Use of silane phosphates / phosphites, lithium-ion batteries and electric devices

Abstract

The present application belongs to the field of battery materials, and specifically relates to the use of silane phosphate ester / phosphite, a lithium ion battery and an electric device. The lithium ion battery of the present application comprises a positive electrode sheet and an electrolyte, the positive electrode sheet comprises a lithium supplementing agent Li a M b O c , a, b, c are as described herein, the electrolyte comprises a first additive, the first additive is selected from one or more of a compound of formula I and a compound of formula II, in formula I and formula II, R1-R 18 As described herein. The present application adds a first additive to the electrolyte of the lithium ion battery containing the lithium supplementing agent, which can achieve the inhibition of the gas production of the lithium supplementing system battery.

Description

Technical Field

[0001] This invention belongs to the field of battery materials, specifically relating to the uses of silane phosphate esters / phosphites, lithium-ion batteries, and electrical devices. Background Technology

[0002] Lithium-ion batteries have become the mainstream power source for portable electronic devices, electric vehicles, and energy storage systems due to their high energy density, long cycle life, and low self-discharge rate. However, during the first charge and discharge cycle, a solid electrolyte interphase (SEI) film forms on the negative electrode surface, consuming some lithium ions and causing irreversible capacity loss. Furthermore, with increasing cycle count, the continuous loss of active lithium leads to battery capacity decay, affecting its performance and lifespan. To address these issues, lithium replenishment technology has emerged.

[0003] Lithium replenishment technology introduces an additional lithium source during battery manufacturing to compensate for lithium losses during the first and subsequent cycles, thereby improving the battery's initial capacity, cycle life, and energy density. Positive electrode lithium replenishment technology is an important method, involving the addition of lithium-rich compounds to the positive electrode material to release additional lithium ions during the first charge, compensating for the lithium consumed in the formation of the SEI film at the negative electrode. Lithium ferrite (Li5FeO4, LFO), as a lithium-rich positive electrode material, possesses a high theoretical specific capacity (approximately 700 mAh / g) and low cost, making it a research hotspot for positive electrode lithium replenishment technology. However, LFO undergoes irreversible decomposition during charging, generating LiFeO2 and O2. The released O2 further reacts with organic solvents in the electrolyte, producing gases such as CO2. Gas accumulation leads to increased internal pressure within the cell, causing cell swelling and potentially triggering a series of safety issues. Simultaneously, the gas damages the cell interface, resulting in decreased cell cycle performance and increased internal resistance.

[0004] There are currently four common methods to address the gas generation problem of LFO: First, adjust the chemical composition or physical structure of LFO through material modification techniques, such as element doping (e.g., Al, Mg) or surface coating (e.g., Li3PO4). While this method can suppress LFO decomposition, it may reduce the lithium replenishment efficiency of the material or hinder lithium-ion diffusion, leading to a decrease in battery energy density. Second, use lithium nickel oxide (Li2NiO2, LNO) to replace or partially replace LFO. However, the lithium replenishment efficiency of LNO is low because the lithium replenishment capacity of LNO (400mAh / g) is much smaller than that of LFO. Third, staged charge and discharge (e.g., pre-charging, high-voltage pulse). While this method can reduce gas generation, it significantly extends the battery production cycle, reduces equipment utilization, and increases manufacturing costs. Fourth, introduce new solvents to replace the easily oxidized and decomposed solvent ethylene carbonate (EC). Although this solvent is more stable than EC, it usually cannot achieve the dielectric constant of EC. Replacing EC will affect the conductivity of the electrolyte, resulting in poor film quality and deteriorating charge and discharge performance.

[0005] Therefore, how to solve the negative effects of gas generation caused by lithium replenishment agents such as LFO without affecting battery performance or increasing production costs is a problem that urgently needs to be solved. Summary of the Invention

[0006] This invention addresses the aforementioned problems in the prior art by proposing applications of silane phosphate / phosphite, lithium-ion batteries, and electrical devices. The invention adds a first additive to the electrolyte of a lithium-ion battery containing a lithium replenishing agent (e.g., Li5FeO4) to suppress the generation of gas from the lithium replenishing agent.

[0007] Specifically, one aspect of the present invention provides a first additive in the presence of lithium supplementation agent Li a M b O c Applications in the electrolyte of lithium-ion batteries, or in the presence of lithium-ion supplementing agents such as Li. a M b O c Applications in lithium-ion batteries, or in improving lithium-ion batteries containing lithium supplementation agents. a M b O c For applications in the gas generation, cycle performance, and / or storage performance of lithium-ion batteries, the first additive is selected from one or more compounds of formula I and formula II:

[0008]

[0009] In Formula I, R1, R2, R3, R4, R5, R6, R7, R8 and R9 are each independently selected from C1-C4 alkyl, C2-C4 alkenyl, C2-C4 alkynyl and unsubstituted or substituted C6-C10 aryl, and R1, R2, R3, R4, R5, R6, R7, R8 and R9 are not simultaneously C1-C4 alkyl;

[0010] In Equation II, R 10 R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 Each is independently selected from C1-C4 alkyl, C2-C4 alkenyl, C2-C4 alkynyl and unsubstituted or substituted C6-C10 aryl, and R 10 R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 They are not all C1-C4 alkyl groups.

[0011] In one or more embodiments, the substituents on the C6-C10 aryl groups substituted in Formula I and Formula II are selected from one or more of halogens, C1-C4 alkyl groups, C2-C4 alkenyl groups, and C2-C4 alkynyl groups.

[0012] In one or more embodiments, formula Li a M b O c In the given information, 1≤a≤5, 1≤b≤3, 1≤c≤4, and M is selected from one or more of Ni, Co, Mn, Fe, Al, Ti, V, and Mo.

[0013] In one or more embodiments, the lithium supplement includes Li5FeO4.

[0014] In one or more embodiments, the lithium supplement is Li5FeO4.

[0015] In one or more embodiments, the lithium supplement is Li5FeO4 and Li2NiO2, and the mass ratio of Li5FeO4 to Li2NiO2 is preferably 1:(0.2-5), more preferably 1:(0.25-4).

[0016] In one or more embodiments, in Formula I, R1, R2, R3, R4, R5, R6, R7, R8 and R9 are each independently selected from C1-C4 alkyl, C2-C4 alkenyl and phenyl; preferably, R1, R2, R3, R4, R5, R6, R7, R8 and R9 are each independently selected from methyl, vinyl and phenyl.

[0017] In one or more embodiments, in Formula II, R 10 R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 Each is independently selected from C1-C4 alkyl, C2-C4 alkenyl, and phenyl; preferably, R 10 R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 Each is independently selected from methyl, vinyl, and phenyl.

[0018] In one or more embodiments, in Formula I, R1, R4 and R7 are the same, R2, R5 and R8 are the same, and R3, R6 and R9 are the same.

[0019] In one or more embodiments, in Formula II, R 10 R 13 and R 16 Same, R 11 R 14 and R 17 Same, R 12 R 15 and R 18 same.

[0020] In one or more embodiments, the first additive is selected from one or more of compounds A, B, C, D, E, F, G, and H:

[0021]

[0022] In one or more embodiments, the first additive in the electrolyte has a mass fraction of 0.001wt%-5wt%, preferably 0.01wt%-5wt%, more preferably 0.1wt%-5wt%, more preferably 0.1wt%-3wt%, more preferably 0.3wt%-3wt%, for example 0.3wt%-1wt%, 0.5wt%-1wt%.

[0023] In one or more embodiments, the lithium-ion battery includes a positive electrode sheet, the positive electrode sheet including a positive electrode material layer; the positive electrode material layer including a positive electrode active material and the lithium replenishing agent, wherein the mass ratio of the lithium replenishing agent to the total mass of the lithium replenishing agent and the positive electrode active material is 0.1wt%-5wt%, preferably 0.5wt%-4wt%, more preferably 1wt%-3.5wt%, for example 1.6wt%-2wt%.

[0024] In one or more embodiments, the lithium-ion battery includes a positive electrode sheet, the positive electrode sheet including a positive electrode material layer; the positive electrode material layer including a positive electrode active material and the lithium replenishing agent, the positive electrode active material being selected from one or more of lithium iron phosphate, lithium manganese iron phosphate, lithium manganese oxide, lithium cobalt oxide, nickel cobalt manganese ternary positive electrode material, nickel cobalt aluminum ternary positive electrode material, and nickel cobalt manganese aluminum quaternary positive electrode material.

[0025] In one or more embodiments, the positive electrode material layer is disposed on one or both surfaces of the positive electrode current collector.

[0026] Another aspect of the present invention provides a secondary battery, the secondary battery comprising a positive electrode, a negative electrode, an electrolyte, and a separator, wherein the positive electrode comprises a positive current collector and a positive electrode material layer, and the positive electrode material layer comprises a positive electrode active material and a lithium supplementing agent Li. a M b O c The electrolyte comprises a lithium salt, a solvent, and a first additive as described in any embodiment herein.

[0027] In one or more embodiments, the secondary battery is a lithium-ion battery.

[0028] In one or more embodiments, formula Li a M b O c In the given information, 1≤a≤5, 1≤b≤3, 1≤c≤4, and M is selected from one or more of Ni, Co, Mn, Fe, Al, Ti, V, and Mo.

[0029] In one or more embodiments, the lithium supplement includes Li5FeO4.

[0030] In one or more embodiments, the lithium supplement is Li5FeO4.

[0031] In one or more embodiments, the lithium supplement is Li5FeO4 and Li2NiO2, and the mass ratio of Li5FeO4 to Li2NiO2 is preferably 1:(0.2-5), more preferably 1:(0.25-4).

[0032] In one or more embodiments, the first additive in the electrolyte has a mass fraction of 0.001wt%-5wt%, preferably 0.01wt%-5wt%, more preferably 0.1wt%-5wt%, more preferably 0.1wt%-3wt%, more preferably 0.3wt%-3wt%, for example 0.3wt%-1wt%, 0.5wt%-1wt%.

[0033] In one or more embodiments, the mass ratio of the lithium replenishing agent to the total mass of the lithium replenishing agent and the positive electrode active material is 0.1wt%-5wt%, preferably 0.5wt%-4wt%, more preferably 1wt%-3.5wt%, for example 1.6wt%-2wt%.

