Cathode foil, battery, comprising the cathode foil, and current-consuming device

Abstract

Cathode foil, characterized in that it comprises the following: a cathode collector; a first active cathode material layer provided on at least one surface of the cathode collector, wherein the first active cathode material layer comprises lithium nickel manganese oxide particles, wherein a particle size Dn50 of the lithium nickel manganese oxide particles is a µm, where a is in a range of 1 ≤ a ≤ 4; and a second active cathode material layer provided on a surface of the first active cathode material layer facing away from the cathode collector, wherein the second active cathode material layer comprises lithium nickel manganese oxide particles, wherein a particle size Dn50 of the lithium nickel manganese oxide particles is b µm, where b is in a range of 5 ≤ b ≤ 8; and wherein a thickness fraction of the second active cathode substance layer, which is calculated on the basis of a total thickness of the first active cathode substance layer and the second active cathode substance layer, M b is, where M b lies in a range of 0.5 to 0.8.

Description

Technical field

[0001] The present invention relates to the technical field of batteries, in particular a cathode foil, a battery comprising the cathode foil, and a current-consuming device. Technical background

[0002] Lithium-ion power batteries require high energy density and high output power, leading to significant interest in the development of high-voltage cathode materials. Spinel-like lithium nickel manganese oxide (LNMO) materials possess a crystal structure that offers three-dimensional lithium-ion transport pathways and exhibits favorable ionic conductivity. They are characterized by a high voltage platform of 4.7 V (compared to Li / Li). +) and achieve a theoretical specific capacity of 147 mAh / g, which represents considerable potential. However, the substantial band gap of LNMO (0.5601 eV) results in poor conductivity within the system. Under high-voltage operating conditions, side reactions at the cathode interface with the electrolyte solution are intensified, leading to increased formation of interfacial byproducts. Content of the invention

[0003] The purpose of the present invention is to provide a cathode foil, a battery comprising the cathode foil, and a power-consuming device by overcoming the above shortcomings in the prior art, whereby the cathode foil used by LNMO can exhibit both good kinetic performance and good cycle performance.

[0004] To achieve the above purpose, according to a first aspect, the present invention provides a cathode foil comprising the following: a cathode collector; a first active cathode material layer provided on at least one surface of the cathode collector, wherein the first active cathode material layer comprises lithium nickel manganese oxide particles, wherein a particle size Dn50 of the lithium nickel manganese oxide particles is a µm, where a is in a range of 1 ≤ a ≤ 4; and a second active cathode material layer provided on a surface of the first active cathode material layer facing away from the cathode collector, wherein the second active cathode material layer comprises lithium nickel manganese oxide particles, wherein a particle size Dn50 of the lithium nickel manganese oxide particles is b µm, where b is in a range of 5 ≤ b ≤ 8; and wherein a thickness fraction of the second active cathode substance layer, which is calculated on the basis of a total thickness of the first active cathode substance layer and the second active cathode substance layer, M b is, where M b lies in a range of 0.5 to 0.8.

[0005] According to a second aspect, the present invention provides a battery comprising a cathode foil as described above.

[0006] According to a third aspect, the present invention provides a power-consuming device comprising a battery as described above.

[0007] Compared to the prior art, the present invention has the following advantageous effects: The present invention enables a layered distribution of LNMO according to a specific particle size Dn50, whereby the thickness ratio between the layers is maintained within an optimal range. This ensures that LNMO exhibits high kinetic performance while simultaneously reducing side reactions (even at high voltage) with the electrolyte solution. It improves the packing density and the uniformity of the pore size within the cathode film, thereby effectively improving both the kinetic performance and the cycle performance of the cathode film. Description of embodiments

[0008] The technical solution in the embodiments of the present invention is explained clearly and completely below, so that the purpose, the technical solutions, and the advantages of the embodiments of the present invention become clearer. Obviously, the described embodiments do not represent all embodiments, but only a subset of the embodiments of the present invention. All other embodiments that a person skilled in the art in this field could obtain from the embodiments in the present invention without any creative work should be considered to be covered by the scope of protection of the present invention.

[0009] The present invention includes, among the technical features described in an open manner, a closed technical solution with the listed features, and also an open technical solution with the listed features.

[0010] Within the scope of the present invention, a numerical interval is considered continuous within said numerical interval unless otherwise specified, and includes a minimum and a maximum value of the range, as well as each value between these minimum and maximum values. If the range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. If several ranges are specified to describe a feature or property, the ranges may also be combined. In other words, unless otherwise specified, all ranges disclosed herein are to be understood as encompassing all subranges contained therein.

[0011] The specific dispersion and mixing treatments are not specifically limited within the scope of the present invention.

