Battery

Abstract

Battery, including: a positive electrode plate comprising an active material layer of the positive electrode, wherein the active material layer of the positive electrode comprises an active material of the positive electrode, wherein a mass fraction of the active material of the positive electrode based on a total mass of the active material layer of the positive electrode is designated as B, and wherein a specific surface area of ​​the active material of the positive electrode is designated as C m 2 / g is designated; a negative electrode plate comprising an active material of the negative electrode, wherein a specific surface area of ​​the active material of the negative electrode is designated as E m 2 / g is designated; and an electrolyte comprising a compound represented by formula 1 and LiBF4, wherein a mass fraction of the compound represented by formula 1 based on a total mass of the electrolyte is designated as G, where the battery follows a formula of 0.20 ≤ (10 × B × G × E 2 ) / C ≤ 3.88 is satisfied,

Description

PRIORITY NOTICE

[0001] This application claims the priority and benefits of patent application no. 202411069923.2, filed with the Chinese National Intellectual Property Administration on August 6, 2024, the entire contents of which are incorporated herein by reference. AREA

[0002] The present disclosure relates to the field of batteries and in particular to a battery. BACKGROUND

[0003] Lithium-ion batteries are widely used in consumer electronics, electric vehicles, and energy storage due to their high energy density and cycle life. Currently, the discharge capacity of lithium-ion batteries is primarily increased by raising the upper cutoff voltage or the compaction density to meet consumer demand for high-capacity lithium-ion batteries.

[0004] During high-frequency charge-discharge cycling of batteries, metal ions from the active material of the positive electrode tend to dissolve, further catalyzing the oxidative degradation of the electrolyte and generating gas. This leads to reduced stability of the solid-electrolyte interface (SEI) and the cathode-electrolyte interface (CEI), impairs the intercalation / deintercalation capability of lithium ions between the positive and negative electrodes, and causes rapid capacity loss in the battery. Consequently, the battery's fast-charge cycle performance deteriorates, and this problem is particularly pronounced at high voltages.

[0005] Therefore, the question of how to improve the fast-charging cycle performance of high-voltage lithium-ion batteries became an urgent problem to be solved. SUMMARY

[0006] The present invention aims to at least partially solve one of the problems existing in the prior art. Therefore, it is an object of the present disclosure to provide a battery that exhibits excellent fast-charge cycle performance.

[0007] A first aspect of the present disclosure provides a battery comprising a positive electrode plate, a negative electrode plate, and an electrolyte. The positive electrode plate comprises an active material layer of the positive electrode. The active material layer of the positive electrode comprises an active material of the positive electrode. A mass fraction of the active material of the positive electrode, based on a total mass of the active material layer of the positive electrode, is denoted as B, and a specific surface area of ​​the active material of the positive electrode is denoted as C m 2 / g. The negative electrode plate comprises a negative electrode active material. A specific surface area of ​​the negative electrode active material is designated as E m 2 The electrolyte comprises a compound represented by formula 1 and LiBF4. A mass fraction of the compound represented by formula 1, based on a total mass of the electrolyte, is denoted as G. The battery satisfies a formula of 0.20 ≤ (10 × B × G × E 2 ) / C ≤ 3.88,

[0008] The battery of the present disclosure comprises the positive electrode plate, the negative electrode plate, and the electrolyte. The electrolyte comprises the compound represented by Formula 1 and LiBF4. Although the compound represented by Formula 1 can preferably form a stable SEI film on the surface of the negative electrode to improve the battery's cycle performance, gas evolution still occurs during long-term cycling during the battery's fast-charging process, which compromises the battery's safety. In contrast, LiBF4 can not only inhibit gas evolution but also participate in the formation of a stable CEI, thereby inhibiting the dissolution of metal ions from the active material of the positive electrode and improving the stability of the positive electrode. Consequently, the combined use of the two can improve the battery's cycle performance during fast charging.However, the inventors discovered that in practical battery cycling processes, the compound represented by Formula 1 and LiBF4 in the electrolyte have only a limited effect on the battery's fast-charging capability, particularly its fast-charge cycle performance. The battery's fast-charge cycle performance is also closely related to the mass fraction B of the active material in the positive electrode's active material layer and its specific surface area C m. 2 / g of the active material of the positive electrode, the surface E m 2 / g of the active material of the negative electrode in the negative electrode plate and the mass fraction G of the compound represented by formula 1 in the electrolyte together. The inventors have further recognized that under stringent conditions, for example, high voltage and high-frequency charge-discharge cycling of the battery, when the above parameters yield a formula of 0.20 ≤ (10 × B × G × E 2) / C ≤ 3.88, ensuring optimal compatibility between the positive electrode, the negative electrode, and the battery electrolyte. This minimizes the adverse effects of the active materials of the positive and negative electrodes on the battery's fast-charge and cycle performance, allowing the battery to exhibit excellent fast-charge cycle performance under high voltage. This is because the overall battery performance is jointly determined by the parameters of the electrolyte, the positive electrode, the negative electrode, and the separator. In the present disclosure, adhesion between the active material of the positive electrode and the electrode plate, thereby improving the battery's cycle performance, can only be guaranteed if the amount of active material of the positive electrode meets the formula described above.On the other hand, only when the specific surface areas of the positive and negative electrodes meet the formula described above can lithium ions be rapidly intercalated and deintercalated on the formed SEI and CEI film, resulting in excellent kinetic performance and further improving the battery's fast-charging performance. In this way, if the parameters described above meet the specified formula, the battery exhibits excellent fast-charging cycle performance under high voltage.

