Battery

Abstract

Battery, including: an electrolyte comprising a first additive and a second additive, wherein the first additive has a structure represented by formula 1 and wherein the second additive comprises at least one of tripropargyl phosphate, propyl bis(2-propynyl) phosphate or ethyl bis(2-propynyl) phosphate; and a negative electrode plate comprising a negative electrode active material, wherein the negative electrode active material comprises the element silicon,

Description

PRIORITY NOTICE

[0001] This application claims priority from Chinese patent application No. 202510094491.9, filed with the Chinese National Intellectual Property Administration on January 21, 2025, 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] Silicon has an extremely high theoretical specific capacity (4200 mAh / g) and a low potential for lithium intercalation and can provide channels for deintercalation / intercalation of Li +It can provide power in multiple directions. However, it also exhibits problems, such as poor conductivity, particle pulverization, unstable solid-electrolyte interface (SEI) growth, and volume expansion. These problems ultimately lead to a reduction in the Coulombic efficiency and cycle life of silicon-based lithium-ion batteries, as well as poor fast-charge cycle performance. Consequently, regulating the electrolyte composition and improving the stability of the SEI film are crucial for improving the electrochemical performance of silicon-based lithium-ion batteries. SUMMARY

[0004] The present disclosure aims to solve, at least to some extent, one of the technical problems existing in the prior art. Therefore, it is an objective of the present disclosure to provide a battery that exhibits good surface flatness and excellent fast-charge cycle performance.

[0005] For this purpose, the present disclosure provides a battery. The battery comprises an electrolyte and a negative electrode plate. The electrolyte comprises a first additive and a second additive. The first additive has a structure represented by formula 1. The second additive comprises at least one of tripropargyl phosphate, propyl bis(2-propynyl) phosphate, or ethyl bis(2-propynyl) phosphate. The negative electrode plate comprises an active material of the negative electrode. The active material of the negative electrode comprises the element silicon.

[0006] Given that the electrode interface of existing secondary batteries is susceptible to damage during cycling, the present disclosure provides a battery. The battery comprises a first additive and a second additive. During battery operation, the two additives undergo electropolymerization and adhere together to the surfaces of the positive and negative electrodes to maintain interface flatness, thereby promoting the battery's cycle stability.

[0007] Specifically, the first additive (the compound represented by formula 1) undergoes deesterification to form a long-chain hydrocarbon polymer with the byproducts Li₂SO₄ and Li₂CO₃. Li₂SO₄ has the ability to oxidize other unsaturated groups (for example, carbon-carbon triple bonds C≡C), thereby promoting the polymerization of other additives. Li₂CO₃ can effectively attenuate the reductive decomposition of ethylene carbonate (EC) in the electrolyte at 0.75 V and inhibit the formation of lithium alkyl carbonate at 0.6 V, thus maintaining electrolyte stability and preventing Li₂ loss. + This reduces the power consumption and improves the cycle stability of the lithium-ion battery.

[0008] Specifically, the second additive contains unsaturated alkynyl groups at both ends, which serve as polymerization sites during polymerization to form long-chain polymers. During the actual charge-discharge process, the second additive can be firmly anchored to the surfaces of the positive and negative electrodes via C≡C junctions without decomposing. This maintains interfacial flatness, reduces volume expansion and pulverization of the negative silicon electrode, and consequently promotes the battery's cycle stability. However, when the concentration of the second additive reaches a certain level, its adsorption mode changes from horizontal to vertical adsorption. This hinders lithium ion transport and reduces the uniformity of the interfacial film, resulting in increased impedance and other adverse effects.

[0009] Li₂SO₄, generated by the polymerization of the first additive, oxidizes the C≡C structure in the second additive, promoting C≡C polymerization through bond cleavage. Simultaneously, the reaction product is adsorbed at the interface, reducing the likelihood of vertical adsorption of the second additive and thus mitigating its adverse effects on the negative electrode structure. This maintains the interface flatness, reduces volume expansion and pulverization of the negative silicon electrode, and consequently improves the battery's fast-charge cycle stability.

[0010] According to one embodiment of the present disclosure, the mass ratio of the first additive to the second additive is 1 : (0.1 to 2), preferably 1 : (0.1 to 1). Consequently, the interface flatness of the battery can be improved, thereby improving its fast-charge cycle performance.

[0011] According to one embodiment of the present disclosure, the battery further comprises a third additive. The third additive has a structure represented by formula 2: where R 12 , R 13 and R 14 each are independently selected from H, C1- to C6-alkyl or C2- to C4-alkenyl, provided that R 12 , R 13 and R 14 not all are H at the same time and that at least one of R 12 , R 13 or R 14 contains a carbon-carbon double bond; or R 12 and one at R 12 bonded atom together form C2 to C4 alkenyl and R 13 and R 14 each are independently selected from H, C1- to C6-alkyl or C2- to C4-alkenyl; or R 12 and R 13 and to R 12 and R 13 bonded atoms jointly form C3 to C8 cycloalkenyl and R 14 H is.

[0012] Specifically, at least one of R contains 12 , R 13 or R 14The third additive structure contains a carbon-carbon double bond, which can undergo electropolymerization during battery operation and adheres to the surface of the negative electrode to maintain its surface flatness, thereby promoting the battery's cycle stability. There are two main polymerization pathways: In the first, the olefin group undergoes bond cleavage and repolymerization, distributing cyclic ester components at both ends of the polymer chain; in the second, a low-grade polymerization occurs, with the CO bond preferentially being cleaved, followed by parallel polymerization of C=C bonds, resulting in a long-chain, high-molecular-weight polymer. The polymerization process of the second mode is more stable than that of the first.However, excessive addition of the third additive leads to the generation of a large number of long-chain polymers, which hinders lithium ion transfer and significantly increases the interfacial charge transfer impedance. The first additive in the present disclosure can mitigate the adverse effects of the third additive on lithium ion transfer, ultimately ensuring stable long-cycle and high-temperature battery storage performance. That is, the combination of the third additive with the first and second additives can further maintain the battery's interfacial flatness, thereby improving the battery's fast-charge cycle stability.

[0013] According to one embodiment of the present disclosure, R 12 , R 13 and R 14 each independently selected from H, C1- to C4-alkyl or C2- to C4-alkenyl, provided that R 12 , R 13 and R14 not all are H at the same time and that at least one of R 12 , R 13 or R 14 contains a carbon-carbon double bond; or R 12 and one at R 12 The bonded atom together form C2-C4 alkenyl, and R 13 and R 14 are each independently selected from C1- to C4-alkyl or C2- to C4-alkenyl; or R 12 and R 13 and to R 12 and R 13 The bonded atoms together form C7 to C8 cycloalkenyl, and R 14 is H. Consequently, the surface flatness of the battery can be improved, thereby improving its fast-charging cycle performance.

