Battery

Abstract

Battery comprising: a positive electrode plate, a negative electrode plate, a separator and an electrolyte, wherein: the negative electrode plate has a porosity φ in the unit %; the separator has a thickness t in the unit µm and a pore size R in the unit µm; a ratio of the total mass of the electrolyte to the discharge capacity of the battery N in the unit g / Ah; and the electrolyte comprises an electrolyte additive, wherein the electrolyte additive comprises a sulfate ester compound and a first lithium salt additive, wherein the first lithium salt additive comprises an oxalate-containing lithium salt and the sulfate ester compound has a structure represented by formula I: Formula I, wherein: R1 and R8 are each independently selected from hydrogen or C1 to C5 hydrocarbyl; R2, R3, R4, R5, R6, and R7 each independently from C1- to C3-alkylenes, C1- to C3- alkoxy, an oxygen atom, or are selected; and n is an integer in the range of 0 to 4, and a mass fraction of the sulfate ester compound in the electrolyte C in the unit %; and the battery corresponds to formula A: 0.01 ≤ φ × N × C 10 4 × t × R ≤ 0.5

Description

[0001] This application claims priority from Chinese patent application No. 202411283546.2 entitled “BATTERY”, filed with the Chinese National Intellectual Property Administration on September 13, 2024, the entire disclosure of which is incorporated herein by reference. TECHNICAL AREA

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

[0003] With the development of the renewable energy industry, higher energy density in power batteries has become a key research and development focus. Using a high-energy-density active material for the negative electrode and a high-specific-energy active material for the positive electrode can effectively increase the energy density of a lithium-ion battery. However, current high-energy-density batteries tend to exhibit adverse effects under high-temperature conditions, such as gas generation and solid-electrolyte interface film (SEI) rupture, resulting in poor high-temperature performance. Consequently, there is an urgent need to develop a battery with improved high-temperature performance. SUMMARY

[0004] In a first aspect of the present disclosure, the present disclosure provides a battery. The battery comprises a positive electrode plate, a negative electrode plate, a separator, and an electrolyte. The negative electrode plate has a porosity φ in the unit %. The separator has a thickness t in the unit µm and a pore size R in the unit µm. A ratio of a total mass of the electrolyte to a discharge capacity of the battery is N in the unit g / Ah. The electrolyte comprises an electrolyte additive. The electrolyte additive comprises a sulfate ester compound and a first lithium salt additive. The first lithium salt additive comprises an oxalate-containing lithium salt. The sulfate ester compound has a structure characterized by the

[0005] Formula I is represented as follows: Formula I. R1 and R8 are each independently selected from hydrogen or C1- to C5-hydrocarbyl; R2, R3, R4, R5, R6, and R7 are each independently selected from C1- to C3-alkylene, C1- to C3-alkoxy, an oxygen atom, or n; and n is an integer in the range of 0 to 4. A mass fraction of the sulfate ester compound in the electrolyte is C in the unit %.

[0006] Battery corresponds to formula A: 0.01≤φ×N×C104×t×R≤0.5 Formula A. Consequently, the battery can effectively alleviate problems such as gas generation and SEI film tearing / reconstruction in high-energy-density batteries, thereby improving the battery's high-temperature performance.

[0007] In some embodiments, φ ranges from 60% to 80%; and / or t ranges from 12 µm to 20 µm; and / or R ranges from 0.03 µm to 0.12 µm; and / or C ranges from 0.1% to 10%; and / or N ranges from 2.0 to 5.0. Consequently, the high-temperature performance of the battery can be further improved.

[0008] In some embodiments, R1 and R8 are each independently selected from hydrogen; at least one of R2, R3 or R4 is selected, and at least one of R2, R3 or R4 is selected from an oxygen atom; at least one of R5, R6 or R7 is selected, and at least one of R5, R6 or R7 is selected from an oxygen atom; n is 2.

[0009] In some embodiments, the sulfate ester compound has one of the following structures:

[0010] In some embodiments, the first lithium salt additive comprises at least one of lithium difluoro(oxalato)borate, lithium bis(oxalato)borate, lithium tetrafluoro(oxalato)phosphate, lithium difluorobis(oxalato)phosphate, or lithium tris(oxalato)phosphate. Consequently, the high-temperature performance, conductivity performance, and cycle life of the battery can be improved.

[0011] In some embodiments, the molar ratio of the first lithium salt additive to the sulfate ester compound is 1 : (1 to 5). Consequently, the inhibitory effect of the sulfate ester compound on the first lithium salt additive can be further enhanced. As a result, the hindered first lithium salt additive is less likely to move freely.

[0012] In some embodiments, the mass fraction of the first lithium salt additive in the electrolyte ranges from 0.1% to 5%; and / or the mass fraction of the sulfate ester compound in the electrolyte ranges from 1% to 10%. Consequently, the stability of the battery under high-temperature and long-cycle conditions can be improved.

[0013] In some embodiments, the electrolyte additive further comprises an electrolyte lithium salt. The electrolyte lithium salt comprises at least one of LiBF4, LiPF6, LiAsF6, or LiN(SO2F)2. Consequently, the electrolyte lithium salt can further inhibit the corrosion of the SEI film and the cathode electrolyte interphase film (CEI film) by hydrofluoric acid.

[0014] In some embodiments, the mass ratio of the electrolyte lithium salt to the first lithium salt additive is 1 : (0.4 to 2).

[0015] In some embodiments, the mass fraction of the electrolyte lithium salt in the electrolyte ranges from 0.1% to 1%. Consequently, the stability of the battery under high temperature and long cycle conditions can be further improved.

[0016] In some embodiments, the positive electrode plate comprises a positive electrode current collector and an active material layer of the positive electrode, arranged on at least one side of the positive electrode current collector. The active material layer of the positive electrode comprises an active material of the positive electrode. The active material of the positive electrode comprises at least one lithium iron phosphate or a ternary material. The ternary material corresponds to a chemical formula of LiNi. x Co y M1 z1 M2 z2O2. M1 and M2 are distinct from each other and each independently selected from Al, Mn or Fe; and 0 < x ≤ 1, 0 < y < 1, 0 < z1 < 1, 0 ≤ z2 < 1 and x + y + z1 + z2 = 1.

[0017] In some embodiments, the negative electrode plate comprises a negative electrode current collector and an active material layer of the negative electrode, arranged on at least one side of the negative electrode current collector. The active material layer of the negative electrode comprises an active material of the negative electrode, and a mass fraction of silicon in the active material of the negative electrode is greater than 8%. DETAILED DESCRIPTION OF THE EXECUTION FORMS

[0018] The embodiments described below are purely illustrative and are intended to explain, not limit, the present disclosure.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as they would generally be understood by a person skilled in the field of the present disclosure. The terms in the present disclosure serve solely to describe exemplary embodiments and are not intended to limit the present disclosure. Unless otherwise specified, numerical values ​​of various parameters mentioned in the present disclosure can be measured using various measurement methods commonly used in the field (for example, they can be measured using methods set forth in the embodiments of the present disclosure).

[0020] Words such as “comprehensive”, “including” and “exhibiting”, and all variants thereof, used in the description and claims of the present disclosure, are open-ended expressions, meaning that they contain content specified in the present disclosure but do not exclude other content.