[0012] The reagents or instruments used without manufacturer information are all commercially available products on the market.

[0013] In the present invention, the terms “first”, “second”, and similar expressions are not used to limit the number of times. cathode foil

[0014] The present invention provides a cathode foil comprising the following: a cathode collector; a first active cathode material layer provided on at least one surface of the cathode collector, wherein the first active cathode material layer comprises lithium nickel manganese oxide particles (hereinafter referred to as the "first lithium nickel manganese oxide particles"), wherein a particle size Dn50 of the lithium nickel manganese oxide particles is a µm, where a is in a range of 1 ≤ a ≤ 4; and a second active cathode material layer provided on a surface of the first active cathode material layer facing away from the cathode collector, wherein the second active cathode material layer comprises lithium nickel manganese oxide particles (hereinafter referred to as the "second lithium nickel manganese oxide particles"), wherein a particle size Dn50 of the lithium nickel manganese oxide particles is b µm, where b is in a range of 5 ≤ b ≤ 8; and wherein a thickness fraction of the second active cathode substance layer, which is calculated on the basis of a total thickness of the first active cathode substance layer and the second active cathode substance layer, M b is, where M b lies in a range of 0.5 to 0.8.

[0015] The first lithium nickel manganese oxide particles exhibit a relatively small particle size (Dn50) and favorable kinetic performance. Their placement within the first active cathode layer, adjacent to the cathode collector, reduces their contact with the electrolyte solution, thereby minimizing reactions between the particles and the electrolyte. The second lithium nickel manganese oxide particles have a larger particle size (Dn50), a reduced specific surface area, high strength, and excellent structural stability. Their placement within the second active cathode layer, further away from the cathode collector, minimizes side reactions between the cathode interface and the electrolyte solution, even under high-voltage conditions.Furthermore, the first lithium nickel manganese oxide particles with a smaller particle size of Dn50 and the second lithium nickel manganese oxide particles with a larger particle size of Dn50 are each located in the first and second active cathode material layers, respectively. During pressing, the pressure is transferred from the second active cathode material layer to the first active cathode material layer. This arrangement, supported by the second lithium nickel manganese oxide particles, minimizes damage to the first lithium nickel manganese oxide particles, increases the pressing density, and creates more uniform pore sizes within the cathode film. As a result, ion and electron transport is smoother, with reduced resistance and lower polarization, leading to improved kinetic and cycle performance.

[0016] At the same time, controlling the particle size Dn50 (a) of the first lithium nickel manganese oxide particles, the particle size Dn50 (b) of the second lithium nickel manganese oxide particles and the thickness fraction (M) allows b Within the above-mentioned suitable areas, the placement of the second active cathode material layer allows the first lithium nickel manganese oxide particles and the second lithium nickel manganese oxide particles to not only function more effectively, but also further improves the compaction and pore size uniformity of the cathode foil. Consequently, the cathode foil exhibits improved kinetic and cycle performance.

[0017] The present invention enables a layered distribution of LNMO according to a specific particle size Dn50, whereby the thickness ratio between the layers is maintained within an optimal range. This ensures that the LNMO exhibits high kinetic performance while simultaneously reducing side reactions (even at high voltage) with the electrolyte solution. It improves the packing density and the uniformity of the pore size within the cathode film, thereby effectively improving both the kinetic and cycle performance of the cathode film.

[0018] For example, a is 1.00, 1.30, 1.55, 1.80, 2.05, 2.20, 2.55, 2.72, 3.00, 3.25, 3.50, 3.75, 4.00 or any value in a range between any two of these values.

[0019] For example, b is 5.00, 5.25, 5.40, 5.65, 5.80, 6.00, 6.25, 6.40, 6.65, 6.80, 7.00, 7.25, 7.40, 7.65, 7.80, 8.00 or any value in a range between any two of these values.

[0020] For example, M is b 0.50, 0.52, 0.54, 0.56, 0.58, 0.60, 0.62, 0.64, 0.66, 0.68, 0.70, 0.72, 0.74, 0.76, 0.78, 0.80 or any value in a range between any two of these values.

[0021] The particle size values ​​Dn50(a) of the first lithium nickel manganese oxide particles and the particle size Dn50(b) of the second lithium nickel manganese oxide particles can both be regulated by adjusting the following process conditions: calcination conditions (such as calcination temperature and time), milling conditions (such as milling speed and rotational speed; when using a sand mill, regulation can also be achieved by adjusting the abrasive-to-material ratio, i.e., the mass ratio of abrasive particles to material, as defined below; when using a ball mill, regulation can also be achieved by adjusting the ball-to-material ratio).