[0009] In some embodiments, 95% ≤ B ≤ 99%.

[0010] In some embodiments, 0.2 ≤ C ≤ 2.

[0011] In some embodiments, 0.2 ≤ E ≤ 3.5.

[0012] In some embodiments, 0.5% ≤ G ≤ 3%.

[0013] In some embodiments, the mass ratio of the compound represented by formula 1 to LiBF4 is (0.5 to 3) : (0.1 to 1).

[0014] In some embodiments, a mass fraction of LiBF4 based on the total mass of the electrolyte ranges from 0.1% to 1%.

[0015] In some embodiments, the electrolyte also includes a nitrile compound.

[0016] In some embodiments, the nitrile compound includes at least one of succinonitrile, adiponitrile, 1,2-bis(2-cyanoethoxy)ethane, 1,2,3-tris(2-cyanoxy)propane, 1,3,6-hexanetricarbonitrile or tetracyanoethylene.

[0017] In some embodiments, the mass fraction of the nitrile compound, based on the total mass of the electrolyte, ranges from 0.2% to 3%.

[0018] In some embodiments, the mass ratio of the compound represented by formula 1 to LiBF4 and to the nitrile compound is (0.5 to 3) : (0.1 to 1) : (0.2 to 3).

[0019] In some embodiments, the active material of the positive electrode comprises at least one of lithium cobalt oxide, a ternary nickel-cobalt-manganese material, a ternary nickel-cobalt-aluminium material, a lithium-rich manganese material, a lithium nickel-manganese oxide material, lithium manganese iron phosphate, or lithium manganese oxide.

[0020] In some embodiments, the active material of the negative electrode comprises at least one of graphite or a silicon-carbon material.

[0021] Further aspects and advantages of the present disclosure are partly provided in the following description, or become partly obvious from the following description, or can be learned from the practical implementation of the present disclosure. DETAILED DESCRIPTION OF THE EXECUTION FORMS

[0022] The embodiments of the present disclosure are described in detail below, which is intended to explain the present disclosure and not to limit it.

[0023] During high-frequency charge-discharge cycling of batteries, metal ions from the active material of the positive electrode tend to dissolve, further catalyzing the oxidative degradation of the electrolyte and generating gas. This leads to reduced stability of the SEI and CEI, impairs the intercalation / deintercalation capability of lithium ions between the positive and negative electrodes, and causes rapid capacity loss in the battery. Consequently, the battery's fast-charge cycle performance deteriorates, and this problem is particularly pronounced at high voltage.

[0024] A first aspect of the present disclosure provides a battery comprising a positive electrode plate, a negative electrode plate, and an electrolyte. The positive electrode plate comprises an active material layer of the positive electrode. The active material layer of the positive electrode comprises an active material of the positive electrode. A mass fraction of the active material of the positive electrode, based on a total mass of the active material layer of the positive electrode, is denoted as B, and a specific surface area of ​​the active material of the positive electrode is denoted as C m 2 / g. The negative electrode plate comprises a negative electrode active material. A specific surface area of ​​the negative electrode active material is designated as E m 2The electrolyte comprises a compound represented by formula 1 and LiBF4. A mass fraction of the compound represented by formula 1, based on a total mass of the electrolyte, is denoted as G. The battery satisfies a formula of 0.20 ≤ (10 × B × G × E 2 ) / C ≤ 3.88,

[0025] The value of (10 × B × G × E 2 ) / C can be, for example, 0.20, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 3.88, etc.

[0026] The battery of the present disclosure comprises the positive electrode plate, the negative electrode plate, and the electrolyte. The electrolyte comprises the compound represented by Formula 1 and LiBF4. Although the compound represented by Formula 1 can preferably form a stable SEI film on the surface of the negative electrode to improve the battery's cycle performance, gas evolution still occurs during long-term cycling during the battery's fast-charging process, which compromises the battery's safety. In contrast, LiBF4 can not only inhibit gas evolution but also participate in the formation of a stable CEI, thereby inhibiting the dissolution of metal ions from the active material of the positive electrode and improving the stability of the positive electrode. Consequently, the combined use of the two can improve the battery's cycle performance during fast charging.However, the inventors discovered that in practical battery cycling processes, the compound represented by Formula 1 and LiBF4 in the electrolyte have only a limited effect on the battery's fast-charging capability, particularly its fast-charge cycle performance. The battery's fast-charge cycle performance is also closely related to the mass fraction B of the active material in the positive electrode's active material layer and its specific surface area C m. 2 / g of the active material of the positive electrode, the surface E m 2 / g of the active material of the negative electrode in the negative electrode plate and the mass fraction G of the compound represented by formula 1 in the electrolyte together. The inventors have further recognized that under stringent conditions, for example, high voltage and high-frequency charge-discharge cycling of the battery, when the above parameters yield a formula of 0.20 ≤ (10 × B × G × E 2 ) / C ≤ 3.88, the compatibility between the positive electrode, the negative electrode and the electrolyte of the battery is optimal, which can minimize the adverse effects of the active material of the positive electrode and the active material of the negative electrode on the fast charge performance and the cycle performance of the battery, so that the battery can exhibit excellent fast charge cycle performance under high voltage.