[0021] In a first aspect of the present disclosure, the present disclosure provides a battery. The battery comprises a positive electrode plate, a negative electrode plate, a separator, and an electrolyte. The negative electrode plate has a porosity φ in the unit %. The separator has a thickness t in the unit µm and a pore size R in the unit µm. A ratio of a total mass of the electrolyte to a discharge capacity of the battery is N in the unit g / Ah. The electrolyte comprises an electrolyte additive. The electrolyte additive comprises a sulfate ester compound and a first lithium salt additive. The first lithium salt additive comprises an oxalate-containing lithium salt. The sulfate ester compound has a structure characterized by the Formula I is represented as follows: R1 and R8 are each independently selected from hydrogen or C1- to C5-hydrocarbyl; R2, R3, R4, R5, R6, and R7 are each independently selected from C1- to C3-alkylene, C1- to C3-alkoxy, and an oxygen atom; and n is an integer in the range of 0 to 4. A mass fraction of the sulfate ester compound in the electrolyte is C in the unit %. The battery corresponds to formula A: 0.01≤φ×N×C104×t×R≤0.5 Formula A. Consequently, the battery can effectively alleviate problems such as gas generation or SEI film tearing / reconstruction in high energy density batteries, thereby improving the battery's high-temperature performance.

[0022] In the present disclosure, the sulfate ester compound has a pincer-shaped structure, and this pincer-shaped structure is surrounded by several doubly bonded oxygen atoms (for example, carbonyl groups or sulfur-oxygen double bonds) and singly bonded oxygen atoms. The oxalate-containing lithium salt has an X-shaped structure, and its molecular structure also features several carbonyl groups. When these two polar molecules are mixed, due to the spatial stereostructures of the two polar molecules, bulky structures of the carbonyl groups and the sulfur-oxygen double bonds can intrude into the structural gap of the oxalate-containing lithium salt, thereby restricting the free movement of the oxalate-containing lithium salt to a certain extent.On the other hand, when mixed, the two polar molecules experience mutual repulsion due to the large number of carbonyl groups and / or sulfur-oxygen double bonds in their structures. This mutually repulsive alignment force causes the molecules of the oxalate-containing lithium salt and the molecules of the sulfate ester compound to rotate relative to each other in order to compensate for this repulsion. That is, the planar configurations of the two substances tend to transition from a quasi-parallel state to an overlapping state. This facilitates the tendency of the large, bulky carbonyl groups and sulfur-oxygen double bonds in the sulfate ester compound to intrude into the structural gaps of the molecules of the oxalate-containing lithium salt, thus inhibiting steric hindrance at the oxalate-containing lithium salt.The repulsion between the two polar molecules promotes the restriction of the free movement of the oxalate-containing lithium salt molecules by the pincer-like structure of the sulfate ester. Furthermore, under the dual effects of intermolecular repulsion and spatial constriction, it is less likely that the impeded oxalate-containing lithium salt will move freely.

[0023] When the electrolyte additive is used in a battery, the reduced free movement of the oxalate-containing lithium salt can decrease the direct contact between the oxalate group and the electrode plate, making the occurrence of a gassing reaction by the oxalate group less likely. Simultaneously, damage to the SEI film caused by battery swelling due to gassing is reduced. Consequently, the battery's stability under high-temperature and long-cycle conditions is improved.

[0024] Furthermore, φ × C × N in formula A can summarize the overall influence of favorable factors. Specifically, if the porosity φ of the negative electrode plate is high, the lithium-ion transfer rate can be increased, thereby improving the fast-charge cycle performance. If the mass fraction C in the sulfate ester compound in the electrolyte is higher within a certain range, the performance improvement effect is greater. The ratio N of the total mass of the electrolyte to the discharge capacity of the battery reflects the fact that the sulfate ester compound has a high discharge capacity. t × R in formula A can summarize the overall influence of adverse factors.Specifically, if the separator thickness t is too thick or if the separator pore size R is too large, the internal impedance of the battery increases, and large molecular impurities pass through the separator and induce side reactions at the electrode plate, thus degrading the battery's performance. Accordingly, if... φ×N×C104×t×R If the battery is too small, its internal impedance will be too high, and adverse side effects will be amplified. φ×N×C104×t×R If the voltage is too high, the battery's output voltage becomes unstable, and it is possible that toxic gases will be produced.

[0025] Furthermore, when the sulfate ester compound is used in combination with the first lithium salt additive, the aforementioned battery is applicable to a battery system using a positive electrode with medium nickel content and a negative electrode based on silicon and can exert beneficial effects in this battery system.

[0026] It should be noted that in the electrolyte additive of the present disclosure, the alignment force generated by the mutual repulsion between the polar molecules and the spatial confinement effect does not completely prevent the oxalate-containing lithium salt from exerting its advantages. Instead, it effectively slows down the movement of the oxalate-containing lithium salt, making the occurrence of the gas generation reaction less likely, thereby reducing damage to the SEI film and effectively promoting the performance stability of the battery under high-temperature and long-cycle conditions.

[0027] The term “C1-hydrocarbyl to C5-hydrocarbyl” refers to a saturated straight-chain or branched hydrocarbon component comprising 1 to 5 carbon atoms, for example CH3- or C2H5-.

[0028] The term “C1-alkylene to C3-alkylene” refers to a straight-chain saturated hydrocarbyl comprising 1 to 3 carbon atoms, for example methylene or ethylene.

[0029] The term “C1-alkoxy to C3-alkoxy” refers to an -OR component, where R is a C1-alkyl to C3-alkyl, for example ethoxy or n-propoxy.

[0030] For example, n is an integer in the range of 0 to 4, such as 0, 1, 2, 3 or 4.

[0031] The sulfate ester compound has a pincer-shaped structure, and the pincer-shaped structure is surrounded by several doubly bonded oxygen atoms (for example, carbonyl groups or sulfur-oxygen double bonds) and singly bonded oxygen atoms.

[0032] When the first lithium salt additive is used in the battery electrolyte, it helps improve the battery's high-temperature performance, conductivity, and cycle life. This is because the oxalate group in the first lithium salt additive has high electronegativity towards fluorine and can also form covalent bonds with carbon elements, thereby increasing the electrolyte's boiling point. Simultaneously, it can cause compounds in the electrolyte to form small solvent agglomerates, thus promoting the electrolyte's fluidity and conductivity.

[0033] In some embodiments, φ ranges from 60% to 80%; and / or t ranges from 12 µm to 20 µm; and / or R ranges from 0.03 µm to 0.12 µm; and / or C ranges from 0.1% to 10%; and / or N ranges from 2.0 to 5.0. Consequently, the high-temperature performance of the battery can be further improved.

[0034] If the porosity φ of the negative electrode lies within the aforementioned range, this can provide more space for expansion. It effectively reduces the volume expansion of the active material of the negative electrode, for example, a silicon-based material, and effectively preserves the integrity of the SEI film of the negative electrode.

[0035] If the thickness of the separator is within the aforementioned range, this can not only impede the movement of the oxalate-containing lithium salt, but also have less adverse effects on the transfer rate of lithium ions.

[0036] If the ratio N of the total mass of the electrolyte to the discharge capacity of the battery is within the aforementioned range, the discharge capacity of the battery is better.

[0037] If the pore size R of the separator is within the aforementioned range, the migration capacity of the lithium ions in the electrolyte is better.

[0038] In some embodiments, R1 and R8 are each independently selected from hydrogen; at least one of R2, R3 or R4 is selected, and at least one of R2, R3 or R4 is selected from an oxygen atom; at least one of R5, R6 or R7 is selected, and at least one of R5, R6 or R7 is selected from an oxygen atom; n is 2.

[0039] In some embodiments, the sulfate ester compound has one of the following structures:

[0040] In some embodiments, the first lithium salt additive comprises at least one of lithium difluoro(oxalato)borate, lithium bis(oxalato)borate, lithium tetrafluoro(oxalato)phosphate, lithium difluorobis(oxalato)phosphate, or lithium tris(oxalato)phosphate. Consequently, this is useful for improving high-temperature performance, conductivity performance, and cycle performance.