[0022] The present invention does not restrict the test method for the particle size Dn50(a) of the first lithium nickel manganese oxide particles and the particle size Dn50(b) of the second lithium nickel manganese oxide particles. A person skilled in the art can use conventional technical means to test the particle size Dn50(a) of the first lithium nickel manganese oxide particles and the particle size Dn50(b) of the second lithium nickel manganese oxide particles. For example, the particle size Dn50(a) of the first lithium nickel manganese oxide particles and the particle size Dn50(b) of the second lithium nickel manganese oxide particles can be tested using the following method:

[0023] Take an empty battery and disassemble it to obtain the cathode foil. The cathode foil is then subjected to cross-section polishing (CP). Observe and measure using a scanning electron microscope (SEM) with a magnification set to 5Kx. The upper, middle, and lower regions of each active substance layer are selected and photographed. Measure the particle size distribution (PSD) of all particles in these three regions and determine an average particle size Dn50 for 50% of the particle count in these three regions. Calculate the average Dn50 value across these three regions to obtain the average particle size Dn50 of each active substance layer, i.e., the particle size Dn50(a) of the first lithium nickel manganese oxide particles and the particle size Dn50(b) of the second lithium nickel manganese oxide particles.

[0024] The thickness fraction (M) bThe second active cathode substance layer can be controlled by adjusting the coating gap width of the coating machine, the coating speed, the solids content of the slurry, and other factors.

[0025] The present invention restricts the test method for the thickness fraction (M). b ) of the second active cathode substance layer is not included, and a person skilled in the art can determine the thickness fraction (M b ) of the second active cathode substance layer using conventional technical means. The thickness fraction (M b The second active cathode substance layer can be tested, for example, using the following method:

[0026] Taking an empty battery and disassembling it to obtain the cathode foil, the cathode foil is then subjected to CP sectioning; using SEM (scanning electron microscopy), the thickness of the first active cathode substance layer and the thickness of the second active cathode substance layer are determined in cross-section and then calculated to determine the thickness fraction (M b ) to obtain the second active cathode substance layer.

[0027] In some of these embodiments, a and b satisfy the following relationship formula: 0.125 ≤ a / b ≤ 0.5. For example, a / b is 0.125, 0.01, 0.200, 0.250, 0.300, 0.355, 0.405, 0.455, 0.500, or any value in a range between any two of these values.

[0028] In one of the preferred embodiments, a and b satisfy the following relationship formula: 0.3 ≤ a / b < 0.4. For example, a / b is 0.300, 0.315, 0.320, 0.345, 0.350, 0.365, 0.370, 0.385, 0.390, 0.400 or any value in a range between any two of these values.

[0029] If a / b is in the range of 0.125 to 0.5, particularly in the range of 0.3 to 0.4, the difference in volume change between the first lithium nickel manganese oxide particles and the second lithium nickel manganese oxide particles during the lithium debedding process is reduced, while the roles of the first nickel manganese oxide particles and the second nickel manganese oxide particles are improved. This prevents the interface between the first active cathode material layer and the second active cathode material layer from generating large stresses and cracking or delamination, resulting in better kinetic and cycle performance of the cathode foil.

[0030] In some of these embodiments, a is in the range of 2 µm to 3 µm to enable better kinetic and cycle performance of the cathode foil. For example, a is 2.00 µm, 2.15 µm, 2.20 µm, 2.35 µm, 2.40 µm, 2.55 µm, 2.60 µm, 2.75 µm, 2.80 µm, 2.95 µm, 3.00 µm, or any value in the range between any two of these values.

[0031] In some of these embodiments, b is in the range of 6 µm to 7 µm to enable better kinetic and cycle performance of the cathode foil. For example, b is 6.00 µm, 6.15 µm, 6.20 µm, 6.35 µm, 6.40 µm, 6.55 µm, 6.60 µm, 6.75 µm, 6.80 µm, 6.95 µm, 7.00 µm, or any value in the range between two of these values.

[0032] In some of these embodiments, M b in the range of 0.6 to 0.7 to enable better kinetic and cycle performance of the cathode foil. For example, M b0.60, 0.61, 0.62, 0.63, 0.64, 0.65, 0.66, 0.67, 0.68, 0.69, 0.70 or any value in a range between any two of these values.

[0033] In some of these embodiments, the emission rate of transition metal ions after 200 cycles at 25°C is k%; where the cathode foil fulfills the following: 0.06 ≤ k / M b ≤ 0.3. For example, k / M b 0.06, 0.07, 0.08, 0.09, 0.10, 0.12, 0.14, 0.16, 0.18, 0.20, 0.22, 0.24, 0.26, 0.28, 0.29, 0.30 or any value in a range between any two of these values.

