Lithium ion battery and electric device using the same

Abstract

The application provides a lithium ion battery and an electric device, which comprises a positive electrode, a negative electrode and an electrolyte, the negative electrode comprises a negative electrode active layer, the negative electrode active layer comprises a negative electrode active material, the positive electrode comprises a positive electrode active layer, the positive electrode active layer comprises carbon nanotubes and a positive electrode active material, and the positive electrode active material is doped with titanium elements; the electrolyte comprises a solvent, an additive and an electrolyte salt, the first solvent comprises fluoroethylene carbonate, the second solvent comprises ethyl butyrate, the first additive comprises ethylene glycol bis (propyl cyanide) ether, and the second additive comprises a lithium salt additive; the lithium ion battery satisfies: 0.84 <= (A+C+D)*10000 / X <= 7.88; 0.05 <= (C+D)*100 / (B+W) <= 3.16; 3.23 <= (C+H) / B <= 97.30; and 5 <= A <= 30, 5 <= B <= 30, 0.5 <= C <= 4, 0.3 <= D <= 3, 0.5 <= H <= 6, 300 <= X <= 1200, 1 <= W <= 30; the lithium ion battery provided by the application improves the thermal shock safety and high-low temperature cycle performance through the above-mentioned multi-component cooperation and the relationship formula satisfied by the multi-components.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a lithium-ion battery and an electrical device thereof. Background Technology

[0002] In the field of electrochemical energy storage technology, lithium-ion batteries are the core power source for portable electronic devices, electric vehicles, and large-scale energy storage systems. Their application environments are becoming increasingly harsh and diverse. This requires batteries to have high intrinsic safety, high efficiency in a wide temperature range (especially at low temperatures), and long-term cycle stability. However, there are certain contradictions and trade-offs among these key performance characteristics. For example, in order to improve low-temperature discharge performance and rate capability, the introduction of low-viscosity, low-melting-point ester solvents (such as linear carboxylic acid esters) into the electrolyte can reduce ion migration resistance, but they have poor thermal and electrochemical stability. Under high temperature or thermal abuse conditions, they are prone to decomposition to generate gas and cause thermal runaway, which impairs safety performance. On the other hand, common strategies to enhance thermal safety, such as building a stable interface film (CEI) on the positive electrode surface or introducing physical thermal barriers (such as high thermal conductivity fillers), may increase the lithium-ion cross-interface transport impedance, which restricts low-temperature performance and long-term cycle life.

[0003] Existing technologies mostly focus on optimizing single components or single properties, lacking a scheme to synergistically optimize electrolyte chemistry, electrode material bulk modification, and electrode structural characteristics. Although existing research has proposed the improvement effect of fluoroethylene carbonate (FEC) on the SEI film of the negative electrode and the enhancement of positive electrode stability by polynitrile additives, it has not correlated these effects with the low-viscosity solvents coexisting in the electrolyte, the conductive / thermal network in the positive electrode, and the active interface of the negative electrode. For example, when titanium (Ti) doping is used to stabilize the structure of high-nickel positive electrode materials, the quantitative relationship between its optimal doping amount and the total amount of specific film-forming components in the electrolyte has not been clearly given. Therefore, the above optimization methods are difficult to fundamentally solve the problem of balancing the overall performance of batteries, which is not conducive to the comprehensive improvement of lithium-ion battery thermal shock safety, low-temperature performance, and high-temperature cycle stability. Summary of the Invention

[0004] To address the technical problem of the difficulty in synergistically optimizing thermal shock safety and high and low temperature cycling performance in existing lithium-ion batteries, a lithium-ion battery and power device are provided.

[0005] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: On one hand, the present invention provides a lithium-ion battery, including a positive electrode, a negative electrode and an electrolyte, wherein the negative electrode includes a negative electrode active layer and the negative electrode active layer includes a negative electrode active material, the positive electrode includes a positive electrode active layer and the positive electrode active layer includes carbon nanotubes and a positive electrode active material, and the positive electrode active material is doped with titanium. The electrolyte comprises a solvent, an additive, and an electrolyte salt. The solvent comprises a first solvent and a second solvent. The additive comprises a first additive and a second additive. The first solvent comprises fluoroethylene carbonate (FEC), the second solvent comprises ethyl butyrate (EB), the first additive comprises ethylene glycol bis(propionitrile) ether (DENE), and the second additive comprises lithium salt additives. The lithium-ion battery meets the following conditions: 0.84≤(A+C+D)*10000 / X≤7.88; 0.05≤(C+D)*100 / (B+W)≤3.16; 3.23≤(C+H) / B≤97.30; Furthermore, 5≤A≤30, 5≤B≤30, 0.5≤C≤4, 0.3≤D≤3, 0.5≤H≤6, 300≤X≤1200, and 1≤W≤30; Wherein, A% is the mass percentage of the first solvent in the electrolyte; B% represents the mass percentage of the second solvent in the electrolyte; C% represents the mass percentage of the first additive in the electrolyte; D% represents the mass percentage of the second additive in the electrolyte; H% represents the mass percentage of carbon nanotubes in the positive electrode active layer; X represents the content of titanium in the positive electrode active material, in ppm; W represents the specific surface area of ​​the negative electrode active material, in m². 2 / g.

[0006] Optionally, the lithium-ion battery satisfies the following conditions: 1.00≤(A+C+D)*10000 / X≤6.00.

[0007] Optionally, the lithium-ion battery satisfies the following conditions: 0.10≤(C+D)*100 / (B+W)≤2.61.

[0008] Optionally, the lithium-ion battery satisfies the following conditions: 3.47≤(C+H) / B≤40.40.

[0009] Optionally, the lithium-ion battery satisfies one of the following conditions: (1) 10 ≤ A ≤ 25; (2) 10≤B≤25; (3) 1≤C≤3; (4) 0.5≤D≤2; (5) 1≤H≤5; (6) 500≤X≤1000; (7) 4≤W≤20.

[0010] Optionally, the lithium salt additive includes one or more of lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium di(oxalate)borate, lithium difluorophosphate, lithium di(oxalate)borate, and lithium tetrafluoroborate.

[0011] Optionally, the electrolyte salt includes lithium hexafluorophosphate.

[0012] Optionally, the positive electrode active material includes transition metal lithium oxide; The chemical formula of the transition metal lithium oxide is Li 1+x Ni y Co z M (1-y-z) O2, where -0.1≤x≤1; 0≤y≤1, 0≤z≤1, and 0≤y+z≤1; M is selected from one or more of Mg, Zn, Ga, Ba, Al, Cr, Sn, V, Mn, Sc, Nb, Mo, and Zr.