[0041] The first lithium salt additive is, for example, lithium difluoro(oxalato)borate. Lithium difluoro(oxalato)borate is advantageous for improving conductivity performance as well as optimizing high and low temperature performance and thermal stability.

[0042] In some embodiments, the molar ratio of the first lithium salt additive to the sulfate ester compound is 1 : (1 to 5). Consequently, the inhibitory effect of the sulfate ester compound on the first lithium salt additive can be further enhanced. As a result, the hindered first lithium salt additive is less likely to move freely.

[0043] In some embodiments, the molar ratio of the first lithium salt additive to the sulfate ester compound is 1 : (1 to 5), for example 1 : 1, 1 : 1.6, 1 : 2, 1 : 3, 1 : 3.4, 1 : 4 or 1 : 5.

[0044] In some embodiments, the molar ratio of the first lithium salt additive to the sulfate ester compound is 1 : (2 to 4). Consequently, the sulfate ester compound is in a slightly excess state relative to the first lithium salt additive, which can further enhance the inhibitory effect of the sulfate ester compound on the first lithium salt additive, thereby making it more difficult for the hindered first lithium salt additive to move freely.

[0045] In some embodiments, the mass fraction of the first lithium salt additive in the electrolyte ranges from 0.1% to 5%.

[0046] For example, the mass fraction of the first lithium salt additive in the electrolyte is 0.1%, 0.5%, 1%, 1.5%, 2%, 3%, 4%, 5%, etc. Consequently, the stability of the battery under high temperature and long cycle conditions can be further improved.

[0047] In some embodiments, a mass fraction C of the sulfate ester compound in the electrolyte ranges from 1% to 10%.

[0048] For example, the mass fraction of the sulfate ester compound in the electrolyte is 1%, 1.07%, 1.4%, 1.7%, 2%, 3%, 3.4%, 4%, 5%, 6%, 6.9%, 7%, 8%, 8.7%, 9%, 10%, etc. Consequently, the stability of the battery under high temperature and long cycle conditions can be further improved.

[0049] The electrolyte contains fluorine. As the battery reaction progresses, the fluorine produces hydrogen fluoride, which corrodes the SEI and CEI films. This leads to battery problems, such as a reduction in high-temperature storage capacity, gas generation, and swelling.

[0050] In some embodiments, the electrolyte additive further comprises an electrolyte lithium salt. The electrolyte lithium salt comprises at least one of LiBF4, LiPF6, LiAsF6, or LiN(SO2F)2. Consequently, the electrolyte lithium salt can further inhibit the corrosion of the SEI and CEI films by hydrofluoric acid. As a result, the first lithium salt additive, the sulfate ester compound, and the electrolyte lithium salt interact with each other, making it more difficult for the oxalate-containing lithium salt to move freely. In addition, the first lithium salt additive can also inhibit the hydrolysis of the oxalate-containing lithium salt. Simultaneously, due to the fluorine-containing lithium salt, the generation of fluoride ions can be reduced, leading to reduced formation of hydrofluoric acid, which in turn reduces the corrosion of the SEI and CEI films by hydrofluoric acid.In this way, the high-temperature storage capacity of the battery is increased, and gas generation and battery swelling are effectively reduced.

[0051] Furthermore, the electrolyte is the lithium salt LiBF4. LiBF4 is more stable at high temperatures, which is useful for further inhibiting the generation of hydrogen fluoride and consequently improves the high-temperature performance of the battery.

[0052] In some embodiments, the mass ratio of the electrolyte lithium salt to the first lithium salt additive is 1 : (0.4 to 2).

[0053] In some embodiments, the mass ratio of the electrolyte lithium salt to the sulfate ester compound is 1 : (1- 2), for example 1 : 0.5, 1 : 2, 1 : 3, 1 : 1.5, 1 : 75 or 1 : 2.

[0054] In some embodiments, the mass fraction of the electrolyte lithium salt in the electrolyte ranges from 0.1% to 1%. Consequently, the stability of the battery under high temperature and long cycle conditions can be further improved.

[0055] For example, the mass fraction of the electrolyte lithium salt in the electrolyte is 0.1%, 0.15%, 0.3%, 0.5%, 0.8%, 1%, etc. Consequently, the stability of the battery under high temperature and long cycle conditions can be improved.

[0056] In the present disclosure, the electrolyte may optionally comprise a second additive. The second additive can be selected based on specific applications of the electrolyte in various batteries.

[0057] In some embodiments, the second additive comprises at least one of ethylene sulfate (DTD), vinylene carbonate, fluoroethylene carbonate (FEC), vinylethylene carbonate, ethylene sulfate, 1,3-propanesultone, 1,3-propylenesultone, ethylene sulfite, tris(trimethylsilyl)borate, or tris(trimethylsilyl)phosphate. Consequently, the electrolyte is particularly suitable for use in batteries with a negative silicon electrode to further improve the battery's cycle life and high-temperature storage performance.

[0058] In some embodiments, the mass fraction of the second additive in the electrolyte ranges from 0.5% to 20%, for example 0.5%, 1%, 1.5%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15% or 20%.

[0059] In the present disclosure, the electrolyte can be a non-aqueous electrolyte, and a solvent of the non-aqueous electrolyte is an organic solvent.

[0060] In some embodiments, the organic solvent comprises at least one of ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate, dimethyl carbonate, diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl propyl carbonate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, γ-butyrolactone, γ-valerolactone, δ-valerolactone or ε-caprolactone.

[0061] In some embodiments, the mass fraction of the organic solvent in the electrolyte ranges from 10% to 80%.

[0062] In some embodiments, the organic solvent comprises EC, PC, EMC, and DEC. EC has a high dielectric constant, which ensures complete dissolution and ionization of the lithium salts. This effectively improves the electrolyte's conductivity to guarantee cycle life. EMC and DEC are linear carbonates that, compared to cyclic carbonates (EC), offer the advantages of low viscosity and a low melting point. Consequently, a mixture of PC, EMC, DEC, and EC is used as the electrolyte solvent to improve battery performance.

[0063] In some embodiments, the mass ratio of the organic solvent to the sulfate ester compound in the electrolyte is (8 to 170) : 1, for example 8 : 1, 15 : 1, 30 : 1, 40 : 1, 75 : 1, 95 : 1, 120 : 1, 140 : 1 or 170 : 1. Consequently, the stability of the battery under high temperature and long cycle conditions can be further improved.

[0064] In the present disclosure, the electrolyte may further comprise a third lithium salt. The third lithium salt further comprises at least one of lithium perchlorate, lithium bis(fluorosulfonyl)imide, lithium difluorophosphate, or lithium hexafluoroarsenate.

[0065] In some embodiments, the mass fraction of the third lithium salt in the electrolyte ranges from 10% to 20%, for example 10%, 13%, 15%, 18% or 20%.

[0066] In general, in addition to the electrolyte, a battery also comprises a positive electrode plate, a negative electrode plate, and a separator. During the charging and discharging process, active ions are intercalated and deintercalated between the positive and negative electrode plates. The electrolyte facilitates ion conduction between the positive and negative electrodes. The separator is positioned between the positive and negative electrode plates and primarily prevents a short circuit between them while allowing ions to flow through.

