Non-aqueous electrolyte and battery

Abstract

The application belongs to the technical field of lithium batteries, and particularly relates to a non-aqueous electrolyte and a battery. The non-aqueous electrolyte comprises an additive, an electrolyte salt and an organic solvent; the additive comprises a first additive and a second additive; the first additive comprises lithium (fluorosulfonyl)(trifluoromethylsulfonyl) imide, and the second additive comprises 2-thiophene boronic acid; the mass percentage of the first additive is a%, and the mass percentage of the second additive is b% based on the mass of the non-aqueous electrolyte; the non-aqueous electrolyte satisfies 0.5 <= a / b <= 100; and 0.05 <= a <= 5, and 0.01 <= b <= 1. In the application, the first additive and the second additive are used in combination, so that the high and low temperature cycle and discharge performance of the battery can be improved, the battery can have excellent safety performance, and the high and low temperature performance and safety performance of the battery can be simultaneously considered.

Description

Technical Field

[0001] This invention belongs to the field of lithium battery technology, specifically relating to a non-aqueous electrolyte and a battery. Background Technology

[0002] Lithium-ion batteries (LIBs) combine environmental friendliness with high energy / power density, long cycle life, and high energy conversion efficiency, and are now widely used in aerospace, portable electronic devices, energy storage, and new energy vehicles. With the large-scale application and technological advancements of lithium-ion batteries, increasingly higher demands are being placed on battery performance, such as higher energy density, better fast-charging capabilities, and longer lifespan. However, achieving optimal performance at both high and low temperatures remains a significant challenge in lithium battery performance breakthroughs.

[0003] As one of the four main materials in ion batteries, the electrolyte plays a crucial role in forming the interfacial film and ion transport, significantly impacting various aspects of battery performance. However, while low-viscosity solvents can improve impedance and low-temperature performance, they typically exhibit poorer thermal stability. Conversely, additives with good film-forming stability often result in higher film-forming impedance. These characteristics necessitate adjustments to the electrolyte's proportions to meet battery performance requirements. Furthermore, with increasingly stringent policy and customer demands for battery safety, electrolytes are required to avoid degrading or even improve various aspects of battery safety, such as thermal shock, overcharge / over-discharge, and nail penetration. Therefore, developing additives with low film-forming impedance and high-stability interfacial films to achieve both high and low temperature performance while maintaining safety has always been a key research direction for electrolytes. Summary of the Invention

[0004] Therefore, the purpose of this invention is to provide a non-aqueous electrolyte and battery to solve the problem of high and low temperature performance and safety performance that are difficult to achieve in existing lithium-ion batteries.

[0005] To achieve the above objectives, the present invention adopts the following technical solution.

[0006] A non-aqueous electrolyte comprises an additive, an electrolyte salt, and an organic solvent; the additive comprises a first additive and a second additive; the first additive comprises (fluorosulfonyl)(trifluoromethanesulfonyl)iminolithium, and the second additive comprises 2-thiopheneboronic acid;

[0007] Based on the mass of the non-aqueous electrolyte, the mass percentage of the first additive is a%, and the mass percentage of the second additive is b%.

[0008] The non-aqueous electrolyte satisfies the following conditions: 0.5≤a / b≤100; and 0.05≤a≤5, 0.01≤b≤1.

[0009] The non-aqueous electrolyte provided by this invention uses (fluorosulfonyl)(trifluoromethanesulfonyl)iminolithium (LiFTFSI) as the first additive and 2-thiopheneboronic acid as the second additive, and the contents of the first and second additives are limited. Through extensive research, the inventors discovered that when the mass percentage content 'a' of the first additive and the mass percentage content 'b' of the second additive satisfy 0.5 ≤ a / b ≤ 100, 0.05 ≤ a ≤ 5, and 0.01 ≤ b ≤ 1, the first and second additives exert a synergistic effect, making the electrolyte quality more stable, and the prepared battery can achieve better high and low temperature performance and safety performance. The reasons are speculated to be twofold. First, lithium (fluorosulfonyl)(trifluoromethanesulfonyl)imino (LiFTFSI), as the primary additive, can improve lithium-ion migration while participating in film formation and enhancing the interface. LiFTFSI exhibits strong thermal stability and hydrolysis resistance, resulting in more stable electrolyte quality and superior high-temperature performance of the prepared battery. Second, 2-thiopheneboronic acid is also a film-forming agent that balances high and low-temperature performance by increasing the LiF component content in the film, thus achieving a balance between high and low-temperature battery performance. The resulting interfacial film is dense, has high mechanical strength, and good stability, inhibiting the dissolution of transition metal ions and suppressing side reactions on the positive electrode side, thereby improving battery performance under high voltage. Simultaneously, 2-thiopheneboronic acid can alter the reaction pathway of LiFTFSI during thermal shock, reducing exothermic side reactions and gas generation, significantly increasing the battery's thermal runaway initiation temperature and decreasing the maximum temperature reached after thermal runaway. Therefore, the combined use of these two additives can raise the upper limit of the primary additive's usage, thereby improving battery performance.

[0010] In this invention, the (fluorosulfonyl)(trifluoromethanesulfonyl)iminolithium is the compound shown in structural formula 3:

[0011] Structure 3;

[0012] The 2-thiopheneboronic acid is the compound shown in structural formula 4:

[0013] Structure 4.

[0014] In some embodiments, when the relationship a / b < 0.5, it indicates that the content of the first additive LiFTFSI in the non-aqueous electrolyte is too low, or the content of the second additive is too high. Insufficient LiFTFSI content makes it difficult to improve high and low temperature performance, while excessive second additive leads to excessively high electrolyte costs, hindering commercial application. Furthermore, excessively thick films not only fail to improve electrochemical performance but also degrade impedance, exacerbate battery heat generation, electrolyte grading, and side reactions. When the relationship a / b > 100, it indicates that the content of the first additive LiFTFSI in the non-aqueous electrolyte is too high, or the content of the second additive is too low. Excessive first additive corrodes the aluminum foil under high voltage and significantly degrades battery safety performance, while insufficient second additive not only fails to reduce the safety risks posed by the first additive but also fails to exert its own improving effect. This prevents the synergistic effect between the two additives from being fully realized, thus failing to achieve both excellent high and low temperature performance and safety performance. Preferably, the non-aqueous electrolyte satisfies: 2 ≤ a / b ≤ 10. Within this range, the first and second additives achieve an optimal ratio, and their synergistic effect is fully realized.