[0034] In one or more embodiments, the positive electrode active material is selected from one or more of lithium iron phosphate, lithium manganese iron phosphate, lithium manganese oxide, lithium cobalt oxide, nickel cobalt manganese ternary positive electrode material, nickel cobalt aluminum ternary positive electrode material, and nickel cobalt manganese aluminum quaternary positive electrode material.

[0035] In one or more embodiments, the lithium salt is selected from one or more of lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium perchlorate, lithium hexafluoroarsenate, and lithium trifluoromethanesulfonate.

[0036] In one or more embodiments, the lithium salt has a mass fraction of 6 wt%-20 wt%, preferably 10 wt%-15 wt%, in the electrolyte.

[0037] In one or more embodiments, the solvent is selected from one or more of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, γ-butyrolactone, methyl formate, ethyl formate, methyl acetate, ethyl propionate, propyl propionate, ethyl butyrate, and propyl butyrate.

[0038] In one or more embodiments, the electrolyte further comprises a second additive, the second additive including one or more of carbonate film-forming additives, silicon-based phosphate film-forming additives, silicon-based phosphite film-forming additives, silicon-based borate film-forming additives, sulfide additives, lithium salt additives, silane additives, and dehydration and deacidification additives.

[0039] In one or more embodiments, the carbonate film-forming additive is preferably selected from one or more of vinylene carbonate, fluoroethylene carbonate, ethylene ethylene carbonate, and [4,4'-bis-1,3-dioxane]-2,2'-dione.

[0040] In one or more embodiments, the silicone phosphate additive is preferably selected from one or more of tris(trimethylsilane) phosphate, tris(vinyldimethylsilane) phosphate, and diethyltrimethylsilane phosphate.

[0041] In one or more embodiments, the silicon-based phosphite additive is preferably selected from one or more of tris(trimethylsilane) phosphite, tris(vinyldimethylsilane) phosphite, and diethyltrimethylsilane phosphite.

[0042] In one or more embodiments, the silyl borate film-forming additive is preferably selected from one or more of tris(trimethylsilane)borate, tris(vinyldimethylsilane)borate, and diethyltrimethylsilyl borate.

[0043] In one or more embodiments, the sulfur-based additive is preferably selected from one or more of vinyl sulfate, vinyl sulfite, propylene-1,3-sulfonyl lactone, methylene disulfonate, 1,3-propane sulfonyl lactone, 1,3-butane sulfonyl lactone, 1,3-propanediol cyclosulfonate, 1,3-propene sulfonyl lactone, glyoxal disulfate, vinyl disulfate, and 1,3-propanedisulfonic anhydride.

[0044] In one or more embodiments, the lithium salt additive is preferably selected from one or more of lithium difluorophosphate, lithium difluorooxalate borate, lithium difluorodioxalate phosphate, lithium tetrafluoroborate, and lithium tetrafluorooxalate phosphate.

[0045] In one or more embodiments, the silane additive is preferably selected from one or more of tetravinylsilane, vinyltrimethylsilane, divinyldimethylsilane, trivinylmethylsilane, allyltriethylsilane, diallyldiethylsilane, triallylethylsilane, and tetraallylsilane.

[0046] In one or more embodiments, the dehydration and deacidification additive is selected from one or more of carbodiimide dehydration and deacidification additives, isocyanate dehydration and deacidification additives, nitrogen-containing silane dehydration and deacidification additives, urea dehydration and deacidification additives, and oxygen-containing silane dehydration and deacidification additives.

[0047] In one or more embodiments, the isocyanate-based acid and water removal additive is preferably selected from one or more of hexamethylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, terephthalic diisocyanate, 4,4-diisocyanate dicyclohexylmethane, isophthalic diisocyanate, naphthalene diisocyanate, and toluene diisocyanate.

[0048] In one or more embodiments, the carbodiimide deacidifying and dehydrating additive is preferably dicyclohexylcarbodiimide.

[0049] In one or more embodiments, the nitrogen-containing silane deacidifying and dehydrating additive is preferably a hexamethyldisilazane nitrogen-containing silane.

[0050] In one or more embodiments, the urea-based acid and water desiccant is preferably O-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethylurea hexafluorophosphate.

[0051] In one or more embodiments, the oxygen-containing silane deacidifying and dehydrating additive is preferably diphenyldimethoxysilane.

[0052] In one or more embodiments, the mass fraction of the second additive in the electrolyte is preferably 0.01wt%-5wt%, more preferably 0.05wt%-3wt%, even more preferably 0.1wt%-3wt%, for example 0.5wt%-3wt%, 1wt%-3wt%, 2wt%-3wt%, 2.5wt%-3wt%.

[0053] In one or more embodiments, the second additive comprises vinylene carbonate, lithium difluorophosphate, vinyl sulfate, and tris(trimethylsilane) phosphate; preferably, the mass fractions of vinylene carbonate, lithium difluorophosphate, vinyl sulfate, and tris(trimethylsilane) phosphate in the electrolyte are 1.8wt%-2.5wt%, 0.15wt%-0.2wt%, 0.4wt%-0.5wt%, and 0.15wt%-0.2wt%, respectively; preferably, the lithium salt is lithium difluorosulfonylimide and lithium hexafluorophosphate, the mass ratio of lithium difluorosulfonylimide to lithium hexafluorophosphate is preferably 1:1-1:2, and the mass fraction of the lithium salt in the electrolyte is preferably 10wt%-15wt%; preferably, the solvent is ethylene carbonate and ethyl methyl carbonate, the mass ratio of ethylene carbonate to ethyl methyl carbonate is preferably 1:1-1:3; preferably, the first additive is compound C. The mass fraction of the first additive in the electrolyte is preferably 0.3wt%-3wt%, for example 0.3wt%-1wt%, or 0.5wt%-1wt%.

[0054] In one or more embodiments, the second additive comprises vinylene carbonate, fluoroethylene carbonate, and vinyl sulfate; preferably, the mass fractions of vinylene carbonate, fluoroethylene carbonate, and vinyl sulfate in the electrolyte are 1.8 wt%-2.5 wt%, 0.4 wt%-0.5 wt%, and 0.4 wt%-0.5 wt%, respectively; preferably, the lithium salt is lithium bis(fluorosulfonyl)imide, and the mass fraction of the lithium salt in the electrolyte is preferably 10 wt%-15 wt%; preferably, the solvent is ethylene carbonate and ethyl methyl carbonate, and the mass ratio of ethylene carbonate to ethyl methyl carbonate is preferably 1:1-1:3; preferably, the first additive is compound C. The mass fraction of the first additive in the electrolyte is preferably 0.3wt%-3wt%, for example 0.3wt%-1wt%, or 0.5wt%-1wt%.

[0055] In one or more embodiments, the positive electrode material layer is disposed on one or both surfaces of the positive electrode current collector.

[0056] In one or more embodiments, the negative electrode sheet includes a negative electrode current collector and a negative electrode material layer, the negative electrode material layer including a negative electrode active material, the negative electrode active material preferably selected from one or more of artificial graphite, natural graphite, soft carbon, hard carbon, silicon, silicon-carbon composite material and silicon-oxygen material; preferably, the negative electrode material layer is disposed on one or both surfaces of the negative electrode current collector.

[0057] In one or more embodiments, the lithium supplement further includes one or more of lithium oxide, lithium fluoride, and lithium nitride.

[0058] In one or more embodiments, the mass ratio of the lithium replenishing agent to the total mass of the lithium replenishing agent and the positive electrode active material is 0.1wt%-5wt%, preferably 0.5wt%-4wt%, more preferably 1wt%-3.5wt%, for example 1.6wt%-2wt%.

[0059] In one or more embodiments, the diaphragm is a PP diaphragm, a PE diaphragm, a ceramic diaphragm, or an adhesive-coated diaphragm.

[0060] Another aspect of the present invention provides an electrical device comprising a secondary battery as described in any embodiment herein.

[0061] Another aspect of the invention provides the use of the first additive described in any embodiment herein in improving the gas generation, cycle performance and / or storage performance of a secondary battery containing Li5FeO4.

[0062] In one or more embodiments, the secondary battery is as described in any of the embodiments herein.

[0063] The present invention achieves the following beneficial effects: By adding a first additive to the electrolyte of a lithium-ion battery containing a lithium replenishing agent (e.g., Li5FeO4), the first additive can capture the active oxygen generated by the decomposition of the lithium replenishing agent, inhibit the side reaction between the active oxygen and the electrolyte, suppress the gas production of the lithium replenishing agent (e.g., LFO), and improve the storage and cycle performance of the lithium battery; preferably, by compounding a second additive, the stability of the positive electrode film formation can be effectively improved, further suppressing the gas production of the lithium replenishing agent (e.g., LFO), and further improving the storage and cycle performance of the lithium battery. Attached Figure Description

[0064] Figure 1 Compound C prepared in this invention 1 H NMR spectrum. Detailed Implementation

[0065] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used herein are explained and defined in general terms below. Unless otherwise specified, all technical and scientific terms used herein have the common meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0066] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0067] In this document, the terms “contains,” “includes,” “containing,” and similar terms encompass the meanings of “basically composed of” and “composed of.” For example, when this document discloses “A contains B and C,” “A is basically composed of B and C” and “A is composed of B and C” should be considered as having been disclosed in this document.

[0068] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0069] Unless otherwise specified, percentages refer to mass percentages and proportions refer to mass ratios in this article.

[0070] In this article, the sum of the percentages of all components in the composition is 100%.

[0071] In this document, when describing embodiments or examples, it should be understood that it is not intended to limit the invention to those embodiments or examples. Rather, all alternatives, modifications, and equivalents of the methods and materials described herein are covered within the scope of this invention.

[0072] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0073] use

[0074] This invention includes the use of a first additive in a secondary battery containing Li5FeO4 (lithium iron oxide rich in lithium). This invention also includes the use of the first additive in improving the gas generation, cycle performance, and / or storage performance of lithium-ion batteries containing Li5FeO4 (lithium iron oxide rich in lithium). The secondary battery is preferably a lithium-ion battery. In the various uses provided by this invention, the electrolyte can be as described in any embodiment herein. In the various uses provided by this invention, the secondary battery can be as described in any embodiment herein.