[0067] In some embodiments, the positive electrode plate comprises a positive electrode current collector and an active material layer of the positive electrode, arranged on at least one side of the positive electrode current collector. The active material layer of the positive electrode comprises an active material of the positive electrode. The active material of the positive electrode comprises at least one lithium iron phosphate or a ternary material. The ternary material corresponds to a chemical formula of LiNi. x Co y M1 z1 M2 z2 O2, where M1 and M2 are different from each other and are each independently selected from Al, Mn or Fe; and 0 < x ≤ 1, 0 < y < 1, 0 < z1 < 1, 0 ≤ z2 < 1 and x + y + z1 + z2 = 1.

[0068] In some embodiments, when the ternary material is a cobalt-containing active material of the positive electrode, the concentration of oxalate near the electrode is significantly reduced due to the dual effects of spatial confinement and intermolecular repulsion between the sulfate ester compound and the first lithium salt additive. Consequently, the probability of the oxalate reacting with dissolved cobalt ions to form cobalt oxalate deposits is considerably reduced, which in turn reduces deposit-induced damage to the electrode plate and lowers the battery impedance. The sulfate ester compound can undergo a complexation reaction with the dissolved cobalt ions, thereby reducing the occurrence of side reactions of dissolved cobalt ions in the battery system and improving battery stability under high-temperature and long-cycle conditions.Furthermore, a portion of the sulfate ester compound at the negative electrode of the battery can decompose to form the SEI film, which can restrict the deintercalation of the co-ions. Consequently, the electrolyte comprising the electrolyte additive according to the first aspect of this disclosure, or the electrolyte according to the second aspect of this disclosure, is particularly suitable for use in combination with the cobalt-containing active material of the positive electrode in the battery system.

[0069] The active material of the positive electrode includes, for example, LiNi. 0,6 Co 0,2 Mn 0.2 O2(NCM622), LiNi 0,6 Co 0,1 Mn 0,3 O2(NCM613) or LiNi 0,5 Co 0,2 Mn 0,3 O2(NCM523) etc.

[0070] In some embodiments, the active material of the positive electrode comprises lithium iron phosphate. Consequently, the sulfate ester compound can undergo a complexation reaction with dissolved metal ions (e.g., Fe ions), thereby suppressing side reactions of dissolved Co ions in the battery system, which improves the battery's stability under high-temperature and long-cycle conditions. Furthermore, some of the sulfate ester compound can also decompose at the negative electrode of the battery, forming the SEI film, which can restrict the deintercalation of the metal ions.

[0071] In some embodiments, the active material layer of the positive electrode may further comprise a binder. Specific examples of the binder include, but are not limited to, one or more of the following: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene propylene terpolymer, or styrene-butadiene rubber (SBR).

[0072] In some embodiments, the active material layer of the positive electrode may further comprise a conductive agent. Specific examples of the conductive agent include, but are not limited to, superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and the like.

[0073] In some embodiments, the positive electrode current collector can be a metal foil, for example an aluminum foil.

[0074] In some embodiments, the negative electrode plate comprises a negative electrode current collector and a negative electrode active material layer arranged on at least one side of the negative electrode current collector. The negative electrode active material layer comprises a negative electrode active material, and the silicon mass fraction of the negative electrode active material is greater than 8%. Increasing the specific capacity of the negative electrode active material can effectively improve the battery's energy density. Currently, the specific capacity of graphite materials has reached its theoretical upper limit (372 mAh / g), while a maximum specific capacity of silicon-based negative electrode active materials can reach 4200 mAh / g. Silicon-based negative electrode active materials have excellent application prospects.The volume of the silicon-based active materials of the negative electrode changes significantly during the battery's charging and discharging process. Due to excessive changes in the volume expansion and contraction of the silicon-based negative electrode itself, repeated cracking and SEI film formation occur on the electrode's surface during repeated charge and discharge cycles. This leads to continuous electrolyte consumption and results in relatively poor battery cycle performance. In the present disclosure, these problems, including corrosion and gas generation of the SEI film, can be effectively improved by optimizing the composition of the electrolyte additive.

[0075] In some embodiments, the active material layer of the negative electrode may further comprise a binder. Specific examples of the binder include, but are not limited to, one or more styrene-butadiene rubber (SBR), polyacrylic acid (PAA), polyacrylamide (PAM), or polyvinylidene fluoride (PVDF).

[0076] In some embodiments, the active material layer of the negative electrode may further comprise a conductive agent. Specific examples of the conductive agent include, but are not limited to, superconducting carbon, acetylene black, carbon black, graphene, and the like.

[0077] In some embodiments, the active material layer of the negative electrode may further comprise a thickening agent, for example sodium carboxymethyl cellulose (CMC-Na).

[0078] The present disclosure does not impose any particular restrictions regarding the type of separator, and various separators with a porous structure and good stability can be selected, for example a polyethylene (PE) separator, a polypropylene separator or a ceramic-coated PE separator.

[0079] The concept of the present revelation is described below by means of specific examples. It should be noted that the following examples serve only to illustrate the present revelation and should not be interpreted as limiting its scope.

[0080] The following examples are:

[0081] Connection 1:, CAS: 2520352-94-5;

[0082] Connection 2:, CAS: 201419-80-9.

[0083] Connection 3:

[0084] Connection 4:

[0085] Connection 5:

[0086] The following examples are used to illustrate applications of the electrolyte additive and the electrolyte comprising it in a lithium-ion battery with a positive electrode NCM613 according to the present disclosure. Example 1a Production of the positive electrode plate:

[0087] An active material NCM613 of a positive electrode, a binder polyvinylidene fluoride (PVDF), a conductive agent SP, and a conductive agent CNT were mixed in a weight ratio of 95:3:0.5:1.5, and N-methylpyrrolidone (NMP) was added to form a slurry with a solids content regulated to 55%. The mixture was stirred in a vacuum mixer until a homogeneous and free-flowing positive electrode slurry was obtained. The positive electrode slurry was uniformly applied to an aluminum foil with a thickness of 16 µm. The aluminum foil coated with the positive electrode slurry was dried in an oven at 120 °C for 8 hours. Finally, calendering was performed to reduce the compacted density of the positive electrode plate to 3.5 g / cm³. 3 to regulate, followed by longitudinal separation to obtain the positive electrode plate. Production of the negative electrode plate:

[0088] Graphite / zirconia-silicon-carbon 550-M5-230415, as the active material of the negative electrode, a conductive agent SP, a binder SBR (JSR-104A), and a thickener CMC (crt30000PA) were mixed at a weight ratio of 95:1.5:2:1.5, and water was added to form a slurry with a solids content regulated to 45%. The mixture was stirred in a vacuum mixer to obtain a negative electrode slurry. The negative electrode slurry was uniformly applied to a 9 µm thick copper foil. The copper foil coated with the negative electrode slurry was dried in an oven at 85 °C for 5 hours. Finally, calendering was performed to reduce the compacted density of the negative electrode plate to 1.6 g / cm³. 3The process involved regulating the porosity, followed by longitudinal separation to obtain the negative electrode plate. The porosity φ of the negative electrode plate was 70%. Production of the electrolyte:

[0089] In an argon-filled glovebox (with a moisture content of < 10 ppm and an oxygen content of < 1 ppm), the solvents EC, PC, DEC, and EMC were mixed uniformly at a mass ratio of 3:3:4:10 to obtain an organic solvent. The electrolyte additives (compound 1 and a first lithium salt additive (lithium difluoro(oxalate)borate), an electrolyte lithium salt (LiBF4), and a second additive (FEC and DTD)) were added to the organic solvent and stirred uniformly to obtain a non-aqueous electrolyte. The mass of the electrolyte was 9 g. Manufacturing the separator:

[0090] A double-layered, ceramic-coated PP separator was selected. The separator had a thickness t of 16 µm and a pore size R of 0.08 µm. Manufacturing of the lithium-ion battery:

[0091] The positive electrode plate, separator, and negative electrode plate, manufactured as described above, were wound to obtain an unfilled, unencapsulated cell. The unencapsulated cell was placed in an outer packaging, and the prepared electrolyte was injected into the dried, unencapsulated cell. The cell was then subjected to vacuum sealing, standing, forming, shaping, and smoothing to obtain a lithium-ion battery. The battery's discharge capacity was determined by first fully charging the battery, then discharging it to 0.5C (half the battery's capacity), and then multiplying the discharge time by the discharge current to obtain the discharge capacity.