[0013] Optionally, the negative electrode active material includes one or more of graphite, silicon-carbon composite materials, and lithium metal materials.

[0014] On the other hand, the present invention provides an electrical device including the aforementioned lithium-ion battery.

[0015] The beneficial effects of this application are as follows: The lithium-ion battery provided in this application uses fluoroethylene carbonate as the first solvent to construct a stable negative electrode SEI film, ethyl butyrate as the second solvent to reduce electrolyte viscosity and ensure low-temperature ion transport, ethylene glycol bis(propionitrile) ether as the first additive to form a dense positive electrode CEI film, and lithium salt additives as the second additive to optimize the inorganic components at the interface. Combined with titanium doping in the positive electrode active material to enhance the stability of the positive electrode phase structure, and carbon nanotubes in the positive electrode active layer to construct a three-dimensional conductive / thermal conductive network, the relationship between the parameters of each component is adjusted to form a relationship where 0.84≤(A+C+D)*10000 / X≤7.88, which can balance the interfacial film formation ability and the stability of the positive electrode structure. The formula 0.05≤(C+D)*100 / (B+W)≤3.16 better adapts to the additive dosage and low-temperature kinetic requirements, ensuring interface integrity without hindering ion transport. The formula 3.23≤(C+H) / B≤97.30 suppresses the risk of thermal decomposition of the second solvent through the dual thermal stabilization mechanism of the first additive and carbon nanotubes. Furthermore, the limited range of each parameter avoids performance degradation caused by excessive or insufficient single component. This achieves multi-dimensional synergy of interface regulation, electrode structure-level transport optimization, and bulk-level stability enhancement, simultaneously improving the thermal shock safety, low-temperature cycle performance, and high-temperature cycle performance of lithium-ion batteries. Detailed Implementation

[0016] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0017] This invention provides a lithium-ion battery, comprising a positive electrode, a negative electrode, and an electrolyte. The negative electrode comprises a negative electrode active layer, which comprises a negative electrode active material. The positive electrode comprises a positive electrode active layer, which comprises carbon nanotubes and a positive electrode active material. The positive electrode active material is doped with titanium. The electrolyte includes a solvent, an additive, and an electrolyte salt. The solvent includes a first solvent and a second solvent. The additive includes a first additive and a second additive. The first solvent includes fluoroethylene carbonate, the second solvent includes ethyl butyrate, the first additive includes ethylene glycol bis(propionitrile) ether, and the second additive includes lithium salt additives. The lithium-ion battery meets the following conditions: 0.84≤(A+C+D)*10000 / X≤7.88; 0.05≤(C+D)*100 / (B+W)≤3.16; 3.23≤(C+H) / B≤97.30; Furthermore, 5≤A≤30, 5≤B≤30, 0.5≤C≤4, 0.3≤D≤3, 0.5≤H≤6, 300≤X≤1200, and 1≤W≤30; Wherein, A% is the mass percentage of the first solvent in the electrolyte; B% represents the mass percentage of the second solvent in the electrolyte; C% represents the mass percentage of the first additive in the electrolyte; D% represents the mass percentage of the second additive in the electrolyte; H% represents the mass percentage of carbon nanotubes in the positive electrode active layer; X represents the content of titanium in the positive electrode active material, in ppm; W represents the specific surface area of ​​the negative electrode active material, in m². 2 / g.

[0018] It should be noted that in this application, fluoroethylene carbonate (FEC) is used to construct a stable negative electrode SEI film, solving the problems of easy damage and numerous side reactions at the negative electrode interface during high and low temperature cycling; ethyl butyrate (EB) reduces the viscosity of the electrolyte, ensuring rapid lithium ion transport at low temperatures and solving the problem of high ion migration resistance at low temperatures; ethylene glycol bis(propionitrile) ether (DENE) forms a dense positive electrode CEI film, inhibiting positive electrode electrolyte oxidation and metal ion dissolution; lithium salt additives optimize the inorganic composition of the interface film, improve the ionic conductivity and mechanical strength of the interface film, and compensate for the interface performance defects of a single film-forming additive.

[0019] Titanium doping in the positive electrode active material can enhance the stability of the bulk phase structure of the positive electrode, suppress lattice phase transitions and oxygen loss under high pressure or high temperature, and solve the problem of cycle decay caused by the instability of the intrinsic structure of the positive electrode. Carbon nanotubes (CNTs) construct a three-dimensional conductive or thermally conductive network, which not only improves the electronic conductivity of the electrode, but also enhances the thermal conductivity and mechanical integrity, solves the risk of thermal runaway caused by poor heat dissipation and low mechanical strength of the electrode, and at the same time makes up for the deficiency that titanium doping can only optimize the bulk phase structure and cannot improve the electrode transmission performance.

[0020] The lithium-ion battery provided in this application uses fluoroethylene carbonate as the first solvent to construct a stable negative electrode SEI film, ethyl butyrate as the second solvent to reduce electrolyte viscosity and ensure low-temperature ion transport, ethylene glycol bis(propionitrile) ether as the first additive, whose multiple cyano (-CN) functional groups have a strong coordination ability to transition metal ions on the positive electrode surface, enabling preferential reaction to form a dense positive electrode CEI film, lithium salt additives as the second additive to optimize the inorganic components of the interface, and titanium doping in the positive electrode active material to modify and enhance the stability of the positive electrode phase structure. Furthermore, carbon nanotubes in the positive electrode active layer construct a three-dimensional conductive / thermal conductive network. Simultaneously, by controlling the relationship between the parameters of each component, a relational formula is formed, where 0.84≤(A+C+D)*10000 / X≤ 7.88 can balance the interfacial film-forming ability and the stability of the cathode structure, avoiding insufficient interfacial protection or excessive impedance; the relationship 0.05≤(C+D)*100 / (B+W)≤3.16 can better adapt to the additive dosage and low-temperature kinetic requirements, ensuring the integrity of the interface without hindering ion transport; the relationship 3.23≤(C+H) / B≤97.30 suppresses the risk of thermal decomposition of the second solvent through the dual thermal stabilization mechanism of the first additive and carbon nanotubes, and the limited range of each parameter avoids the performance degradation caused by the excess or deficiency of a single component, thereby achieving multi-dimensional synergy of interface regulation, electrode structure-level transport optimization and bulk-level stability enhancement, and simultaneously improving the thermal shock safety, low-temperature cycle performance and high-temperature cycle performance of lithium-ion batteries.