[0027] It is understood that the unit of specific surface area of ​​the active material of the positive electrode and the active material of the negative electrode is m 2 / g is, but the present disclosure does not limit the unit of the specific surface area of ​​the active material of the positive electrode and the active material of the negative electrode. The unit of specific surface area can, for example, also be m 2 / kg, cm 2 / g etc. If the unit of specific surface area is a different unit than m² 2 / g is and the value after converting the unit to m 2 Since the value ranges from 0.20 to 3.88, this is also within the scope of protection of the present disclosure.

[0028] In some embodiments, 95% ≤ B ≤ 99%. For example, B can be 95%, 96%, 96.5%, 97%, 98%, 98.5%, 99%, etc. A larger amount of the positive electrode active material can provide a higher theoretical capacity. However, if it exceeds a certain range, the adhesion between the positive electrode active material and a binder becomes deficient, resulting in a significant reduction in electrical conductivity and thus affecting the battery's cycle performance. By keeping the positive electrode active material within the range described above, the present disclosure ensures stable battery conductivity and allows (10 × B × G × E) 2 ) / C should be kept within the range of 0.20 to 3.88. This will improve the battery's fast-charging cycle performance under high voltage.

[0029] In some embodiments, 0.2 ≤ C ≤ 2. C can be, for example, 0.2, 0.3, 0.6, 0.9, 1.3, 1.5, 2, etc. The active material of the positive electrode has active sites on its surface. The larger the specific surface area of ​​the active material of the positive electrode, the greater the number of active sites. LiBF4, in combination with the active sites on the surface of the active material of the positive electrode, can form the CEI. If the specific surface area is too small, it is difficult for LiBF4 to form a complete CEI on the surface of the positive electrode. Conversely, if the specific surface area is too large, there is a tendency to form a thicker CEI, which is not conducive to the deintercalation of lithium ions. By keeping the specific surface area of ​​the active material of the positive electrode within the range of 0.2 m² 2 / g up to 2 m 2According to the present disclosure, a low-impedance, high-stability CEI film can be formed, thereby improving kinetic performance and holding (10 × B × G × E). 2 ) / C within the range of 0.20 to 3.88. In this way, the fast-charging cycle performance of the battery under high voltage can be improved.

[0030] In some embodiments, 0.2 ≤ E ≤ 3.5. E can be, for example, 0.2, 0.8, 1.2, 1.6, 2, 2.8, 3.5, etc. The negative electrode material also has active sites on its surface. However, if the difference in specific surface area between the active material of the positive electrode and the active material of the negative electrode is large, this also leads to a discrepancy in the kinetics between the positive and negative electrodes of the battery. By keeping the specific surface area of ​​the active material of the negative electrode within the range of 0.2 m²2 / g up to 3.5 m 2 In the present disclosure, the specific surface area of ​​the active material of the positive electrode can be adapted to that of the active material of the negative electrode, thereby improving the kinetic performance of the battery. This also facilitates (10 × B × G × E 2 ) / C should be kept within the range of 0.20 to 3.88. This will improve the battery's fast-charging cycle performance under high voltage.

[0031] In some embodiments, 0.5% ≤ G ≤ 3%. For example, G is 0.5%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, etc. If G is within this range, the content of the compound represented by Formula 1 in the electrolyte is moderate, ensuring the formation of an effective, low-impedance, and highly stable CEI and SEI film on the surfaces of the positive and negative electrodes and the retention of (10 × B × G × E 2) / C within the range of 0.20 to 3.88 can facilitate this. In this way, the fast-charging cycle performance of the battery under high voltage can be improved.

[0032] Since the cycle life and fast-charge performance of lithium-ion batteries are jointly determined by the positive electrode plate, the negative electrode plate, and the electrolyte, the inventors discovered that when the compound represented by Formula 1 and LiBF4 are added to the electrolyte, the cycle life and fast-charge performance of the battery can be optimized by adjusting the values ​​of B, G, E, and C. If the active material of the positive electrode has a higher mass fraction of B, more of the active material of the positive electrode participates in the reaction, thus providing more lithium ions and increasing the battery's capacity. A larger specific surface area C of the active material of the positive electrode means more sites for the intercalation / deintercalation of lithium ions, thereby increasing the charge-discharge frequency of the battery.Similarly to C, the specific surface area E of the negative electrode's active material influences lithium ion diffusion and the reaction rate at the negative electrode, and experiments have shown that the specific surface area of ​​the negative electrode's active material has a quadratic effect on battery performance. The mass fraction G of the compound represented by Formula 1 in the electrolyte influences the quality of SEI formation in the electrolyte, thereby affecting cycle performance.

[0033] This means that, based on experience and experimental results, within a certain range each of the parameters correlates positively with cycle and fast charging performance. By dividing the product of (10 × B × G × E 2The specific surface area C of the active material of the positive electrode is normalized in such a way that the formula is applied to active materials of the positive electrode with different specific surface areas. In other words, increasing B, E, or G can potentially increase battery performance, but a larger C is required to maintain the charge-discharge frequency and cycle stability.

[0034] The specific physical meaning of the formula (10 × B × G × E 2 ) / C represents the degree of conformity between the positive electrode, the negative electrode, and the electrolyte in the battery. Experiments have shown that when the value of (10 × B × G × E 2The coefficient of friction (C) / C ranges from 0.20 to 3.88, ensuring optimal matching between the positive electrode, the negative electrode, and the battery electrolyte. This minimizes the adverse effects of the positive and negative electrode active materials on the battery's fast-charge and cycle performance, allowing the battery to exhibit excellent fast-charge cycle performance under high voltage. An excessively large or small value of this formula leads to a poor match between the positive and negative electrodes, affecting lithium ion transport between them and ultimately impacting the battery's cycle performance and rate capability.