[0075] First Additive

[0076] In some implementations, the first additive is a compound of formula I or formula II:

[0077]

[0078] In Formula I, R1, R2, R3, R4, R5, R6, R7, R8 and R9 are each independently selected from C1-C4 alkyl, C2-C4 alkenyl, C2-C4 alkynyl and unsubstituted or substituted C6-C10 aryl, and R1, R2, R3, R4, R5, R6, R7, R8 and R9 are not simultaneously C1-C4 alkyl;

[0079] In formula II, R 10 R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 Each is independently selected from C1-C4 alkyl, C2-C4 alkenyl, C2-C4 alkynyl and unsubstituted or substituted C6-C10 aryl, and R 10 R 11 R 12 R 13 R 14 R15 R 16 R 17 and R 18 They are not both C1-C4 alkyl groups;

[0080] The substituents on the substituted C6-C10 aryl group are selected from halogens, C1-C4 alkyl groups, C2-C4 alkenyl groups, and C2-C4 alkynyl groups.

[0081] In one or more embodiments, in Formula I, R1, R2, R3, R4, R5, R6, R7, R8, and R9 are each independently selected from C1-C4 alkyl, C2-C4 alkenyl, and phenyl; preferably, R1, R2, R3, R4, R5, R6, R7, R8, and R9 are each independently selected from methyl, vinyl, and phenyl. In some embodiments, in Formula I, R1, R4, and R7 are the same, R2, R5, and R8 are the same, and R3, R6, and R9 are the same.

[0082] In one or more embodiments, in Formula II, R 10 R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 Each is independently selected from C1-C4 alkyl, C2-C4 alkenyl, and phenyl; preferably, R 10 R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 Each is independently selected from methyl, vinyl, and phenyl. In some embodiments, in formula II, R... 10 R 13 and R 16 Same, R 11 R 14 and R 17 Same, R 12 R 15 and R 18 same.

[0083] In some preferred embodiments, the first additive is selected from one or more of compounds A, B, C, D, E, F, G, and H:

[0084]

[0085] In one or more embodiments, the first additive has a mass fraction of 0.001 wt%-5 wt% in the electrolyte, preferably 0.01 wt%-5 wt%, more preferably 0.1 wt%-5 wt%, even more preferably 0.1 wt%-3 wt%, even more preferably 0.3 wt%-3 wt%, for example 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1.0 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, 2.0 wt%, 2.1 wt%, 2.2 wt%, 2.3 wt%, 2.4 wt%, 2.5 wt%, 2.6 wt%, 2.7 wt%, 2.8 wt%, 2.9 wt%, or 3.0 wt%.

[0086] Secondary batteries

[0087] The secondary battery of the present invention includes a positive electrode, a negative electrode, an electrolyte, and a separator. The electrolyte can be a semi-solid electrolyte or a liquid electrolyte. Liquid electrolytes are also called electrolyte solutions.

[0088] In some embodiments, the secondary battery of the present invention includes a positive electrode, a negative electrode, an electrolyte, and a separator; in some embodiments, the secondary battery of the present invention is a lithium-ion battery.

[0089] The electrolyte of the present invention comprises a lithium salt, a solvent, and a first additive as described in any of the embodiments herein.

[0090] In some embodiments, the first additive has a mass fraction of 0.001 wt%-5 wt% in the electrolyte, preferably 0.01 wt%-5 wt%, more preferably 0.1 wt%-5 wt%, even more preferably 0.1 wt%-3 wt%, even more preferably 0.3 wt%-3 wt%, for example 0.5 wt%-1 wt%, for example 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%. wt%, 0.9wt%, 1.0wt%, 1.1wt%, 1.2wt%, 1.3wt%, 1.4wt%, 1.5wt%, 1.6wt%, 1.7wt%, 1.8wt%, 1.9wt %, 2.0wt%, 2.1wt%, 2.2wt%, 2.3wt%, 2.4wt%, 2.5wt%, 2.6wt%, 2.7wt%, 2.8wt%, 2.9wt%, 3.0wt%.

[0091] In some embodiments, the lithium salt is selected from one or more of lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium perchlorate, lithium hexafluoroarsenate, and lithium trifluoromethanesulfonate.

[0092] In some embodiments, the lithium salt has a mass fraction of 6wt%-20wt% in the electrolyte, preferably 10wt%-15wt%, for example 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%.

[0093] In some embodiments, the solvent is selected from one or more of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, γ-butyrolactone, methyl formate, ethyl formate, methyl acetate, ethyl propionate, propyl propionate, ethyl butyrate, and propyl butyrate.

[0094] In some embodiments, the electrolyte further includes a second additive, which includes one or more of the following: carbonate film-forming additives, silicon-based phosphate film-forming additives, silicon-based phosphite film-forming additives, silicon-based borate film-forming additives, sulfur-based additives, lithium salt additives, silane additives, and dehydration and deacidification additives.

[0095] The alkane film-forming additives are preferably selected from one or more of vinylene carbonate, fluoroethylene carbonate, ethylene ethylene carbonate, and [4,4'-bis-1,3-dioxane]-2,2'-dione.

[0096] The silicon-based phosphate additives are preferably selected from one or more of tris(trimethylsilane) phosphate, tris(vinyldimethylsilane) phosphate and diethyltrimethylsilane phosphate.

[0097] The silicon-based phosphite additives are preferably selected from one or more of tris(trimethylsilane) phosphite, tris(vinyldimethylsilane) phosphite, and diethyltrimethylsilane phosphite.

[0098] The silyl borate film-forming additives are preferably selected from one or more of tris(trimethylsilane)borate, tris(vinyldimethylsilane)borate, and diethyltrimethylsilyl borate.

[0099] The sulfur-based additives are preferably selected from one or more of vinyl sulfate, vinyl sulfite, propylene-1,3-sulfonyl lactone, methylene disulfonate, 1,3-propane sulfonyl lactone, 1,3-butane sulfonyl lactone, 1,3-propanediol cyclosulfonate, 1,3-propene sulfonyl lactone, glyoxal disulfate, vinyl disulfate, and 1,3-propanedisulfonic anhydride.

[0100] The lithium salt additive is preferably selected from one or more of lithium difluorophosphate, lithium difluorooxalate borate, lithium difluorodioxalate phosphate, lithium tetrafluoroborate, and lithium tetrafluorooxalate phosphate.

[0101] The silane additives are preferably selected from one or more of tetravinylsilane, vinyltrimethylsilane, divinyldimethylsilane, trivinylmethylsilane, allyltriethylsilane, diallyldiethylsilane, triallylethylsilane, and tetraallylsilane.

[0102] The dehydrating and deacidifying additives are preferably selected from one or more of the following: carbodiimide-based dehydrating and deacidifying additives, isocyanate-based dehydrating and deacidifying additives, nitrogen-containing silane-based dehydrating and deacidifying additives, urea-based dehydrating and deacidifying additives, and oxygen-containing silane-based dehydrating and deacidifying additives. Isocyanate-based dehydrating and deacidifying additives are preferably selected from one or more of the following: hexamethylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, terephthalic diisocyanate, 4,4-diisocyanate dicyclohexylmethane, m-phenylenediamine diisocyanate, naphthalene diisocyanate, and toluene diisocyanate. Carbodiimide-based dehydrating and deacidifying additives are preferably dicyclohexylcarbodiimide. Nitrogen-containing silane-based dehydrating and deacidifying additives are preferably hexamethyldisilazane nitrogen-containing silanes. Urea-based dehydrating and deacidifying agents are preferably O-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethylurea hexafluorophosphate. The preferred deacid and dehydration additives are oxygen-containing silanes, specifically diphenyldimethoxysilane.

[0103] In some embodiments, the mass fraction of the second additive in the electrolyte is preferably 0.01wt%-5wt%, more preferably 0.05wt%-3wt%, for example 0.05wt%, 0.1wt%, 0.5wt%, 1wt%, 2wt%, 2.5wt%, 2.6wt%, 2.7wt%, 2.8wt%, 2.9wt%, and 3wt%.

[0104] In some preferred embodiments, the second additive includes vinylene carbonate, lithium difluorophosphate, vinyl sulfate, and tris(trimethylsilane) phosphate. In such embodiments, preferably, the mass fraction of vinylene carbonate in the electrolyte is 1.8 wt%-2.5 wt%, for example 1.9 wt%, 2 wt%, 2.1 wt%, 2.2 wt%, 2.3 wt%, or 2.4 wt%; the mass fraction of lithium difluorophosphate in the electrolyte is 0.15 wt%-0.2 wt%, for example 0.16 wt%, 0.17 wt%, 0.18 wt%, or 0.19 wt%; the mass fraction of vinyl sulfate in the electrolyte is 0.4 wt%-0.5 wt%, for example 0.42 wt%, 0.44 wt%, 0.46 wt%, or 0.48 wt%; and the mass fraction of tris(trimethylsilane)phosphate in the electrolyte is 0.15 wt%-0.2 wt%, for example 0.16 wt%, 0.17 wt%, 0.18 wt%, or 0.19 wt%. In this type of embodiment, preferably, the lithium salt is lithium difluorosulfonylimide and lithium hexafluorophosphate, with a preferred mass ratio of 1:1 to 1:2, such as 5:6, 5:7, 5:8, or 5:9. Using vinylene carbonate, lithium difluorophosphate, vinyl sulfate, and tris(trimethylsilane)phosphate as second additives, particularly further combining lithium difluorosulfonylimide and lithium hexafluorophosphate as lithium salts, is beneficial for improving battery cycle performance and reducing gas production. In this type of embodiment, the mass fraction of the lithium salt in the electrolyte is preferably 10wt%-15wt%, such as 11wt%, 12wt%, 13wt%, or 14wt%; preferably, the solvent is ethylene carbonate and ethyl methyl carbonate, with a preferred mass ratio of ethylene carbonate to ethyl methyl carbonate of 1:1 to 1:3, such as 1:2, 3:7, or 3:8; preferably, the first additive is compound C. The mass fraction of compound C in the electrolyte is preferably 0.3wt%-3wt%, for example 0.3wt%-1wt%, or 0.5wt%-1wt%.