[0021] Furthermore, the mass percentage of the first solvent in the electrolyte is 5 ≤ ​​A ≤ 30%, ensuring that the first solvent, fluoroethylene carbonate, has a sufficient amount to construct a stable negative electrode SEI film. Previous experiments have shown that if the mass percentage of the first solvent in the electrolyte is less than 5%, the negative electrode SEI film formation and high-voltage stability are insufficient; if it is greater than 30%, the electrolyte viscosity is too high, the ionic conductivity decreases, and the risk of side reactions on the positive electrode side increases. The mass percentage of the second solvent in the electrolyte is 5 ≤ ​​B ≤ 30%, which allows the second solvent to... Ethyl butyrate fully utilizes its low-temperature viscosity-reducing effect. However, if the content is below 5%, its effect on improving low-temperature performance is limited; if it is above 30%, the thermal stability of the electrolyte is severely deteriorated, and the risk of thermal runaway increases dramatically. The mass percentage of the first additive in the electrolyte should be 0.5% ≤ C ≤ 4%. This helps ensure that the first additive, ethylene glycol bis(propionitrile) ether, forms a dense positive electrode CEI film without generating excessively high interfacial resistance. If the content is below 0.5%, the positive electrode CEI film protection is insufficient, and thermal stability cannot be guaranteed; if it is above 4%, the CEI film impedance is too high, severely hindering ion transport. Impaired cycle life; the mass percentage of the second additive in the electrolyte should be 0.3 ≤ D ≤ 3% to optimize the inorganic components at the interface. If it is below 0.3%, the synergistic optimization effect on the interface film is limited; if it is above 3%, it may increase the electrolyte viscosity and lead to uneven growth of the interface film; the mass percentage of carbon nanotubes in the positive electrode active layer should be 0.5 ≤ H ≤ 6% to enable the carbon nanotubes to effectively construct a three-dimensional conductive or thermally conductive network without clogging the electrode pores. If it is below 0.5%, an effective conductive / thermally conductive network cannot be formed. The improvement in safety is not significant; above 6%, it severely clogs electrode pores, hinders lithium-ion transport, and significantly increases impedance; the content of titanium in the positive electrode active material should be 300≤X≤1200, titanium doping fully strengthens the positive electrode phase structure, if below 300ppm, the structural stability effect is weak; above 1200ppm, it may introduce lattice defects or occupy lithium sites, reducing specific capacity and ion diffusion coefficient; the specific surface area of ​​the negative electrode active material should be 1≤W≤30, ensuring that the negative electrode has sufficient lithium-ion intercalation and deintercalation reaction sites, if below 1m 2 / g, insufficient reaction sites, slow kinetics at low temperatures; above 30m 2 / g, the side reactions are severe, which accelerates the consumption of active lithium and deteriorates thermal stability and cycle performance; The reasonable ranges of the above parameters are mutually compatible, which together constitute the synergy of lithium-ion battery electrolyte-positive electrode-negative electrode. This ensures that each component can perform its core function without degrading the performance of other components, thereby ensuring the synergistic improvement of battery thermal shock safety, low-temperature cycle performance and high-temperature cycle performance.

[0022] Furthermore, the mass percentage of the first solvent in the electrolyte includes, but is not limited to, 5%, 8%, 10%, 15%, 20%, 25%, or 30%. The mass percentage of the second solvent in the electrolyte includes, but is not limited to, 5%, 6%, 8%, 10%, 15%, 17%, 20%, 25%, or 30%. The mass percentage of the first additive in the electrolyte includes, but is not limited to, 0.5%, 0.8%, 1%, 2%, 2.5%, 3%, 3.8%, or 4%. The second additive has a mass percentage in the electrolyte including, but not limited to, 0.3%, 0.4%, 0.5%, 1%, 1.3%, 2%, 2.7%, or 3%. The mass percentage of carbon nanotubes in the positive electrode active layer includes, but is not limited to, 0.5%, 0.8%, 1%, 2%, 2.5%, 3%, 4%, 5%, 5.8%, or 6%. The content of titanium in the positive electrode active material includes, but is not limited to, 300ppm, 400ppm, 500ppm, 600ppm, 700ppm, 800ppm, 900ppm, 1000ppm, 1100ppm or 1200ppm. The specific surface area of ​​the negative electrode active material includes, but is not limited to, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 10%, 12%, 15%, 20%, 25%, 28%, or 30%.

[0023] Furthermore, the method for determining the titanium content doped in the positive electrode active material includes: A suitable amount of positive electrode active layer powder was precisely scraped from the prepared positive electrode. The sample was pretreated by microwave digestion with concentrated acid (a mixture of nitric acid and hydrofluoric acid). The titanium (Ti) content in the digestion solution was tested using inductively coupled plasma optical emission spectrometry (ICP-OES). The mass content of titanium in the positive electrode active material was calculated, and the unit was ppm.

[0024] Methods for determining the carbon nanotube content in the positive electrode active layer include: The material of the positive electrode active layer was scraped from the positive electrode, ground into a uniform powder, and accurately weighed. Thermogravimetric analysis (TGA) was used for testing. In a dry air atmosphere, the temperature was increased from room temperature to 900℃ at a rate of 10℃ / min. Carbon nanotubes (CNTs) underwent oxidative decomposition within a characteristic temperature range of 500-700℃. By analyzing the thermogravimetric (TG) curve, the percentage of weight loss due to CNT oxidation within this characteristic weight loss range was accurately calculated. After subtracting the background weight loss from other components such as binders and conductive carbon black, the mass percentage (H) of CNTs in the positive electrode active layer could be calculated.

[0025] Determination of the specific surface area of ​​the negative electrode active material: The nitrogen adsorption BET method was used, and a specific surface area and porosity analyzer was used to test the specific surface area of ​​the negative electrode active material (such as artificial graphite) to obtain its value, with the unit being m². 2 / g.

[0026] In some embodiments, the lithium-ion battery satisfies the following conditions: 1.00≤(A+C+D)*10000 / X≤6.00.

[0027] Specifically, further limiting the above relationship to 1.00≤(A+C+D)*10000 / X≤6.00 is beneficial for further matching the ratio of interfacial film-forming components to titanium doping amount, thereby further improving the high-temperature cycle stability and thermal shock safety of the battery.