[0035] In some embodiments, the mass fraction of LiBF4, based on the total mass of the electrolyte, ranges from 0.1% to 1%. For example, it can be 0.1%, 0.3%, 0.5%, 0.7%, 0.9%, 1%, etc. Maintaining the mass fraction of LiBF4 within the range described above is sufficient to inhibit gas evolution and participate in the formation of a stable CEI, thereby preventing the dissolution of metal ions from the active material of the positive electrode. Consequently, the high-voltage fast-charging cycle performance of the battery can be improved.

[0036] In some embodiments, the mass ratio of the compound represented by Formula 1 to LiBF4 is (0.5 to 3) : (0.1 to 1). For example, it can be 2 : 0.5, 2 : 0.1, 2 : 1, 0.5 : 0.5, 3 : 0.5, etc. If the mass ratio of the compound represented by Formula 1 to LiBF4 in the electrolyte is maintained within the range described above, a synergistic effect of the compound represented by Formula 1 and LiBF4 can be fully exploited. This inhibits the dissolution of metal ions from the active material of the positive electrode and improves the stability of the positive and negative electrodes, further improving the battery's cycle performance during fast charging.

[0037] In some embodiments, the electrolyte also includes a nitrile compound. If the battery's charging cutoff voltage exceeds 4.5 V, the metal ions in the active material of the positive electrode can still dissolve under high voltage and catalyze the decomposition of the electrolyte, producing gas. Therefore, further introduction of the nitrile compound into the electrolyte can improve the high-voltage fast-charging cycle performance. This is primarily due to the strong complex formation between cyanide and metal ions, which not only inhibits the dissolution of metal ions from the active material of the positive electrode and prevents excessive oxidative decomposition of the electrolyte during cycling, but also improves the CEI (Cold Breakdown Index) and increases battery stability.Consequently, the combined use of the compound represented by Formula 1, LiBF4 and the nitrile compound in the electrolyte can further improve the fast charging cycle performance of the battery under high voltage.

[0038] In some embodiments, the mass ratio of the compound represented by formula 1 to LiBF4 and to the nitrile compound is (0.5 to 3) : (0.1 to 1) : (0.2 to 3). For example, it can be 1 : 0.5 : 2, 0.5 : 0.5 : 2, 3 : 0.5 : 2, 1 : 0.1 : 2, 1 : 1 : 2, 1 : 0.5 : 0.2, 1 : 0.5 : 3, etc. In this way, by keeping the mass ratio of the compound represented by Formula 1 to LiBF4 and the nitrile compound within the range described above, the synergistic effect of the compound represented by Formula 1, LiBF4 and the nitrile compound can be fully exploited, which further improves the fast charging cycle performance of the battery under a high voltage above 4.5 V.

[0039] In some embodiments, the nitrile compound comprises at least one of succinonitrile, adiponitrile, 1,2-bis(2-cyanoethoxy)ethane, 1,2,3-tris(2-cyanooxy)propane, 1,3,6-hexanetricarbonitrile, or tetracyanoethylene. The nitrile compound described above, which serves as the electrolyte additive, can further improve the fast-charging cycle performance of the battery at high voltages above 4.5 V.

[0040] In some embodiments, the mass fraction of the nitrile compound, based on the total mass of the electrolyte, ranges from 0.2% to 3%. It can be, for example, 0.2%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, etc. In this way, maintaining the concentration of the nitrile compound in the electrolyte within the range described above can reduce the inadequacy of metal ion dissolution inhibition caused by an excessively low amount of the nitrile compound, and thereby further improve the fast-charge cycle performance of the battery at high voltages above 4.5 V.

[0041] In some embodiments, the active material of the positive electrode comprises at least one of the following: lithium cobalt oxide, a ternary nickel-cobalt-manganese material, a ternary nickel-cobalt-aluminum material, a lithium-rich manganese material, a lithium nickel-manganese oxide material, lithium manganese iron phosphate, or lithium manganese oxide. The active material of the positive electrode described above exhibits high energy density and excellent cycle performance, thereby improving the cycle stability of the battery under high voltage.

[0042] In some embodiments, the battery is a lithium-ion battery. The active material of the positive electrode comprises lithium cobalt oxide, which exhibits excellent cycle performance and high energy density, as well as a low probability of side reactions with the compound represented by Formula 1, LiBF4, and the nitrile compound in the electrolyte of the present disclosure, and possesses strong high-voltage resistance. In this way, the fast-charging cycle performance of the battery under high voltage can be improved.

[0043] In some embodiments, the electrolyte further comprises a non-aqueous organic solvent. The non-aqueous organic solvent comprises at least one of the following: ethylene carbonate, propylene carbonate, γ-butyrolactone, phenyl acetate, 1,4-butane sultone, ethyl methyl carbonate, diethyl carbonate, methyl propyl carbonate, methyl formate, ethyl acetate, methyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, 1,2-dimethoxyethane, 2,2,3,3-tetrafluoro-1-(1,1,2,2-tetrafluoroethoxy)propane, methyl trifluoroethyl carbonate, (2,2,2)-trifluoroethyl carbonate, 2,2-difluoroethyl acetate, 2,2-difluoroethyl propionate, or 2,2-difluoroethyl methyl carbonate. The mass fraction of the non-aqueous, organic solvent in the electrolyte ranges from 60% to 80%. For example, it can be 60%, 65%, 70%, 75%, 80%, etc.If the solvent is within the range described above, it can be ensured that the battery has stable electrochemical properties.