[0014] According to one embodiment of the present disclosure, R 12 , R 13 and R 14 each independently selected from H, C1-alkyl or C2-alkenyl, provided that R 12 , R 13 and R 14not all are H at the same time and that at least one of R 12 , R 13 or R 14 contains a carbon-carbon double bond; or R 12 and one at R 12 The bonded atom together form C2-alkenyl and R 13 and R 14 are each independently selected from C1-alkyl or C2-alkenyl; or R 12 and R 13 and to R 12 and R 13 The bonded atoms together form C7-cycloalkenyl, and R 14 is H. Consequently, the surface flatness of the battery can be improved, thereby improving the fast-charging cycle performance of the battery.

[0015] According to one embodiment of the present disclosure, the third additive comprises at least one of the following compounds:

[0016] Consequently, the surface flatness of the battery can be improved, thereby improving its fast-charging cycle performance.

[0017] According to one embodiment of the present disclosure, the mass ratio of the first additive to the second additive and to the third additive is 1 : (0.1 to 2) : (0.1 to 1), preferably 1 : (0.1 to 1) : (0.1 to 0.2). Consequently, the interface flatness of the battery can be improved, thereby improving its fast-charge cycle performance.

[0018] According to one embodiment of the present disclosure, the battery comprises an electrolyte. Based on the total mass of the electrolyte, the mass fraction of the second additive ranges from 0.05% to 5%, preferably from 0.1% to 1%. Consequently, the interfacial flatness of the battery can be improved, thereby enhancing its fast-charge cycle performance.

[0019] According to one embodiment of the present disclosure, the mass fraction of the second additive, based on the total mass of the electrolyte, ranges from 0.05% to 1%, preferably from 0.1% to 0.4%. Consequently, the interfacial flatness of the battery can be improved, thereby improving its fast-charge cycle performance.

[0020] According to one embodiment of the present disclosure, the mass fraction of the third additive, based on the total mass of the electrolyte, ranges from 0.01% to 0.5%, preferably from 0.05% to 0.1%. Consequently, the interfacial flatness of the battery can be improved, thereby improving its fast-charge cycle performance.

[0021] According to one embodiment of the present disclosure, the electrolyte further comprises a lithium salt. The lithium salt comprises at least one of lithium hexafluorophosphate or lithium bis(fluorosulfonyl)imide. Consequently, the gas generation of the battery can be reduced, thereby improving its cycle performance.

[0022] According to one embodiment of the present disclosure, the lithium salt comprises lithium hexafluorophosphate and lithium bis(fluorosulfonyl)imide, and a mass ratio of lithium hexafluorophosphate to lithium bis(fluorosulfonyl)imide is (2 to 5): 1. Consequently, the gas generation of the battery can be reduced, thereby improving its cycle performance.

[0023] According to one embodiment of the present disclosure, the battery further comprises an active material for the positive electrode. The active material of the positive electrode comprises at least one of the following: lithium iron phosphate material, LiCoO2 material, a lithium-rich manganese-based material (aLi2MnO3·(1-a)LiMO2), LiNi x Co y Mn z O2 material, a lithium nickel manganese oxide (LiNi) 0,5 Mn 1,5 O4) material or a lithium manganese iron phosphate LiFe b Mn 1-b PO4, where 0 ≤ a ≤ 1; 0 ≤ b ≤ 1; x + y + z = 1; and M comprises at least one of Ni, Co, or Mn. Consequently, the cycle performance of the battery can be improved.

[0024] According to one embodiment of the present disclosure, the battery is a cylindrical battery.

[0025] According to one embodiment of the present disclosure, the cylindrical battery is a cylindrical 18650 battery and has an energy density ranging from 230 Wh / kg to 250 Wh / kg.

[0026] One active material of the positive electrode of the cylindrical battery is LiNi. x1 M 1- x O2, where M comprises at least one of Co or Mn and 0.8 ≤ x ≤ 0.9.

[0027] The negative electrode plate comprises a collector for negative electrode current and an active material layer of the negative electrode, arranged on at least one surface of the collector for negative electrode current. The mass fraction of silicon in the active material layer of the negative electrode ranges from 5% to 8%.

[0028] Further aspects and advantages of the embodiments of the present disclosure are at least partially provided in the following description, or become partially obvious from the following description, or can be learned from the practical implementation of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] These and other aspects and advantages of the present disclosure will become obvious and easier to understand from the following descriptions with reference to the accompanying drawings. Fig. Figure 1 shows scanning electron microscope images of different degrees of flatness according to the present disclosure. DETAILED DESCRIPTION OF THE EXECUTION FORMS

[0030] The embodiments of the present disclosure are described in detail below. The embodiments described below are purely illustrative and are intended to explain, not limit, the present disclosure.

[0031] Furthermore, terms such as "first" and "second" are used herein for descriptive purposes and not with the intention of indicating or implying a relative meaning or implicitly showing the number of technical features specified. Consequently, a feature designated as "first" and "second" may comprise at least one feature. In the description of this disclosure, the expression "a plurality of" means at least two, for example, two or three, unless otherwise specified.

[0032] Endpoint values ​​or any values ​​of ranges disclosed in this disclosure are not limited to the exact ranges or values. These ranges or values ​​should be understood to include values ​​that are close to these ranges or values. With regard to numerical ranges, one or more new numerical ranges may be obtained by combining point values ​​within the relevant ranges, an endpoint value and a single point value within the relevant ranges, and single point values ​​within the relevant ranges, and these numerical ranges should be considered to be specifically disclosed in this disclosure.

[0033] For the sake of clarity in understanding this disclosure, certain technical and scientific terms are specifically defined below. Unless otherwise clearly defined elsewhere in this document, all other technical and scientific terms used herein shall have the meanings commonly understood by general technical personnel in the field to which this disclosure relates.

[0034] Words used herein, such as "comprehensive" or "including", are open-ended expressions, meaning that they contain content specified in the present disclosure, but do not exclude other content.

[0035] The amount of electrolyte additives constitutes only a small fraction of the electrolyte in a lithium-ion battery. However, suitable amounts of additives can form a SEI on the surface of an active material of a negative electrode, which is referred to in the present disclosure as an interfacial film, and can reduce the problem of side reactions that occur after direct contact between the negative electrode material and the electrolyte.

[0036] However, silicon-based negative electrodes suffer from problems such as particle pulverization, unstable SEI growth, and volume expansion. These problems ultimately lead to a reduction in the coulombic efficiency and cycle life of silicon-based lithium-ion batteries, as well as poor fast-charge cycle performance. Consequently, regulating the electrolyte composition and improving the stability of the SEI film are crucial for improving the electrochemical performance of silicon-based lithium-ion batteries.

[0037] In light of this, the present disclosure provides a battery. The battery comprises an electrolyte and a negative electrode plate. The electrolyte comprises a first additive and a second additive. The first additive has a structure represented by formula 1. The second additive comprises at least one of tripropargyl phosphate (CAS: 1779-34-6), (2-propynyl)dibutyl phosphate (CAS: 18687-46-2), or ethyldiprop-2-ynyl phosphate (CAS: 69695-73-4). The negative electrode plate comprises a negative electrode active material. The negative electrode active material comprises the element silicon.