[0015] Lithium bis(fluorosulfonyl)imide (LiFSI) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) are both amide-type electrolyte salts and have long been considered strong competitors to LiPF6. Both possess excellent solubility, good hydrolysis resistance, and temperature stability. However, their inherent disadvantage of corroding aluminum foil makes them difficult to replace LiPF6. Therefore, they are more often used as small-volume additives in battery electrolyte systems. As electrolyte additives, LiFSI and LiTFSI can improve interfacial film stability while forming a low-resistance interfacial film. Compared to LiPF6, LiFSI and LiTFSI can increase the electrolyte ion migration rate and are less prone to hydrolysis to produce HF, making them rare additives that balance high and low temperature performance. However, their performance characteristics still differ significantly, and they are suited to different battery systems: LiTFSI has a lower onset potential for corroding aluminum foil (~3.8V), making it prone to corroding the current collector within the normal battery voltage range, thus degrading battery performance; while LiFSI has a higher corrosion potential (~4.35V), making it more widely used in lithium iron phosphate systems with lower upper voltage limits (~3.65V), but this degrades battery safety performance, limiting its use in high-capacity batteries. The core difference in performance between LiFSI and LiTFSI stems from the structural difference in their anionic terminal groups, namely the difference between -F and -CF3. On one hand, the stability of the FS bond is weaker than that of the CS bond, resulting in a faster hydrolysis rate and weaker thermal stability for LiFSI compared to LiTFSI; on the other hand, the -CF3 group in LiTFSI makes the overall anionic volume larger, limiting its effect on improving the ionic conductivity of the electrolyte, and TFSI... - It has poor compatibility with the negative electrode of the battery, making it difficult to form a dense and stable SEI film on the surface of the negative electrode.

[0016] Lithium (fluorosulfonyl)(trifluoromethanesulfonyl)imino (LiFTFSI) shares some structural similarities with common LiFSI and LiTFSI, incorporating two anionic groups. This results in high solubility in electrolytes and a low aluminum foil corrosion potential of around 4.2V. Traditional electrolyte salt LiPF6 inherently passivates aluminum foil; the higher corrosion potential of LiFTFSI synergizes with the passivation effect of LiPF6, laying a solid foundation for its application in ternary battery systems with higher upper voltage limits. Simultaneously, similar to LiFSI, LiFTFSI can form a film on the negative electrode surface, increasing the LiF component content in the SEI film, thereby enhancing interfacial film stability and improving the battery's high-temperature performance. Furthermore, its thermal stability and hydrolysis resistance are superior to LiFSI; even with higher addition levels in the electrolyte, it does not degrade electrolyte quality or battery safety performance, and it avoids battery performance degradation caused by additive hydrolysis products.

[0017] The anionic group of LiFTFSI can be considered a fusion of LiFSI and LiTFSI. Many of its properties, such as the initiation potential for etching aluminum foil, thermal stability, hydrolysis resistance, and ionic conductivity, fall between the two. However, in terms of high-temperature performance, LiFTFSI inherits the advantage of LiFSI's ability to decompose and form a highly stable SEI film rich in LiF components. Furthermore, its better thermal stability and hydrolysis resistance reduce the degradation of battery performance by hydrolysis byproducts compared to LiFSI. In contrast, LiTFSI has poor compatibility with the battery anode and struggles to form a dense and stable SEI film on the anode surface. Therefore, LiFTFSI offers superior high-temperature performance improvement compared to both LiFSI and LiTFSI. In summary, LiFTFSI has no significant weaknesses compared to LiFSI and LiTFSI, and it excels in high-temperature performance improvement, while its low-temperature performance improvement falls somewhere in between. It is a novel additive that balances both high and low temperature performance.

[0018] In some embodiments, if the mass percentage 'a' of lithium (fluorosulfonyl)(trifluoromethanesulfonyl)imino (LiFTFSI) in the non-aqueous electrolyte is too low, its effect on improving the battery will not be significant. However, if the value of 'a' is too high, on the one hand, it will significantly increase the cost of the electrolyte and the performance improvement effect will not increase significantly after reaching its limit. On the other hand, excessively high LiFTFSI will significantly increase the safety risk of the battery and it is difficult to completely suppress it with the second additive. Furthermore, if the difference between its usage and that of lithium hexafluorophosphate is too large, the passivation effect of lithium hexafluorophosphate on aluminum foil cannot completely suppress its corrosion, resulting in a large amount of aluminum ions dissolving out and degrading battery performance. Specifically, the mass percentage (a%) of lithium (fluorosulfonyl)(trifluoromethanesulfonyl)imino (LiFTFSI) in the non-aqueous electrolyte is 0.05%, 0.08%, 0.1%, 0.2%, 0.3%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.3%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, or any combination of these values; in a preferred embodiment, the mass percentage of the first additive is 0.5% to 3%. Within this preferred range, the performance improvement effect of LiFTFSI on the battery is fully and stably manifested, while LiFTFSI at this content does not cause significant battery safety risks. Its potential safety hazards can be fully suppressed by the second additive, effectively avoiding the corrosive effect of LiFTFSI on aluminum foil, and fundamentally preventing the battery performance from deteriorating due to aluminum ion dissolution.