[0105] In some preferred embodiments, the second additive includes vinylene carbonate, fluoroethylene carbonate, and vinyl sulfate. In these embodiments, preferably, the mass fraction of vinylene carbonate in the electrolyte is 1.8 wt%-2.5 wt%, for example, 1.9 wt%, 2 wt%, 2.1 wt%, 2.2 wt%, 2.3 wt%, or 2.4 wt%; the mass fraction of fluoroethylene carbonate in the electrolyte is 0.4 wt%-0.5 wt%, for example, 0.42 wt%, 0.44 wt%, 0.46 wt%, or 0.48 wt%; and the mass fraction of vinyl sulfate in the electrolyte is 0.4 wt%-0.5 wt%, for example, 0.42 wt%, 0.44 wt%, 0.46 wt%, or 0.48 wt%. In these embodiments, preferably, the lithium salt is lithium bis(fluorosulfonyl)imide. Using vinylene carbonate, fluoroethylene carbonate, and ethylene sulfate as second additives, especially with the further addition of lithium bis(fluorosulfonyl)imide as the lithium salt, is beneficial for improving battery cycle performance and reducing gas production. In such embodiments, the mass fraction of the lithium salt in the electrolyte is preferably 10wt%-15wt%, for example 11wt%, 12wt%, 13wt%, or 14wt%; preferably, the solvent is ethylene carbonate and ethyl methyl carbonate, and the mass ratio of ethylene carbonate to ethyl methyl carbonate is preferably 1:1-1:3, for example 1:2, 3:7, or 3:8; preferably, the first additive is compound C. The mass fraction of compound C in the electrolyte is preferably 0.3wt%-3wt%, for example 0.3wt%-1wt%, or 0.5wt%-1wt%.

[0106] The positive electrode includes a positive current collector and a positive electrode material layer. In this invention, the positive electrode material layer includes a positive electrode active material and a lithium supplement agent Li. a M b O c Formula Li a M b O c In the given information, 1≤a≤5, 1≤b≤3, 1≤c≤4, and M is selected from one or more of Ni, Co, Mn, Fe, Al, Ti, V, and Mo.

[0107] In a preferred embodiment, the lithium replenishing agent comprises Li5FeO4. For example, the lithium replenishing agent can be Li5FeO4, or it can be a combination of Li5FeO4 and Li2NiO2. When the lithium replenishing agent is Li5FeO4 and Li2NiO2, the mass ratio of Li5FeO4 to Li2NiO2 is preferably 1:(0.2-5), more preferably 1:(0.25-4).

[0108] In this invention, the mass ratio of Li5FeO4 to the total mass of Li5FeO4 and the positive electrode active material can be 0.1wt%-5wt%, preferably 0.5wt%-4wt%, more preferably 1wt%-3.5wt%, for example 1.6wt%-2wt%, such as 0.1wt%, 0.2wt%, 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, and 5wt%.

[0109] In this invention, the positive electrode active material can be selected from one or more of lithium iron phosphate, lithium manganese iron phosphate, lithium manganese oxide, lithium cobalt oxide, nickel cobalt manganese ternary positive electrode material, nickel cobalt aluminum ternary positive electrode material, and nickel cobalt manganese aluminum quaternary positive electrode material.

[0110] In this invention, the lithium replenishing agent may optionally include other lithium replenishing agents besides Li5FeO4, such as one or more of Li2NiO2, lithium oxide, lithium fluoride and lithium nitride.

[0111] In some embodiments, the lithium supplement also includes Li2NiO2, and the mass ratio of Li5FeO4 to Li2NiO2 is preferably 1:(0.2-5), more preferably 1:(0.25-4), for example 1:0.25, 1:0.5, 1:1, 1:2, 1:3, 1:4.

[0112] In this invention, the ratio of the mass of the lithium replenishing agent to the total mass of the lithium replenishing agent and the positive electrode active material can be 0.1wt%-5wt%, preferably 0.5wt%-4wt%, more preferably 1wt%-3.5wt%, for example 1.6wt%-2wt%, such as 0.1wt%, 0.2wt%, 0.5wt%, 1wt%, 1.2wt%, 1.4wt%, 1.6wt%, 1.8wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, and 5wt%.

[0113] The positive electrode material layer typically also includes a conductive agent and a binder. The positive electrode material layer is obtained by coating a positive electrode slurry (comprising positive electrode active material, lithium supplementer, conductive agent, binder, and solvent) onto a positive electrode current collector, followed by baking, rolling, slitting, and cutting processes. The positive electrode current collector can be aluminum foil. The solvent for the positive electrode slurry can be N-methylpyrrolidone (NMP). The conductive agent for the positive electrode can be conductive carbon black (SP). The binder for the positive electrode can be polyvinylidene fluoride (PVDF). The mass ratio of the components in the positive electrode material layer can be conventional. For example, in the positive electrode material layer, the mass fraction of the positive electrode active material can be 90wt%-98wt%, the mass fraction of the conductive agent can be 0.5wt%-4wt%, and the mass fraction of the binder can be 0.5wt%-4wt%.

[0114] The positive electrode material layer is disposed on one or both surfaces of the positive electrode current collector.

[0115] The negative electrode sheet includes a negative current collector and a negative electrode material layer. The negative current collector can be copper foil. The negative electrode material layer includes a negative electrode active material. The negative electrode active material can include one or more of the following: artificial graphite, natural graphite, soft carbon, hard carbon, silicon, silicon-carbon composites, and silicon-oxygen materials.

[0116] The negative electrode material layer also includes one or both of a conductive agent and a binder. The conductive agent is used to improve the electrode conductivity. Conductive agents that can be used in the negative electrode include conductive carbon black (SP), acetylene black, carbon nanotubes, carbon nanowires, carbon nanospheres, carbon fibers, and graphene. The binder in the negative electrode is used to improve the adhesion between the negative electrode active material particles and between the negative electrode active material particles and the current collector. Binders that can be used in the negative electrode include vinylidene fluoride, polytetrafluoroethylene, acrylonitrile copolymers, polyacrylic acid (PAA), polybutylene acrylate, polyacrylonitrile, and styrene-butadiene rubber (SBR). The negative electrode material layer may also contain a thickener, such as carboxymethyl cellulose (CMC). In some embodiments, the conductive agent in the negative electrode material layer is SP, the binder is SBR, and the thickener is CMC. The mass fraction of the negative electrode material in the negative electrode material layer can be conventional. For example, in the negative electrode material layer, the mass fraction of the negative electrode active material can be 90wt%-98wt%, the mass fraction of the conductive agent can be 0.5wt%-4wt%, the mass fraction of the binder can be 0.5wt%-4wt%, and the mass fraction of the thickener can be 1wt%-4wt%.

[0117] The negative electrode material layer can be obtained by coating a negative electrode slurry containing the components of the negative electrode material layer and a solvent onto a negative electrode current collector, followed by baking, rolling, slitting, and cutting. The solvent for the negative electrode slurry can be deionized water.

[0118] The negative electrode material layer is disposed on one or both surfaces of the negative electrode current collector.

[0119] In some implementations, the diaphragm may be selected from one or more of PP diaphragms, PE diaphragms, ceramic diaphragms, and coated diaphragms.

[0120] The positive and negative electrode sheets and the separator are first passed through a winding machine in sequence to obtain a bare cell. Then, a secondary battery, such as a lithium-ion battery, is produced by hot pressing, ultrasonic welding, encapsulation, vacuum baking, electrolyte injection, wetting, formation, and capacity testing.

[0121] Electrical appliances

[0122] The present invention also includes secondary power devices incorporating the present invention. In some embodiments, the secondary battery of the present invention can be used in, but is not limited to, the following power devices: laptops, pen-based computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, stereo headphones, video recorders, LCD TVs, portable cleaners, portable CD players, mini CDs, transceivers, electronic notebooks, calculators, memory cards, portable recorders, radios, backup power supplies, motors, automobiles, motorcycles, electric bicycles, bicycles, lighting fixtures, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries, drones, and lithium-ion capacitors, etc.

[0123] The present invention will be described below by way of specific embodiments. It should be understood that these embodiments are merely illustrative and are not intended to limit the scope of the invention. The methods, reagents, and materials used in the embodiments and comparative examples are conventional methods, reagents, and materials in the art, unless otherwise stated. The starting material compounds in the embodiments and comparative examples are all commercially available.

[0124] Compound preparation examples

[0125] The preparation process of compound C is as follows: Finely ground potassium dihydrogen phosphate (2.72 g, 20 mmol) and 10 mL of formamide (which acts as a solvent and catalyst) were added to a dry 100 mL Schlenk flask to form a heterogeneous suspension; then, under rapid stirring, a formamide solution containing dimethylvinylchlorosilane (6.03 g, 50 mmol) was slowly added dropwise. To prevent the reaction from being violently exothermic and generating hydrochloric acid gas, the reaction temperature was maintained at ≤80 °C for 3 h; then, 30 mL of dry petroleum ether was added and stirred thoroughly. The final product was extracted, and the upper petroleum ether organic phase was subjected to vacuum distillation (45 °C, ~20 mbar) to remove the solvent and residual chlorosilane and other byproducts. The temperature was then increased further, and the fraction at 90-110 °C was collected.

[0126] Compound C 1 The H NMR results are as follows Figure 1 As shown.

[0127] Compounds A, B, D, and E are prepared by replacing dimethylvinylchlorosilane in the raw materials for preparing compound C with dimethylphenylchlorosilane, methyldiphenylchlorosilane, methyldivinylchlorosilane, or trivinylchlorosilane, respectively.

[0128] Compound F was prepared by replacing potassium dihydrogen phosphate with triethyl phosphite and dimethylvinylchlorosilane with dimethylphenylchlorosilane in the raw materials for preparing compound C.

[0129] Compound G is prepared by replacing triethyl phosphite with potassium dihydrogen phosphate in the raw materials for preparing compound C.

[0130] Compound H is prepared by replacing potassium dihydrogen phosphate with triethyl phosphite and dimethylvinylchlorosilane with trivinylchlorosilane in the raw materials for preparing compound C.

[0131] Electrolyte preparation example

[0132] (1) Preparation of basic electrolyte 1

[0133] Prepare lithium-ion battery electrolyte in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm): First, mix ethylene carbonate (EC) and ethyl methyl carbonate (EMC) uniformly in a mass ratio of 3:7. Then, add 2 wt% vinylene carbonate (VC), 0.5 wt% fluoroethylene carbonate (FEC), 0.5 wt% ethylene sulfate (DTD), 5 wt% lithium bis(fluorosulfonyl)imide (LiFSI), and 7 wt% lithium hexafluorophosphate (LiPF6). After mixing evenly, the desired basic electrolyte 1 is obtained. The mass percentage of each component mentioned above is the ratio of the mass of that component to the total mass of the basic electrolyte.