[0038] The battery according to the present disclosure comprises the electrolyte and the negative electrode containing silicon, and the electrolyte comprises the first additive and the second additive, which can undergo electropolymerization during battery operation and adhere to the surface of the negative electrode to maintain the interfacial flatness of the negative electrode, thereby reducing volume expansion and pulverization of the negative silicon electrode, which promotes the cycle stability of the battery.

[0039] Specifically, the second additive contains unsaturated alkynyl groups at both ends, which serve as polymerization sites during polymerization to form long-chain polymers. During the actual charge-discharge process, the second additive can be firmly anchored to the surfaces of the positive and negative electrodes via C≡C for polymerization. This maintains interfacial flatness, mitigates volume expansion and pulverization of the negative silicon electrode, and consequently promotes the battery's cycle stability. However, when the concentration of the second additive reaches a certain level, its adsorption mode changes from horizontal to vertical adsorption. This hinders lithium ion transport and reduces the uniformity of the interfacial film, resulting in increased impedance and susceptibility of the negative electrode surface to pulverization.Simultaneously, the Li2SO4 byproduct of the first additive exhibits the ability to oxidize other unsaturated groups (such as C=C and C≡C), thereby promoting polymerization. For example, Li2SO4 oxidizes the C≡C in the second additive structure, promoting C≡C polymerization through bond cleavage, while reducing the likelihood of vertical adsorption of the second additive. This mitigates adverse effects of the second additive on the negative electrode interface and ensures stable long-cycle and high-temperature battery performance.

[0040] According to a specific embodiment of the present disclosure, the mass ratio of the first additive to the second additive is 1 : (0.1 to 2). With an excessive proportion of the first additive, the proportion of lithium carbonate in the battery is relatively high, causing CO2 to move back and forth, which in turn leads to significant gas generation in the system. With an excessive proportion of the second additive, the probability of vertical adsorption at the interface is greatly increased, which in turn affects the desolvation and transport of lithium ions and is unfavorable for the stability of the surface structure of the negative electrode. The selection can be made based on actual requirements. To give some specific examples, the mass ratio of the first additive to the second additive can be 1 : 0.1, 1 : 0.5, 1 : 1, 1 : 2, etc., preferably 1 : (0.1 to 1).Consequently, the surface flatness of the battery can be improved, thereby improving its fast-charging cycle performance.

[0041] The process of electropolymerization of the compound represented by formula 1 during battery operation is as follows:

[0042] The compound represented by formula 1 undergoes deesterification to form a long-chain hydrocarbon polymer with the byproducts Li₂SO₄ and Li₂CO₃. Li₂SO₄ has the ability to oxidize other unsaturated groups (e.g., C≡C), thereby promoting the polymerization of other additives. Li₂CO₃ can effectively attenuate the reductive decomposition of ethylene carbonate in the electrolyte at 0.75 V and inhibit the formation of lithium alkyl carbonate at 0.6 V, thus maintaining electrolyte stability and preventing the loss of Li₂. + This reduces the power consumption and improves the cycle stability of the lithium-ion battery.

[0043] Specifically, the second additive comprises at least one of tripropargyl phosphate, (2-propynyl)dibutyl phosphate or ethyldiprop-2-ynyl phosphate.

[0044] According to a specific embodiment of the present disclosure, the second additive comprises tripropargyl phosphate (TPP). TPP is oxidized (loses electrons) in front of a primary solvent. The acidic corrosive substance F in the electrolyte, which has a high electronegativity, attacks the carbon core of TPP, causing cleavage of the π-bond in C≡C, forming a covalent CF bond, and a chain addition reaction takes place at the positive electrode. As TPP accepts electrons, H protons in the electrolyte, due to their relatively high electrophilicity, approach the electron cloud of the alkynyl p-orbital, forming a covalent CH bond, and a chain addition reaction takes place at the negative electrode.

[0045] According to a specific embodiment of the present disclosure, the battery further comprises a third additive. The third additive has a structure represented by formula 2: R 12 , R 13 and R 14 are each independently selected from H, C1- to C6-alkyl or C2- to C4-alkenyl, provided that R 12 , R 13 and R 14 not all are H at the same time and that at least one of R 12 , R 13 , or R 14 contains a carbon-carbon double bond; or R 12 and one at R 12 The bonded atoms together form C2 to C4 alkenyls, and R 13 and R 14 are each independently selected from H, C1- to C6-alkyl or C2- to C4-alkenyl; or R 12 and R 13 and to R 12 and R 13 The bonded atoms together form C3 to C8 cycloalkenyl, and R 14 is H.

[0046] Specifically, the polymerization reaction of the third additive can be classified into two modes. (1) At least one of R 12 and R 13 The third additive structure contains a carbon-carbon double bond that can serve as a polymerization site. This means the olefin bond is cleaved and then undergoes the polymerization reaction, distributing cyclic ester components at both ends of the polymer chain. This pathway can be verified by Fourier-transform infrared spectroscopy (FTIR), which shows stable peaks at 1795 cm⁻¹. -1 (C=O) and 1063 cm -1(CO) shows. (2) The C=O bond in the third additive structure is cleaved, followed by parallel polymerization of carbon-carbon double bonds to form a long-chain polymer with a high molecular weight. Compared with the first polymerization mode, the polymer obtained in this polymerization mode has a lower degree of polymerization, while its polymerization reaction is more stable. The polymers obtained after the reaction adhere to the surfaces of the positive and negative electrodes, protecting the interfaces of the positive and negative electrodes so that they retain their flatness, and thus promoting the cycle stability of the battery.

[0047] According to specific embodiments of the present disclosure, R 12 , R 13 and R 14 each independently selected from H, C1- to C4-alkyl or C2- to C4-alkenyl, provided that R 12 , R 13 and R14 not all are H at the same time and that at least one of R 12 , R 13 , or R 14 contains a carbon-carbon double bond; or R 12 and one at R 12 The bonded atoms together form C2 to C4 alkenyls, and R 13 and R 14 are each independently selected from C1- to C4-alkyl or C2- to C4-alkenyl; or R 12 and R 13 and to R 12 and R 13 The bonded atoms together form C7 to C8 cycloalkenyl, and R 14is H. Consequently, the steric hindrance caused by an excessively long carbon chain can be reduced, mitigating the problem of low film formation efficiency at the interface between the material and the electrolyte. Simultaneously, the additive can undergo polymerization via two different pathways to obtain long-chain polymers that then adhere to the surfaces of the positive and negative electrodes, protecting the interfaces and maintaining their flatness, thereby promoting the battery's cycle stability.