[0044] In some embodiments of the present disclosure, the electrolyte further comprises a lithium salt. The lithium salt comprises at least one of LiPF6, LiAsF6, LiClO4, LiB(C2O4)2, LiBF2C2O4, LiN(SO2F)2, LiN(SO2CF3)2, LiPO2F2, LiPF2(C2O4)2, or LiPF4C2O4. The mass fraction of the lithium salt in the electrolyte ranges from 10% to 18%. For example, it may be 10%, 12%, 14%, 15%, 18%, etc. Maintaining the electrolyte salt within the range described above can ensure that the battery exhibits stable electrochemical performance.

[0045] A typical battery consists of a positive electrode plate, a negative electrode plate, an electrolyte, and a separator. During charging and discharging, active ions are intercalated into and deintercalated from the positive and negative electrode plates. The electrolyte facilitates the flow of ions between the positive and negative electrode plates. The separator, located between the positive and negative electrode plates, primarily prevents a short circuit between them while allowing the free flow of ions.

[0046] The positive electrode plate comprises a positive current collector and the active material layer of the positive electrode, arranged on at least one surface of the positive current collector. The active material layer of the positive electrode comprises the positive electrode active material described above.

[0047] In some embodiments of the present disclosure, the positive current collector may comprise a metal foil or a composite material positive current collector. The metal foil may, for example, be aluminum foil. The composite material positive current collector may comprise a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. For example, the composite material positive current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, etc.) on the polymer material substrate (for example, polypropylene (PP), polyethylene glycol terephthalate (PET), polybutylene terephthalate (PBT), etc.).

[0048] In some embodiments of the present disclosure, the active material layer of the positive electrode may optionally comprise a conductive agent. Examples of the conductive agent include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, or carbon nanofibers.

[0049] In some embodiments of the present disclosure, the active material layer of the positive electrode may optionally comprise a binder. The binder may, for example, comprise at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), a vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, or a fluorinated acrylate resin.

[0050] In some embodiments of the present disclosure, the positive electrode can be prepared in the following manner: The aforementioned components for preparing the positive electrode plate, for example the active material of the positive electrode, a conductive agent and a binder, are dissolved in a solvent (for example N-methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is applied as a layer to the positive current collector, and after processes such as drying and cold pressing, the positive electrode plate can be obtained.

[0051] The negative electrode plate comprises a negative current collector and an active material layer of the negative electrode, arranged on at least one surface of the negative current collector. The active material layer of the negative electrode comprises an active material of the negative electrode.

[0052] In some embodiments of the present disclosure, the negative current collector can be a metal foil or a composite material current collector. For example, copper foil can be used as the metal foil. The composite material current collector can comprise a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. For example, the composite material current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, etc.) on the polymer substrate (for example, polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), etc.).

[0053] In some embodiments of the present disclosure, the active material of the negative electrode can be a negative electrode active material that is generally known for use in batteries in the art. For example, the negative electrode active material can comprise at least one of natural graphite, synthetic graphite, soft carbon, hard carbon, mesocarbon microspheres, nanocarbon, elemental silicon, silicon oxide compounds, silicon-carbon compounds, silicon alloys, elemental tin, tin oxide compounds, tin-carbon compounds, tin alloys, or lithium titanate.

[0054] In some embodiments of the present disclosure, the active material of the negative electrode comprises at least one of graphite or a silicon-carbon material. The above-described active material of the negative electrode can be better matched to the active material of the positive electrode and to the electrolyte, adapt to high-voltage and high-frequency battery scenarios, and allow the battery to exhibit excellent fast-charge cycle performance under high voltage.

[0055] In some embodiments of the present disclosure, the active material layer of the negative electrode may optionally further comprise a binder. The binder may comprise at least one of the following: styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), or carboxymethyl chitosan (CMCS).

[0056] In some embodiments of the present disclosure, the active material layer of the negative electrode may optionally further comprise a conductive means. The conductive means may comprise at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, or carbon nanofibers.

[0057] In some embodiments of the present disclosure, the active material layer of the negative electrode may optionally further comprise additional additives such as a thickening agent (for example, sodium carboxymethyl cellulose (CMC-Na)).

[0058] In some embodiments of the present disclosure, the negative electrode can be prepared in the following manner: The aforementioned components for preparing the negative electrode plate, for example the active material of the negative electrode, a conductive agent, a binder and all other components, are dispersed in a solvent (for example deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative current collector, and after processes such as drying and cold pressing, the negative electrode plate can be obtained.

[0059] The present disclosure does not impose any specific restrictions regarding the type of separator; and any known porous separator with good chemical and mechanical stability may be selected.

[0060] In some embodiments of the present disclosure, the separator may be made of a material comprising at least one of glass fiber, nonwoven fabric, polyolefin film, aromatic polyamide film, polytetrafluoroethylene film or polyethersulfone film.

[0061] In some embodiments of the present disclosure, the separator may have a thickness ranging from 10 µm to 12 µm, for example 10 µm, 11 µm, 12 µm, etc.