[0019] With the increasing demand for energy density, both ternary and LCO systems are constantly evolving towards higher upper voltage limits. However, under high voltage conditions, the corrosion of aluminum foil by LiFTFSI becomes more difficult to suppress. More importantly, because LiFTFSI contains the same anionic groups as LiFSI, it also degrades battery safety performance. This not only lowers the battery's thermal runaway initiation temperature but also shortens the time from the onset of self-heating reaction to thermal runaway during thermal shock, lowering the battery's thermal runaway temperature point and significantly increasing safety risks. Due to these safety shortcomings, the amount of LiFTFSI added to high-voltage, high-capacity batteries is severely limited, making it difficult to fully utilize its inherent advantages in improving high and low temperature battery performance. Therefore, through extensive experimental research, it was discovered that the mechanism by which LiFTFSI degrades safety performance involves the initial decomposition to generate NSO2F and NSO2CF3 free radicals. These free radicals then react with the solvent in a highly thermal decomposition reaction. Simultaneously, the aluminum ions generated from the corrosion of the aluminum foil catalyze and accelerate related side reactions, further exacerbating safety hazards. The second additive can effectively capture and react with NSO2F and NSO2CF3 free radicals, reducing the free radical concentration in the system and generating products mainly composed of BN bonds, which have minimal impact on battery performance. Furthermore, the second additive itself can reduce battery impedance and improve interfacial film stability. In summary, the second additive can improve battery performance while increasing the thermal runaway temperature of batteries containing LiFTFSI electrolyte and reducing the maximum temperature achievable after thermal runaway. Therefore, the combined use of LiFTFSI and the second additive can significantly improve the battery's high and low temperature cycling and discharge performance while ensuring excellent safety performance, ultimately achieving a balance between high and low temperature performance and safety.

[0020] In some embodiments, the second additive, due to its unique structure, can preferentially react with the NSO2F and NSO2CF3 free radicals generated from the decomposition of LiFTFSI to form a stable product dominated by BN bonds and to form an S-containing interfacial film. This does not degrade battery performance, and the reaction pathway generates less heat, thereby improving the battery's thermal runaway start temperature and maximum temperature. Furthermore, it can also participate in film formation to improve interfacial film stability, resulting in a dense film with low impedance, reducing the dissolution of transition metal ions from the positive electrode. Its central boron atom has Lewis acidity and can react with PF6 in the electrolyte. -The coordination of anions and carbonate solvents weakens the binding force between anions and lithium ions, thereby reducing side reactions of the electrolyte on the electrode surface. If the content of the second additive is too high, the film will be too thick, leading to a significant increase in battery impedance and heat generation, thus degrading battery performance. If the content of the second additive is too low, it will be difficult to compensate for the degradation of safety performance caused by LiFTFSI, and the improvement on electrochemical performance will also be very limited. It will be difficult for the battery to achieve both high and low temperature performance and safety performance. Specifically, the mass percentage b% of the second additive in the non-aqueous electrolyte is 0.01%, 0.03%, 0.05%, 0.08%, 0.1%, 0.2%, 0.3%, 0.5%, 0.8%, 1%, or any combination of these values. In a preferred embodiment, the mass percentage b% of the second additive is 0.1% to 0.5%. Within this preferred range, the concentration of free radicals in the system can be significantly reduced, the corrosion of aluminum foil and the catalytic acceleration effect of aluminum ions on side reactions can be suppressed, the degradation of battery safety performance caused by LiFTFSI can be fully compensated, and the role of the second additive in reducing battery impedance and improving the stability of the interfacial film can be fully utilized. Ultimately, the high and low temperature electrochemical performance and safety performance of the battery can be optimally balanced, achieving a high efficiency of both.

[0021] In some embodiments, the organic solvent is selected from one or more of cyclic carbonates, linear carbonates, carboxylic esters, and ethers.

[0022] In some preferred embodiments, the cyclic carbonate includes one or more of vinylene carbonate, propylene carbonate, ethylene carbonate, and butene carbonate.

[0023] In some preferred embodiments, the linear carbonate includes one or more of dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, and methyl propyl carbonate.

[0024] In some preferred embodiments, the carboxylic acid ester includes one or more of methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, methyl butyrate, methyl isobutyrate, methyl trimethylacetate, and ethyl trimethylacetate.

[0025] In some preferred embodiments, the ethers include one or more of ethylene glycol dimethyl ether, 1,3-dioxolane, and 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether.

[0026] In some preferred embodiments, the organic solvent is a mixture of ethylene carbonate, diethyl carbonate, and methyl ethyl carbonate.

[0027] In some preferred embodiments, the electrolyte salt is selected from LiPF6, LiBOB, LiDFOB, LiPO2F2, LiBF4, LiSbF6, LiAsF6, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiC(SO2CF3)3, LiN(SO2F)2, LiClO4, LiAlCl4, LiCF3SO3, and Li2B. 10 Cl 10 At least one of the following: lithium salts of lower aliphatic carboxylic acids.

[0028] In some embodiments, the mass content of the electrolyte salt is 5% to 20% based on 100% of the mass of the non-aqueous electrolyte. Specifically, the mass content of the electrolyte salt, based on 100% of the mass of the non-aqueous electrolyte, can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, or any combination thereof. In a preferred embodiment, the mass content of the electrolyte salt is 8% to 15% based on 100% of the mass of the non-aqueous electrolyte.

[0029] In some embodiments, the non-aqueous electrolyte further includes auxiliary additives selected from at least one of cyclic carbonate compounds, cyclic sulfate compounds, sulfonyl lactone compounds, phosphate compounds, borate ester compounds, and nitrile compounds;

[0030] Based on the total mass of the non-aqueous electrolyte as 100%, the content of the auxiliary additives is 0.01~30%.

[0031] In some preferred embodiments, the cyclic carbonate compound is selected from at least one of vinylene carbonate, ethylene ethylene carbonate, methylene carbonate, fluoroethylene carbonate, trifluoromethyl ethylene carbonate, difluoroethylene carbonate, or a compound represented by structural formula 1 below:

[0032] Structural Formula 1,

[0033] In structural formula 1, R 21 R 22 R 23 R 24 R 25 R 26 Each is independently selected from one of the following: hydrogen atom, halogen atom, or C1-C5 group.

[0034] In some embodiments, the C1-C5 groups include, but are not limited to, cyano, ester, alkyl, trifluoromethyl, or sulfonate groups.

[0035] In some preferred embodiments, the compound represented by structural formula 1 includes at least one of the compounds represented by compounds 1-1 to 1-6 below:

[0036]

[0037] Compound 1-1, Compound 1-2, Compound 1-3

[0038]

[0039] Compounds 1-4, Compounds 1-5, Compounds 1-6.

[0040] In some preferred embodiments, the cyclic sulfate compound is selected from vinyl sulfate, 4-methylvinyl sulfate, propylene sulfate, etc. , , At least one of them.