[0048] According to specific embodiments of the present disclosure, R 12 , R 13 and R 14 each independently selected from H, C1-alkyl or C2-alkenyl, provided that R 12 , R 13 and R 14 not all are H at the same time and that at least one of R 12 , R 13 , or R 14contains a carbon-carbon double bond; or R 12 and one at R 12 The bonded atom together form C2-alkenyl, and R 13 and R 14 are each independently selected from C1-alkyl or C2-alkenyl; or R 12 and R 13 and to R 12 and R 13 The bonded atoms together form C7-cycloalkenyl, and R 14 is H. Consequently, the steric hindrance caused by an excessively long carbon chain can be further reduced, mitigating the problem of low film formation efficiency at the interface between the material and the electrolyte. Simultaneously, the additive can undergo polymerization via two different pathways to obtain long-chain polymers that then adhere to the surfaces of the positive and negative electrodes, protecting the interfaces and maintaining their flatness, thus promoting the battery's cycle stability.

[0049] According to one specific embodiment of the present disclosure, the third additive comprises at least one of the following compounds:

[0050] Specifically, formula 3-1 has CAS number 142429-71-8, formula 3-2 has CAS number 96548-13-9, formula 3-3 has CAS number 25326-19-6, and formula 3-4 has CAS number 4427-96-7.

[0051] Taking the compound represented by formula 3-4 as an example, its electropolymerization process during battery operation proceeds as follows:

[0052] According to a specific embodiment of the present disclosure, the mass ratio between the first additive, the second additive, and the third additive is 1 : (0.1 to 2) : (0.1 to 1). The adsorption of the present polymerization product at the surface of the interfacial film is influenced by different additive ratios. With an excessive proportion of the first additive, the proportion of lithium carbonate in the battery is relatively high, causing a back-and-forth movement of CO2, which in turn leads to significant gas generation in the system. With an excessive proportion of the second additive, the probability of vertical adsorption at the interface is greatly increased, which in turn affects the desolvation and transport of lithium ions. With an excessive proportion of the third additive, an excessive number of molecules fail to aggregate and are not properly adsorbed at the interface.In this case, the number of free molecules in the electrolyte is increased, and the reaction mechanisms can primarily involve general redox reactions that produce gases such as CO₂ and O₂. The selection can be made based on the actual requirements. To give some concrete examples, the mass ratio between the first additive, second additive, and third additive can be 1:0.1:1, 1:1:0.2, 1:1:1, 1:0.1:0.1, 1:2:0.1, 1:2:1, etc., preferably 1:(0.1 to 1) :(0.1 to 2). Consequently, the interfacial flatness can be improved, thereby enhancing the battery's fast-charging cycle performance.

[0053] According to one particular embodiment of the present disclosure, the battery comprises an electrolyte. Based on the total mass of the electrolyte, the mass fraction of the second additive ranges from 0.05% to 5%, for example, 0.05%, 0.1%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, and 5%. If the fraction of the first additive is within the aforementioned range, electropolymerization can proceed effectively during battery operation to form long-chain polymers that adhere to the surfaces of the positive and negative electrodes, thereby maintaining the surface flatness and thus improving the fast-charge cycle stability of the battery. In some embodiments of the present disclosure, the mass fraction of the first additive, based on the total mass of the electrolyte, ranges from 0.1% to 1%.

[0054] According to a specific embodiment of the present disclosure, the mass fraction of the second additive, based on the total mass of the electrolyte, ranges from 0.05% to 1%, for example, 0.05%, 0.1%, 0.5%, and 1%. If the fraction of the second additive lies within the aforementioned range, electropolymerization can effectively occur during battery operation to form long-chain polymers that adhere to the surfaces of the positive and negative electrodes, thereby maintaining interfacial flatness and thus improving the fast-charge cycle stability of the battery. At the same time, the combination of the second additive with the first additive also mitigates the adverse effect of the second additive on the interfacial stability of the battery, thereby ensuring stable long-cycle and high-temperature storage performance of the battery.In some embodiments of the present disclosure, the mass fraction of the second additive, based on the total mass of the electrolyte, ranges from 0.1% to 0.4%.

[0055] According to one specific embodiment of the present disclosure, the mass fraction of the third additive, based on the total mass of the electrolyte, ranges from 0.01% to 0.5%, for example, 0.01%, 0.05%, 0.1%, and 0.5%. If the fraction of the third additive is within the aforementioned range, electropolymerization can effectively occur during battery operation to form long-chain polymers that adhere to the surfaces of the positive and negative electrodes, thereby maintaining the surface flatness and thus improving the fast-charge cycle stability of the battery. Simultaneously, the combination of the third additive with the first and second additives can also ensure the stable long-cycle and high-temperature storage performance of the battery. In some embodiments of the present disclosure, the mass fraction of the third additive, based on the total mass of the electrolyte, ranges from 0.05% to 0.1%.

[0056] According to a specific embodiment of the present disclosure, the electrolyte further comprises a lithium salt. The lithium salt comprises at least one of lithium hexafluorophosphate or lithium bis(fluorosulfonyl)imide. Consequently, adding the electrolyte to the lithium-ion battery can reduce gas generation and improve the battery's cycle performance.

[0057] According to a specific embodiment of the present disclosure, the lithium salt comprises lithium hexafluorophosphate and lithium bis(fluorosulfonyl)imide, and a mass ratio of lithium hexafluorophosphate to lithium bis(fluorosulfonyl)imide is (2 to 5):1. Consequently, adding the two aforementioned lithium salts to the electrolyte can further reduce gas generation and improve the cycle performance of the battery. The mass ratio of lithium hexafluorophosphate to lithium bis(fluorosulfonyl)imide can be 2:1, 3:1, 4:1, 5:1, etc. Consequently, if the ratio of the two lithium salts is kept within the aforementioned range, adding the electrolyte to the lithium-ion battery can reduce gas generation and improve the cycle performance of the battery.

[0058] According to one particular embodiment of the present disclosure, the electrolyte further comprises a solvent. The solvent comprises a cyclic organic solvent and / or a linear organic solvent.

[0059] Specifically, the cyclic organic solvent may include one or more of cyclic carbonates, for example ethylene carbonate (EC) and propylene carbonate (PC), one or more of cyclic carboxylates such as γ-butyrolactone, γ-valerolactone and ε-caprolactone, one or more of cyclic esters such as tetrahydrofuran, 3-methyltetrahydrofuran, 1,3-dioxolane and 1,4-dioxolane, or one or more of linear sulfones such as dimethyl sulfone, monofluoromethyl, methyl sulfone and trifluoromethyl isopropyl sulfone.

[0060] Specifically, the linear organic solvent may comprise one or more of linear carbonates, for example dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC) and methyl propyl carbonate (MPC), one or more of linear carboxylates such as methyl acetate, ethyl acetate, methyl propionate and ethyl propionate, or one or more of linear ethers such as ethyl ether, bis(2-fluoroethyl) ether and bis(2,2-difluoroethyl) ether.

[0061] According to a specific embodiment of the present disclosure, the electrolyte may further comprise additional additives. The additional additives are selected from at least one of vinylene carbonate (VC), fluoroethylene carbonate (FEC), ethylene sulfate (DTD), 1,3-propanesultone (PS), ethylene sulfite (ES), or lithium difluorobis(oxalato)phosphate (LiODFP). A mass fraction of the conventional additives in the electrolyte ranges from 0.5% to 5%, for example, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5%.