[0034] In a preferred embodiment, the cathode foil fulfills the following: 0.1 ≤ k / M b ≤0.2.

[0035] k% = Transition metal ion content in the anode foil, determined after 200 cycles at 25°C / Transition metal ion content in the cathode foil before the cycles (100%). The inventor discovered during research that the amount of transition metal ions released (k) after 200 cycles at 25°C accurately reflects the degree of capacity degradation in the battery. When k / Mb is controlled in the range of 0.06 < k / M < 0.3, particularly in the range of 0.1 ≤ k / M ≤ 0.2, the structural stability of LNMO in the cathode foil is improved, and simultaneously, the cathode foil's density is higher and pore size uniformity is better, which contributes to improved kinetic and cycle performance of the cathode foil.

[0036] In some of these embodiments, k lies in a range of 0.05 ≥ k ≤ 0.2. For example, k is 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.16, 0.18, 0.20, or any value in a range between any two of these values.

[0037] If the value of k is controlled within the suitable range described above, not only is the surface stability of the cathode foil improved, but the SEI film (i.e., the solid electrolyte interface film formed on the surface of the active anode material) is also less affected by transition metal ions, exhibits better stability and lower impedance, and thus facilitates lithium ion transport. Therefore, the cycle life and kinetic performance of the battery are improved with this cathode foil.At the same time, the surface of the cathode layer is not so easy to passivate and the ion and electron transport capability is good, giving the cathode foil better kinetic performance.

[0038] The amount (k) of transition metal ions released after 200 cycles at 25°C can be adjusted by changing the thickness of the coating layer (if present), the particle size Dn50 (a) of the first lithium nickel manganese oxide particles, the particle size Dn50 (b) of the second lithium nickel manganese oxide particles, and the thickness fraction (M). b ) the second active cathode substance layer and the like.

[0039] The present invention does not restrict the test method for the emission quantity (k) of transition metal ions after 200 cycles at 25°C. A person skilled in the art can determine the emission quantity (k) of transition metal ions after 200 cycles at 25°C using conventional technical means. For example, the emission quantity (k) of transition metal ions after 200 cycles at 25°C can be tested by the following method:

[0040] Take an empty battery and disassemble it to obtain the cathode foil. Immerse the cathode foil in DMC (dimethyl carbonate) at room temperature (e.g., 25°C, see below) for 1 hour to remove the electrolyte solution. Remove and dry. Scrape the cathode material from the collector surface and, after the cathode material has dissolved, use ICP (inductively coupled plasma) to measure the total mass of Ni and Mn. The sum of the two is M1. Five parallel samples (i.e., five batteries were used for the test) were measured, and the average value of M1 was calculated and recorded as M1.

[0041] Take an empty battery and disassemble it to obtain the cathode and anode foils. Mix the obtained cathode and anode foils with the electrolyte solution (ethylene carbonate (EC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC)) in a volume ratio of 1:1:1 to obtain an organic solvent. Dissolve the completely dried lithium salt LiPF6 in the mixed organic solvent to obtain an electrolyte solution with LiPF6 at a concentration of 1 mol / L. Determine the capacity at 25°C for 2 cycles and then at 25°C for 200 cycles at a rate of 1C. Then disassemble it to obtain the anode foil. Immerse the anode foil in DMC (dimethyl carbonate) at room temperature (e.g., 25°C, see below) for 1 hour to remove the electrolyte solution. Remove and dry.Scraping off the anode material on the surface of the collector and measuring the total mass M2 of Ni and Mn using ICP after the anode material has dissolved, using 5 parallel samples (i.e., 5 batteries were used for the test), and calculating the average value of M2, which is considered as... M2¯ is being recorded.

[0042] Calculates to obtain k, k%=M2¯ / M1¯×100%;

[0043] The dissolution procedure is as follows: Disperse the cathode material or the anode material in 20 mL of water, add 10 mL of nitric acid (66% HNO3 mass content), disperse and heat until the cathode material or the anode material is completely dissolved, then make up the mixture with water to 100 mL to obtain the solution to be tested, and then perform an ICP test with the solution to be tested;

[0044] The operating conditions of the ICP instrument are as follows: gas flow rate 0.5 L / min, power 1150 W;

[0045] The procedure for determining the capacity is as follows: charging with 0.33C constant current and constant voltage to 4.75V, where the cut-off current at constant voltage ≤ 0.05C, discharging with 0.33C constant current to 3.5V, and repeating the charging and discharging process twice;

[0046] The cycle procedure is as follows: charging with constant current and constant voltage at a rate of 1C up to an upper limit voltage of 4.75V, charging with constant voltage at this voltage until the current is less than or equal to 0.05C; and then discharging at 1C down to a lower limit voltage of 3.5V and repeating the above charging and discharging process 200 times.