[0041] In some preferred embodiments, the sulfonyl lactone compound is selected from 1,3-propanesulfonyl lactone, 1,4-butanesulfonyl lactone, propenyl-1,3-sulfonyl lactone, etc. At least one of them.

[0042] In some embodiments, the phosphate ester compounds include saturated phosphate ester compounds and unsaturated phosphate ester compounds, wherein the saturated phosphate ester compounds include tris(trimethylsilane) phosphate esters, and the unsaturated phosphate ester compounds include compounds represented by structural formula 2 below:

[0043] Structural Formula 2,

[0044] R 31 R 32 R 33 Each is independently selected from C1-C5 saturated hydrocarbon groups, unsaturated hydrocarbon groups, halohydrocarbon groups, and -Si(C m H 2m+1 )3, m is a natural number from 1 to 3, and R 31 R 32 R 33 At least one of them is an unsaturated hydrocarbon group.

[0045] In some preferred embodiments, the compound represented by structural formula 2 includes at least one of the following: triargyl phosphate, diallyl methyl phosphate, diallyl ethyl phosphate, diallyl propyl phosphate, diallyl trifluoromethyl phosphate, diallyl-2,2,2-trifluoroethyl phosphate, diallyl-3,3,3-trifluoropropyl phosphate, diallyl hexafluoroisopropyl phosphate, triallyl phosphate, diallyl methyl phosphate, diallyl ethyl phosphate, diallyl propyl phosphate, diallyl trifluoromethyl phosphate, diallyl-2,2,2-trifluoroethyl phosphate, diallyl-3,3,3-trifluoropropyl phosphate, and diallyl hexafluoroisopropyl phosphate.

[0046] In some embodiments, the borate ester compounds include tris(trimethylsilane)borate and tris(triethylsilane)borate.

[0047] In some embodiments, the nitrile compound includes at least one selected from succinic acid, glutaronitrile, ethylene glycol bis(propionitrile) ether, hexanetrionitrile, adiponitrile, heptanonitrile, octanilide, nonadionitrile, and sebaconitrile.

[0048] In some preferred embodiments, the content of any one of the optional substances in the auxiliary additive in the non-aqueous electrolyte is less than 10%, preferably 0.1-5%, and more preferably 0.1-3%. Specifically, the content of any one of the optional substances in the auxiliary additive can be 0.05%, 0.08%, 0.1%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 7.8%, 8%, 8.5%, 9%, 9.5%, or 10%.

[0049] In some embodiments, when the auxiliary additive is selected from fluoroethylene carbonate, the content of fluoroethylene carbonate is 0.05-30% based on 100% of the total mass of the non-aqueous electrolyte.

[0050] The present invention also provides a battery, comprising a positive electrode, a negative electrode, a separator, and the aforementioned non-aqueous electrolyte.

[0051] In some embodiments, the positive electrode includes a positive electrode material layer containing a positive electrode active material, and the negative electrode includes a negative electrode material layer containing a negative electrode active material;

[0052] The positive electrode active material is selected from at least one of ternary materials, phosphate materials, lithium cobalt oxide materials, lithium-rich manganese materials, or lithium nickel manganese oxide materials.

[0053] The negative electrode active material is selected from one or more of silicon-based negative electrodes and carbon-based negative electrodes.

[0054] In some preferred embodiments of the present invention, the ternary material comprises Li q Ni x Co y M 1-x-y O 2-g R g Li materials or surfaces with a coating layer q Ni x Co y M 1-x-y O 2-g R g At least one of the materials, wherein 0.9≤q≤1.2, 0.01≤x≤0.96, y>0, 1-xy>0, 0≤g≤1, M includes one or two of Mn and Al, and zero or one or more of Sr, Mg, Ti, Ca, Zr, Zn, Si, Fe, B, Ga, Cr, W, V, Nb, Ce, and R includes one or more of N, F, S and Cl.

[0055] In some preferred embodiments of the present invention, the phosphate material includes materials with the molecular formula Li. r Mn α Fe β A 1-α-β PO 4-n G n Li materials or surfaces with a coating layer r Mn α Fe β A 1-α-β PO 4-n G n At least one of the materials, wherein 0.9≤r≤1.1, 0≤α≤0.8, 0.2≤β≤1, 0≤n≤0.1, A is selected from one or more of Ti, Mg, V, Cr, Zr, Nb, Zn, Al, Na, K, Mo, W, Ni, Co, Ga, Sn, Sb, Ge and W, and G includes one or more of N, F, S and Cl.

[0056] In some preferred embodiments of the present invention, the lithium cobalt oxide material includes lithium cobalt oxide or lithium cobalt oxide doped and / or coated with any one or more elements selected from Ni, Mn, Mg, Al, Zr, W, F, B, Cr, Mo and rare earth elements.

[0057] In some preferred embodiments of the present invention, the lithium nickel manganese oxide material comprises LiNi x' L' y’ Mn （2-x'-y'）O4, or LiNi with a coating layer on its surface x' L' y’ Mn （2-x'-y'） At least one of the O4 materials, 0.3≤x'≤0.6, 0.01≤y'≤0.2, and L' is selected from one or more of Co, Al, Sr, Mg, Ti, Ca, Zr, Zn, Si and Fe.

[0058] In a more preferred embodiment of the present invention, the positive electrode active material may include LiCoO2, LiFePO4, or LiFe 0.4 Mn 0.6 PO4, LiMn2O4, LiNi 0.5 Co 0.2 Mn 0.3 O2, LiNi 0.6 Co 0.2 Mn 0.2 O2, LiNi 0.7 Co 0.1 Mn 0.2 O2, LiNi 0.8 Co 0.1 Mn 0.1 O2, LiNi 0.8 Co 0.15 Al 0.05 O2, LiNi 0.9 Co 0.05 Mn 0.05 O2, LiNi 0.5 Co 0.2 Mn 0.2 Al 0.1 O2, LiNi 0.5 Co 0.2 Al 0.3 One or more of O2.

[0059] In some embodiments, the positive electrode further includes a positive electrode current collector, and the positive electrode material layer is disposed on the surface of the positive electrode current collector.

[0060] The positive electrode current collector is selected from a metallic material that can conduct electrons; preferably, the positive electrode current collector includes at least one of Al, Ni, tin, copper, and stainless steel; in a more preferred embodiment, the positive electrode current collector is selected from aluminum foil.