[0062] It should be noted that conventional additives are those commonly used in engineering, which can be selected by a person skilled in the art according to their specific needs and are therefore not described in detail herein. The properties and advantages described for the aforementioned electrolyte additives are also applicable to the electrolyte and are therefore not described in detail herein.

[0063] According to a specific embodiment of the present disclosure, the battery further comprises an active material for the positive electrode. The active material of the positive electrode comprises at least one of the following: lithium iron phosphate material, LiCoO2 material, a lithium-rich manganese-based material (aLi2MnO3·(1-a)LiMO2), a LiNi x Co y Mn z O2 material, a lithium nickel manganese oxide (LiNi0.5Mn1.504) material or lithium manganese iron phosphate (LiFe b Mn 1-3PO4), where 0 ≤ a ≤ 1, 0 ≤ b ≤ 1, x + y + z = 1, and M comprises one of Ni, Co or Mn. Consequently, the cycle performance of the battery can be improved.

[0064] According to a specific embodiment of the present disclosure, the active material of the positive electrode comprises LiNi. x M 1-xO2 (M comprises at least one of Co or Mn, and 0.8 ≤ x ≤ 0.9). This high-nickel ternary material is a preferred material for the positive electrode in current and future automotive power batteries due to its advantages such as low cost, high energy density, high reversible capacity, and environmental friendliness. Furthermore, the combination of the aforementioned high-nickel ternary material and the electrolyte according to the present disclosure can further improve the high-voltage cycle stability of the battery and reduce battery gas generation. Specifically, x can be selected to be 0.8, 0.85, 0.9, etc.

[0065] A typical battery consists of a positive electrode plate, a negative electrode plate, an electrolyte, and a separator. During the charging / 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 electrode plates. The separator, positioned between the positive and negative electrode plates, primarily prevents a short circuit between them while allowing ions to flow through.

[0066] The positive electrode plate comprises a positive electrode current collector and a positive electrode active material layer arranged on at least one surface of the positive electrode current collector. The positive electrode active material layer comprises the positive electrode active material described above.

[0067] In some embodiments of the present disclosure, the positive electrode current collector may comprise a metal foil or a composite material positive electrode current collector. The metal foil may, for example, be an aluminum foil. The composite material positive electrode current collector may comprise a polymer material substrate layer and a metal layer formed on at least one surface of the polymer material substrate layer. For example, the composite material negative electrode current collector may be formed by depositing a metal material (for example, aluminum, aluminum alloys, nickel, and nickel alloys) on a polymer material substrate (for example, polypropylene (PP), polyethylene terephthalate (PET), and polybutylene terephthalate (PBT)).

[0068] In some embodiments of the present disclosure, the active material layer of the positive electrode may optionally further comprise a conductive agent. For example, the conductive agent may comprise at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, or carbon nanofibers.

[0069] In some embodiments of the present disclosure, the active material layer of the positive electrode may optionally further comprise a binder. The binder may, for example, comprise at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, or fluorinated acrylate resin.

[0070] In some embodiments of the present disclosure, the positive electrode plate can be produced by the following method. The aforementioned components for producing the positive electrode plate, for example, the active material of the positive electrode, the conductive agent, and the 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 current collector of the positive electrode, followed by processes such as drying and cold calendering, and thus the positive electrode plate can be obtained.

[0071] The negative electrode plate comprises a negative current collector and a negative electrode active material layer arranged on at least one surface of the negative current collector. The negative electrode active material layer comprises a negative active material.

[0072] In some embodiments of the present disclosure, the negative electrode current collector can be a metal foil or a composite material current collector. For example, a copper foil can be used as the metal foil. The composite material current collector can comprise a polymer material substrate layer and a metal layer formed on at least one surface of the polymer material substrate layer. The composite material current collector can be formed by depositing a metal material (for example, copper, copper alloys, nickel, and nickel alloys) onto a polymer material substrate (for example, substrates of polypropylene (PP), polyethylene terephthalate (PET), and polybutylene terephthalate (PBT)).

[0073] In some embodiments of the present disclosure, the active material of the negative electrode can be a silicon-containing battery active material known in the art. For example, the active material of the negative electrode can be at least one of elemental silicon, a silicon-oxygen compound, a silicon-carbon compound, or CVD silicon, and is used in combination with natural graphite, synthetic graphite, soft carbon, hard carbon, mesocarbon microspheres, and nanocarbon. The mass fraction of silicon in the active material of the negative electrode ranges from 5% to 8%.

[0074] In some embodiments of the present disclosure, the negative active material layer may optionally further comprise a binder. The binder may comprise at least one of 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).

[0075] In some embodiments of the present disclosure, the active material layer of the negative electrode may optionally further comprise a conductive agent. The conductive agent may comprise at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, or carbon nanofibers.

[0076] 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)).

[0077] In some embodiments of the present disclosure, the negative electrode plate can be produced by the following method. The aforementioned components for producing the negative electrode plate, for example, the active material of the negative electrode, the conductive agent, the binder, and any other components, are dissolved in a solvent (for example, deionized water) to form a negative electrode slurry; and the negative electrode slurry is applied as a layer to the current collector of the negative electrode, followed by processes such as drying and cold calendering, and thus the negative electrode plate can be obtained.

[0078] The present disclosure does not impose any particular restrictions regarding the type of separator; and any known separator with a porous structure that exhibits good chemical and mechanical stability may be selected.

[0079] In some embodiments of the present disclosure, the separator material may comprise at least one of glass fiber, nonwoven fabric, polyolefin film, aromatic polyamide film, polytetrafluoroethylene film, or polyethersulfone film. 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, and 12 µm.

[0080] In some embodiments of the present disclosure, the battery is a cylindrical battery comprising the aforementioned electrolyte, active material of the positive electrode and active material of the negative electrode.

[0081] In some embodiments of the present disclosure, the cylindrical battery is a cylindrical 18650 battery and has an energy density ranging from 230 Wh / kg to 250 Wh / kg.

[0082] One active material of the positive electrode of the cylindrical battery is LiNi. x M 1-x O2, where M includes at least one of Co or Mn, and 0.8 ≤ x ≤ 0.9.

[0083] The negative electrode plate comprises a collector for negative electrode current and an active material layer of the negative electrode, arranged on at least one surface of the collector for negative electrode current. The mass fraction of silicon in the active material layer of the negative electrode ranges from 5% to 8%.

[0084] The aforementioned electrolyte exhibits good compatibility with the active material of the positive electrode and the active material of the negative electrode, which is advantageous for improving the electrochemical performance of the battery.