[0028] In some embodiments, the lithium-ion battery satisfies the following conditions: 0.10≤(C+D)*100 / (B+W)≤2.61.

[0029] Specifically, by further limiting the above relationship to 0.10≤(C+D)*100 / (B+W)≤2.61, the amount of film-forming additives and low-temperature kinetic requirements can be more accurately matched, avoiding the problem of insufficient interface protection due to slightly less additives at the boundary of the basic range, or slight obstruction of ion transport due to slightly more additives, and further extending the low-temperature cycle life.

[0030] In some embodiments, the lithium-ion battery satisfies the following conditions: 3.47≤(C+H) / B≤40.40.

[0031] Specifically, the above relationship is further limited to 3.47≤(C+H) / B≤40.40 to further optimize the ratio of thermally stable component to thermally unstable solvent, thereby increasing the thermal shock pass rate while maintaining better electrochemical kinetic performance.

[0032] In some embodiments, the lithium-ion battery satisfies one of the following conditions: (1) 10 ≤ A ≤ 25; (2) 10≤B≤25; (3) 1≤C≤3; (4) 0.5≤D≤2; (5) 1≤H≤5; (6) 500≤X≤1000; (7) 4≤W≤20.

[0033] Specifically, the 10≤A≤25 and 10≤B≤25 enable the SEI film formation effect of the first solvent and the low-temperature viscosity reduction effect of the second solvent to achieve the optimal balance, avoiding both insufficient functionality due to excessively low solvent content and deterioration of electrolyte thermal stability or viscosity due to excessively high content. 1≤C≤3、0.5≤D≤2, so that the CEI film formation effect of the first additive and the interface optimization of the second additive can achieve a better synergistic effect, avoiding excessive interface impedance caused by excessive additives or interface protection failure caused by insufficient additives. 500≤X≤1000ppm, 4≤W≤20m 2 / g, which makes the structural stability of titanium doping and the reaction interface scale of the negative electrode more consistent with the overall electrochemical system of the battery, improves the efficiency of lithium ion insertion / extraction, reduces the occurrence of side reactions, and further improves the stability of battery cycle performance.

[0034] In some embodiments, the lithium salt additive includes one or more of lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium dioxalateborate, lithium difluorophosphate, lithium difluorooxalateborate, and lithium tetrafluoroborate.

[0035] Using any one or more of the above-mentioned lithium salt additives as the second additive is beneficial for optimizing battery performance; Specifically, this type of lithium salt additive is a functional lithium salt with excellent compatibility in the field of lithium-ion batteries. It can effectively participate in the formation process of the positive and negative electrode interface films, optimize the inorganic composition of the interface film, and improve the ionic conductivity, mechanical strength and thermal stability of the interface film. This makes the negative electrode SEI film constructed by the first solvent fluoroethylene carbonate and the positive electrode CEI film formed by the first additive ethylene glycol bis(propionitrile) ether have better protective performance, reducing interfacial side reactions and lithium-ion loss. At the same time, this type of lithium salt has good compatibility with the first solvent fluoroethylene carbonate, the second solvent ethyl butyrate and the first additive ethylene glycol bis(propionitrile) ether in the electrolyte. It will not react adversely with other components of the electrolyte, which can ensure the chemical stability of the electrolyte system and avoid electrolyte performance degradation due to component incompatibility.

[0036] In some embodiments, the electrolyte salt comprises lithium hexafluorophosphate.

[0037] Specifically, the electrolyte salts described above are highly compatible with the electrolyte solvent and additive system of the present invention. This ensures that the electrolyte has high ionic conductivity, providing a sufficient lithium source for lithium-ion transport. It also synergistically participates in the construction and optimization of the electrode interface film, forming a functional complement with the first solvent fluoroethylene carbonate, the first additive ethylene glycol bis(propionitrile) ether, and lithium salt additives. This further enhances the stability of the interface film and the ion transport efficiency. Furthermore, it does not react adversely with components such as the second solvent ethyl butyrate. This approach balances the chemical stability and electrochemical performance of the electrolyte, thereby achieving the synergistic optimization of battery thermal shock safety and high and low temperature cycling performance.

[0038] In some embodiments, the positive electrode active material includes transition metal lithium oxide; The chemical formula of the transition metal lithium oxide is Li 1+x Ni y Co z M (1-y-z) O2, where -0.1≤x≤1; 0≤y≤1, 0≤z≤1, and 0≤y+z≤1; M is selected from one or more of Mg, Zn, Ga, Ba, Al, Cr, Sn, V, Mn, Sc, Nb, Mo, and Zr.

[0039] Specifically, the transition metal lithium oxide Li 1+x Ni y Co z M (1-y-z) The layered crystal structure of O2 provides a smooth transport channel for lithium-ion insertion and extraction. Furthermore, the various choices of transition metal lithium oxide (M) elements can form a dual doping modification effect with the titanium elements doped in the positive electrode active material, further enhancing the thermal and electrochemical stability of the positive electrode phase structure. This avoids phase transitions and oxygen loss in the positive electrode material under high voltage and high / low temperature cycling, improving the cycle life and thermal safety of the positive electrode active material. At the same time, this type of transition metal lithium oxide has excellent compatibility with the carbon nanotube conductive network in the positive electrode, which can fully utilize the electron transport advantages of the three-dimensional conductive network, reduce the internal resistance of the electrode, and thus form a performance synergy with the interface protection and low temperature transport characteristics of the electrolyte system, promoting the simultaneous improvement of the thermal shock safety and high / low temperature cycling performance of lithium-ion batteries.

[0040] The positive electrode includes a positive current collector. In this application, there is no particular limitation on the type of positive current collector, which can be any known material suitable for use as a positive current collector, including aluminum, stainless steel, nickel plating, titanium, tantalum metal materials, as well as carbon cloth and carbon paper.

[0041] The positive electrode active layer also includes a positive electrode conductive agent, a positive electrode binder, and a solvent.

[0042] In some embodiments, the present invention does not limit the type of positive conductive agent mentioned, and any known conductive agent may be used.

[0043] In some embodiments, the positive electrode conductive agent mentioned in this invention includes at least one of carbon materials such as natural graphite, artificial graphite, acetylene black, needle coke, carbon nanotubes, and graphene.

[0044] In some embodiments, the present invention does not limit the type of positive electrode binder, and any known positive electrode binder may be used.