[0062] The embodiments of the present disclosure are described in detail below. It should be noted that the embodiments described below are purely illustrative and are intended to explain, not limit, the present disclosure. Furthermore, unless explicitly stated otherwise, all reagents used in the following embodiments are commercially available or can be synthesized according to the methods described herein or known methods. All unspecified reaction conditions can be readily determined by a person skilled in the art. Example 11. Production of the positive electrode plate

[0063] The active material of the positive electrode (lithium cobalt oxide), the binder polyvinylidene fluoride (PVDF), conductive carbon black, and conductive carbon nanotubes were uniformly mixed in a weight ratio of 95 : 2.3 : 2 : 0.7. N-methylpyrrolidone (NMP) was added, and the mixture was stirred in a vacuum mixer until a homogeneous, free-flowing positive electrode slurry was obtained. The positive electrode slurry was coated at a coating weight of 35 g / m². 2 The material was evenly applied to the positive current collector / aluminum foil, dried at 85 °C, and then subjected to cold pressing, followed by trimming, cutting, and longitudinal separation. After longitudinal separation, it was dried at 85 °C under vacuum conditions for 4 hours, and then the tabs were welded to form the positive electrode plate. The specific surface area of ​​the lithium cobalt oxide plate was 0.6 m². 2 / G 2. Production of the negative electrode plate

[0064] Graphite, the active material of the negative electrode, the conductive agent carbon black, the thickening agent sodium carboxymethylcellulose (CMC-Na), and the binder styrene-butadiene rubber were mixed in a weight ratio of 95:1.5:1:2.5. Deionized water was added, and the mixture was stirred in a vacuum mixer to obtain the negative electrode slurry. The negative electrode slurry was applied at a coating weight of 20 g / m². 2The graphite was applied evenly to the negative current collector / copper foil, dried at 85 °C, and then subjected to cold pressing, followed by trimming, cutting, and longitudinal separation. After longitudinal separation, it was dried at 85 °C under vacuum conditions for 4 hours, and then the tabs were welded to form the negative electrode plate. The specific surface area of ​​the graphite electrode was 1.6 m². 2 / G. 3. Preparation of the electrolyte

[0065] In an argon-filled glovebox (humidity < 10 ppm, oxygen < 1 ppm), the solvents ethylene carbonate, propylene carbonate, diethyl carbonate, and propyl propionate were mixed uniformly at a mass ratio of 1:1:1:2. Completely dried hexafluorophosphate was rapidly added to the solvent mixture until the molarity of the lithium hexafluorophosphate in the electrolyte was 1 mol / L. Then, the compound represented by Formula 1, LiBF4, and succinonitrile were added successively and thoroughly mixed to obtain the electrolyte. The mass fraction of the compound represented by Formula 1 in electrolyte G was 2%, the mass fraction of LiBF4 in the electrolyte was 0.2%, and the mass fraction of succinonitrile in the electrolyte was 2%. 4. Separator

[0066] A polyethylene separator with a thickness of 8 µm was selected. 5. Production of the lithium-ion battery

[0067] The positive electrode plate, the negative electrode plate, and the separator, manufactured by the methods described above, were assembled by winding to form a lithium-ion battery measuring 4.7 mm thick, 55 mm wide, and 60 mm long. The battery was baked at 85 °C for 10 hours and injected with the previously prepared electrolyte. The battery was left to stand for 24 hours and then placed in an environment of 45 °C under a pressure of 3 kg. It was then charged to 4.5 V at 0.1 C (195 mA) and left to stand for more than 24 hours under the same pressure and temperature conditions (to fully activate the battery).

[0068] The battery satisfied the equation (10 × B × G × E 2 ) / C = 0.81.

[0069] The manufacturing processes of the lithium-ion batteries in Examples 2 to 27 and the comparison examples 1 to 8 were basically the same as those in Example 1, except that the electrolyte composition, the active material of the positive electrode and the active material of the negative electrode differed, as shown in Table 1.