[0085] If specific techniques or conditions are not specified in examples, the techniques or conditions described in the literature on the subject or in product instructions should be followed. All reagents and instruments used for which no manufacturers are indicated are commercially available, conventional products. Example 1 1. Preparation of the electrolyte: EC and DMC in a mass ratio of 3:7 were used as solvents. After mixing, lithium salts (LiPF6 and LiFSI), electrolyte additives, vinylene carbonate (VC), and 1,3-propanesultone (PS) were added according to their mass fractions, and the mixture was blended uniformly to obtain the electrolyte. 2. Production of the positive electrode plate: LiNi 0,8 Co 0,8 Mn 0,1O2 as the active material of the positive electrode, the conductive agent SuperP (conductive carbon black), carbon nanotubes, and the binder PVDF (polyvinylidene fluoride) were mixed in a mass ratio of 94 : 2.5 : 1.5 : 2 and vacuum-stirred until the mixture exhibited a specific viscosity and uniform flowability. The slurry was then uniformly applied to both sides of an aluminum foil, followed by drying at 85 °C, cold calendering, edge trimming, cutting of the sheets, longitudinal separation, and vacuum drying at 85 °C for 10 hours. After welding on tabs, the positive electrode plate had an areal density of 30 mg / cm². 2 manufactured. 3. Production of the negative electrode plate: CVD silicon, graphite material, conductive agent SuperP (conductive carbon black, SP), thickener CMC (sodium carboxymethylcellulose), and binder SBR (styrene-butadiene rubber emulsion) were thoroughly mixed in a mass ratio of 7.5 : 87 : 2 : 1.5 : 2 to form a uniform slurry. The slurry was applied to both sides of an aluminum foil, followed by drying at 85 °C, cold calendering, edge trimming, cutting of the sheets, longitudinal separation, and vacuum drying at 85 °C for 12 hours. After welding on tabs, the negative electrode plate had an areal density of 12 mg / cm². 2 receive. 4. Separator: A porous polyethylene polymer film with a thickness of 9 µm was used as a substrate, and an adhesive coating of 2 µm was applied to both sides of the substrate. 5. Battery Manufacturing: The positive electrode plate, separator, and negative electrode plate were wound together to form an electrode coil. The separator was placed between the positive and negative electrode plates to provide insulation. The electrode coil was placed in a housing (made of nickel-plated stainless steel), and the negative electrode current collector was laser-welded to the housing. After drying, the electrolyte was injected. Following a settling period, the cell underwent formation by charging to 4.2 V at 0.1 C and 45 °C, followed by capacity classification and other downstream processes, thus completing battery manufacturing.

[0086] The processes for manufacturing the lithium-ion batteries of Examples 2 to 28 and all comparison examples were the same as those of Example 1, with one difference in the electrolyte compositions, as shown in Table 1. Additive 2-1 was tripropargyl phosphate, additive 2-2 was propyl bis(2-propynyl) phosphate, and additive 2-3 was ethyl bis(2-propynyl) phosphate.

[0087] Example 29 differed from Example 1 in the material of the positive electrode. In Example 29, the active material of the positive electrode was lithium iron phosphate (LiFePO4, LFP), with the mixing ratio LFP : SP : PVDF = 95 : 2.5 : 2.5 in the given slurry, and the charging / discharging voltage range of the battery was from 2 V to 3.65 V. [Table 1] First additive Second additive Third additive Lithium salt (wt%) Amount of first additive (wt%) Amount of second additive (wt.%) Mass ratio of the first additive to the second additive Amount of third additive (wt%) Mass ratio of the first additive to the second and third additives Example 1 1-1 2-1 / 10% LiPF6 + 2% LiFSI 0,05 % 0,10 % 1 : 2 / / Example 2 1-1 2-1 / 10% LiPF6 + 2% LiFSI 0,10 % 0,10 % 1 : 1 / / Example 3 1-1 2-1 / 10% LiPF6 + 2% LiFSI 0,20 % 0,10 % 1 : 0,5 / / Example 4 1-1 2-1 / 10% LiPF6 + 2% LiFSI 0,50 % 0,10 % 1 : 0,2 / / Example 5 1-1 2-1 / 10% LiPF6 + 2% LiFSI 0,80 % 0,10 % 1 : 0,125 / / Example 6 1-1 2-1 / 10% LiPF6 + 2% LiFSI 1,00 % 0,10 % 1:0,1 / / Example 7 1-1 2-1 / 10% LiPF6 + 2% LiFSI 2,00 % 0,10 % 1:0,05 / / Example 8 1-1 2-1 / 10% LiPF6 + 2% LiFSI 5,00 % 0,10 % 1:0,02 / / Example 9 1-1 2-1 / 10% LiPF6 + 2% LiFSI 0,50 % 0,05 % 10:1 / / Example 10 1-1 2-1 / 10% LiPF6 + 2% LiFSI 0,50 % 0,20 % 5:2 / / Example 11 1-1 2-1 / 10% LiPF6 + 2% LiFSI 0,50 % 0,30 % 5:3 / / Example 12 1-1 2-1 / 10% LiPF6 + 2% LiFSI 0,50 % 0,40 % 5:4 / / Example 13 1-1 2-1 / 10% LiPF6 + 2% LiFSI 0,50 % 0,50 % 1:1 / / Example 14 1-1 2-1 / 10% LiPF6 + 2% LiFSI 0,50 % 1,00 % 1:2 / / Example 15 1-1 2-1 / 10% LiPF6 + 2% LiFSI 0,025% 0,05 % 1:2 / / Example 16 1-1 2-1 / 10% LiPF6 + 2% LiFSI 0,05 % 0,01 % 1:0,2 / / Example 17 1-1 2-1 / 10% LiPF6 + 2% LiFSI 6% 1,5 % 4:1 / / Example 18 1-1 2-2 / 10% LiPF6 + 2% LiFSI 0,50 % 0,10 % 1:2 / / Example 19 1-1 2-3 / 10% LiPF6 + 2% LiFSI 0,50 % 0,10 % 1:2 / / Example 20 1-1 2-1 3-4 10% LiPF6 + 2% LiFSI 0,50 % 0,10 % 5:1 0,01% 1:0,2:0,02 Example 21 1-1 2-1 3-4 10% LiPF6 + 2% LiFSI 0,50 % 0,10 % 5:1 0,05% 1:0,2:0,1 Example 22 1-1 2-1 3-4 10% LiPF6 + 0,50 % 0,10 % 5:1 0,08 % 1 : 0,2 : 0,16 2% LiFSI Example 23 1-1 2-1 3-4 10% LiPF6 + 2% LiFSI 0,50% 0,10% 5:1 0,1% 1:0,2:0,2 Example 24 1-1 2-1 3-4 10% LiPF6 + 2% LiFSI 0,50% 0,10% 5:1 0,2% 1:0,2:0,4 Example 25 1-1 2-1 3-4 10% LiPF6 + 2% LiFSI 0,50% 0,10% 5:1 0,5% 1:0,2:1 Example 26 1-1 2-1 3-1 10% LiPF6 + 2% LiFSI 0,50% 0,10% 5:1 0,05% 1:0,2:0,1 Example 27 1-1 2-1 3-2 10% LiPF6 + 2% LiFSI 0,50% 0,10% 5:1 0,05% 1:0,2:0,1 Example 28 1-1 2-1 3-3 10% LiPF6 + 2% LiFSI 0,50% 0,10% 5:1 0,05% 1:0,2:0,1 Example 29 1-1 2-1 / 10% LiPF6 + 2% LiFSI 0,50 % 0,10 % 1:2 / / Example 30 1-1 2-1 / 10% LiPF6 + 2% LiFSI 0,05 % 0,25 % 1:5 / / Example 31 1-1 2-1 3-4 10% LiPF6 + 2% LiFSI 0,50 % 0,10 % 5:1 1,00% 1:0,2:2 Example 32 1-1 2-1 3-4 10% LiPF6 + 2% LiFSI 0,50% 1,50% 1:3 1,00% 1:3:2 Comparative example 1 / 2-1 3-4 10% LiPF6 + 2% LiFSI / 0,10% / 0,05% / Comparative example 2 1-1 / 3-4 10% LiPF6 + 2% LiFSI 0,50% / / 0,05 % / Comparative example 3 1-1 / / 10% LiPF6 + 2% LiFSI 0,50% / / / / Comparative example 4 / 2-1 / 10% LiPF6 + 2% LiFSI / 0,05 % / / / Comparative example 5 / / 3-4 10% LiPF6 + 2% LiFSI / / / 0,05% / Comparative example 6 / / / 10% LiPF6 + 2% LiFSI / / / / /