[0061] In some embodiments, the positive electrode active material layer further includes a positive electrode binder and a positive electrode conductive agent, and the positive electrode active material, the positive electrode binder and the positive electrode conductive agent are blended to obtain the positive electrode material layer.

[0062] In some embodiments, based on the total mass of the positive electrode material layer as 100%, the mass percentage of the positive electrode binder is 0.5% to 3%, and the mass percentage of the positive electrode conductive agent is 0.5% to 3%.

[0063] The positive electrode binder includes at least one of the following: polyvinylidene fluoride, copolymers of polyvinylidene fluoride, polytetrafluoroethylene, copolymers of polyvinylidene fluoride and hexafluoropropylene, copolymers of tetrafluoroethylene and hexafluoropropylene, copolymers of tetrafluoroethylene and perfluoroalkyl vinyl ethers, copolymers of ethylene and tetrafluoroethylene, copolymers of polyvinylidene fluoride and tetrafluoroethylene, copolymers of polyvinylidene fluoride and trifluoroethylene, copolymers of polyvinylidene fluoride and trichloroethylene, copolymers of polyvinylidene fluoride and fluorinated vinylides, copolymers of polyvinylidene fluoride, hexafluoropropylene and tetrafluoroethylene, thermoplastic polyimide, thermoplastic resins such as polyethylene and polypropylene, acrylic resins, and styrene-butadiene rubber.

[0064] In some embodiments, the positive electrode conductive agent includes one or more of carbon nanotubes, SP, and graphite powder. More preferably, the conductive agent is carbon nanotubes.

[0065] In some embodiments, the content of carbon nanotubes is 0.1% to 2% of the total weight of the cathode material; preferably, the content of carbon nanotubes is 0.5% to 2% of the total weight of the cathode material.

[0066] In some embodiments, the compaction density of the positive electrode is 2.0 g / cm³. 3 ~4.4 g / cm 3 More preferably, the compaction density of the positive electrode is 2.3 g / cm³. 3 ~4.2 g / cm 3 .

[0067] In some embodiments, the bifacial density of the positive electrode is 20 mg / cm³. 2 ~70 mg / cm 2 More preferably, the bifacial density of the positive electrode is 30 mg / cm³. 2 ~50 mg / cm 2 .

[0068] In some preferred embodiments, the carbon-based anode includes, but is not limited to, graphite, hard carbon, soft carbon, graphene, and mesophase carbon microspheres.

[0069] The graphite mentioned includes, but is not limited to, one or more of the following: natural graphite, artificial graphite, amorphous carbon, carbon-coated graphite, graphite-coated graphite, and resin-coated graphite. The natural graphite may be flake graphite, flaky graphite, soil graphite, and / or graphite particles obtained by using these graphites as raw materials and subjecting them to spheroidization, densification, or other treatments. The artificial graphite may be obtained by graphitizing organic materials such as coal tar pitch, heavy crude oil from coal, atmospheric residue, heavy crude oil from petroleum, aromatic hydrocarbons, nitrogen-containing cyclic compounds, sulfur-containing cyclic compounds, polystyrene, polyvinyl chloride, polyvinyl alcohol, polyacrylonitrile, polyvinyl butyral, natural polymers, polyphenylene sulfide, polyphenylene ether, furfuryl alcohol resin, phenolic resin, and imide resin at high temperatures. The amorphous carbon can be amorphous carbon particles obtained by heat treatment at a temperature range (400~2200℃) using easily graphitizable carbon precursors such as tar and pitch as raw materials, or amorphous carbon particles obtained by heat treatment using difficult-to-graphitize carbon precursors such as resin as raw materials. The carbon-coated graphite can be obtained by mixing natural graphite and / or artificial graphite with carbon precursors such as tar, pitch, and resin (organic compounds), and heat treatment at a temperature range (400~2300℃) at least once. The obtained natural graphite and / or artificial graphite are used as the core graphite, and amorphous carbon is used to coat it to obtain a carbon-graphite composite. The carbon-graphite composite can be in the form where the entire or part of the surface of the core graphite is coated with amorphous carbon, or it can be in the form of multiple primary particles composited using carbon derived from the aforementioned carbon precursors as a binder. Alternatively, carbon-graphite composites can be obtained by reacting hydrocarbon gases such as benzene, toluene, methane, propane, and aromatic volatile components with natural and / or artificial graphite at high temperatures, causing carbon to deposit on the graphite surface. The graphite-coated graphite can be obtained by mixing natural and / or artificial graphite with carbon precursors of easily graphitized organic compounds such as tar, asphalt, and resin, and subjecting the mixture to heat treatment at least once within a temperature range of approximately 2400-3200°C. Using the resulting natural and / or artificial graphite as the core graphite, and coating the entire or part of the surface of the core graphite with graphitized materials, graphite-coated graphite can be obtained. The resin-coated graphite can be obtained by mixing natural and / or artificial graphite with resin, drying at a temperature below 400°C, and using the resulting natural and / or artificial graphite as the core graphite, then coating the core graphite with resin. The aforementioned organic compounds, such as tar and asphalt resin, can be listed as carbonizable organic compounds selected from coal-based heavy crude oil, direct-flow heavy crude oil, decomposed petroleum heavy crude oil, aromatic hydrocarbons, N-ring compounds, S-ring compounds, polystyrene, organic synthetic polymers, natural polymers, thermoplastic resins, and thermosetting resins.

[0070] In some embodiments, the negative electrode further includes a negative electrode current collector, and the negative electrode material layer is disposed on the surface of the negative electrode current collector. The material of the negative electrode current collector may be the same as that of the positive electrode current collector, and will not be described in detail here.

[0071] In some embodiments, the negative electrode material layer further includes a negative electrode binder and a negative electrode conductive agent, and the negative electrode active material, the negative electrode binder, and the negative electrode conductive agent are blended to obtain the negative electrode material layer. The negative electrode binder and the negative electrode conductive agent can be the same as the positive electrode binder and the positive electrode conductive agent, respectively, and will not be described in detail here.

[0072] In some embodiments, the compaction density of the negative electrode is 1.0 g / cm³. 3 ~2.0 g / cm 3 More preferably, the compaction density of the negative electrode is 1.4 g / cm³. 3 ~1.8 g / cm 3 .