[0047] In some of these embodiments, the first lithium nickel manganese oxide particles have a disordered Fd-3m structure, while the second lithium nickel manganese oxide particles have an ordered P4332 structure. The disordered structure of lithium nickel manganese oxide (space group Fd3m) is a face-centered cubic lattice, and unlike the ordered structure (space group P4332), the Mn and Ni ions in the disordered structure are randomly distributed at the 16d sites, rather than being ordered at specific locations. Lithium nickel manganese oxide with a disordered structure has higher conductivity and a higher ion diffusion coefficient, typically by 2.5 orders of magnitude higher than that of the ordered structure. This is mainly due to the presence of a small amount of Mn. 3+ due to the disordered structure, whose radius is larger than that of Mn 4+This increases the lattice parameter, which is to some extent beneficial for Li+ diffusion and electron conduction; the LNMO structure of the ordered Fd-3m structure is stable. The first lithium nickel manganese oxide particles exhibit a disordered Fd-3m structure, while the second lithium nickel manganese oxide particles exhibit an ordered P4332 structure, resulting in improved kinetic and cycle performance of the cathode foil.

[0048] The present invention does not restrict the testing method for the crystal structure of lithium nickel manganese oxide in each active layer of the cathode foil, and the person skilled in the art can test the crystal structure of lithium nickel manganese oxide in each active layer of the cathode foil using conventional technical means. For example, the crystal structure of lithium nickel manganese oxide in each active layer of the cathode foil can be tested by Raman spectroscopy after each material of the active layer has been scraped off separately. If an obvious cleavage peak phenomenon is observed in the corresponding F during Raman spectroscopy, 2g(1) -Peak at around 594 cm -1This occurrence indicates that the degree of disorder in Ni / Mn has increased, leading to a transformation of the ordered structure into a disordered Fd-3m structure. The test conditions for Raman spectroscopy can be determined as follows: the laser wavelength is 514 nm, and the Raman shift interval is 100 cm⁻¹. -1 up to 2000 cm -1 ; and the Raman spectrometer can be selected as the RM2000 confocal micro-Raman spectroscopy analyzer from Renishaw, UK.

[0049] In some of these embodiments, the total thickness of the first active cathode substance layer and the second active cathode substance layer is 100 µm to 160 µm, for example 100 µm, 110 µm, 120 µm, 130 µm, 140 µm, 150 µm, 160 µm or any value in a range between two of these values.

[0050] The first lithium nickel manganese oxide particles and the second lithium nickel manganese oxide particles are of the spinel type with the chemical formula LiNi x Mn 2-xO4, where x > 0, for example 0.1, 0.2, 0.3, 0.4, 0.5, or any value in a range between any two of these values. Their surfaces may either both be free of the coating material, or some or all surfaces of at least the first lithium nickel manganese oxide particles and the second lithium nickel manganese oxide particles may be coated with a coating layer formed from the coating material. The coating material may optionally contain at least one of the following materials: aluminum oxide, titanium oxide, lithium phosphate, zirconium oxide, tantalum oxide, magnesium oxide, iron oxide, and the like. In some embodiments, the thickness of the coating layer on the surface of the first lithium nickel manganese oxide particles is 5 nm to 50 nm, for example 5 nm, 8 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm or any value in a range between two of these values.In some embodiments, the thickness of the coating layer on the surface of the second lithium nickel manganese oxide particles is 5 nm to 50 nm, for example, 5 nm, 8 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, or any value in a range between any two of these values. If the first lithium nickel manganese oxide particles and the second lithium nickel manganese oxide particles are both provided with a coating layer on their surfaces, the material of the coating layer, its thickness, and the like are independent of each other.

[0051] The first lithium nickel manganese oxide particles and the second lithium nickel manganese oxide particles can either be free of dopants or contain dopants. The present invention does not restrict the type of dopant in the first lithium nickel manganese oxide particles and the second lithium nickel manganese oxide particles; for example, at least one of the elements Si, Mg, P, Co, Al, Cr, Nb, etc., can be selected. Whether the first lithium nickel manganese oxide particles and the second lithium nickel manganese oxide particles contain dopants or not, as well as the types of dopants and their concentrations, are independent of each other and do not affect each other.