[0092] The differences between examples 2a to 19a and the comparison examples 1a to 3a and example 1a are shown in Table 1-1. [Table 1-1] Sulfate ester compound First lithium salt additive Electrolyte lithium salt Molar ratio of the first lithium salt additive to the sulfate ester compound Mass ratio of the electrolyte lithium salt to the first lithium salt additive Ratio of total electrolyte mass to battery discharge capacity N / (g / Ah) φ×N×C104×t×R Nr. type Salary, wt.% type Salary, wt.% type Salary, wt.% Example 1a Connection 1 3,40 Lithium difluoro-(oxalato)borate 0,3 LiBF4 0,15 0,1 0,5 4,95 0,09 Example 2a Connection 1 1,39 Lithium difluoro-(oxalato)borate 0,3 LiBF4 0,15 0,5 0,5 5,25 0,04 Example 3a Connection 1 0,69 Lithium difluoro-(oxalato)borate 3 LiBF4 0,15 1 0,05 7,33 0,03 Example 4a Connection 1 23,23 Lithium difluoro-(oxalato)borate 5 LiBF4 0,15 0,5 0,03 4,05 0,52 Example 5a Connection 1 0,46 Lithium difluoro-(oxalato)borate 0,1 LiBF4 0,15 0,5 1,5 8,42 0,02 Example 6a Connection 1 1,39 Lithium difluoro-(oxalato)borate 0,3 LiBF4 1 0,5 3,33 7,41 0,06 Example 7a Connection 1 1,39 Lithium difluoro-(oxalato)borate 0,3 LiBF4 0,1 0,5 0,33 8,62 0,07 Example 8a Connection 1 1,39 Lithium difluoro-(oxalato)borate 0,3 LiBF4 0,5 0,5 1,67 5,13 0,04 Example 9a Connection 1 0,1 Lithium difluoro-(oxalato)borate 0,02 LiBF4 0,15 0,5 7,5 12,36 0,01 Example 10a Connection 1 5 Lithium difluoro-(oxalato)borate 1,07 LiBF4 0,15 0,5 0,14 4,91 0,14 Example 11a Connection 1 10 Lithium difluoro-(oxalato)borate 2,15 LiBF4 0,15 0,5 0,07 4,14 0,23 Example 12a Connection 2 1,39 Lithium difluoro-(oxalato)borate 0,3 LiBF4 0,15 0,5 0,5 5,36 0,04 Example 13a Connection 3 1,39 Lithium difluoro-(oxalato)borate 0,3 LiBF4 0,15 0,5 0,5 5,41 0,04 Example 14a Connection 4 1,39 Lithium difluoro-(oxalato)borate 0,3 LiBF4 0,15 0,5 0,5 5,38 0,04 Example 15a Connection 5 1,39 Lithium difluoro-(oxalato)borate 0,3 LiBF4 0,15 0,5 0,5 5,47 0,04 Example 16a Connection 1 1,39 Lithium tetrafluoro-(oxalato)phosphate 0,3 LiBF4 0,15 0,5 0,5 5,36 0,04 Example 17a Connection 1 1,39 Lithium difluoro-(oxalato)borate 0,3 LiPF6 0,15 0,5 0,5 5,37 0,04 Example 18a Connection 1 1,39 Lithium difluoro-(oxalato)borate 0,3 LiN(SO2F)2 0,15 0,5 0,5 5,44 0,04 Example 19a Connection 1 1,39 Lithium difluoro-(oxalato)borate 0,3 / / 0,5 / 14,31 0,11 Comparative example 1a Connection 1 1,39 / / LiBF4 0,15 / / 16,15 0,12 Comparative example 2a / / Lithium difluoro-(oxalato)borate 0,3 LiBF4 0,15 / 0,5 21,16 / Comparative example 3a / / / / LiBF4 0,15 / / 23,26 /

[0093] The differences between examples 20a to 27a and example 1a are shown in Table 1-2. [Table 1-2] Nr. Porosity φ / % of the negative electrode plate Separator thickness (t / µm) Pore ​​size R / µm of the separator Ratio of total electrolyte mass to battery discharge capacity N / (g / Ah) φ×N×C104×t×R Example 1a 70 16 0,08 4,95 0,09 Example 20a 60 16 0,08 4,95 0,03 Example 21a 80 16 0,08 4,95 0,04 Example 22a 70 12 0,08 4,95 0,05 Example 23a 70 20 0,08 4,95 0,03 Example 24a 70 16 0,03 4,95 0,10 Example 25a 70 16 0,12 4,95 0,03 Example 26a 70 16 0,08 2 0,02 Example 27a 70 16 0,08 3,5 0,03

[0094] The following tests were performed on the preceding examples and comparison examples, and the test results are shown in Table 2. (1) High-temperature storage performance test:

[0095] The lithium-ion battery was placed in a constant-temperature box at 60 °C and left for 6 hours. The battery was charged to an upper limit voltage of 4.4 V at a constant current and voltage of 1 C, with a cutoff current of 0.05 C. After the battery was fully charged, it was left for 5 minutes and then discharged at a constant current of 1 C to a cutoff voltage of 2.75 V. The gas production volume of the fully charged battery (100% state of charge) was measured before storage using the water displacement method. After 60 days of storage, the capacity retention rate and the gas production volume were measured using the water displacement method.

[0096] Capacity maintenance rate (%) = Remaining capacity after discharge / Initial capacity × 100%.

[0097] Gas production volume using the water displacement method (m³) 3) = (Initial weight - weight after water displacement) / density of water. (2) High-temperature cycle performance test:

[0098] At 45 °C, the lithium-ion battery was initially charged to a voltage of 4.5 V at a constant current of 1 C. At this time, the thickness of the lithium-ion battery was recorded as H0. The lithium-ion battery was then discharged to 2.75 V at a constant current of 1 C, and the initial capacity before storage was recorded as C0. The lithium-ion battery was then initially charged to a voltage of 4.5 V at a constant current of 0.3 C, and the initial capacity was recorded as Q0. The capacity after 800 cycles was recorded as Q1. The capacity retention rate after 500 cycles at 1 C was calculated using formula (1): Capacity retention rate after 500 cycles at 45 °C(%)=Q1 / Q0×100% (3) Room temperature cycle performance test:

[0099] The manufactured lithium-ion battery was placed in a 25°C environment, charged to 4.5 V at a constant current of 1 C, and then discharged to 2.75 V at a constant current of 1 C. The initial capacity was recorded as Q0, and the capacity after 800 cycles was recorded as Q1. The capacity retention rate after 500 cycles at 1 C was calculated using formula (1): Capacity retention rate after 500 cycles(%)=Q1 / Q0×100%

