V).
Examples 2 to 9, comparative examples 1 and 2
Examples 2 to 9 and comparative examples 1 and 2 were the same as example 1 except that the components and the proportions of the electrolytic solution were different from example 1. See table 1 for details.
TABLE 1 composition ratios of respective components of the electrolytes prepared in examples 1 to 9 and comparative examples 1 and 2
Test example
The silicon carbon lithium ion pouch batteries prepared in examples 1 to 9 and comparative examples 1 and 2 were subjected to a full cell performance test.
(1) And (3) testing the normal-temperature cycle performance: at 25 ℃, the battery after capacity grading is charged to 4.3V at constant current and constant voltage according to 1C, the current is cut off at 0.05C, then the battery is discharged to 2.7V at constant current according to 1C, and the capacity retention rate of the 1000 th cycle is calculated after 1000 cycles of charge/discharge according to the cycle, and the calculation formula is as follows:
the 1000 th cycle capacity retention (%) was (1000 th cycle discharge capacity/first cycle discharge capacity) × 100%.
(2) Thickness expansion and capacity retention and recovery rate test in 55 ℃ high-temperature storage: firstly, the silicon-carbon lithium ion soft package battery is placed at normal temperature and is circularly charged and discharged for 3 times (4.3V-2.7V) at 0.5C, and the discharge capacity C before the storage of the battery is recorded0Then charging the battery to 4.3V full-voltage at constant current and constant voltage, and testing the thickness d of the battery before high-temperature storage by using a vernier caliper1Then the battery is put into a thermostat with the temperature of 55 ℃ for storage for 7 days, the battery is taken out after the storage is finished, and the thermal thickness d of the stored battery is tested2Calculating the thickness expansion rate of the battery after the battery is stored for 7 days at the constant temperature of 55 ℃; after the battery is cooled for 24 hours at room temperature, the battery is discharged to 2.7V at a constant current of 0.5C, then charged to 4.3V at a constant current and a constant voltage of 0.5C, and the discharge capacity C after the battery is stored is recorded1And a charging capacity C2And calculating the capacity residual rate and the capacity recovery rate after the battery is stored for 7 days at the constant temperature of 55 ℃, wherein the calculation formula is as follows:
thickness expansion rate of battery after storage at 55 ℃ for 7 days ═ d2-d1)/d1*100％；
Capacity remained after high-temperature storage for 7 days at 55 DEG CResidual rate is C1/C0*100％；
Capacity recovery rate C after high-temperature storage at 55 ℃ for 7 days2/C0*100％。
(3) And (3) testing the low-temperature cycle performance: under the condition of low temperature of minus 20 ℃, the battery after capacity grading is charged to 4.3V at constant current and constant voltage of 0.3C, the current is cut off at 0.05C, then the battery is discharged to 2.7V at constant current of 0.5C, and according to the cycle, the cycle capacity retention rate of 50 weeks is calculated after 50 cycles of charging/discharging. The calculation formula is as follows:
the 50 th cycle capacity retention (%) (50 th cycle discharge capacity/first cycle discharge capacity) × 100%.
The results of the above performance tests are shown in table 2.
Table 2 lithium ion battery electrical performance test results
As shown in fig. 1, fig. 2 and fig. 3, the fluorine-containing silyl sulfimide compounds having the structure of general formula i) in the present invention can effectively improve the normal temperature, low temperature and high temperature cycle performance of a silicon-carbon negative electrode lithium ion power battery, have excellent electrochemical performance in a wide temperature range from-20 ℃ to 55 ℃, well solve the technical problem that the high and low temperature performance of the existing silicon-carbon negative electrode lithium ion battery cannot be considered, and effectively expand the application range of the silicon-carbon negative electrode lithium ion battery.
Further, compared with a comparative example 2 which singly uses the fluorine-containing phenyl sulfonate compound with the structure of the general formula I), a comparative example 1 which does not add the fluorine-containing phenyl sulfonate compound with the structure of the general formula I), and comparative examples 3 and 4 which further add lithium difluorophosphate or lithium difluorosulfonimide, the invention jointly uses the fluorine-containing silyl sulfonyl imide compound with the structure of the general formula I), lithium difluorophosphate and lithium difluorosulfonimide additive and conventional film-forming additive in the electrolyte, so that the electrolyte has excellent film-forming performance on the surface of an electrode, and the electrochemical performance of the electrolyte is improved.
Having described embodiments of the present invention, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.