[0134] (2) Preparation of basic electrolyte 2

[0135] Prepare lithium-ion battery electrolyte in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm): First, mix ethylene carbonate (EC) and ethyl methyl carbonate (EMC) uniformly in a mass ratio of 3:7. Then, add 2 wt% ethylene carbonate (VC), 0.5 wt% fluoroethylene carbonate (FEC), 0.5 wt% methanedisulfonate (MMDS), 5 wt% lithium bis(fluorosulfonyl)imide (LiFSI), and 7 wt% lithium hexafluorophosphate (LiPF6). After mixing evenly, the desired basic electrolyte 2 is obtained. The mass percentage of each component mentioned above is the ratio of the mass of that component to the total mass of the basic electrolyte.

[0136] (3) Preparation of basic electrolyte 3

[0137] Prepare lithium-ion battery electrolyte in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm): First, mix ethylene carbonate (EC) and ethyl methyl carbonate (EMC) uniformly in a mass ratio of 3:7. Then, add 2 wt% vinylene carbonate (VC), 0.2 wt% lithium difluorophosphate (LiPO2F2), 0.5 wt% ethylene sulfate (DTD), 0.2 wt% tris(trimethylsilane) phosphate (TMSP), 5 wt% lithium difluorosulfonylimide (LiFSI), and 7 wt% lithium hexafluorophosphate (LiPF6). After mixing evenly, the desired basic electrolyte 3 is obtained. The mass percentage of each component mentioned above is the ratio of the mass of that component to the total mass of the basic electrolyte.

[0138] (4) Preparation of basic electrolyte 4

[0139] Prepare lithium-ion battery electrolyte in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm): First, mix ethylene carbonate (EC) and ethyl methyl carbonate (EMC) uniformly in a mass ratio of 3:7. Then, add 2 wt% vinylene carbonate (VC), 0.5 wt% fluoroethylene carbonate (FEC), 0.5 wt% ethylene sulfate (DTD), 0.1 wt% hexamethylene diisocyanate (HDI), 5 wt% lithium bis(fluorosulfonyl)imide (LiFSI), and 7 wt% lithium hexafluorophosphate (LiPF6). After mixing evenly, the desired basic electrolyte 4 is obtained. The mass percentage of each component mentioned above is the ratio of the mass of that component to the total mass of the basic electrolyte.

[0140] (5) Preparation of basic electrolyte 5

[0141] Prepare lithium-ion battery electrolyte in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm): First, mix ethylene carbonate (EC) and ethyl methyl carbonate (EMC) uniformly in a mass ratio of 3:7. Then, add 2 wt% vinylene carbonate (VC), 0.5 wt% fluoroethylene carbonate (FEC), 0.5 wt% 1,3-propanesulfonate lactone (PS), 5 wt% lithium difluorosulfonylimide (LiFSI), and 7 wt% lithium hexafluorophosphate (LiPF6). After mixing evenly, the desired basic electrolyte 5 is obtained. The mass percentage of each component mentioned above is the ratio of the mass of that component to the total mass of the basic electrolyte.

[0142] (6) Preparation of basic electrolyte 6

[0143] Prepare lithium-ion battery electrolyte in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm): First, mix ethylene carbonate (EC) and ethyl methyl carbonate (EMC) uniformly in a mass ratio of 3:7. Then, add 2 wt% vinylene carbonate (VC), 0.5 wt% fluoroethylene carbonate (FEC), 0.5 wt% ethylene sulfate (DTD), and 12 wt% lithium hexafluorophosphate (LiPF6). After mixing evenly, the desired basic electrolyte 6 is obtained. The mass percentage of each component mentioned above is the ratio of the mass of that component to the total mass of the basic electrolyte.

[0144] (7) Preparation of basic electrolyte 7

[0145] Prepare lithium-ion battery electrolyte in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm): First, mix ethylene carbonate (EC) and ethyl methyl carbonate (EMC) uniformly in a mass ratio of 3:7. Then, add 2 wt% vinylene carbonate (VC), 0.5 wt% fluoroethylene carbonate (FEC), 0.5 wt% ethylene sulfate (DTD), and 12 wt% lithium bis(fluorosulfonyl)imide (LiFSI). After mixing evenly, the desired basic electrolyte 7 is obtained. The mass percentage of each component mentioned above is the ratio of the mass of that component to the total mass of the basic electrolyte.

[0146] (8) Preparation of basic electrolyte 8

[0147] Prepare lithium-ion battery electrolyte in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm): First, mix ethylene carbonate (EC) and ethyl methyl carbonate (EMC) uniformly in a mass ratio of 3:7. Then, add 2 wt% vinylene carbonate (VC), 0.5 wt% fluoroethylene carbonate (FEC), 0.5 wt% ethylene sulfate (DTD), 7 wt% lithium bis(fluorosulfonyl)imide (LiFSI), and 5 wt% lithium hexafluorophosphate (LiPF6). After mixing evenly, the desired basic electrolyte 8 is obtained. The mass percentage of each component mentioned above is the ratio of the mass of that component to the total mass of the basic electrolyte.

[0148] (9) Preparation of basic electrolyte 9

[0149] Prepare lithium-ion battery electrolyte in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm): First, mix ethylene carbonate (EC), propylene carbonate (PC), and dimethyl carbonate (DMC) uniformly in a mass ratio of 2.5:0.5:7. Then, add 2 wt% vinylene carbonate (VC), 0.5 wt% fluoroethylene carbonate (FEC), 0.5 wt% ethylene sulfate (DTD), 5 wt% lithium bis(fluorosulfonyl)imide (LiFSI), and 7 wt% lithium hexafluorophosphate (LiPF6). After mixing evenly, the desired basic electrolyte 9 is obtained. The mass percentage of each component mentioned above is the ratio of the mass of that component to the total mass of the basic electrolyte.

[0150] (10) Preparation of basic electrolyte 10

[0151] Prepare lithium-ion battery electrolyte in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm): First, mix ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) uniformly in a mass ratio of 3:3:4. Then, add 2 wt% vinylene carbonate (VC), 0.5 wt% fluoroethylene carbonate (FEC), 0.5 wt% ethylene sulfate (DTD), 5 wt% lithium bis(fluorosulfonyl)imide (LiFSI), and 7 wt% lithium hexafluorophosphate (LiPF6). After mixing evenly, the desired basic electrolyte 10 is obtained. The mass percentage of each component mentioned above is the ratio of the mass of that component to the total mass of the basic electrolyte.

[0152] Example 1

[0153] Preparation of the electrolyte used in Example 1: The lithium-ion battery electrolyte was prepared in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm). 99.5 wt% of the base electrolyte 1 and 0.5 wt% of the first additive compound A were mixed evenly to obtain the desired electrolyte.

[0154] The preparation process of the battery in Example 1 is as follows:

[0155] (1) Preparation of positive electrode

[0156] In N-methylpyrrolidone (NMP), positive electrode active material LFP (LiFePO4), lithium supplementer LFO (Li5FePO4), conductive agent conductive carbon black (SP), and binder PVDF (polyvinylidene fluoride) are added. Following a homogenization process, the mixture is stirred until homogeneous, and the viscosity and solid content are adjusted to a suitable coating consistency, ensuring the positive electrode material layer meets the following composition: 95.4 wt% LFP + 2.0 wt% LFO + 0.8 wt% SP + 1.8 wt% PVDF. The positive electrode slurry is then uniformly coated on both sides of a 13 μm thick aluminized composite film current collector. After baking, rolling, slitting, and cutting processes, positive electrode sheet A is obtained. The single-sided areal density of the positive electrode material layer on the positive electrode sheet is 18.03 mg / cm³. 2 The compacted density is 2.55 g / cm³. 3 .

[0157] (2) Preparation of negative electrode

[0158] Add 95.7 wt% of the negative electrode active material, artificial graphite, 1.5 wt% of the conductive agent SP, 1.0 wt% of SBR (styrene-butadiene rubber), and 1.8 wt% of CMC (sodium carboxymethyl cellulose) to deionized water. Following the homogenization process, stir until homogeneous, then adjust the slurry to a suitable viscosity and solid content for coating, ensuring the negative electrode material layer composition meets the requirements of 95.7 wt% artificial graphite + 1.5 wt% SP + 1.0 wt% SBR + 1.8 wt% CMC. Then, uniformly coat the negative electrode slurry on both sides of a 6 μm thick copper foil current collector. After baking, rolling, slitting, and cutting, obtain negative electrode sheet A. The single-sided areal density of the negative electrode material layer on the negative electrode sheet is 8.78 mg / cm³. 2 The compacted density is 1.57 g / cm³. 3 .

[0159] (3) Preparation of lithium-ion batteries

[0160] The positive and negative electrode sheets and PE separator (9μm PE + 3μm CCS + 2μm PCS) are first passed through a winding machine in sequence to obtain a bare cell. Then, a 2Ah square soft-pack lithium-ion battery is produced by hot pressing, ultrasonic welding, encapsulation, vacuum baking, electrolyte injection, wetting, formation, and capacity testing.

[0161] Example 2

[0162] Preparation of the electrolyte used in Example 2: The lithium-ion battery electrolyte was prepared in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm). 99.5 wt% of the base electrolyte 1 and 0.5 wt% of the first additive compound B were mixed evenly to obtain the desired electrolyte.

[0163] The preparation process of the battery in Example 2 is the same as that in Example 1.

[0164] The only difference between the battery in Example 2 and the battery in Example 1 is the electrolyte.

[0165] Example 3

[0166] Preparation of the electrolyte used in Example 3: The lithium-ion battery electrolyte was prepared in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm). 99.5 wt% of the base electrolyte 1 and 0.5 wt% of the first additive compound C were mixed evenly to obtain the desired electrolyte.

[0167] The preparation process of the battery in Example 3 is the same as that in Example 1.

[0168] The only difference between the battery in Example 3 and the battery in Example 1 is the electrolyte.

[0169] Example 4

[0170] Preparation of the electrolyte used in Example 4: The lithium-ion battery electrolyte was prepared in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm). 99.5 wt% of the base electrolyte 1 and 0.5 wt% of the first additive compound D were mixed evenly to obtain the desired electrolyte.