[0100] The relevant test results of the above examples and comparison examples are shown in Table 2. [Table 2] Nr. Capacity retention rate after 500 cycles at 45 °C, % Gas production volume determined by water displacement method after full load at 60 °C, cm³ 3 Capacity retention after 60 days of storage at 60 °C, % Gas production volume determined by the water displacement method after 60 days of storage at 60 °C, cm³ 3 Capacity retention rate after 500 cycles at room temperature, % Example 1a 82,2 1,47 81,1 3,21 83,1 Example 2a 84,3 1,38 84,2 3,19 85,7 Example 3a 78,2 1,52 78,3 3,87 77,3 Example 4a 72,6 1,66 71,2 3,92 73,8 Example 5a 73,7 1,64 74,4 3,72 72,1 Example 6a 69,5 2,04 68,5 4,98 69,8 Example 7a 75,1 1,67 75,9 3,68 76,4 Example 8a 82,1 1,48 83,4 3,22 83,7 Example 9a 74,3 1,72 73,5 3,77 72,3 Example 10a 70,2 1,88 71,5 3,24 72,2 Example 11a 69,9 1,84 70,9 3,98 71,7 Example 12a 83,1 1,43 81,7 3,31 82,8 Example 13a 81,2 1,39 84,7 3,47 83,6 Example 14a 83,3 1,41 83,6 3,39 81,7 Example 15a 80,9 1,32 81,3 3,26 81,5 Example 16a 76,6 1,62 73,5 4,01 77,4 Example 17a 76,1 1,69 73,0 4,08 76,8 Example 18a 75,7 1,71 72,6 4,11 76,4 Example 19a 74,9 1,77 71,4 4,14 75,3 Example 20a 72,5 1,99 68,5 4,30 72,4 Example 21a 73,8 1,90 69,7 4,25 73,5 Example 22a 73,2 1,92 69,4 4,28 73,1 Example 23a 72,8 1,95 69,0 4,29 72,7 Example 24a 74,1 1,88 70,3 4,22 74,2 Example 25a 72,0 2,07 68,1 4,33 71,8 Example 26a 74,8 1,80 71,2 4,15 75,0 Example 27a 74,3 1,83 70,7 4,17 74,6 Comparative example 1a 63,3 2,43 63,2 4,76 63,5 Comparative example 2a 62,2 2,56 64,1 4,98 60,5 Comparative example 3a 60,8 2,78 61,1 5,03 61,2

[0101] Table 2 above shows that the gas generation volumes of the lithium-ion batteries of Examples 1a to 27a were lower than those of the lithium-ion batteries of Comparative Examples 1a to 3a, and the cycle performance and high-temperature performance of the lithium-ion batteries of Examples 1a to 27a were also better than those of the lithium-ion batteries of Comparative Examples 1a to 3a. This shows that when the electrolyte additive or electrolyte of the present disclosure is used in the battery, the free movement of the impeded oxalate-containing lithium salt is reduced, thereby reducing the contact between the oxalate group and the electrodes of the battery.As a result, the occurrence of the gas generation reaction of the oxalate group is less likely, while the damage to the SEI film caused by battery swelling due to gas generation is reduced, thereby improving the stability of the battery under high temperature and long cycle conditions.

[0102] Comparing Examples 1a-15a with Example 16a, the gas generation volume of the lithium-ion battery in Example 16a was slightly increased, and its cycle life and high-temperature performance were slightly reduced. This suggests that the lithium salt electrolyte is beneficial for improving the battery's high-temperature and long-cycle performance and reducing gas generation. Comparing Example 1a with Comparison Example 1a, the high-temperature and cycle life of the lithium-ion battery in Example 1a were better than those in Comparison Example 1a. This is because the effect of the first lithium salt additive on improving high-temperature and cycle life was reduced when the electrolyte additive or electrolyte did not contain the first lithium salt additive (e.g., lithium difluoro(oxalato)borate).Comparing Example 1a with Comparison Example 2a, the gas generation volume of the lithium-ion battery in Example 1a was lower than that of the lithium-ion battery in Comparison Example 2a, and the cycle life and high-temperature performance of the lithium-ion battery in Example 1a were also better than those of the lithium-ion battery in Comparison Example 2a. This is because the restrictive effect between the sulfate ester compound and the first lithium salt additive was weakened when the electrolyte additive or the electrolyte did not contain a sulfate ester compound. As a result, the gas generation reaction of the first lithium salt additive was intensified, which affected the high-temperature and long-cycle performance of the battery.Comparing Example 1a with Comparison Example 3a, the gas generation volume of the lithium-ion battery in Example 1a was lower than that of the lithium-ion battery in Comparison Example 3a, and the cycle performance and high-temperature performance of the lithium-ion battery in Example 1a were also better than those of the lithium-ion battery in Comparison Example 3a. This suggests that the simultaneous presence of these two components (the first lithium salt additive and the sulfate ester compound) in the electrolyte additive or the electrolyte can improve the high-temperature and room-temperature cycle performance of the battery.

[0103] The following examples are used to illustrate applications of the electrolyte additive and the electrolyte comprising the same from the present disclosure in a lithium-ion battery with a positive LiFePO4 electrode. Example 1b

[0104] Example 1b was the same as Example 1a, except for the production of the positive electrode plate.

[0105] A lithium iron phosphate active material for the positive electrode, a conductive agent carbon black SP, a binder polyvinylidene fluoride, and a dispersant polyacrylate were mixed at a mass ratio of 97.2 : 0.8 : 1.8 : 0.2, followed by high-speed stirring and dispersion to obtain a positive electrode slurry. The resulting positive electrode slurry was used to fabricate the positive electrode plate. The positive electrode plate exhibited a one-sided areal density of 230 g / m². 2 and a compressed density of 2.50 g / cm³ 3 on.

[0106] The differences between examples 2b to 11b and the comparison examples 1b to 3b and example 1b are shown in Table 3. [Table 3] Nr. Sulfate ester compound First lithium salt additive Electrolyte lithium salt Molar ratio of the first lithium salt additive to the sulfate ester compound Mass ratio of electrolyte lithium salt to first lithium salt additive N / (g / Ah) Ratio of the total mass of the electrolyte to the discharge capacity of the battery φ×N×C104×t×R type Salary, wt.% type Salary, wt.% type Salary, wt.% Example 1b Connection 1 0,3 Lithium difluoro-(oxalato)borate 3,40 LiBF4 0,15 0,1 0,5 8,61 0,01 Example 2b Connection 1 0,3 Lithium difluoro-(oxalato)borate 1,39 LiBF4 0,15 0,5 0,5 9,13 0,02 Example 3b Connection 1 3 Lithium difluoro-(oxalato)borate 0,69 LiBF4 0,15 1 0,05 5,27 0,09 Example 4b Connection 2 0,3 Lithium difluoro-(oxalato)borate 1,39 LiBF4 0,15 0,5 0,5 10,28 0,02 Example 5b Connection 3 0,3 Lithium difluoro-(oxalato)borate 1,39 LiBF4 0,15 0,5 0,5 10,33 0,02 Example 6b Connection 4 0,3 Lithium difluoro-(oxalato)borate 1,39 LiBF4 0,15 0,5 0,5 10,31 0,02 Example 7b Connection 5 0,3 Lithium difluoro-(oxalato)borate 1,39 LiBF4 0,15 0,5 0,5 10,38 0,02 Example 8b Connection 1 0,3 Lithium tetrafluoro-(oxalato)phosphate 1,39 LiBF4 0,15 0,5 0,5 9,57 0,02 Example 9b Connection 1 0,3 Lithium difluoro-(oxalato)borate 1,39 LiBF4 0,15 0,5 0,5 9,18 0,02 Example 10b Connection 1 0,3 Lithium difluoro-(oxalato)borate 1,39 LiN(SO2F)2 0,15 0,5 0,5 9,77 0,02 Example 11b Connection 1 0,3 Lithium difluoro-(oxalato)borate 1,39 / / 0,5 / 12,26 0,02 Comparative example 1b Connection 1 / / 1,39 LiBF4 0,15 / / 16,34 / Comparative example 2b / 0,3 Lithium difluoro-(oxalato)borate / LiBF4 0,15 / 0,5 18,25 0,03 Comparative example 3b 13 / / / / LiBF4 0,15 / 21,43 /