[0045] In some embodiments, the positive electrode binder includes at least one of polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, polyimide, aromatic polyamide, cellulose, and nitrocellulose.

[0046] In some embodiments, the negative electrode active material includes one or more of graphite, silicon-carbon composite materials, and lithium metal materials.

[0047] The negative electrode active layer also includes a negative electrode conductive agent, a negative electrode binder, a thickener, and a solvent. The negative electrode conductive agent includes at least one of carbon materials such as natural graphite, artificial graphite, acetylene black, needle coke, carbon nanotubes, and graphene. The negative electrode binder includes styrene-butadiene latex, the thickener includes CMC, and the solvent includes deionized water.

[0048] The application does not impose any particular restrictions on the negative electrode current collector, as long as it can achieve the purpose of this application. For example, it can be copper foil, copper alloy foil, nickel foil, stainless steel foil, titanium foil, foamed nickel, foamed copper, or composite current collector, etc.

[0049] In some preferred embodiments, the negative current collector comprises copper foil.

[0050] In the lithium-ion battery mentioned in this application, a separator is usually provided between the positive and negative electrodes to prevent short circuits. This application does not impose any particular restrictions on the material and shape of the separator, as long as it does not significantly impair the effectiveness of this application.

[0051] In some embodiments, the diaphragm comprises a porous sheet-like or non-woven material with excellent liquid retention properties, and the diaphragm comprises a resin or glass fiber diaphragm material, which includes, but is not limited to, polyolefins, aromatic polyamides, polytetrafluoroethylene, polyethersulfone, and polyethylene.

[0052] In some implementations, the outer packaging of a lithium-ion battery can be a rigid shell, such as a hard plastic shell, aluminum shell, or steel shell. Alternatively, the outer packaging can be a soft pack, such as a pouch.

[0053] The material for flexible packaging can be plastic, such as polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0054] This application does not impose any particular restrictions on the shape of the lithium-ion battery; it can be cylindrical, square, or any other arbitrary shape.

[0055] Another embodiment of the present invention provides an electrical device including the aforementioned lithium-ion battery.

[0056] The aforementioned electrical device includes the lithium-ion battery described in this application. The lithium-ion battery provided in this application uses a first solvent, fluoroethylene carbonate, to construct a stable negative electrode SEI film; a second solvent, ethyl butyrate, to reduce electrolyte viscosity and ensure low-temperature ion transport; a first additive, ethylene glycol bis(propionitrile) ether, to form a dense positive electrode CEI film; and a second additive, lithium salts, to optimize the interface inorganic components. Furthermore, titanium doping in the positive electrode active material enhances the stability of the positive electrode phase structure. Carbon nanotubes in the positive electrode active layer construct a three-dimensional conductive / thermal conductive network. Simultaneously, by adjusting the relationship between the parameters of each component, a relational formula is formed, where the formula 0.84 ≤ (A+C+D)*10000 / X ≤ 7.88, which balances the interface composition. The membrane capability and cathode structure stability are improved, avoiding insufficient interface protection or excessive impedance. The relationship 0.05≤(C+D)*100 / (B+W)≤3.16 can better adapt to the additive dosage and low-temperature kinetic requirements, ensuring interface integrity without hindering ion transport. The relationship 3.23≤(C+H) / B≤97.30 suppresses the risk of thermal decomposition of the second solvent through the dual thermal stabilization mechanism of the first additive and carbon nanotubes. The limited range of each parameter avoids performance degradation caused by excessive or insufficient single component. This achieves multi-dimensional synergy of interface regulation, electrode structure-level transport optimization and bulk-level stability enhancement, simultaneously improving the thermal shock safety, low-temperature cycle performance and high-temperature cycle performance of lithium-ion batteries.

[0057] Specifically, the electrical devices may include mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but are not limited to these.

[0058] Table 1 Continued from Table 1 Continued from Table 1 Continued from Table 1 Continued from Table 1 Continued from Table 1 The present invention will be further illustrated by the following examples.

[0059] Example 1 This embodiment illustrates the lithium-ion battery disclosed in this invention. The preparation of the lithium-ion battery includes the following steps: Preparation of positive electrode The positive electrode current collector is made of 12μm thick aluminum foil. The positive electrode active material (lithium cobalt oxide LiCoO2, with a titanium doping content of 800ppm), conductive agent acetylene black (Super P), carbon nanotubes (CNTs) and binder polyvinylidene fluoride (PVDF) are mixed in a mass ratio (active material):(Super P):(CNTs):(PVDF)=94.0:2.0:2.0:2.0, wherein the mass percentage of CNTs in the positive electrode active layer is 2%. The above substances are mixed and then thoroughly mixed with N-methyl-2-pyrrolidone (NMP) solvent in a vacuum planetary mixer until a uniform positive electrode slurry with suitable viscosity is formed. The positive electrode slurry is then uniformly coated on both sides of an aluminum foil current collector, dried at 120°C, and rolled and punched to obtain the positive electrode.

[0060] Preparation of negative electrode The negative electrode current collector is made of 8μm thick copper foil, and artificial graphite (with a specific surface area W of 6m²) is used. 2 A mixture of conductive agent acetylene black (Super P), thickener sodium carboxymethyl cellulose (CMC), and binder styrene-butadiene rubber (SBR) in a mass ratio of 96.0:1.0:1.5:1.5 was prepared by adding deionized water as a solvent and stirring to form a uniform negative electrode slurry. This slurry was then coated on both sides of a copper foil, dried, cold-pressed, and die-cut to obtain the negative electrode.

[0061] Preparation of electrolyte Electrolyte was prepared in a glove box filled with argon gas and with water and oxygen content both below 0.1 ppm. First, ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed at a mass ratio of 3:7 to form a basic solvent system. Lithium salt LiPF6 was added to this basic solvent to a concentration of 1.0 mol / L, and stirred until completely dissolved to obtain the basic electrolyte. Then, fluoroethylene carbonate (FEC), ethyl butyrate (EB), ethylene glycol bis(propionitrile) ether (DENE), and lithium bis(fluorosulfonyl)imide (LiFSI) were added to the basic electrolyte in sequence. By precise weighing, the mass percentages of the above four components in the final electrolyte were A=5%, B=15%, C=2%, and D=1%, respectively. After all components were added, they were thoroughly stirred and mixed to obtain the final electrolyte. The determination of the content of each component in the electrolyte was carried out by qualitative and quantitative analysis of the prepared electrolyte using gas chromatography-mass spectrometry (GC-MS) to confirm the mass percentage (A, B, C) of each solvent (FEC, EB) and additive (DENE).