[0073] In some embodiments, the bifacial density of the negative electrode is 10 mg / cm³. 2 ~35 mg / cm 2 More preferably, the bifacial density of the negative electrode is 15 mg / cm³. 2 ~30 mg / cm 2 .

[0074] In some embodiments, the battery further includes a separator located between the positive electrode and the negative electrode.

[0075] The diaphragm can be a conventional diaphragm, such as a ceramic diaphragm, a polymer diaphragm, a non-woven fabric, or an inorganic-organic composite diaphragm, including but not limited to single-layer PP (polypropylene), single-layer PE (polyethylene), double-layer PP / PE, double-layer PP / PP, and triple-layer PP / PE / PP diaphragms.

[0076] Compared with the prior art, the present invention has the following advantages:

[0077] In the non-aqueous electrolyte provided by this invention, lithium (fluorosulfonyl)(trifluoromethanesulfonyl)imino (LiFTFSI) is used as the first additive and 2-thiopheneboronic acid is used as the second additive. When the mass percentage content 'a' of the first additive and the mass percentage content 'b' of the second additive satisfy 0.5 ≤ a / b ≤ 100, 0.05 ≤ a ≤ 5, and 0.01 ≤ b ≤ 1, the first additive and the second additive exert a synergistic effect, making the electrolyte quality more stable. Moreover, the prepared battery can achieve better high-temperature performance and safety performance. Detailed Implementation

[0078] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0079] Unless otherwise specified, all reagents, materials, and instruments used in the following description are conventional reagents, materials, and instruments, all of which are commercially available. The reagents involved can also be synthesized using conventional synthetic methods. Unless otherwise specified, the methods in the examples are conventional methods in the art. Monomers conforming to this invention are commercially available.

[0080] Example 1

[0081] This embodiment provides a method for preparing a lithium-ion battery, including the following steps:

[0082] 1. Preparation of positive electrode sheet

[0083] Step 1: Weigh out the positive electrode active material NCM811, conductive agent (super P+CNT) and binder polyvinylidene fluoride (PVDF) in a mass ratio of 93:4:3.

[0084] Step 2: Add PVDF as a binder to N-methyl-2-pyrrolidone (NMP) solvent, stir thoroughly to obtain PVDF adhesive.

[0085] Step 3: Add the positive electrode active material and conductive agent (super P+CNT) to the PVDF adhesive solution, and stir thoroughly to obtain the positive electrode slurry.

[0086] Step 4: The prepared positive electrode slurry is uniformly coated on the positive electrode current collector (e.g., aluminum foil), and then dried, rolled, die-cut or slit to obtain the positive electrode sheet.

[0087] 2. Preparation of negative electrode sheet

[0088] Step 1: Weigh out each material according to the negative electrode sheet ratio of graphite (Shanghai Shanshan, FSN-1): conductive carbon (super P): sodium carboxymethyl cellulose (CMC): styrene-butadiene rubber (SBR) = 96.3:1.0:1.2:1.5 (mass ratio).

[0089] Step 2: First, add CMC to pure water and stir thoroughly (e.g., stirring time 120 minutes) to prepare a transparent CMC solution with a solid content of 1.5%.

[0090] Step 3: Add conductive carbon (super P) to the CMC adhesive solution and stir thoroughly (e.g., stirring time 90 min) to prepare the conductive adhesive.

[0091] Step 4: Continue adding graphite and stir thoroughly to obtain the desired negative electrode slurry.

[0092] Step 5: The prepared negative electrode slurry is evenly coated on copper foil, and then dried, rolled, die-cut or slit to obtain the negative electrode sheet.

[0093] 3. Preparation of non-aqueous electrolytes

[0094] Ethylene carbonate (EC), diethyl carbonate (DEC), and methyl ethyl carbonate (EMC) were mixed in a mass ratio of EC:DEC:EMC = 1:1:1. 2.0% by mass of the first additive (LiFTFSI) and 0.3% by mass of the second additive (2-thiopheneboronic acid) were added, followed by the addition of lithium hexafluorophosphate (LiPF6) to a molar concentration of 1 mol / L.

[0095] 4. Lithium-ion battery cell manufacturing

[0096] The prepared positive electrode sheet and the prepared negative electrode sheet are assembled into a stacked soft-pack battery cell.

[0097] 5. Electrolyte injection and formation of battery cells

[0098] In a glove box with the dew point controlled below -40°C, the electrolyte prepared above was injected into the cell, vacuum sealed, and left to stand for 72 hours. Then, the first charge was performed according to the following steps: 0.05C constant current charging for 180 minutes, 0.1C constant current charging for 120 minutes, 0.2C constant current charging for 120 minutes, followed by a second vacuum sealing, and then a full charge at 0.2C (100% SOC). After resting at room temperature for 72 hours, a full discharge at 0.2C (0% SOC) was performed.

[0099] Examples 2-26, Comparative Examples 1-23

[0100] Examples 2-26 and Comparative Examples 1-23 are used to illustrate the non-aqueous electrolyte and battery disclosed in this invention. They include most of the operating steps in Example 1, but differ in the following aspects: the type of positive electrode active material, the type of negative electrode active material, the content of additives (including the first additive and the second additive), the value of the relationship a / b, and the types and contents of auxiliary additives, as shown in Tables 1-4.

[0101] Performance testing:

[0102] The lithium-ion batteries prepared in Examples 1-26 and Comparative Examples 1-23 were tested for high-temperature cycling and high-temperature storage performance.

[0103] 1. High-temperature cycling performance test:

[0104] At 45°C, the lithium-ion batteries prepared in the examples and comparative examples were fully charged at a constant current and constant voltage rate of 1C (e.g., the conventional upper limit voltage for ternary systems is 4.2V), with a cutoff current of 0.05C, and then discharged at a 1C rate. This cycle was repeated for three weeks, and the discharge capacity of the last week was taken as the initial 100% SOC capacity. Full charge-discharge cycle tests were then performed using the same charge-discharge mode until the capacity of the lithium-ion battery decayed to 80% of its initial capacity, and the number of cycles was recorded.