[0107] The examples and comparison examples mentioned above were subjected to the aforementioned high-temperature storage performance test, high-temperature cycle performance test, and room temperature cycle performance test. The test results are shown in Table 4. [Table 4] Nr. Capacity retention rate after 500 cycles at 45 °C, % Gas production volume using the water displacement method after full loading at 60 °C, cm³ 3 Capacity retention after 60 days of storage at 60 °C, % Gas production volume measured using the water displacement method after 60 days of storage at 60 °C, cm³ 3 Capacity retention rate after 500 cycles at room temperature, % Example 1b 83,2 1,46 83,5 3,41 84,8 Example 2b 84,6 1,33 84,9 3,23 85,4 Example 3b 77,5 1,76 75,2 3,74 77,6 Example 4b 83,4 1,39 82,6 3,26 82,5 Example 5b 83,2 1,36 82,7 3,31 84,5 Example 6b 83,6 1,45 83,1 3,37 84,1 Example 7b 82,1 1,42 82,7 3,42 83,3 Example 8b 73,4 1,57 74,4 3,87 74,3 Example 9b 74,1 1,53 74,9 3,83 74,8 Example 10b 72,9 1,62 73,8 3,88 73,6 Example 11b 72,5 1,66 73,2 3,91 73,1 Comparative example 1b 60,2 2,43 63,3 4,31 62,6 Comparative example 2b 63,1 2,02 62,8 4,59 64,4 Comparative example 3b 62,2 2,66 61,9 5,07 63,1

[0108] Table 4 above shows that the gas generation volumes of the lithium-ion batteries of Examples 1b to 11b were lower than those of the lithium-ion batteries of Comparison Examples 1b to 3b, and the cycle performance and high-temperature performance of each of the lithium-ion batteries of Examples 1b to 11b were also better than those of the lithium-ion batteries of Comparison Examples 1b to 3b. This shows that the electrolyte additive or electrolyte of the present disclosure, when used in the battery, can improve the stability of the battery under high-temperature and long-cycle conditions and reduce gas generation.

[0109] Comparing examples 1b to 7b with example 8b, the gas generation volume of the lithium-ion battery in example 8b was slightly increased, and the cycle performance and high-temperature performance of the lithium-ion battery in example 8b were slightly reduced, suggesting that the electrolyte lithium salt was beneficial for improving the high-temperature and long-cycle performance of the battery and reducing gas generation.

[0110] Comparing Example 1b with Comparison Example 1b, the high-temperature performance and cycle performance of the lithium-ion battery in Example 1b were better than those in Comparison Example 1b. This is because the effect of the first lithium salt additive on improving the high-temperature performance and cycle performance of the battery is reduced when the electrolyte additive or electrolyte does not contain the first lithium salt additive (e.g., lithium difluoro(oxalato)borate).

[0111] Comparing Example 1b with Example 2b, the gas generation volume of the lithium-ion battery in Example 1b was lower than that of the lithium-ion battery in Example 2b, and the cycle life and high-temperature performance of the lithium-ion battery in Example 1b were also better than those of the lithium-ion battery in Example 2b. This is because the restrictive effect between the sulfate ester compound and the first lithium salt additive was weakened when the electrolyte additive or the electrolyte did not contain a sulfate ester compound. As a result, the gas generation reaction of the first lithium salt additive was intensified, which affected the high-temperature and long-cycle performance of the battery.

[0112] Comparing Example 1b with Comparison Example 3b, the gas generation volume of the lithium-ion battery in Example 1b was lower than that of the lithium-ion battery in Comparison Example 3b, and the cycle performance and high-temperature performance of the lithium-ion battery in Example 1b were also better than those of the lithium-ion battery in Comparison Example 3b. This suggests that the simultaneous presence of these two components (the first lithium salt additive and the sulfate ester compound) in the electrolyte additive or the electrolyte can improve the high-temperature and room-temperature cycle performance of the battery.

[0113] The following examples serve to illustrate the applications of the electrolyte additive and the electrolyte containing it of the present disclosure in a lithium-ion battery with a silicon-oxygen negative electrode. Example 1c

[0114] Example 1c was the same as example 1a, except for the fabrication of the negative electrode plate.

[0115] SI420 / Zichen SIO-1300L-240116 as the active material for the negative electrode, a conductive agent SP, a binder SBR (JSR-104A), a thickener CMC (crt30000PA), and a conductive material CNT were mixed in a weight ratio of 94.94:1.5:2:1.5:0.06, and water was added to form a slurry, with the solids content controlled to 49.05%. The mixture was stirred in a vacuum mixer to obtain a negative electrode slurry. The negative electrode slurry was uniformly applied to a 9 µm thick copper foil. The copper foil coated with the negative electrode slurry was dried for 5 hours at 80 °C. Finally, the negative electrode plate was calendered to a density of 1.4 g / cm³. 3The material was compacted and then cut to obtain the negative electrode plate. The porosity φ of the negative electrode plate was 70%.

[0116] The differences between examples 2c to 7c and the comparison examples 1c to 3c as well as example 1c are shown in Table 5. [Table 5] Nr. Sulfate ester compound First lithium salt additive Electrolyte lithium salt Molar ratio of the first lithium salt additive to the sulfate ester compound Mass ratio of electrolyte lithium salt to first lithium salt additive N / (g / Ah) Ratio of the total mass of the electrolyte to the discharge capacity of the battery φ×N×C104×t×R type Salary, wt.% type Salary, wt.% type Salary, wt.% Example 1c Connection 1 3.40 Lithium difluoro-(oxalato)borate 0.3 LiBF4 0.15 0.1 0.5 4.62 0.08 Example 2c Connection 1 1.39 Lithium difluoro-(oxalato)borate 0.3 LiBF4 0.15 0.5 0.5 4.71 0.04 Example 3c Connection 1 0.69 Lithium difluoro-(oxalato)borate 3 LiBF4 0.15 1 0.05 7.04 0.03 Example 4c Connection 1 23.23 Lithium difluoro-(oxalato)borate 5 LiBF4 0.15 0.5 0.03 3.45 0.44 Example 5c Connection 1 1.39 Lithium tetrafluoro-(oxalato)phosphate 0.3 LiBF4 0.15 0.5 0.5 5.12 0.04 Example 6c Connection 1 1.39 Lithium difluoro-(oxalato)borate 0.3 LiPF6 0.15 0.5 0.5 5.14 0.04 Example 7c Connection 1 1.39 Lithium difluoro-(oxalato)borate 0.3 LiN(SO2F)2 0.15 0.5 0.5 5.21 0.04 Comparative example 1c Connection 1 1.39 / / LiBF4 0.15 / / 15.34 0.11 Comparative example 2c / / Lithium difluoro-(oxalato)borate 0.3 LiBF4 0.15 / 0.5 20.23 / Comparative example 3c / / / / LiBF4 0.15 / / 24.57 /