[0088] The forward slash ( / ) means "not added".

[0089] The cycle performance and the negative electrode interface of the lithium-ion batteries obtained in the examples and comparison examples were characterized. The characterization results are shown in Table 2. 1. Cycle test: At 25 °C, the battery was charged to 4.3 V at a constant current of 1.5 C and then discharged to a cutoff current of 0.05 C at a constant voltage of 4.3 V. The battery was then discharged to a constant current of 1.0 C. The charge and discharge process was repeated for 500 cycles. The discharge capacities of the 500th cycle and the first cycle were recorded, and the capacity retention rate was determined as the ratio of the two. 2. Interface Characterization: At 25 °C, the battery was charged to 4.3 V at a constant current of 1.5 C and then charged to a cutoff current of 0.05 C at a constant voltage of 4.3 V. The battery was then discharged to a constant current of 1.0 C. The charging and discharging process was repeated for 100 cycles. The discharge capacities of the 100th cycle and the first cycle were recorded, and the capacity retention rate was determined as the ratio of the two. After 100 cycles, the battery was disassembled, and portions of the negative electrode were examined using a scanning electron microscope. Based on the interface flatness, the results were classified into four levels: L1, L2, L3, and L4. Specifically: L1 (Excellent): The electrode plate remained generally flat, with uniform particle size and no obvious large cracks. L2 (Good): The electrode plate maintained good overall flatness, without significant particle separation boundaries, but with some obviously locally present large cracks. L3 (Moderate): The particle boundaries were clear and not narrow. L4 (Deficient): The surface of the electrode plate was obviously lithium-plated and heavily powdered, and during disassembly there was significant film detachment and powder leakage. [Table 2] Capacity maintenance rate after 500 cycles Indicators of the state of the interface Example 1 90,17% L3 Example 2 92,68% L1 Example 3 92,87% L1 Example 4 93,56% L1 Example 5 93,21% L1 Example 6 92,59% L1 Example 7 90,46% L2 Example 8 90,19% L2 Example 9 90,31% L2 Example 10 92,13% L1 Example 11 91,70% L1 Example 12 90,35% L2 Example 13 90,25% L2 Example 14 90,02% L2 Example 15 87,54% L3 Example 16 86,98% L3 Example 17 87,02% L3 Example 18 90,04% L2 Example 19 90,09% L2 Example 20 93,28% L1 Example 21 93,71% L1 Example 22 93,98% L1 Example 23 92,02 % L2 Example 24 91,75% L2 Example 25 91,16% L2 Example 26 94,12% L1 Example 27 93,17% L1 Example 28 94,13% L1 Example 29 96,21% L1 Example 30 89,21% L3 Example 31 89,03% L3 Example 32 88,87 % L4 Comparison example 1 82,95 % L4 Comparison example 2 84,32 % L4 Comparison example 3 78,01 % L4 Comparison example 4 79,12 % L4 Comparison example 5 76,91 % L4 Comparison example 6 75,98 % L4 Analysis of the experimental results:

[0090] As can be seen from Examples 1 to 9 and 30, the first and second additives in the examples of the present disclosure were added to the lithium-ion batteries in combination, resulting in a high degree of interfacial flatness and improved cycle performance. Compared to Examples 1 to 19, an increased amount of the second additive was used in Example 30, such that the ratio of the first additive to the second additive was greater than 1 : (0.1 to 2). As a result, the adsorption mode of the second additive changed from horizontal adsorption to vertical adsorption, which hindered lithium-ion transport, reduced the uniformity of the interfacial film, and led to increased impedance and a greater tendency for pulverization of the negative electrode surface.The test results for this example were therefore inferior to those of examples 1 to 19, as also verified by the test results in Table 2. Nevertheless, the test results for example 30 remained superior to those of the comparison examples 1 to 6, indicating that the combined use of the first and second additives in lithium-ion batteries in the present disclosure still offers clear advantages with regard to surface flatness and cycle performance.

[0091] As can be seen from Examples 20 to 28, 31, and 32, when the third additive was added to the electrolyte, the interfacial flatness and cycle performance of the battery were further improved. In contrast to Examples 20 to 28, Example 31 used an increased amount of the third additive, resulting in a ratio between the first, second, and third additives higher than 1 : (0.1 to 2) : (0.1 to 1). Consequently, too many molecules did not aggregate normally and were adsorbed at the interface, leading to an increased number of free molecules in the electrolyte and a reaction mechanism dominated by typical redox reactions, producing gases such as CO2 and O2. Therefore, the test results for Example 31 were inferior to those of Examples 20 to 28, as also verified by the test results in Table 2.Example 32, in which the amounts of the second and third additives were increased simultaneously, similarly shows test results that were inferior to those of Examples 20 to 28, which is consistent with the preceding analysis and is also verified by the test results in Table 2. Nevertheless, the test results of Examples 31 to 32 remained superior to those of the comparison examples 1 to 6, indicating that the combined use of the first, second, and third additives in lithium-ion batteries in the present disclosure still provides clear advantages with respect to surface flatness and cycle performance.

[0092] Examples 1 to 29 show that within the different systems of materials of the positive electrode, the combined use of the first and second additive results in a higher degree of flatness at the interface of the second electrode and improved cycle performance.

[0093] Compared to examples, the solutions in comparative examples 1 to 6 did not improve either the surface flatness or the cycle life of the battery. Comparative example 6 corresponded to a solution without any additives. Comparative examples 1 to 5 showed some improvement in cycle life compared to comparative example 6, but the results were still worse than in the examples of the present disclosure.