[0062] Preparation of lithium-ion batteries The prepared positive electrode, negative electrode, and separator are stacked in sequence, with the separator in the middle of the positive and negative electrodes. The bare cell is made by winding, welding the tabs, inserting it into an aluminum-plastic film shell, baking and dehumidifying, etc. The prepared electrolyte is injected into a glove box, and after standard processes such as vacuum sealing, standing, pre-charging, formation, and aging, a lithium-ion soft pack battery with a rated capacity of 5Ah is obtained.

[0063] Examples 2-46 Examples 2-46 illustrate the lithium-ion battery disclosed in this invention, and include most of the operations in Example 1, except that: In Examples 2-46, the mass percentages of the first solvent (A%), the second solvent (B%), the first additive (C%), the second additive (D%), the type of the second additive, the carbon nanotube mass percentage (H%), the titanium content (X ppm), and the specific surface area of ​​the negative electrode active material (W m²) are all specified. 2 / g, (A+C+D)*10000 / X, (C+D)*100 / (B+W) and (C+H) / B are all based on Table 1 and Table 2.

[0064] Comparative Examples 1-56 Comparative Examples 1-56 are used to illustrate the lithium-ion battery disclosed in this invention, and include most of the operations in Example 1, the difference being: The mass percentages of the first solvent (FEC) (A%), the second solvent (EB) (B%), the first additive (DENE) (C%), the second additive (D%), the carbon nanotubes (CNTs) in the positive electrode active layer (H%), the titanium content (Xppm), and the specific surface area (Wm²) of the negative electrode active material in Comparative Examples 1-56 are also specified. 2 / g, (A+C+D)*10000 / X, (C+D)*100 / (B+W), and (C+H) / B are all based on Table 1 and Table 2.

[0065] Performance testing The following performance tests were performed on Examples 1-46 and Comparative Examples 1-56 prepared above: Thermal shock test The lithium-ion batteries prepared in the above embodiments and comparative examples were charged at 25°C at a rate of 1C to the cutoff voltage and a cutoff current of 0.025C. They were then transferred to an oven and heated to 150°C at a rate of 5°C / min and kept constant for 60 minutes. The batteries were considered to have passed the test if they did not catch fire or explode. The number of test cells was 20.

[0066] 45℃ Cyclic Performance Test The lithium-ion batteries prepared in the above embodiments and comparative examples were charged and discharged at 45°C at a rate of 1C / 1C within the charge and discharge cutoff voltage range. The discharge capacity of the first cycle was recorded as C1, and the discharge capacity of the Nth cycle was recorded as C2. The capacity of the Nth cycle was divided by the capacity of the first cycle to obtain the cycle capacity retention rate R2 = C2 / C1. The number of cycles of the lithium-ion battery when the cycle capacity retention rate R2 was 80% was recorded.

[0067] 0℃ Cyclic Performance Test The lithium-ion batteries prepared in the above embodiments and comparative examples were charged and discharged at 0°C at a rate of 1C / 1C within the charge and discharge cutoff voltage range. The discharge capacity of the first cycle was recorded as Y1, and the discharge capacity of the Nth cycle was recorded as Y2. The capacity of the Nth cycle was divided by the capacity of the first cycle to obtain the cycle capacity retention rate X2 = Y2 / Y1 of the Nth cycle. The number of cycles of the lithium-ion battery when the cycle capacity retention rate X2 was 80% was recorded.

[0068] The test results are entered into Table 2.

[0069] Table 2 Continued from Table 2 Continued from Table 2 Table 2 shows the overall test results of thermal shock, 0°C and 45°C cycling performance of all examples and comparative examples. The test results of examples 1 to 46 are significantly better than those of comparative examples 1 to 56. Examples 1 to 46 all meet the limitations of component selection, parameter range and relationship formula of this application. Compared with the comparative examples, they have excellent comprehensive performance. Specifically, the number of particles passing the thermal shock of the examples is 9 or more, and the number of cycles to 80% capacity retention at 0°C and 45°C is basically more than 490 cycles. Furthermore, in Example 3, the mass percentages of the first solvent and the second solvent are 15%, the mass percentage of the first additive is 2%, the mass percentage of the second additive is 1%, the mass percentage of carbon nanotubes in the positive electrode active layer is 2%, the content of titanium in the positive electrode active material is 800 ppm, and the specific surface area of ​​the negative electrode is 6 m². 2 / g, its lithium-ion battery has the best overall performance, that is, it passes the thermal shock test of 15 cells, retains 80% capacity for 599 cycles at 0℃, and achieves 633 cycles at 45℃. This shows that compared with other examples, the parameters and component ratios passed in Example 3 achieve the best overall performance.

[0070] Specifically, in Examples 1-5, the mass percentage of the first solvent gradually increased from 5% to 30%. The number of particles passing through the thermal shock decreased from 17 to 12 as the mass percentage A of the first solvent increased. The number of cycles at 0°C and 45°C both reached their peaks (599 cycles and 633 cycles) when A=15%. Moreover, when A took other values, the cycle performance decreased. It is speculated that the reason is that the first solvent is the core of the negative electrode SEI film formation. If the content is too low, the SEI film will be unstable, and the negative electrode interface will be easily damaged and side reactions will increase during high and low temperature cycling. If the content is too high, it will significantly increase the electrolyte viscosity, reduce the ionic conductivity, and at the same time exacerbate the side reactions on the positive electrode side. This will not only hinder low-temperature ion transport but also reduce thermal stability and high-temperature cycle performance. That is, when A=15%, the SEI film formation and electrolyte ion transport efficiency can be balanced.

[0071] In Examples 3 and 6-10, the mass percentage of the second solvent gradually increased from 5% to 30%. The number of cycles at 0°C increased from 555 to 622 cycles as the mass percentage B of the second solvent increased. The number of particles passing through the thermal shock decreased from 17 to 13, and the number of cycles at 45°C decreased from 640 to 558. The reason for this is that the second solvent is a low-viscosity solvent, which can reduce the viscosity of the electrolyte and ensure low-temperature ion transport. The higher the content, the better the low-temperature kinetics. However, the second solvent has poor thermal stability. If the content is too high, it will significantly increase the risk of thermal decomposition of the electrolyte and aggravate the interfacial side reactions at high temperatures, resulting in a significant deterioration of thermal shock safety and high-temperature cycling performance.