[0105] 2. Low-temperature discharge performance test:

[0106] At room temperature (25℃), the battery is fully charged at a constant current and constant voltage rate of 0.5C, with a cutoff current of 0.05C. It is then discharged at a rate of 0.5C to the lower limit voltage. This cycle is repeated for three weeks, and the discharge capacity of the last week is taken as the 100% SOC capacity C1 at room temperature. After the battery is fully charged at room temperature at a constant current and constant voltage rate, it is placed in a low temperature environment at 0℃ and left to stand for 4 hours to cool down. Then, it is discharged at a rate of 0.5C to the lower limit voltage at low temperature. The discharge capacity at 0℃ is recorded as C2. The low temperature discharge retention rate of the battery is then calculated as C2 / C1×100%.

[0107] 3. Thermal shock safety performance test

[0108] At 25℃, the battery is charged to the upper limit voltage at a constant current of 0.5C, and then charged to the cutoff current of 0.05C at a constant voltage. The battery is then placed in a thermal shock test chamber, and the temperature inside the chamber is raised from room temperature to 140℃ at a heating rate of 5℃ / min and kept at a constant temperature for 1 hour. The surface temperature of the battery cell is monitored using an infrared scanner or other temperature measuring equipment. The battery is considered to have passed the test if no thermal runaway occurs during the test.

[0109] Test results:

[0110] Table 1 shows the required parameters for the lithium-ion batteries prepared in Examples 1-17 and Comparative Examples 1-10. The differences between Examples 2-17 and Comparative Examples 1-10 and Example 1 lie in the relevant parameters in Table 1. The remaining parameters and preparation steps are the same as those described in Example 1. The specific differences are: the content of the first additive and the second additive and the value of the relationship a / b. Table 1 also discloses the test results of the high-temperature cycle performance, low-temperature discharge performance, and thermal shock safety performance of the lithium-ion batteries.

[0111] Table 1

[0112]

[0113]

[0114] Note: " / " in the table indicates that the item does not exist.

[0115] As shown in the test results in Table 1, in non-aqueous electrolytes, when (fluorosulfonyl)(trifluoromethanesulfonyl)iminolithium (LiFTFSI) is used as the first additive and 2-thiopheneboronic acid is used as the second additive, and the mass percentage content 'a' of the first additive and the mass percentage content 'b' of the second additive are limited to 0.5 ≤ a / b ≤ 100, 0.05 ≤ a ≤ 5, and 0.01 ≤ b ≤ 1, the first and second additives exert a synergistic effect, making the electrolyte quality more stable. Moreover, the prepared battery can achieve better high-temperature performance and safety performance.

[0116] The test results from Example 1 and Comparative Examples 1-10 show that when either or both of the mass percentages of the first additive (a) and the second additive (b) in the non-aqueous electrolyte do not meet the specified range, or when the value of their relationship (a / b) is too large or too small, the effect of the first additive in improving lithium-ion migration and increasing the proportion of LiF components in the interfacial film will be greatly reduced. This not only makes it difficult to guarantee the high and low temperature performance of the battery, but also exacerbates safety risks due to excessive addition. The second additive, on the other hand, cannot effectively suppress the safety hazards caused by the first additive, and its own function is also difficult to fully exert. Ultimately, this results in the lithium-ion battery being unable to simultaneously achieve excellent high and low temperature performance, high temperature cycle performance, and safety performance.

[0117] When the mass percentages of the first additive (a) and the second additive (b) in the non-aqueous electrolyte, along with the relationship a / b, further satisfy 2 ≤ a / b ≤ 10, and 0.5 ≤ a ≤ 3, 0.1 ≤ b ≤ 0.5, the first and second additives achieve their optimal ratio. Under this ratio, the first additive effectively improves lithium-ion migration and participates in the formation of the electrode / electrolyte interface film, significantly increasing the proportion of LiF components in the interface film, thus laying the foundation for the battery to achieve both high and low temperature performance. Simultaneously, the second additive effectively suppresses the safety hazards introduced by the first additive while fully utilizing its own functional characteristics. The synergistic effect of both is fully released, ultimately enabling the lithium-ion battery to achieve even more outstanding high-temperature cycle performance and safety performance while maintaining excellent high and low temperature performance.

[0118] Table 2 shows the required parameters for the lithium-ion batteries prepared in Examples 1, 18-20, and Comparative Examples 11-13. The differences between Examples 18-20 and Comparative Examples 11-13 and Example 1 lie in the relevant parameters in Table 1. The remaining parameters and preparation steps are the same as those described in Example 1. The specific differences are: the type of positive electrode active material, the content of the first additive, the content of the second additive, and the value of the relationship a / b. Table 2 also discloses the test results of the high-temperature cycle performance, low-temperature discharge performance, and thermal shock safety performance of the lithium-ion batteries.

[0119] Table 2

[0120]

[0121]

[0122] As can be seen from the test results in Table 2, for different positive electrode active materials, when the mass percentage content 'a' of the first additive and the mass percentage content 'b' of the second additive in the non-aqueous electrolyte and the value of the relationship a / b meet the corresponding conditions, a lithium-ion battery that balances superior high-temperature performance and safety performance can be obtained. This demonstrates that the battery system of the present invention has universality for different types of positive electrode active materials.

[0123] Table 3 shows the required parameters for the lithium-ion batteries prepared in Examples 1, 21-23, and Comparative Examples 14-16. The differences between Examples 21-23 and Comparative Examples 14-16 and Example 1 lie in the relevant parameters in Table 3. The remaining parameters and preparation steps are the same as those described in Example 1. The specific differences are: the type of negative electrode active material, the content of the first additive, the content of the second additive, and the value of the relationship a / b. Table 3 also discloses the test results of the high-temperature cycle performance, low-temperature discharge performance, and thermal shock safety performance of the lithium-ion batteries.

[0124] Table 3

[0125]

[0126]

[0127] As can be seen from the test results in Table 3, for different negative electrode active materials, when the mass percentage content 'a' of the first additive and the mass percentage content 'b' of the second additive in the non-aqueous electrolyte and the value of the relationship a / b meet the corresponding conditions, lithium-ion batteries that can achieve both superior high-temperature performance and safety performance can be obtained. This demonstrates that the battery system of the present invention has universal applicability to different types of negative electrode active materials.