[0094] The effects of the different types and proportions of additives on battery performance were tested in examples and comparative examples in the present disclosure and specifically analyzed as follows: (1) Compared with Examples 15 to 21, in Comparative Example 1 only the second and third additives were used, but not the first additive. The second additive exhibits a stronger tendency towards vertical adsorption, which hindered lithium-ion transport and reduced the uniformity of the interfacial film, leading to increased impedance. This also affected the third additive, as fewer sites were available for polymerization and adsorption, resulting in many free molecules in the electrolyte that could undergo side reactions at the interface, thereby damaging the interface flatness and reducing the battery's lifetime.

[0095] Similarly, comparison example 4, in which only the second additive was used, also showed damaged surface flatness and a reduced cycle life of the battery compared to examples 1 to 28.

[0096] (2) Compared with Examples 20 to 28, in Comparative Example 2 only the first and third additives were used, but not the second additive. The mechanism of RF attack on the carbon-carbon triple bond to obtain LiF and the interfacial adsorption film could not occur and caused a rapid increase in acidity, which affected the stability of the positive and negative electrodes and reduced the cycle life of the battery.

[0097] Similarly, comparison example 3, in which only the first additive was used, also showed damaged surface flatness and a reduced cycle life of the battery compared to examples 1 to 20, 22 and 24.

[0098] Similarly, comparison example 5, in which only the third additive was used, also showed damaged surface flatness and a reduced cycle life of the battery compared to examples 15 to 21.

[0099] In summary, the combined use of the first and second additives according to the present disclosure results in improved battery performance compared to cases where neither the first nor the second additive is added. Furthermore, the addition of the third additive can further enhance the technical effect.

[0100] References in the description to “an embodiment”, “some embodiments”, “an example”, “a specific example”, or “some examples” mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. The occurrence of the foregoing expressions at different points in this description 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, different embodiments or examples and features of different embodiments or examples described in the description can be combined by the person skilled in the art without mutual contradiction, provided they do not contradict each other.

[0101] 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] CH 202510094491.9

[0001]

Claims

[1] Battery, comprising: an electrolyte comprising a first additive and a second additive, wherein the first additive has a structure represented by formula 1 and wherein the second additive comprises at least one of tripropargyl phosphate, propyl bis(2-propynyl) phosphate or ethyl bis(2-propynyl) phosphate; and a negative electrode plate comprising a negative electrode active material, wherein the negative electrode active material comprises the element silicon, [2] Battery according to claim 1, wherein the mass ratio of the first additive to the second additive is 1 : (0.1 to 2) and preferably 1 : (0.1 to 1). [3] Battery according to claim 1, further comprising a third additive, wherein the third additive has a structure represented by formula 2, where: R 12 , R 13 and R 14each are independently selected from H, C1- to C6-alkyl or C2- to C4-alkenyl, provided that R 12 , R 13 and R 14 not all are H at the same time and that at least one of R 12 , R 13 or R 14 includes a carbon-carbon double bond; or R 12 and one at R 12 bonded atom together form C2 to C4 alkenyl and R 13 and R 14 each are independently selected from H, C1- to C6-alkyl or C2- to C4-alkenyl; or R 12 and R 13 and to R 12 and R 13 bonded atoms jointly form C3 to C8 cycloalkenyl and R 14 H is. [4] Battery according to claim 3, wherein: R 12 , R 13 and R 14 each are independently selected from H, C1- to C4-alkyl or C2- to C4-alkenyl, provided that R 12 , R 13 and R 14not all are H at the same time and that at least one of R 12 , R 13 or R 14 includes a carbon-carbon double bond; or R 12 and one at R 12 The bonded atom together form C2-C4 alkenyl, and R 13 and R 14 are each independently selected from C1- to C4-alkyl or C2- to C4-alkenyl; or R 12 and R 13 and to R 12 and R 13 bonded atoms jointly form C7 to C8 cycloalkenyl and R 14 H is. [5] Battery according to claim 3, wherein: R 12 , R 13 and R 14 each are independently selected for H, C1-alkyl or C2-alkenyl, provided that R 12 , R 13 and R 14 not all are H at the same time and that at least one of R 12 , R 13 or R 14 includes a carbon-carbon double bond; or R 12 and one at R 12 bonded atom together form C2-alkenyl and R 13 and R 14 each are independently selected from C1-alkyl or C2-alkenyl; or R 12 and R 13 and to R 12 and R 13 bonded atoms form C7-cycloalkenyl and R 14 H is. [6] Battery according to claim 3, wherein the third additive comprises at least one of the following compounds: [7] Battery according to any one of claims 3 to 6, wherein the mass ratio of the first additive to the second additive and to the third additive is 1 : (0.1 to 2) : (0.1 to 1) and preferably 1 : (0.1 to 1) : (0.1 to 0.2). [8] Battery according to any one of claims 1 to 7, comprising an electrolyte, wherein, based on a total mass of the electrolyte, a mass fraction of the first additive ranges from 0.05% to 5% and preferably from 0.1% to 1%. [9] Battery according to claim 8, wherein, based on the total mass of the electrolyte, a mass fraction of the second additive ranges from 0.05% to 1% and preferably from 0.1% to 0.4%. [10] Battery according to claim 8, wherein, based on the total mass of the electrolyte, a mass fraction of the third additive ranges from 0.01% to 0.5% and preferably from 0.05% to 0.1%. [11] Battery according to claim 8, wherein the electrolyte further comprises a lithium salt, the lithium salt comprising at least one of lithium hexafluorophosphate or lithium bis(fluorosulfonyl)imide. [12] Battery according to claim 11, wherein the lithium salt comprises lithium hexafluorophosphate and lithium bis(fluorosulfonyl)imide, wherein the mass ratio of lithium hexafluorophosphate to lithium bis(fluorosulfonyl)imide is (2 to 5) :

1. [13] Battery according to any one of claims 1 to 12, further comprising an active material of the positive electrode, wherein the active material of the positive electrode is at least one of lithium iron phosphate material, LiCoO2 material, aLi2MnO3·(1-a)LiMO2 material, LiNi x Co y Mn z O2 material, LiNi 0,5 Mn 1,5 O4 material or LiFe b Mn 1-b PO4 material, where 0 ≤ a ≤ 1; 0 ≤ b ≤ 1; x + y + z = 1; and M comprises at least one of Ni, Co or Mn. [14] Battery according to any one of claims 1 to 13, wherein the battery is a cylindrical battery. [15] Battery according to claim 14, wherein: the cylindrical battery is a cylindrical 18650 battery and has an energy density ranging from 230 Wh / kg to 250 Wh / kg; an active material of the positive electrode of the cylindrical LiNi battery x M 1-xO2 is where M comprises at least one of Co or Mn and 0.8 ≤ x ≤ 0.9; and the negative electrode plate comprises a collector for negative electrode current and an active material layer of the negative electrode, arranged on at least one surface of the collector for negative electrode current, wherein a mass fraction of silicon in the active material layer of the negative electrode ranges from 5% to 8%.

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