[0072] In Examples 3 and 11-15, the mass percentage of the first additive gradually increased from 0.5% to 4%. The number of particles passing through the thermal shock increased from 14 to 18 as the mass percentage C% of the first additive increased. The number of cycles at 0°C and 45°C reached its peak at C=2% (599 cycles and 633 cycles), while the cycle performance continued to decline when C>2%. It is speculated that the reason is that the cyano functional group of the first additive can coordinate with the positive electrode transition metal ions to form a dense CEI film. The higher the content, the stronger the protection of the CEI film and the better the thermal stability. However, a higher content of the first additive will make the CEI film too thick, increase the interfacial impedance, hinder the cross-interface transport of lithium ions, and thus cause a decline in high and low temperature cycle performance.

[0073] In Examples 3 and 16-20, the mass percentage of the second additive gradually increased from 0.3% to 3%. The number of particles passing through the thermal shock gradually increased with the increase of the mass percentage D% of the second additive. The cycle count at 0°C and 45°C was optimal when D=1%, and the cycle performance decreased when D>1%. This is because lithium salt additives can optimize the inorganic composition of the interfacial film and improve the ionic conductivity and mechanical strength of the interfacial film. If the content is too low, the synergistic film-forming effect is limited, and if the content is too high, it will increase the viscosity of the electrolyte and cause uneven growth of the interfacial film, resulting in obstructed ion transport.

[0074] In Examples 3 and 21-25, the carbon nanotube mass percentage (H%) increased from 0.5% to 6%. The number of particles passing through the thermal shock increased from 14 to 18 with increasing carbon nanotube content. The number of cycles at 0°C and 45°C reached its peak at H=2%, and the cycling performance decreased when H>2%. This is because carbon nanotubes can construct a three-dimensional conductive / thermal conductive network. The higher the content, the better the thermal conductivity and electrode mechanical integrity, and the lower the risk of thermal runaway. However, excessive carbon nanotube content will block the electrode pores, hindering the transport of lithium ions within the electrode, leading to deterioration in cycling performance. A low content of 0.5% cannot form an effective network, and the thermal and electrical conductivity effects are not significant.

[0075] In Examples 3 and 26-30, as the titanium doping concentration X increased from 300 to 1200 ppm, the number of particles passing through the thermal shock increased from 14 to 17. The cycle count at 0°C and 45°C was optimal at X=800 ppm, and the cycle performance continued to decline after X>800 ppm. This is because titanium can strengthen the cathode phase structure and suppress lattice phase transitions and oxygen loss under high temperature or high pressure. The higher the doping concentration, the more stable the cathode structure and the better the thermal safety. However, if the titanium content is too high, it will occupy lithium sites or introduce lattice defects, reducing the cathode specific capacity and lithium-ion diffusion coefficient, directly leading to a decline in cycle performance. In addition, a titanium doping concentration of 300 ppm is too low, and its structural stability effect is not significant.

[0076] In Examples 3 and 31-35, the specific surface area W of the negative electrode active material increased from 1 to 30 m².2 / g, the number of cycles at 0℃ increased from 522 cycles to 619 cycles with increasing W, the number of particles passing thermal shock decreased from 17 to 13, and the number of cycles at 45℃ decreased from 559 cycles to 555 cycles. This is because W determines the number of lithium-ion intercalation / deintercalation reaction sites in the negative electrode; the higher the W, the more reaction sites there are, resulting in better low-temperature kinetics. However, excessively high W will lead to an excessively large contact area between the negative electrode and the electrolyte, resulting in vigorous side reactions, accelerated consumption of active lithium, and deterioration of thermal stability and high-temperature cycling performance. A W of 1m... 2 At / g, there are insufficient reaction sites, resulting in extremely low low-temperature ion transport efficiency.

[0077] The specific types of the second additives in Examples 36-40 are different from those in other examples. The number of particles passing the thermal shock test is 15, the number of cycles at 0°C is 596-600, and the number of cycles at 45°C is 631-633. Compared with other examples, there is no significant difference in performance, which shows that the lithium salt additives specified in this application can effectively participate in the formation of the positive and negative electrode interface film and optimize the inorganic composition of the interface film.

[0078] Examples 41-46 define the boundary values ​​of the limiting formula and single component. Compared with other examples, their performance is relatively poor, with fewer than 520 cycles at 0°C and 45°C. In some examples, only 9-11 particles pass the thermal shock test. This is because the parameter ratios in Examples 41-46 are close to the critical values, and the components cannot exert a better synergistic effect, resulting in relatively poor performance, but still better than the performance of the comparative examples.

[0079] In Comparative Example 3, without the first solvent, the number of particles passing through thermal shock was 0, and it cycled for 376 cycles at 0°C and 226 cycles at 45°C. In Comparative Example 7, without the first and second additives, the number of particles passing through thermal shock was 0, and it cycled for 394 cycles at 0°C and 308 cycles at 45°C. In Comparative Example 31, without carbon nanotubes in the positive electrode active layer, the number of particles passing through thermal shock was 7, and it cycled for 417 cycles at 0°C and 428 cycles at 45°C. Without the first solvent, a stable negative electrode SEI film cannot be formed, and the negative electrode interface is completely damaged during thermal shock and cycling, leading to thermal runaway and rapid capacity decay. Without the first and second additives, a dense positive electrode CEI film cannot be formed, and the oxidation of the positive electrode electrolyte and the dissolution of metal ions are aggravated. Without carbon nanotubes, a three-dimensional conductive / thermal conductive network cannot be formed, resulting in poor electrode thermal conductivity, low electron transport efficiency, high risk of thermal runaway, and high cycling impedance.

[0080] Comparative Example 1 lacks the first solvent, second solvent, first additive, second additive, and carbon nanotubes described in this application. Only 2 nanotubes passed the thermal shock test, and the battery cycled only 234 / 247 times at 0℃ / 45℃. It had the worst performance among all comparative examples. The reason is that the absence of multiple components caused the core mechanisms of positive and negative electrode interface protection, electrolyte ion transport, electrode conductivity and thermal conductivity, and positive electrode structural stability to fail. The battery lacked effective interface protection, ion and electron transport was hindered, and thermal stability and cycle performance were lost.