[0052] The present invention does not restrict the method for producing the first lithium nickel manganese oxide particles and the second lithium nickel manganese oxide particles, and the person skilled in the art can produce the first lithium nickel manganese oxide particles and the second lithium nickel manganese oxide particles by conventional technical means. For example, the first lithium nickel manganese oxide particles and the second lithium nickel manganese oxide particles can be produced by a method comprising the following steps:

[0053] Mixing and dispersing the lithium source, the nickel source, and the manganese source in a solvent to obtain a mixture;

[0054] Calcining the mixture at a temperature in the range of 650 to 900°C, cooling and obtaining a bare lithium nickel manganese oxide material;

[0055] Grinding and drying the bare lithium nickel manganese oxide material to obtain lithium nickel manganese oxide particles.

[0056] In the process for preparing the mixture using the lithium source, the nickel source, and the manganese source, the solvent can be selected from at least one of ethanol, NMP, acetonitrile, DMC, and other solvents. In some embodiments, the mixing and dispersing process can be selected from a solid-state process, such as ball milling, sand milling, and the like.

[0057] When producing the first blank lithium nickel manganese oxide material using the mixture, the process conditions for calcination can be set as follows: temperature range of calcination 650°C to 900°C, calcination time 12 hours to 24 hours and heating rate 1°C / hour to 5°C / hour;

[0058] Calcination can be carried out in calcining equipment such as muffle furnaces, tube furnaces, etc.

[0059] In the production of lithium nickel manganese oxide particles using bare lithium nickel manganate material, the milling process can be sand milling, and the conditions for sand milling can be chosen as follows: the sand ratio (mass ratio, the same below) is 8 to 20:1, the rotational speed is 1000 rpm to 3000 rpm, the sand milling time is 4 hours to 24 hours, and the sand particles can be chosen as at least one of aluminum oxide, zirconium oxide, silicon carbide, and boron carbide.

[0060] The lithium source includes, but is not limited to, at least one of lithium hydroxide, lithium carbonate, lithium nitrate, lithium oxalate, lithium dihydrogen phosphate, lithium citrate, or lithium acetate; and / or The nickel source includes, but is not limited to, at least one of nickel carbonate, nickel sulfate, nickel nitrate, nickel chloride, nickel oxalate, and nickel acetate; and / or The manganese source includes at least one of manganese dioxide, manganese hydroxide, manganese oxide and manganese sulfate, but is not limited to these.

[0061] If the first lithium nickel manganese oxide particles or the second lithium nickel manganese oxide particles have a disordered Fd-3m structure, the corresponding calcination temperature is 750 °C to 900 °C and the calcination time is 16 hours to 20 hours;

[0062] If the first lithium nickel manganese oxide particles or the second lithium nickel manganese oxide particles have an ordered P4332 structure, the corresponding calcination temperature is 650 °C to 700 °C and the calcination time is 12 hours to 18 hours.

[0063] Furthermore, the first lithium nickel manganese oxide particles and / or the second lithium nickel manganese oxide particles can be coated. For example, the coating material is applied to the surface of the first lithium nickel manganese oxide particles and / or the second lithium nickel manganese oxide particles using atomic layer deposition (ALD) technology. The coating material can be selected from at least one of aluminum oxide, titanium oxide, zinc oxide, and magnesium oxide; the number of ALD deposition rounds can be chosen between 50 and 500; and the thickness of an ALD deposition round can be chosen between 0.1 nm and 0.3 nm.

[0064] Furthermore, in the production of the first lithium nickel manganese oxide particles and / or the second lithium nickel manganese oxide particles, a specific amount of the dopant source (if present) can be mixed and dispersed together with the lithium source, the nickel source, and the manganese source to produce the first lithium nickel manganese oxide particles and / or the second lithium nickel manganese oxide particles as desired. The dopant source, such as at least one of the following sources (Si, Mg, P, Co, Al, Cr, Nb, etc.), is used to obtain the first lithium nickel manganese oxide particles and / or the second lithium nickel manganese oxide particles containing a specific amount of the dopant.

[0065] In some of these embodiments, the percentage by mass of the first lithium nickel manganese oxide particles in the first active cathode substance layer is 94% to 98%, for example 94%, 95%, 96%, 97%, 98% or any percentage formed in a range between two of these values.

[0066] The first active cathode layer further comprises a conductive agent and a binder. The conductive agent in the first active cathode layer is used to ensure electrical conductivity, and any conductive agent may be used without particular restriction, provided it has suitable electronic conductivity and does not cause any obviously adverse chemical changes in the battery. For example, the conductive agent in the active cathode layer comprises at least one of carbon nanotubes, carbon black, graphite, carbon fibers, activated carbon, mesoporous carbon, or fullerenes, wherein the carbon fibers are, for example, carbon nanofibers and the like; and the carbon black is, for example, SP (Super P, hereinafter referred to as "SP"), acetylene black, cotinine black, and the like.