[0171] The preparation process of the battery in Example 4 is the same as that in Example 1.

[0172] The only difference between the battery in Example 4 and the battery in Example 1 is the electrolyte.

[0173] Example 5

[0174] Preparation of the electrolyte used in Example 5: The lithium-ion battery electrolyte was prepared in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm). 99.5 wt% of the base electrolyte 1 and 0.5 wt% of the first additive compound E were mixed evenly to obtain the desired electrolyte.

[0175] The preparation process of the battery in Example 5 is the same as that in Example 1.

[0176] The only difference between the battery in Example 5 and the battery in Example 1 is the electrolyte.

[0177] Example 6

[0178] Preparation of the electrolyte used in Example 6: The lithium-ion battery electrolyte was prepared in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm). 99.5 wt% of the base electrolyte 1 and 0.5 wt% of the first additive compound F were mixed evenly to obtain the desired electrolyte.

[0179] The preparation process of the battery in Example 6 is the same as that in Example 1.

[0180] The only difference between the battery in Example 6 and the battery in Example 1 is the electrolyte.

[0181] Example 7

[0182] Preparation of the electrolyte used in Example 7: The lithium-ion battery electrolyte was prepared in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm). 99.5 wt% of the base electrolyte 1 and 0.5 wt% of the first additive compound G were mixed evenly to obtain the desired electrolyte.

[0183] The preparation process of the battery in Example 7 is the same as that in Example 1.

[0184] The only difference between the battery in Example 7 and the battery in Example 1 is the electrolyte.

[0185] Example 8

[0186] Preparation of the electrolyte used in Example 8: The lithium-ion battery electrolyte was prepared in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm). 99.5 wt% of the base electrolyte 1 and 0.5 wt% of the first additive compound H were mixed evenly to obtain the desired electrolyte.

[0187] The preparation process of the battery in Example 8 is the same as that in Example 1.

[0188] The only difference between the battery in Example 8 and the battery in Example 1 is the electrolyte.

[0189] Example 9

[0190] Preparation of the electrolyte used in Example 9: The lithium-ion battery electrolyte was prepared in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm). 99.99 wt% of the base electrolyte 1 and 0.01 wt% of the first additive compound C were mixed evenly to obtain the desired electrolyte.

[0191] The preparation process of the battery in Example 9 is the same as that in Example 1.

[0192] The only difference between the battery in Example 9 and the battery in Example 1 is the electrolyte.

[0193] Example 10

[0194] Preparation of the electrolyte used in Example 10: The lithium-ion battery electrolyte was prepared in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm). 99.9 wt% of the base electrolyte 1 and 0.1 wt% of the first additive compound C were mixed evenly to obtain the desired electrolyte.

[0195] The preparation process of the battery in Example 10 is the same as that in Example 1.

[0196] The only difference between the battery in Example 10 and the battery in Example 1 is the electrolyte.

[0197] Example 11

[0198] Preparation of the electrolyte used in Example 11: The lithium-ion battery electrolyte was prepared in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm). 99.7 wt% of the base electrolyte 1 and 0.3 wt% of the first additive compound C were mixed evenly to obtain the desired electrolyte.

[0199] The preparation process of the battery in Example 11 is the same as that in Example 1.

[0200] The only difference between the battery in Example 11 and the battery in Example 1 is the electrolyte.

[0201] Example 12

[0202] Preparation of the electrolyte used in Example 12: The lithium-ion battery electrolyte was prepared in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm). 99.0 wt% of the base electrolyte 1 and 1.0 wt% of the first additive compound C were mixed evenly to obtain the desired electrolyte.

[0203] The preparation process of the battery in Example 12 is the same as that in Example 1.

[0204] The only difference between the battery in Example 12 and the battery in Example 1 is the electrolyte.

[0205] Example 13

[0206] Preparation of the electrolyte used in Example 13: The lithium-ion battery electrolyte was prepared in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm). 97.0 wt% of the base electrolyte 1 and 3.0 wt% of the first additive compound C were mixed evenly to obtain the desired electrolyte.

[0207] The preparation process of the battery in Example 13 is the same as that in Example 1.

[0208] The only difference between the battery in Example 13 and the battery in Example 1 is the electrolyte.

[0209] Example 14

[0210] Preparation of the electrolyte used in Example 14: The lithium-ion battery electrolyte was prepared in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm). 95.0 wt% of the base electrolyte 1 and 5.0 wt% of the first additive compound C were mixed evenly to obtain the desired electrolyte.

[0211] The preparation process of the battery in Example 14 is the same as that in Example 1.

[0212] The only difference between the battery in Example 14 and the battery in Example 1 is the electrolyte.

[0213] Example 15

[0214] Preparation of the electrolyte used in Example 15: The lithium-ion battery electrolyte was prepared in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm). 99.0 wt% of the base electrolyte 1 and 1.0 wt% of the first additive compound C were mixed evenly to obtain the desired electrolyte.

[0215] The preparation process of the battery in Example 15 is basically the same as that in Example 1, except that: in the preparation of the positive electrode sheet, the composition of the positive electrode material layer is adjusted from 95.4wt% LFP + 2.0wt% LFO + 0.8wt% SP + 1.8wt% PVDF to 95.4wt% LFP + 1.6wt% LFO + 0.4wt% LNO + 0.8wt% SP + 1.8wt% PVDF to obtain positive electrode sheet B; the electrolyte used is the electrolyte prepared in Example 15.

[0216] Example 16

[0217] Preparation of the electrolyte used in Example 16: The lithium-ion battery electrolyte was prepared in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm). 99.0 wt% of the base electrolyte 1 and 1.0 wt% of the first additive compound C were mixed evenly to obtain the desired electrolyte.

[0218] The preparation process of the battery in Example 16 is basically the same as that in Example 1, except that: in the preparation of the positive electrode sheet, the composition of the positive electrode material layer is adjusted from 95.4wt% LFP + 2.0wt% LFO + 0.8wt% SP + 1.8wt% PVDF to 95.4wt% LFP + 2.0wt% LFO + 0.8wt% SP + 1.8wt% PVDF to obtain the positive electrode sheet C; the electrolyte used is the electrolyte prepared in Example 16.

[0219] Example 17

[0220] Preparation of the electrolyte used in Example 17: The lithium-ion battery electrolyte was prepared in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm). 99.0 wt% of the base electrolyte 1 and 1.0 wt% of the first additive compound C were mixed evenly to obtain the desired electrolyte.

[0221] The preparation process of the battery in Example 17 is basically the same as that in Example 1, except that: in the preparation of the positive electrode sheet, the composition of the positive electrode material layer is adjusted from 95.4wt% LFP + 2.0wt% LFO + 0.8wt% SP + 1.8wt% PVDF to 95.4wt% NCM523 + 2.0wt% LFO + 0.8wt% SP + 0.5wt% CNT + 1.3wt% PVDF to obtain the positive electrode sheet D; the electrolyte used is the electrolyte prepared in Example 17.

[0222] Example 18

[0223] Preparation of the electrolyte used in Example 18: The lithium-ion battery electrolyte was prepared in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm). 99.0 wt% of the base electrolyte 1 and 1.0 wt% of the first additive compound C were mixed evenly to obtain the desired electrolyte.

[0224] The preparation process of the battery in Example 18 is basically the same as that in Example 1, except that: in the preparation of the positive electrode sheet, the composition of the positive electrode material layer is adjusted from 95.4wt% LFP + 2.0wt% LFO + 0.8wt% SP + 1.8wt% PVDF to 95.4wt% NCM811 + 2.0wt% LFO + 0.8wt% SP + 0.5% CNT + 1.3wt% PVDF to obtain the positive electrode sheet E; the electrolyte used is the electrolyte prepared in Example 18.

[0225] Example 19

[0226] Preparation of the electrolyte used in Example 19: The lithium-ion battery electrolyte was prepared in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm). 99.0 wt% of the base electrolyte 2 and 1.0 wt% of the first additive compound C were mixed evenly to obtain the desired electrolyte.

[0227] The preparation process of the battery in Example 19 is the same as that in Example 1.

[0228] The only difference between the battery in Example 19 and the battery in Example 1 is the electrolyte.

[0229] Example 20

[0230] Preparation of the electrolyte used in Example 20: The lithium-ion battery electrolyte was prepared in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm). 99.0 wt% of the base electrolyte 3 and 1.0 wt% of the first additive compound C were mixed evenly to obtain the desired electrolyte.

[0231] The preparation process of the battery in Example 20 is the same as that in Example 1.

[0232] The only difference between the battery in Example 20 and the battery in Example 1 is the electrolyte.

[0233] Example 21

[0234] Preparation of the electrolyte used in Example 21: The lithium-ion battery electrolyte was prepared in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm). 99.0 wt% of the base electrolyte 4 and 1.0 wt% of the first additive compound C were mixed evenly to obtain the desired electrolyte.

[0235] The preparation process of the battery in Example 21 is the same as that in Example 1.

[0236] The only difference between the battery in Example 21 and the battery in Example 1 is the electrolyte.

[0237] Example 22

[0238] Preparation of the electrolyte used in Example 22: The lithium-ion battery electrolyte was prepared in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm). 99.0 wt% of the base electrolyte 5 and 1.0 wt% of the first additive compound C were mixed evenly to obtain the desired electrolyte.

[0239] The preparation process of the battery in Example 22 is the same as that in Example 1.

[0240] The only difference between the battery in Example 22 and the battery in Example 1 is the electrolyte.

[0241] Example 23

[0242] Preparation of the electrolyte used in Example 23: The lithium-ion battery electrolyte was prepared in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm). 99.0 wt% of the base electrolyte 6 and 1.0 wt% of the first additive compound C were mixed evenly to obtain the desired electrolyte.

[0243] The preparation process of the battery in Example 23 is the same as that in Example 1.

[0244] The only difference between the battery in Example 23 and the battery in Example 1 is the electrolyte.

[0245] Example 24

[0246] Preparation of the electrolyte used in Example 24: The lithium-ion battery electrolyte was prepared in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm). 99.0 wt% of the base electrolyte 7 and 1.0 wt% of the first additive compound C were mixed evenly to obtain the desired electrolyte.

[0247] The preparation process of the battery in Example 24 is the same as that in Example 1.

[0248] The only difference between the battery in Example 24 and the battery in Example 1 is the electrolyte.