[0128] Table 4 shows the required parameters for the lithium-ion batteries prepared in Examples 1, 24-26, and Comparative Examples 17-23. The difference between Examples 24-26 and Comparative Examples 17-23 and Example 1 lies in the relevant parameters in Table 4. The remaining parameters and preparation steps are the same as those described in Example 1. The specific differences are: the type and content of auxiliary additives, the content of the first additive, the content of the second additive, and the value of the relationship a / b. Table 4 also discloses the test results of the high-temperature cycle performance, low-temperature discharge performance, and thermal shock safety performance of the lithium-ion batteries.

[0129] Table 4

[0130]

[0131]

[0132] Note: " / " in the table indicates that the item is not present; DTD represents vinyl sulfate; PS represents propylene sulfite; FEC represents fluoroethylene carbonate.

[0133] As shown in Table 4, when the mass percentages of the first additive (a) and the second additive (b) in the non-aqueous electrolyte, as well as the value of the relationship a / b, meet the corresponding conditions, adding different types of auxiliary additives can yield lithium-ion batteries with both superior high-temperature performance and safety performance. This demonstrates that the battery system of this invention is universally applicable to different types of negative electrode active materials. Furthermore, if either LiFSI or LiTFSI, or a combination of both, is used to replace LiFTFSI, its high-temperature performance and safety performance are both poor. This indicates that LiFTFSI, compared to LiFSI and LiTFSI, has a unique advantage in improving the high-temperature and safety performance of lithium-ion batteries through its combination with 2-thiopheneboronic acid.

[0134] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A non-aqueous electrolyte, characterized in that, It includes additives, electrolyte salts, and organic solvents; the additives include a first additive and a second additive; the first additive includes (fluorosulfonyl)(trifluoromethanesulfonyl)iminolithium, and the second additive includes 2-thiopheneboronic acid; Based on the mass of the non-aqueous electrolyte, the mass percentage of the first additive is a%, and the mass percentage of the second additive is b%. The non-aqueous electrolyte satisfies the following conditions: 0.5≤a / b≤100; and 0.05≤a≤5, 0.01≤b≤1.

2. The non-aqueous electrolyte as described in claim 1, characterized in that, The non-aqueous electrolyte satisfies the following condition: 2≤a / b≤10.

3. The non-aqueous electrolyte as described in claim 1, characterized in that, The mass percentage a% of the first additive satisfies: 0.5≤a≤3.

4. The non-aqueous electrolyte as described in claim 1, characterized in that, The mass percentage b% of the second additive satisfies: 0.1 ≤ b ≤ 0.

5.

5. The non-aqueous electrolyte as described in claim 1, characterized in that, The organic solvent is selected from one or more of cyclic carbonates, linear carbonates, carboxylic esters, and ethers.

6. The non-aqueous electrolyte as described in claim 1, characterized in that, The electrolyte salts are selected from LiPF6, LiBOB, LiDFOB, LiPO2F2, LiBF4, LiSbF6, LiAsF6, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiC(SO2CF3)3, LiN(SO2F)2, LiClO4, LiAlCl4, LiCF3SO3, and Li2B. 10 Cl 10 At least one of the following: lower aliphatic lithium carboxylates; and / or, Based on the mass of the non-aqueous electrolyte as 100%, the mass content of the electrolyte salt is 5% to 20%.

7. The non-aqueous electrolyte as described in claim 1, characterized in that, The non-aqueous electrolyte further includes auxiliary additives, which are selected from at least one of cyclic carbonate compounds, cyclic sulfate compounds, sulfonyl lactone compounds, phosphate compounds, borate ester compounds, and nitrile compounds; and / or, Based on the total mass of the non-aqueous electrolyte as 100%, the content of the auxiliary additives is 0.01~30%.

8. The non-aqueous electrolyte as described in claim 7, characterized in that, The cyclic carbonate compound is selected from at least one of vinylene carbonate, ethylene ethylene carbonate, methylene carbonate, fluoroethylene carbonate, trifluoromethyl ethylene carbonate, difluoroethylene carbonate, or the compound shown in structural formula 1 below: Structural Formula 1, In structural formula 1, R 21 R 22 R 23 R 24 R 25 R 26 Each is independently selected from one of the following: hydrogen atom, halogen atom, C1-C5 group; and / or, The cyclic sulfate compounds are selected from vinyl sulfate, 4-methylvinyl sulfate, propylene sulfate, etc. , , At least one of them; and / or, The sulfonyl lactone compounds are selected from 1,3-propanesulfonyl lactone, 1,4-butanesulfonyl lactone, propenyl-1,3-sulfonyl lactone, and so on. At least one of them; and / or, The phosphate ester compounds include saturated phosphate ester compounds and unsaturated phosphate ester compounds, wherein the saturated phosphate ester compounds include tris(trimethylsilane) phosphate esters, and the unsaturated phosphate ester compounds include compounds represented by structural formula 2 below: Structural Formula 2, In structural formula 2, R 31 R 32 R 33 Each is independently selected from C1-C5 saturated hydrocarbon groups, unsaturated hydrocarbon groups, halohydrocarbon groups, and -Si(C m H 2m+1 )3, m is a natural number from 1 to 3, and R 31 R 32 R 33 At least one of them is an unsaturated hydrocarbon group; and / or, The borate ester compounds include tris(trimethylsilane)borate and tris(triethylsilane)borate; and / or, The nitrile compounds include at least one of butadionitrile, glutaronitrile, ethylene glycol bis(propionitrile) ether, hexanetrionitrile, adiponitrile, heptacyanide, octadionitrile, nonadionitrile, and sebaconitol.

9. A battery, characterized in that, It includes a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte as described in any one of claims 1 to 8.

10. The battery as claimed in claim 9, characterized in that, The positive electrode includes a positive electrode material layer containing a positive electrode active material, and the negative electrode includes a negative electrode material layer containing a negative electrode active material. The positive electrode active material is selected from at least one of ternary materials, phosphate materials, lithium cobalt oxide materials, lithium-rich manganese materials, or lithium nickel manganese oxide materials. The negative electrode active material is selected from one or more of silicon-based negative electrodes and carbon-based negative electrodes.

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