[0067] In some of these embodiments, the percentage by mass of the conductive agent in the first active cathode substance layer is 0.05% to 3.5%, for example 0.05%, 0.08%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5% or any value in a range between two of these values.

[0068] The binder in the first active cathode substance layer is used to improve the bonding between the first LNMO particles and the bonding between the first LNMO particles and the cathode collector. Any binder may be used without particular restriction, provided it has suitable binder properties and does not cause obviously adverse chemical changes in the battery. For example, the binder in the first active cathode substance layer includes a fluoropolyolefin-based binder, and the fluoropolyolefin-based binder includes, but is not limited to, polyvinylidene fluoride (PVDF), copolymers of vinylidene fluoride, or modified derivatives thereof (e.g., carboxylic acid, acrylic acid, acrylonitrile, and other modifications thereof).

[0069] In some of these embodiments, the percentage by mass of the binder in the first active cathode substance layer is 0.5% to 2.5%, for example 0.5%, 1%, 1.5%, 2%, 2.5% or any value in a range between two of these values.

[0070] In some of these embodiments, the percentage by mass of the second lithium nickel manganese oxide particles in the second active cathode substance layer is 94% to 98%, for example 94%, 95%, 96%, 97%, 98% or any value in a range between two of these values.

[0071] The second active cathode layer further comprises a conductive agent and a binder. The conductive agent in the second active cathode layer is used to ensure electrical conductivity, and any conductive agent may be used without particular restriction, provided it has suitable electronic conductivity and does not cause any obviously adverse chemical changes in the battery. For example, the conductive agent in the active cathode layer comprises at least one of carbon nanotubes, carbon black, graphite, carbon fibers, activated carbon, mesoporous carbon, or fullerenes, wherein the carbon fibers are, for example, carbon nanofibers and the like; and the carbon black is, for example, SP (Super P, hereinafter referred to as "SP"), acetylene black, cotinine black, and the like.

[0072] In some of these embodiments, the percentage by mass of the conductive agent in the second active cathode substance layer is 0.05% to 3.5%, for example 0.05%, 0.08%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5% or any value in a range between two of these values.

[0073] The binder in the second active cathode layer is used to improve the bonding between the second LNMO particles and the bonding between the second LNMO particles and the second cathode layer. Any binder may be used without special restriction, provided it has suitable binder properties and does not cause obviously adverse chemical changes in the battery. For example, the binder in the second active cathode layer includes a fluoropolyolefin-based binder, and the fluoropolyolefin-based binder includes, but is not limited to, polyvinylidene fluoride (PVDF), copolymers of vinylidene fluoride, or modified derivatives thereof (e.g., carboxylic acid, acrylic acid, acrylonitrile, and other modifications thereof).

[0074] In some of these embodiments, the percentage by mass of the binder in the second active cathode substance layer is 0.5% to 2.5%, for example 0.5%, 1%, 1.5%, 2%, 2.5% or any value in a range between two of these values.

[0075] The present invention does not impose any special restrictions on the cathode collector, as long as it is electrically conductive, without causing harmful chemical changes in the battery, and can be made of, for example: aluminum, nickel, titanium, stainless steel, burnt carbon; or aluminum or stainless steel that has been surface-treated with carbon, nickel, titanium, silver and the like.

[0076] In the present invention, the cathode foil can be produced using conventional methods. For example:

[0077] Dispersing a first active cathode substance, a conductive agent and a binder in a solvent to obtain a first cathode slurry;

[0078] Dispersing the second active cathode substance, the conductive agent and the binder in the solvent to obtain the second cathode slurry;

[0079] Application of the first and second cathode slurries to at least one side of the cathode collector and obtaining the cathode foil after cold pressing, cutting, and other processes. The solvent comprises, but is not limited to, at least one of N-methylpyrrolidone (NMP) and deionized water. When applying the first and second cathode slurries to at least one side of the cathode collector, the first cathode slurry is applied first, followed by the second cathode slurry. battery

[0080] The present invention further provides a battery comprising a cathode foil, an anode foil and an electrolyte solution;

[0081] In some embodiments, the transition metal elements in the anode foil comprise nickel and manganese; the nickel content in the anode foil is in the range of 50 ppm to 200 ppm, and the manganese content is in the range of 500 ppm to 1500 ppm. For example, the nickel content in the anode foil is 50 ppm, 80 ppm, 100 ppm, 120 ppm, 150 ppm, 170 ppm, 200 ppm, or any value in the range between any two of these values. The manganese content is 500 ppm, 700 ppm, 1000 ppm, 1200 ppm, 1500 ppm, or any value in the range between any two of these values. By controlling the content of the Ni element and the Mn element in the anode foil, damage to the SEI film of the anode by the transition metal ions is reduced and the cycle performance of the battery is improved; at the same time, excessive passivation of the cathode is avoided.