[0117] The examples and comparison examples mentioned above were subjected to the aforementioned high-temperature storage test, the high-temperature cycle test, and the room-temperature cycle test. The test results are listed in Table 6. [Table 6] Nr. Capacity retention rate after 500 cycles at 45 °C, % Gas production volume using the water displacement method after full charge at 60 °C, cm³ 3 Capacity retention after 60 days of storage at 60 °C, % Gas production volume measured using the water displacement method after 60 days of storage at 60 °C, cm³ 3 Capacity retention rate after 500 cycles at room temperature, % Example 1c 85.8 1.35 81.5 3.14 86.6 Example 2c 86.7 1.29 83.2 2.98 87.9 Example 3c 81.3 1.48 77.6 3.45 82.4 Example 4c 76.1 1.69 72.1 3.77 77.2 Example 5c 78.3 1.65 75.1 3.92 79.6 Example 6c 77.9 1.71 74.6 4.03 78.9 Example 7c 77.4 1.77 74.2 4.08 78.2 Comparative example 1c 65.3 2.25 65.7 4.71 66.1 Comparative example 2c 64.6 2.46 65.9 4.87 65.8 Comparative example 3c 62.1 2.87 62.4 5.02 62.9

[0118] Table 6 above shows that the gas generation volumes of the lithium-ion batteries of Examples 1c to 7c were lower than those of the lithium-ion batteries of the comparison examples 1c to 3c, and that the cycle performance and high-temperature performance of each of the lithium-ion batteries of Examples 1c to 7c were also better than those of the lithium-ion batteries of the comparison examples 1c to 3c. This shows that the electrolyte additive or electrolyte of the present disclosure, when used in the battery, can improve the stability of the battery under high-temperature and long-cycle conditions and reduce gas generation.

[0119] When comparing Example 1c with Comparison Example 1c, the high-temperature performance and cycle performance of the lithium-ion battery in Example 1c were better than those of Comparison Example 1c. This is because the effect of the first lithium salt additive on improving the high-temperature performance and cycle performance of the battery is reduced if the electrolyte additive or electrolyte does not contain a first lithium salt additive (e.g., lithium difluoro(oxalato)borate).

[0120] When comparing Example 1c with Example 2c, the gas generation of the lithium-ion battery from Example 1c was lower than that of the lithium-ion battery from Example 2c, and the cycle performance and high-temperature performance of the lithium-ion battery from Example 1c were also better than those of the lithium-ion battery from Example 2c. This is because the restrictive effect between the sulfate ester compound and the first lithium salt additive was weakened when the electrolyte additive or the electrolyte did not contain a sulfate ester compound. As a result, the gas generation reaction of the first lithium salt additive was enhanced, which affected the high-temperature and long-cycle performance of the battery.

[0121] When comparing Example 1c with Comparison Example 3c, the gas generation volume of the lithium-ion battery of Example 1c was lower than that of the lithium-ion battery of Comparison Example 3c, and the cycle performance and high-temperature performance of the lithium-ion battery from Example 1c were also better than those of the lithium-ion battery from Comparison Example 3c, suggesting that the simultaneous presence of these two components (the first lithium salt additive and the sulfate ester compound) in the electrolyte additive or in the electrolyte can improve the high-temperature and room-temperature cycle performance of the battery.

[0122] Unless otherwise specified, all scientific and technical terms used in this disclosure have the same meaning as they would generally be understood by a person skilled in the field of this disclosure. All patents and publications mentioned in this disclosure are incorporated into this document in their entirety by reference. Words used herein, such as "comprehensive" or "including," are open-ended expressions, meaning that they contain content specified in this disclosure but do not exclude other content.

[0123] In the descriptive text of this disclosure, statements referring to expressions such as "an embodiment" and "another embodiment" mean that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. The occurrence of the foregoing expressions at different points in this disclosure does not necessarily imply references to the same embodiment or example of the present disclosure. Furthermore, the specific features, structures, materials, or properties in one or more embodiments or examples may be combined in any suitable manner.Furthermore, various 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. It is also understood that in this description, terms such as "first" and "second" are used for descriptive purposes only and not with the intention of indicating or implying a relative meaning or implicitly showing the number of technical features specified.

[0124] Although embodiments of the present disclosure have been shown and described, it is understood by the person skilled in the art that the foregoing embodiments cannot be interpreted as limiting the present disclosure, and changes, modifications, alternatives and variations 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 202411283546.2

[0001] Cited non-patent literature

[0000] BATTERY”, submitted to the Chinese National Intellectual Property Administration on September 13, 2024

[0001]

Claims

[1] Battery comprising: a positive electrode plate, a negative electrode plate, a separator and an electrolyte, wherein: the negative electrode plate has a porosity φ in the unit %; the separator has a thickness t in the unit µm and a pore size R in the unit µm; a ratio of the total mass of the electrolyte to the discharge capacity of the battery N in the unit g / Ah; and the electrolyte comprises an electrolyte additive, wherein the electrolyte additive comprises a sulfate ester compound and a first lithium salt additive, wherein the first lithium salt additive comprises an oxalate-containing lithium salt and the sulfate ester compound has a structure represented by formula I: Formula I, wherein: R1 and R8 are each independently selected from hydrogen or C1 to C5 hydrocarbyl; R2, R3, R4, R5, R6, and R7 each independently from C1- to C3-alkylenes, C1- to C3- alkoxy, an oxygen atom, or are selected; and n is an integer in the range of 0 to 4, and a mass fraction of the sulfate ester compound in the electrolyte C in the unit %; and the battery corresponds to formula A: 0.01≤φ×N×C104×t×R≤0.5 [2] Battery according to claim 1, wherein: φ ranges from 60% to 80%; and / or t ranges from 12 µm to 20 µm; and / or R ranges from 0.03 µm to 0.12 µm; and / or C ranges from 0.1% to 10%; and / or N ranges from 2.0 to 5.

0. [3] Battery according to claim 1 or 2, wherein: R1 and R8 are each independently selected from hydrogen; at least one of R2, R3 or R4 is selected, and at least one of R2, R3 or R4 is selected from an oxygen atom; at least one of R5, R6 or R7 is selected or chosen, and at least one of R5, R6 or R7 is selected from an oxygen atom; and n 2 is. [4] Battery according to any one of claims 1 to 3, wherein the sulfate ester compound has one of the following structures: [5] Battery according to any one of claims 1 to 4, wherein the first lithium salt additive comprises at least one of lithium difluoro(oxalato)borate, lithium bis(oxalato)borate, lithium tetrafluoro(oxalato)phosphate, lithium difluorobis(oxalato)phosphate or lithium tris(oxalato)phosphate. [6] Battery according to any one of claims 1 to 5, wherein the molar ratio of the first lithium salt additive to the sulfate ester compound is 1 : (1 to 5). [7] Battery according to any one of claims 1 to 6, wherein: a mass fraction of the first lithium salt additive in the electrolyte ranges from 0.1% to 5%; and / or The mass fraction of the sulfate ester compound in the electrolyte ranges from 1% to 10%. [8] Battery according to any one of claims 1 to 7, wherein the electrolyte additive further comprises an electrolyte lithium salt, wherein the electrolyte lithium salt comprises at least one of LiBF4, LiPF6, LiAsF6 or LiN(SO2F)2. [9] Battery according to claim 8, wherein the mass ratio of the electrolyte lithium salt to the first lithium salt additive is 1 : (0.4 to 2). [10] Battery according to claim 8 or 9, wherein the mass fraction of the electrolyte lithium salt in the electrolyte ranges from 0.1% to 1%. [11] Battery according to any one of claims 1 to 10, wherein the positive electrode plate comprises: a positive electrode current collector; and an active material layer of the positive electrode, arranged on at least one side of the positive electrode current collector, wherein the active material layer of the positive electrode comprises an active material of the positive electrode, wherein the active material of the positive electrode comprises at least one of lithium iron phosphate or a ternary material, wherein the ternary material has a chemical formula of LiNi x Co y ml z1 m 2 z2 O2 corresponds to: M1 and M2 are different from each other and each independently selected from a pool of Al, Mn or Fe; and 0