[0081] Comparative Example 29 (without the first additive) and Comparative Example 30 (without the second additive) both had 7 particles passing the thermal shock test and 424-619 cycles, showing slightly better performance than Comparative Example 1, but still far inferior to the examples. This is because the absence of a single additive significantly reduces the interfacial film formation effect; a single film-forming component cannot form a complete interfacial film. Comparative Example 32 (A=1%<5%) had 18 particles passing the thermal shock test, but only 421 / 414 cycles at 0℃ / 45℃. Comparative Example 45 (W=50m) 2 (g>30) Only 2 particles passed the thermal shock test, and the cycle life was 385 / 380 cycles at 0℃ / 45℃. The reason is that if the A content is too low, the SEI film will not form sufficiently, the negative electrode interface protection will fail, and the cycle performance will plummet; if the W content is too high, the negative electrode side reaction will be severe, the active lithium will be consumed rapidly, and the thermal stability will be completely degraded.

[0082] Comparative Example 37 (C=8%>4%) and Comparative Example 41 (H=8%>6%) both had 18 particles that passed the thermal shock test, but only 300~331 cycles at 0℃ / 45℃; Comparative Example 44 (W=0.1m) 2 / g<1) 17 cells passed the thermal shock test, but the cycle life was only 304 / 324 cycles at 0℃ / 45℃. The reason is that the high C and H content leads to the high impedance of the CEI film and the blockage of electrode pores, which will seriously hinder lithium-ion transport. The low W content results in insufficient reaction sites and extremely poor low-temperature kinetics, which ultimately lead to a serious decline in cycle performance.

[0083] Comparative Example 42 (X=100ppm<300): Only 5 cells passed the thermal shock test, achieving 581 cycles at 0℃ and 394 cycles at 45℃. Comparative Example 43 (X=2000ppm>1200): 16 cells passed the thermal shock test, achieving only 292 / 333 cycles at 0℃ / 45℃. This is because too low X results in weak stabilization of the cathode phase structure, exacerbating lattice phase transitions and oxygen loss under thermal shock; while too high X introduces numerous lattice defects, reducing the lithium-ion diffusion coefficient and significantly degrading cycle performance. Furthermore, insufficient surface protection increases interfacial side reactions, affecting cycle performance and thermal stability.

[0084] Comparative Examples 46-50 replaced the first solvent, second solvent, first additive, second additive, and carbon nanotubes (FEC replaced with PC, EB replaced with PP, DENE replaced with PS, lithium salt replaced with DTD, and CNT replaced with ceramic) with other substances. The number of particles passing thermal shock was 7-11, and the number of cycles at 0℃ / 45℃ was 380-426, which was far worse than that of Example 3. The reason is that the substitute components cannot achieve the mechanism of action of the components specified in this application. PC cannot build a stable negative electrode SEI film like FEC. The low-temperature viscosity reduction effect of PP is far worse than that of EB. The cyano coordination film formation effect of DENE cannot be replaced by PS. DTD cannot optimize the inorganic composition of the interface film. Ceramic cannot build a three-dimensional conductive / thermal conductive network like CNT. It can only achieve partial replacement of a single function and cannot meet the requirements of multi-mechanism synergy.

[0085] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A lithium-ion battery, characterized in that, It includes a positive electrode, a negative electrode, and an electrolyte. The negative electrode includes a negative electrode active layer, which includes a negative electrode active material. The positive electrode includes a positive electrode active layer, which includes carbon nanotubes and a positive electrode active material. The positive electrode active material is doped with titanium. The electrolyte includes a solvent, an additive, and an electrolyte salt. The solvent includes a first solvent and a second solvent. The additive includes a first additive and a second additive. The first solvent includes fluoroethylene carbonate, the second solvent includes ethyl butyrate, the first additive includes ethylene glycol bis(propionitrile) ether, and the second additive includes lithium salt additives. The lithium-ion battery meets the following conditions: 0.84≤(A+C+D)*10000 / X≤7.88; 0.05≤(C+D)*100 / (B+W)≤3.16; 3.23≤(C+H) / B≤97.30; Furthermore, 5≤A≤30, 5≤B≤30, 0.5≤C≤4, 0.3≤D≤3, 0.5≤H≤6, 300≤X≤1200, and 1≤W≤30; Wherein, A% is the mass percentage of the first solvent in the electrolyte; B% represents the mass percentage of the second solvent in the electrolyte; C% represents the mass percentage of the first additive in the electrolyte; D% represents the mass percentage of the second additive in the electrolyte; H% represents the mass percentage of carbon nanotubes in the positive electrode active layer; X represents the content of titanium in the positive electrode active material, in ppm; W represents the specific surface area of ​​the negative electrode active material, in m². 2 / g.

2. The lithium-ion battery according to claim 1, characterized in that, The lithium-ion battery meets the following conditions: 1.00≤(A+C+D)*10000 / X≤6.

00.

3. The lithium-ion battery according to claim 1, characterized in that, The lithium-ion battery meets the following conditions: 0.10≤(C+D)*100 / (B+W)≤2.

61.

4. The lithium-ion battery according to claim 1, characterized in that, The lithium-ion battery meets the following conditions: 3.47≤(C+H) / B≤40.

40.

5. The lithium-ion battery according to claim 1, characterized in that, The lithium-ion battery meets one of the following conditions: （1）10≤A≤25； （2）10≤B≤25； （3）1≤C≤3； （4）0.5≤D≤2； （5）1≤H≤5； （6）500≤X≤1000； （7）4≤W≤20。 6. The lithium-ion battery according to claim 1, characterized in that, The lithium salt additives include one or more of lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium dioxaborate, lithium difluorophosphate, lithium difluorooxaborate, and lithium tetrafluoroborate.

7. The lithium-ion battery according to claim 1, characterized in that, The electrolyte salt includes lithium hexafluorophosphate.

8. The lithium-ion battery according to claim 1, characterized in that, The positive electrode active material includes transition metal lithium oxide; The chemical formula of the transition metal lithium oxide is Li 1+x Ni y Co z M (1-y-z) O2, where -0.1≤x≤1; 0≤y≤1, 0≤z≤1, and 0≤y+z≤1; M is selected from one or more of Mg, Zn, Ga, Ba, Al, Cr, Sn, V, Mn, Sc, Nb, Mo, and Zr.

9. The lithium-ion battery according to claim 1, characterized in that, The negative electrode active material includes one or more of graphite, silicon-carbon composite materials, and lithium metal materials.

10. An electrical device, characterized in that, The lithium-ion battery includes any one of claims 1 to 9.

Images