Claims (10)
1. An electrolyte additive, comprising: fluorine-containing silyl sulfimide compounds and fluoroethylene carbonate;
the structural formula of the fluorine-containing silyl sulfimide compound is shown as a general formula I),
wherein R is1、R2And R3Each independently selected from C1-C6An alkyl group; r4And R5Each independently selected from fluorine atom, alkyl, alkoxy, C substituted by fluorine1-C12Any one of linear or branched alkyl, and R4And R5At least one of which is a fluorine atom or C substituted by fluorine1-C12Linear or branched alkyl.
2. The electrolyte additive of claim 1 wherein R is1The R is2And said R3Each independently selected from C1-C2An alkyl group; the R is4And said R5Each independently selected from fluorine atom, alkyl, alkoxy, C substituted by fluorine1-C3Any one of linear or branched alkyl, andthe R is4And said R5At least one of which is a fluorine atom or C substituted by fluorine1-C3Linear or branched alkyl.
3. The electrolyte additive as claimed in claim 1 or 2, wherein the formula i) is selected from the group consisting of formula a1) General formula A2) General formula A3) And general formula A4) At least one of;
4. the electrolyte additive of claim 1, further comprising a film-forming additive other than the fluorosulfonyl imide-based compound and the fluoroethylene carbonate, the film-forming additive comprising: at least one of 1, 3-propane sultone, vinyl sulfate, allyl sulfate, vinyl sulfite, tris (trimethylsilane) phosphate, and tris (trimethylsilane) borate;
preferably, the other film forming additives include: 1, 3-propane sultone and/or vinyl sulfate.
5. An electrolyte for a silicon-carbon negative electrode lithium ion battery, characterized in that the electrolyte comprises the electrolyte additive of any one of claims 1 to 4, an electrolyte lithium salt and a non-aqueous organic solvent.
6. The electrolyte according to claim 5, wherein the mass fraction of the fluorine-containing silyl sulfonyl imide compound in the electrolyte is 0.1% to 3.0%; the mass fraction of the fluoroethylene carbonate in the electrolyte is 7.0-10.0%.
7. The electrolyte of claim 5, wherein the electrolyte comprises the electrolyte additive of claim 3, and the other film-forming additives are present in the electrolyte in an amount of 0.5-5.0% by mass;
preferably, the mass fraction of the 1, 3-propane sultone in the electrolyte is 0.4% -1.0%; the mass fraction of the vinyl sulfate in the electrolyte is 0.75-1.5%.
8. The electrolyte of claim 5, wherein the electrolytic lithium salt comprises: at least one of lithium hexafluorophosphate, lithium difluorobis (oxalato) phosphate, lithium tetrafluorooxalato phosphate, lithium difluorophosphate, lithium bis (oxalato) borate, lithium difluorooxalato borate, lithium tetrafluoroborate, lithium bis (fluorosulfonyl) imide, and lithium bis (trifluoromethanesulfonyl) imide;
preferably, the electrolyte lithium salt includes: lithium hexafluorophosphate and at least one of lithium difluorobis (oxalate) phosphate, lithium tetrafluorooxalate phosphate, lithium difluorophosphate, lithium bis (oxalate) borate, lithium difluorooxalate borate, lithium tetrafluoroborate, lithium bis (fluorosulfonyl) imide and lithium bis (trifluoromethanesulfonyl) imide;
more preferably, the electrolyte lithium salt includes: lithium hexafluorophosphate and at least one of lithium difluorophosphate, lithium bis-fluorosulfonylimide and lithium difluorooxalato borate;
more preferably, the mass fraction of the lithium hexafluorophosphate in the electrolyte is 12.5% -15.0%; at least one of lithium difluorobis (oxalate) phosphate, lithium tetrafluorooxalate phosphate, lithium difluorophosphate, lithium bis (oxalate) borate, lithium difluorooxalate borate, lithium tetrafluoroborate, lithium bis (fluorosulfonyl) imide and lithium bis (trifluoromethanesulfonyl) imide is 0.1-5.0% by mass of the electrolyte.
9. The electrolyte of claim 5, wherein the non-aqueous organic solvent comprises: carbonate compounds and/or carboxylate compounds;
preferably, the carbonate-based compound includes: cyclic carbonates and chain carbonates;
the cyclic carbonate includes: at least one of ethylene carbonate and propylene carbonate;
the chain carbonate includes: at least one of diethyl carbonate, ethyl methyl carbonate, and dimethyl carbonate;
more preferably, the non-aqueous organic solvent comprises: ethylene carbonate, ethyl methyl carbonate, and diethyl carbonate;
more preferably, the mass fraction of the cyclic carbonate in the electrolyte is 20.0% to 40.0%; the mass fraction of the chain carbonate in the electrolyte is 35.0-65.0%;
more preferably, the mass ratio of ethylene carbonate, ethyl methyl carbonate and dimethyl carbonate is 3:5:2 to 1:1: 1.