[0070] Comparison example 1 contained two additives (the compound represented by formula 1 and LiBF4), but the value of the formula (10 × B × G × E 2 ) / C was too small. Comparison example 2 contained three additives (the compound represented by formula 1, LiBF4, and a nitrile compound), but the value of the formula (10 × B × G × E) 2 ) / C was too small. Comparison example 3 contained two additives (the compound represented by formula 1 and LiBF4), but the value of the formula (10 × B × G × E) 2) / C was too large. Comparison example 4 contained three additives (the compound represented by formula 1, LiBF4, and a nitrile compound), but the value of the formula (10 × B × G × E) 2 ) / C was too large. In comparison example 5 and comparison example 7, no LiBF4 had been added to the electrolyte. In comparison example 6 and comparison example 8, the compound represented by formula 1 had not been added to the electrolyte. Table 1 Proportion of active material B of the positive electrode Specific surface area of ​​the active material C of the positive electrode (m 2 / G) Specific surface area of ​​the active material E of the negative electrode (m 2 / G) Proportion of compound G represented by formula 1 Nitrile compound Mass ratio of the compound represented by formula 1 to LiBF4 and to the nitrile compound or mass ratio of the compound represented by formula 1 to LiBF4 (10 × B ×G × E 2 ) / C (m 2 / g) Example 1 95 % 0,6 1,6 2% Succinonitrile 2 : 0,2 : 2 0,81 Example 2 95 % 0,6 1,6 2% / 2 : 0,2 0,81 Example 3 95 % 0,6 1,6 0,50 % / 0,5 : 0,2 0,2 Example 4 95 % 0,6 1,6 1% / 1 : 0,2 0,41 Example 5 95 % 0,6 1,6 2,50 % / 2,5 : 0,2 1,01 Example 6 95 % 0,6 1,6 3 % / 3 : 0,2 1,22 Example 7 95 % 0,6 1,6 2% / 2 : 0,1 0,81 Example 8 95 % 0,6 1,6 2% / 2 : 1 0,81 Example 9 95 % 0,6 1,6 2% Adiponitrile 2 : 0,2 : 2 0,81 Example 10 95 % 0,6 1,6 2% 1,2-Bis(2-cyanoethoxy)ethane 2 : 0,2 : 2 0,81 Example 11 95 % 0,6 1,6 2% 1,2,3-Tris(2-cyanoxy)-propane 2 : 0,2 : 2 0,81 Example 12 95 % 0,6 1,6 2% 1,3,6-Hexanetricarbonitrile 2 : 0,2 : 2 0,81 Example 13 95 % 0,6 1,6 2% Tetracyanoethylene 2 : 0,2 : 2 0,81 Example 14 97 % 0,6 1,6 2% Succinonitrile 2 : 0,2 : 2 0,83 Example 15 99 % 0,6 1,6 2% Succinonitrile 2 : 0,2 : 2 0,84 Example 16 95 % 0,2 1,6 2% Succinonitrile 2 : 0,2 : 2 2,43 Example 17 95 % 2 1,6 2% Succinonitrile 2 : 0,2 : 2 0,24 Example 18 95 % 0,6 2,1 2% Succinonitrile 2 : 0,2 : 2 1,4 Example 19 95 % 0,6 3,5 2% Succinonitrile 2 : 0,2 : 2 3,88 Example 20 95 % 0,6 1,6 0,50 % Succinonitrile 0,5 : 0,2 : 2 0,2 Example 21 95 % 0,6 1,6 1% Succinonitrile 1 : 0,2 : 2 0,41 Example 22 95 % 0,6 1,6 2,50 % Succinonitrile 2,5 : 0,2 : 2 1,01 Example 23 95 % 0,6 1,6 3% Succinonitrile 3 : 0,2 : 2 1,22 Example 24 95 % 0,6 1,6 2% Succinonitrile 2 : 0,1 : 2 0,81 Example 25 95 % 0,6 1,6 2% Succinonitrile 2:1:2 0,81 Example 26 95 % 0,6 1,6 2% Succinonitrile 2 : 0,2 : 0,2 0,81 Example 27 95 % 0,6 1,6 2% Succinonitrile 2 : 0,2 : 3 0,81 Comparative example 1 95 % 0,6 0,7 2% / 2 : 0,2 0,16 Comparative example 2 95 % 0,6 0,7 2% Succinonitrile 2 : 0,2 : 2 0,16 Comparative example 3 95 % 0,2 2,1 2% / 2 : 0,2 4,19 Comparative example 4 95 % 0,2 2,1 2% Succinonitrile 2 : 0,2 : 2 4,19 Comparative example 5 95 % 0,6 1,6 2% Succinonitrile / 0,81 Comparative example 6 95 % 0,6 1,6 0 Succinonitrile / / Comparative example 7 95 % 0,6 1,6 2% / / 0,81 Comparative example 8 95 % 0,6 1,6 0 / / /

[0071] The batteries produced in Examples 1 to 27 and Comparison Examples 1 to 8 were subjected to a room-temperature rapid charge cycle test at 25 °C, and the capacity retention rate and threshold rate of the batteries after 800 cycles were recorded. The performance test results are shown in Table 2.

[0072] At 25 °C, the lithium-ion battery was left to stand for 5 minutes, charged to 4.50 V at a constant current of 2C, and then left to stand for another 5 minutes. It was then charged at a constant current and voltage until the current was less than or equal to 0.05 C, left to stand for another 5 minutes, and then discharged to 3.0 V at a constant current of 1 C. The above procedure was repeated for 800 charge-discharge cycles. The maximum discharge capacity of the first 5 cycles was recorded as Q, and the discharge capacity after 800 cycles was selected as Q1. Consequently, the calculation method for the capacity maintenance rate after 800 cycles was as follows: Capacity retention rate after 800 cycles(%)=Q1 / Q×100.

[0073] The thickness of the new battery was measured using a thickness gauge and recorded as P1, and the thickness of the battery after 800 cycles was recorded as P2. Consequently, the formula for calculating the battery's threshold rate after 800 cycles was as follows: Battery cell threshold rate after 800 cycles (%) = P2 / P1 × 100. Table 2 Capacity retention rate after 800 cycles at 2°C / 1°C and 25°C Battery cell threshold rate after 800 cycles at 2C / 1C and 25 °C Example 1 88,4 % 4,6 % Example 2 78,9 % 10,3 % Example 3 76,5 % 11,2 % Example 4 77,6 % 10,8 % Example 5 78,1 % 10,5 % Example 6 71,8 % 9,8 % Example 7 78,8 % 10,7 % Example 8 72,3 % 9,5 % Example 9 87,1 % 5,3 % Example 10 87,5 % 5,7 % Example 11 86,4 % 6,5 % Example 12 88,3 % 4,8 % Example 13 87,7 % 5,1 % Example 14 88,2 % 4,7 % Example 15 88,9 % 4,3 % Example 16 85,6 % 7,2 % Example 17 84,3 % 8,7 % Example 18 85,3 % 8,3 % Example 19 87,1 % 5,2 % Example 20 83,2 % 8,9 % Example 21 86,8 % 7,4 % Example 22 86,5 % 7,6 % Example 23 85,4 % 8,1 % Example 24 88,3 % 4,7 % Example 25 85,9 % 5,3 % Example 26 83,6 % 7,4 % Example 27 88,7 % 4,8 % Comparative example 1 40,3 % 22,5 % Comparative example 2 55,7 % 20,3 % Comparative example 3 50,3 % 23,6 % Comparative example 4 52,1 % 16,5 % Comparative example 5 45,80 % 25,60 % Comparative example 6 33,60 % 32,20 % Comparative example 7 42,40 % 28,70 % Comparative example 8 30,30 % 53,50 %