[0249] Example 25

[0250] Preparation of the electrolyte used in Example 25: The lithium-ion battery electrolyte was prepared in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm). 99.0 wt% of the base electrolyte 8 and 1.0 wt% of the first additive compound C were mixed evenly to obtain the desired electrolyte.

[0251] The preparation process of the battery in Example 25 is the same as that in Example 1.

[0252] The battery in Example 25 differs from the battery in Example 1 only in the electrolyte.

[0253] Example 26

[0254] Preparation of the electrolyte used in Example 26: The lithium-ion battery electrolyte was prepared in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm). 99.0 wt% of the base electrolyte 9 and 1.0 wt% of the first additive compound C were mixed evenly to obtain the desired electrolyte.

[0255] The preparation process of the battery in Example 26 is the same as that in Example 1.

[0256] The only difference between the battery in Example 26 and the battery in Example 1 is the electrolyte.

[0257] Example 27

[0258] Preparation of the electrolyte used in Example 27: The lithium-ion battery electrolyte was prepared in a glove box (moisture content < 0.01 ppm, oxygen content < 0.01 ppm). 99.0 wt% of the base electrolyte 10 and 1.0 wt% of the first additive compound C were mixed evenly to obtain the desired electrolyte.

[0259] The preparation process of the battery in Example 27 is the same as that in Example 1.

[0260] The battery in Example 27 differs from the battery in Example 1 only in the electrolyte.

[0261] Comparative Example 1

[0262] The electrolyte used in Comparative Example 1 is the base electrolyte 1.

[0263] The preparation process of the battery in Comparative Example 1 is the same as that in Example 1.

[0264] The only difference between the battery in Comparative Example 1 and the battery in Example 1 is the electrolyte.

[0265] Comparative Example 2

[0266] The electrolyte used in Comparative Example 2 was based on electrolyte 1.

[0267] The preparation process of the battery in Comparative Example 2 is basically the same as that in Example 1, except that: the positive electrode is the positive electrode B in Example 15; and the electrolyte used in Comparative Example 2 is the basic electrolyte 1.

[0268] Comparative Example 3

[0269] The electrolyte used in Comparative Example 3 was based on electrolyte 1.

[0270] The preparation process of the battery in Comparative Example 3 is basically the same as that in Example 1, except that: the positive electrode is the positive electrode C in Example 16; and the electrolyte used in Comparative Example 3 is the basic electrolyte 1.

[0271] Comparative Example 4

[0272] The electrolyte used in Comparative Example 4 was based on electrolyte 1.

[0273] The preparation process of the battery in Comparative Example 4 is basically the same as that in Example 1, except that: the positive electrode is the positive electrode D in Example 17; and the electrolyte used in Comparative Example 4 is the basic electrolyte 1.

[0274] Comparative Example 5

[0275] The electrolyte used in Comparative Example 5 was based on electrolyte 1.

[0276] The preparation process of the battery in Example 5 is basically the same as that in Example 1, except that the positive electrode is the positive electrode E in Example 18; and the electrolyte used in Comparative Example 5 is the base electrolyte 1.

[0277] Test case

[0278] The batteries of Examples 1-27 and Comparative Examples 1-5 were subjected to the following tests, and the results are shown in Table 1.

[0279] (1) Battery Cycle Test

[0280] The assembled lithium batteries were tested in a 35°C constant temperature chamber, and charge-discharge cycle tests were performed at a 1P rate.

[0281] Capacity retention rate = C2500 / C1 × 100% (C1 is the discharge capacity in the first cycle, and C2500 is the discharge capacity in the 2500th cycle)

[0282] (2) Gas generation performance test at 60℃

[0283] After the battery cell is fully charged at a 1C rate, the initial volume V1 of the battery cell is tested by the water displacement method. After being stored in a 60℃ high-temperature chamber for 50 days, the battery cell is taken out of the high-temperature chamber and cooled for 60 minutes. The volume V2 of the battery cell after storage is tested again by the water displacement method.

[0284] Volume expansion rate = (V2 - V1) / V1 × 100%

[0285] Table 1: Battery Composition and Performance Test Results

[0286]

[0287]

[0288] As can be seen from the experimental results of Examples 1-8 and Comparative Example 1 in Table 1, when the first additive compound A-compound H are added to electrolyte 1, the first additives all have the effect of improving the cycle capacity retention rate and suppressing gas generation during high-temperature storage of the lithium replenishment system cell. Among them, the first additive compound C has the best effect on improving the cycle capacity retention rate.

[0289] As shown in Table 1, the experimental results of Comparative Example 1, Example 3 and Examples 9-14 indicate that when the content of the first additive compound C in electrolyte 1 is 0.01wt%-5wt%, the higher the amount of the first additive compound C added, the better the effect of suppressing gas generation during high-temperature storage of the lithium-supplemented battery cell. The improvement effect of cycle capacity retention is related to the amount of the first additive compound C added, which first increases and then decreases. When the amount of the first additive compound C added is 1wt%, the improvement effect of cycle capacity retention is the best.

[0290] As shown in Table 1, the experimental results of Examples 12, 15, and Comparative Example 2 indicate that in different lithium replenishment agent formulations, the addition of the first additive compound C to the electrolyte effectively suppresses gas generation during high-temperature storage of the lithium replenishment system cells and improves cycle capacity retention. When the lithium replenishment agent is LFO, the first additive compound C exhibits the best effect in suppressing gas generation during high-temperature storage of the lithium replenishment system cells and improving cycle capacity retention.

[0291] As shown in Table 1, the experimental results of Examples 12, 16-18, and Comparative Examples 3-5 indicate that the first additive compound C improves cycle capacity retention and reduces gas generation during high-temperature storage in systems with different positive electrode active materials, all for the lithium replenishing agent LFO. Specifically, the experimental results of Examples 12 and 16-18 show that when the lithium replenishing agent is LFO and the electrode active material is LFP, the first additive compound C has the best effect in suppressing gas generation during high-temperature storage and improving cycle capacity retention in the lithium replenishing system cell.

[0292] As can be seen from the experimental results of Examples 12 and 19-27 in Table 1, when the electrolyte is the base electrolyte 3 + the first additive, the lithium-supplemented battery cell has the best cycle capacity retention rate and very little gas generation during high-temperature storage (Example 20); when the electrolyte is the base electrolyte 7 + the first additive, the lithium-supplemented battery cell has the least gas generation during high-temperature storage and a very high cycle capacity retention rate (Example 24).

Claims

1. The first additive contains lithium supplement Li a M b O c Applications in the electrolyte of lithium-ion batteries, or in the presence of lithium-ion supplementing agents such as Li. a M b O c Applications in lithium-ion batteries, or in improving lithium-ion batteries containing lithium supplementation agents. a M b O c Applications of lithium-ion batteries in terms of gas generation, cycle performance, and / or storage performance, characterized in that, The first additive is selected from one or more compounds of formula I and formula II: In Formula I, R1, R2, R3, R4, R5, R6, R7, R8 and R9 are each independently selected from C1-C4 alkyl, C2-C4 alkenyl, C2-C4 alkynyl and unsubstituted or substituted C6-C10 aryl, and R1, R2, R3, R4, R5, R6, R7, R8 and R9 are not simultaneously C1-C4 alkyl; In Equation II, R 10 R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 Each is independently selected from C1-C4 alkyl, C2-C4 alkenyl, C2-C4 alkynyl and unsubstituted or substituted C6-C10 aryl, and R 10 R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 They are not both C1-C4 alkyl groups; The substituents on the substituted C6-C10 aryl group are selected from halogens, C1-C4 alkyl groups, C2-C4 alkenyl groups, and C2-C4 alkynyl groups; Formula Li a M b O c In the given information, 1≤a≤5, 1≤b≤3, 1≤c≤4, and M is selected from one or more of Ni, Co, Mn, Fe, Al, Ti, V, and Mo.

2. The application as described in claim 1, characterized in that, The lithium replenishing agent includes Li5FeO4; preferably, the lithium replenishing agent is Li5FeO4, or the lithium replenishing agent is Li5FeO4 and Li2NiO2, wherein the mass ratio of Li5FeO4 to Li2NiO2 is preferably 1:(0.2-5), more preferably 1:(0.25-4); In Formula I, R1, R2, R3, R4, R5, R6, R7, R8 and R9 are each independently selected from C1-C4 alkyl, C2-C4 alkenyl and phenyl; preferably, R1, R2, R3, R4, R5, R6, R7, R8 and R9 are each independently selected from methyl, vinyl and phenyl. In Equation II, R 10 R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 Each is independently selected from C1-C4 alkyl, C2-C4 alkenyl, and phenyl; preferably, R 10 R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 Each is independently selected from methyl, vinyl, and phenyl.

3. The application as described in claim 1, characterized in that, In Equation I, R1, R4, and R7 are the same; R2, R5, and R8 are the same; R3, R6, and R9 are the same. In Equation II, R... 10 R 13 and R 16 Same, R 11 R 14 and R 17 Same, R 12 R 15 and R 18 same; Preferably, the first additive is selected from one or more of compounds A, B, C, D, E, F, G, and H:

4. The application as described in claim 1, characterized in that, The application has one or more of the following characteristics: The first additive has a mass fraction of 0.001wt%-5wt% in the electrolyte, preferably 0.01wt%-5wt%, more preferably 0.1wt%-5wt%, more preferably 0.1wt%-3wt%, more preferably 0.3wt%-3wt%, for example 0.3wt%-1wt%, 0.5wt%-1wt%; The lithium-ion battery includes a positive electrode sheet, the positive electrode sheet including a positive electrode material layer; the positive electrode material layer including a positive electrode active material and a lithium replenishing agent, wherein the mass ratio of the lithium replenishing agent to the total mass of the lithium replenishing agent and the positive electrode active material is 0.1wt%-5wt%, preferably 0.5wt%-4wt%, more preferably 1wt%-3.5wt%, for example 1.6wt%-2wt%; preferably, the positive electrode material layer is disposed on one or both surfaces of the positive electrode current collector; The lithium-ion battery includes a positive electrode sheet, the positive electrode sheet includes a positive electrode material layer; the positive electrode material layer includes a positive electrode active material and the lithium replenishing agent, the positive electrode active material is selected from one or more of lithium iron phosphate, lithium manganese iron phosphate, lithium manganese oxide, lithium cobalt oxide, nickel cobalt manganese ternary positive electrode material, nickel cobalt aluminum ternary positive electrode material and nickel cobalt manganese aluminum quaternary positive electrode material; preferably, the positive electrode material layer is disposed on one or both surfaces of the positive electrode current collector.