10. A silicon-carbon negative electrode lithium ion battery is characterized by comprising: a positive electrode plate, a silicon-carbon negative electrode plate, a diaphragm positioned between the positive electrode plate and the silicon-carbon negative electrode plate, and the electrolyte of any one of claims 5-9;
preferably, the positive electrode sheet includes: an aluminum foil current collector and a positive plate;
the silicon-carbon negative pole piece comprises: copper foil current collector and negative plate.
More preferably, the positive electrode tab includes: a positive electrode active material, a first conductive agent, and a first binder;
the positive active material is LiNi1-x-yCoxMnyO2Wherein x is more than or equal to 0 and less than or equal to 0.5, y is more than or equal to 0 and less than or equal to 0.5, z is more than or equal to 0 and less than or equal to 0.5, and<x+y+z≤1。
more preferably, the negative electrode tab includes: a negative electrode active material, a second conductive agent, and a second binder.
The negative active material is nano silicon or SiOxSilicon carbon material compounded with graphite;
more preferably, the silicon content in the silicon carbon material is 5% -30%.
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| CN113097566A (en) * | 2021-04-01 | 2021-07-09 | 山东海科新源材料科技股份有限公司 | Imide additive containing sulfonated side chain, electrolyte and lithium ion battery thereof |
| CN113782834A (en) * | 2021-10-14 | 2021-12-10 | 九江天赐高新材料有限公司 | Electrolyte containing phenyl sulfonate compound and lithium ion battery |
| CN113948773A (en) * | 2021-10-18 | 2022-01-18 | 傲普(上海)新能源有限公司 | Nonaqueous electrolyte solution and secondary lithium battery |
| CN114335729A (en) * | 2021-12-31 | 2022-04-12 | 天目湖先进储能技术研究院有限公司 | High-voltage additive for lithium battery and electrolyte |
| CN114784377A (en) * | 2022-05-05 | 2022-07-22 | 香河昆仑新能源材料股份有限公司 | Electrolyte containing fluorine silane substituent compound and battery composed of electrolyte |
| CN115472909A (en) * | 2021-06-11 | 2022-12-13 | 比亚迪股份有限公司 | Electrolyte additive, secondary battery electrolyte and secondary battery |
| WO2022267391A1 (en) * | 2021-06-25 | 2022-12-29 | 珠海市赛纬电子材料股份有限公司 | Electrolyte additive, non-aqueous electrolyte, and lithium ion battery |
| WO2023015791A1 (en) * | 2021-08-12 | 2023-02-16 | 湖州昆仑亿恩科电池材料有限公司 | Electrolyte solution and battery comprising electrolyte solution |
| WO2024008000A1 (en) * | 2022-07-04 | 2024-01-11 | 蔚来电池科技(安徽)有限公司 | Secondary battery and apparatus |
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| CN113097566A (en) * | 2021-04-01 | 2021-07-09 | 山东海科新源材料科技股份有限公司 | Imide additive containing sulfonated side chain, electrolyte and lithium ion battery thereof |
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| WO2022267391A1 (en) * | 2021-06-25 | 2022-12-29 | 珠海市赛纬电子材料股份有限公司 | Electrolyte additive, non-aqueous electrolyte, and lithium ion battery |
| WO2023015791A1 (en) * | 2021-08-12 | 2023-02-16 | 湖州昆仑亿恩科电池材料有限公司 | Electrolyte solution and battery comprising electrolyte solution |
| CN113782834A (en) * | 2021-10-14 | 2021-12-10 | 九江天赐高新材料有限公司 | Electrolyte containing phenyl sulfonate compound and lithium ion battery |
| CN113948773A (en) * | 2021-10-18 | 2022-01-18 | 傲普(上海)新能源有限公司 | Nonaqueous electrolyte solution and secondary lithium battery |
| CN114335729A (en) * | 2021-12-31 | 2022-04-12 | 天目湖先进储能技术研究院有限公司 | High-voltage additive for lithium battery and electrolyte |
| CN114335729B (en) * | 2021-12-31 | 2023-06-06 | 天目湖先进储能技术研究院有限公司 | High-voltage additive for lithium battery and electrolyte |
| CN114784377A (en) * | 2022-05-05 | 2022-07-22 | 香河昆仑新能源材料股份有限公司 | Electrolyte containing fluorine silane substituent compound and battery composed of electrolyte |
| WO2024008000A1 (en) * | 2022-07-04 | 2024-01-11 | 蔚来电池科技(安徽)有限公司 | Secondary battery and apparatus |
| WO2024197640A1 (en) * | 2023-03-29 | 2024-10-03 | 宁德时代新能源科技股份有限公司 | Electrolyte additive, electrolyte, secondary battery, and electric device |
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