[0074] The data in Table 2 show that the batteries in Examples 1 to 27 exhibited a significantly higher capacity retention rate and a lower threshold rate than those in Comparison Examples 5 to 8, suggesting that LiBF4 and the compound represented by Formula 1 acted synergistically, ensuring the battery's fast-charge cycle performance at high voltage. Example 1, Examples 9 to 27, and Examples 2 to 8 demonstrate that the nitrile compound can further improve the battery's fast-charge cycle performance at high voltage. Furthermore, in Comparison Examples 2 and 4, the compound represented by Formula 1 and LiBF4 were added in appropriate proportions, and in Comparison Examples 1 and 3, the compound represented by Formula 1, LiBF4, and the nitrile compound were added in appropriate proportions. However, those calculated using the formula (10 × B × G × E) 2) / C calculated values ​​in comparison examples 1 to 4 were not between 0.2 and 3.88, and the capacity retention rates of the batteries were significantly lower than those in examples 1 to 27. These results demonstrate that the addition of the compound represented by formula 1 and LiBF4 to the electrolyte at a value calculated by the formula of 0.2 to 3.88, or the addition of the compound represented by formula 1, LiBF4, and the nitrile compound to the electrolyte at a value calculated by the formula of 0.2 to 3.88, enables excellent high-voltage fast-charge cycle performance.

[0075] In this description, terms such as "one embodiment," "some embodiments," "examples," "specific examples," "some examples," etc., mean that specific features, structures, materials, or properties described in connection with the embodiment or example are included in at least one embodiment or example of this disclosure. In this description, the schematic representations of the foregoing terms need not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or properties described may be combined in one or more embodiments or examples in a suitable manner.Furthermore, different embodiments or examples and features of different embodiments or examples described in the description can be combined by a person skilled in the art without mutual contradiction.

[0076] Although embodiments of the present disclosure have been illustrated and described above, it is understood that these embodiments are merely exemplary and cannot be interpreted as limiting the present disclosure. For the person skilled in the art, changes, alternatives, and modifications can be made to the embodiments without deviating from the scope of the present disclosure. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] CN 202411069923.2

[0001]

Claims

[1] Battery, comprising: a positive electrode plate comprising an active material layer of the positive electrode, wherein the active material layer of the positive electrode comprises an active material of the positive electrode, wherein a mass fraction of the active material of the positive electrode based on a total mass of the active material layer of the positive electrode is designated as B, and wherein a specific surface area of ​​the active material of the positive electrode is designated as C m 2 / g is designated; a negative electrode plate comprising an active material of the negative electrode, wherein a specific surface area of ​​the active material of the negative electrode is designated as E m 2 / g is designated; and an electrolyte comprising a compound represented by formula 1 and LiBF4, wherein a mass fraction of the compound represented by formula 1 based on a total mass of the electrolyte is designated as G, where the battery follows a formula of 0.20 ≤ (10 × B × G × E 2 ) / C ≤ 3.88 is satisfied, [2] Battery according to claim 1, wherein 95% ≤ B ≤ 99%. [3] Battery according to claim 1, wherein 0.2 ≤ C ≤ 2. [4] Battery according to claim 1, wherein 0.2 ≤ E ≤ 3.

5. [5] Battery according to claim 1, wherein 0.5% ≤ G ≤ 3%. [6] Battery according to any one of claims 1 to 5, wherein a mass ratio of the compound represented by formula 1 to LiBF4 is (0.5 to 3) : (0.1 to 1). [7] Battery according to any one of claims 1 to 5, wherein a mass fraction of LiBF4 based on the total mass of the electrolyte ranges from 0.1% to 1%. [8] Battery according to any one of claims 1 to 5, wherein the electrolyte further comprises a nitrile compound. [9] Battery according to claim 8, wherein: a mass ratio of the compound represented by formula 1 to LiBF4 and to the nitrile compound (0.5 to 3) : (0.1 to 1) : (0.2 to 3); and / or a mass fraction of the nitrile compound based on the total mass of the electrolyte ranges from 0.2% to 3%; and / or the nitrile compound is at least one of succinonitrile, adiponitrile, 1,2-bis(2-cyanoethoxy)ethane, 1,2,3-tris(2-cyanooxy)propane, 1,3,6-hexanetricarbonitrile or tetracyanoethylene. [10] Battery according to any one of claims 1 to 5, wherein: the active material of the positive electrode comprises at least one of lithium cobalt oxide, a ternary nickel-cobalt-manganese material, a ternary nickel-cobalt-aluminum material, a lithium-rich manganese material, a lithium nickel-manganese oxide material, lithium manganese iron phosphate, or lithium manganese oxide; and / or The active material of the negative electrode comprises at least one of graphite or a silicon-carbon material.