5. A lithium-ion battery, characterized in that, The lithium-ion battery includes a positive electrode, a negative electrode, an electrolyte, and a separator. The positive electrode includes a positive current collector and a positive electrode material layer. The positive electrode material layer includes a positive electrode active material and a lithium supplement agent (Li). a M b O c The electrolyte comprises a lithium salt, a solvent, and a first additive, wherein the first additive is selected from one or more compounds of formula I and formula II: In Formula I, R1, R2, R3, R4, R5, R6, R7, R8 and R9 are each independently selected from C1-C4 alkyl, C2-C4 alkenyl, C2-C4 alkynyl and unsubstituted or substituted C6-C10 aryl, and R1, R2, R3, R4, R5, R6, R7, R8 and R9 are not simultaneously C1-C4 alkyl; In Equation II, R 10 R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 Each is independently selected from C1-C4 alkyl, C2-C4 alkenyl, C2-C4 alkynyl and unsubstituted or substituted C6-C10 aryl, and R 10 R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 They are not both C1-C4 alkyl groups; The substituents on the substituted C6-C10 aryl group are selected from halogens, C1-C4 alkyl groups, C2-C4 alkenyl groups, and C2-C4 alkynyl groups; Formula Li a M b O c In the given information, 1≤a≤5, 1≤b≤3, 1≤c≤4, and M is selected from one or more of Ni, Co, Mn, Fe, Al, Ti, V, and Mo.

6. The lithium-ion battery as described in claim 5, characterized in that, The lithium replenishing agent includes Li5FeO4; preferably, the lithium replenishing agent is Li5FeO4, or the lithium replenishing agent is Li5FeO4 and Li2NiO2, wherein the mass ratio of Li5FeO4 to Li2NiO2 is preferably 1:(0.2-5), more preferably 1:(0.25-4); In Formula I, R1, R2, R3, R4, R5, R6, R7, R8 and R9 are each independently selected from C1-C4 alkyl, C2-C4 alkenyl and phenyl; preferably, R1, R2, R3, R4, R5, R6, R7, R8 and R9 are each independently selected from methyl, vinyl and phenyl. In Equation II, R 10 R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 Each is independently selected from C1-C4 alkyl, C2-C4 alkenyl, and phenyl; preferably, R 10 R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 Each is independently selected from methyl, vinyl, and phenyl.

7. The lithium-ion battery as described in claim 5, characterized in that, In Equation I, R1, R4, and R7 are the same; R2, R5, and R8 are the same; R3, R6, and R9 are the same. In Equation II, R... 10 R 13 and R 16 Same, R 11 R 14 and R 17 Same, R 12 R 15 and R 18 same; Preferably, the first additive is selected from one or more of compounds A, B, C, D, E, F, G, and H:

8. The lithium-ion battery as described in claim 5, characterized in that, The first additive has a mass fraction of 0.001wt%-5wt% in the electrolyte, preferably 0.01wt%-5wt%, more preferably 0.1wt%-5wt%, even more preferably 0.1wt%-3wt%, even more preferably 0.3wt%-3wt%, for example 0.3wt%-1wt%, 0.5wt%-1wt%.

9. The lithium-ion battery as described in claim 5, characterized in that, The mass ratio of the lithium replenishing agent to the total mass of the lithium replenishing agent and the positive electrode active material is 0.1wt%-5wt%, preferably 0.5wt%-4wt%, more preferably 1wt%-3.5wt%, for example 1.6wt%-2wt%.

10. The lithium-ion battery as described in claim 5, characterized in that, The positive electrode active material is selected from one or more of lithium iron phosphate, lithium manganese iron phosphate, lithium manganese oxide, lithium cobalt oxide, nickel cobalt manganese ternary positive electrode material, nickel cobalt aluminum ternary positive electrode material, and nickel cobalt manganese aluminum quaternary positive electrode material.

11. The lithium-ion battery as described in claim 5, characterized in that, The lithium-ion battery has one or more of the following characteristics: The lithium salt is selected from one or more of lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium perchlorate, lithium hexafluoroarsenate, and lithium trifluoromethanesulfonate; The lithium salt in the electrolyte has a mass fraction of 6wt%-20wt%, preferably 10wt%-15wt%; The solvent is selected from one or more of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, γ-butyrolactone, methyl formate, ethyl formate, methyl acetate, ethyl propionate, propyl propionate, ethyl butyrate, and propyl butyrate. The electrolyte further comprises a second additive, which includes one or more of the following: carbonate film-forming additives, silicone phosphate film-forming additives, silicone phosphite film-forming additives, silicone borate film-forming additives, sulfur-based additives, lithium salt additives, silane additives, and dehydration and deacidification additives; the carbonate film-forming additives are preferably selected from one or more of vinylene carbonate, fluorovinyl carbonate, ethylene ethylene carbonate, and [4,4'-bis-1,3-dioxane]-2,2'-dione; the silicone phosphate additives are preferably selected from one or more of tris(trimethylsilane) phosphate, tris(vinyldimethylsilane) phosphate, and diethyltrimethylsilane phosphate; the silicone phosphite additives... The additive is preferably selected from one or more of tris(trimethylsilane) phosphite, tris(vinyldimethylsilane) phosphite, and diethyltrimethylsilyl phosphite; the silanolite film-forming additive is preferably selected from one or more of tris(trimethylsilane) borate, tris(vinyldimethylsilane) borate, and diethyltrimethylsilyl borate; the sulfur-based additive is preferably selected from one or more of vinyl sulfate, vinyl sulfite, propylene-1,3-sulfonyl lactone, methylene disulfonate, 1,3-propane sulfonyl lactone, 1,3-butane sulfonyl lactone, 1,3-propanediol cyclosulfonate, 1,3-propene sulfonyl lactone, glyoxal disulfate, vinyl disulfate, and 1,3-propanedisulfonic anhydride; the lithium salt additive... The preferred selection is one or more of lithium difluorophosphate, lithium difluorooxalate borate, lithium difluorodioxalate phosphate, lithium tetrafluoroborate, and lithium tetrafluorooxalate phosphate. The silane additive is preferably selected from one or more of tetravinylsilane, vinyltrimethylsilane, divinyldimethylsilane, trivinylmethylsilane, allyltriethylsilane, diallyldiethylsilane, triallylethylsilane, and tetraallylsilane. The dehydration and deacidification additive is preferably selected from one or more of carbodiimide dehydration and deacidification additives, isocyanate dehydration and deacidification additives, nitrogen-containing silane dehydration and deacidification additives, urea dehydration and deacidification additives, and oxygen-containing silane dehydration and deacidification additives. The isocyanate dehydration and deacidification additive is preferably selected from hexamethylene diisocyanate, di... The electrolyte contains one or more of the following: phenylmethane diisocyanate, isophorone diisocyanate, terephthalic diisocyanate, 4,4-diisocyanate dicyclohexylmethane, isophenyl dimethyl isocyanate, naphthalene diisocyanate, and toluene diisocyanate; the carbodiimide-based deacidifying and dehydrating additive is preferably dicyclohexylcarbodiimide; the nitrogen-containing silane-based deacidifying and dehydrating additive is preferably hexamethyldisilazane; the urea-based deacidifying and dehydrating agent is preferably O-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethylurea hexafluorophosphate; the oxygen-containing silane-based deacidifying and dehydrating additive is preferably diphenyldimethoxysilane; the second additive has a mass fraction of 0.01 wt% to 5 wt% in the electrolyte, more preferably 0.The first additive is preferably 0.5 wt%-3 wt%, more preferably 0.1 wt%-3 wt%, for example 0.5 wt%-3 wt%, 1 wt%-3 wt%, 2 wt%-3 wt%, or 2.5 wt%-3 wt%. Preferably, the second additive comprises vinylene carbonate, lithium difluorophosphate, vinyl sulfate, and tris(trimethylsilane) phosphate, with the mass fractions of vinylene carbonate, lithium difluorophosphate, vinyl sulfate, and tris(trimethylsilane) phosphate in the electrolyte preferably being 1.8 wt%-2.5 wt%, 0.15 wt%-0.2 wt%, 0.4 wt%-0.5 wt%, and 0.15 wt%-0.2 wt%, respectively. The lithium salt is preferably lithium difluorosulfonylimide and lithium hexafluorophosphate, with the mass ratio of lithium difluorosulfonylimide to lithium hexafluorophosphate preferably being 1:1-1:

2. The solvent is preferably ethylene carbonate and methyl ethyl carbonate, with the mass ratio of ethylene carbonate to methyl ethyl carbonate preferably being 1:1-1:

3. The first additive is preferably compound C. Preferably, the second additive comprises vinylene carbonate, fluoroethylene carbonate, and vinyl sulfate, wherein the mass fractions of vinylene carbonate, fluoroethylene carbonate, and vinyl sulfate in the electrolyte are preferably 1.8wt%-2.5wt%, 0.4wt%-0.5wt%, and 0.4wt%-0.5wt%, respectively. The lithium salt is preferably lithium bis(fluorosulfonyl)imide, and the solvent is preferably ethylene carbonate and ethyl methyl carbonate, wherein the mass ratio of ethylene carbonate to ethyl methyl carbonate is preferably 1:1-1:

3. The first additive is preferably compound C. The positive electrode material layer is disposed on one or both surfaces of the positive electrode current collector; The negative electrode sheet includes a negative electrode current collector and a negative electrode material layer. The negative electrode material layer includes a negative electrode active material, which is preferably selected from one or more of artificial graphite, natural graphite, soft carbon, hard carbon, silicon, silicon-carbon composite materials, and silicon-oxygen materials. Preferably, the negative electrode material layer is disposed on one or both surfaces of the negative electrode current collector. The lithium supplement also includes one or more of lithium oxide, lithium fluoride and lithium nitride; The diaphragm is a PP diaphragm, a PE diaphragm, a ceramic diaphragm, or an adhesive-coated diaphragm.

12. An electrical appliance, characterized in that, The electrical device includes the lithium-ion battery as described in any one of claims 5-11.

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