[0082] The present invention does not restrict the test method for the content of the nickel and manganese elements in the anode foil, and a person skilled in the art can test the content of the nickel and manganese elements in the anode foil using conventional technical means. For example, the content of the nickel and manganese elements in the anode can be tested by the following method:

[0083] Take an empty battery and disassemble it to obtain the cathode and anode foils. Mix the obtained cathode and anode foils with the electrolyte solution (ethylene carbonate (EC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC)) in a volume ratio of 1:1:1 to obtain an organic solvent. Dissolve the completely dried lithium salt LiPF6 in the mixed organic solvent to obtain an electrolyte solution with LiPF6 at a concentration of 1 mol / L. Determine the capacity at 25°C for 2 cycles and then at 25°C for 200 cycles at a rate of 1C. Then disassemble it to obtain the anode foil. Immerse the anode foil in DMC (dimethyl carbonate) at room temperature (e.g., 25°C, see below) for 1 hour to remove the electrolyte solution. Remove and dry.Scraping off the anode material from the surface of the collector and measuring the mass fraction of Ni and Mn using ICP after the anode material has dissolved (the dissolution procedure was the same as above), and determining the content of the Ni element and the Mn element in the anode foil.

[0084] The anode foil of the present invention comprises an anode collector and an active anode material layer provided on at least one surface of the anode collector, wherein the active anode material layer comprises an active anode material.

[0085] The present invention has no particular limitations regarding the active anode material. For example, the active anode material comprises at least one of natural graphite, synthetic graphite, microcarbon spheres in the middle phase (MCMB), hard carbon, soft carbon, silicon, SiO₂. f(0 <f<2, z. B. f=1), Silizium-Kohlenstoff-Komplex und Li4Ti5O 12 , but is not limited to that.

[0086] In some of these embodiments, the percentage by mass of the active anode material in the active anode material layer is 92% to 98%. For example, the content of the active anode substance in the active anode material layer is 92%, 93%, 94%, 95%, 96%, 96.4%, 97%, 98%, or any value in a range between two of these values.

[0087] The active anode material layer may further comprise a conductive agent and / or a binder and / or a thickening agent.

[0088] The conductive material in the active anode material layer is used to ensure electrical conductivity, and any conductive material may be used without particular restriction, provided it has suitable electronic conductivity and does not cause any obviously adverse chemical changes in the battery. For example, the conductive material in the active anode material layer comprises at least one of the following: carbon nanotubes, carbon black, graphite, carbon fibers, activated carbon, mesoporous carbon, fullerenes, wherein the carbon fibers are, for example, carbon nanofibers and the like; and the carbon black is, for example, SP, acetylene black, cotinine black, and the like.

[0089] In some of these embodiments, the percentage by mass of the conductive medium in the active anode material layer is 0.5% to 2.5%, for example 0.5%, 0.8%, 1.0%, 1.2%, 1.5%, 2%, 2.5% or any value in a range between two of these values.

[0090] The binder in the active anode material layer is used to improve the bonding between the particles of the active anode material and the bonding between the active anode material and the anode collector. Any binder may be used without particular restriction, provided it has suitable binder properties and does not cause obviously adverse chemical changes in the battery. For example, the binder in the active anode material layer includes, but is not limited to, at least one of carboxymethylcellulose (CMC), styrene-butadiene rubber, polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl butyral, and aqueous acrylic resin.

[0091] In some of these embodiments, the percentage by mass of the binder in the active anode material layer is 1% to 3%, for example 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.6%, 2.8%, 3% or any value in a range between two of these values.

[0092] The thickening agent in the active anode material layer is used to improve the stability of the anode slurry, and any thickening agent can be used without special restriction, provided it has suitable thickening properties and does not cause significant adverse chemical changes in the battery. The thickening agent in the active anode material layer includes, for example, at least one of carboxymethylcellulose (CMC), styrene-butadiene rubber (SBR), and hydrogenated styrene-butadiene rubber (H-SBR), but is not limited to these.

[0093] In some of these embodiments, the percentage by mass of the thickening agent in the active anode material layer is 0.5% to 2.5%, for example 0.5%, 0.8%, 1.0%, 1.2%, 1.5%, 2%, 2.5% or any value in a range between two of these values.

[0094] The present invention does not impose any special restrictions on the anode collector, as long as it is electrically conductive without causing harmful chemical changes in the battery and can be used, for example: copper, stainless steel, aluminum, nickel, titanium, burnt carbon, or copper or stainless steel, or aluminum-cadmium alloy surface-treated with at least one of carbon, nickel, titanium, silver and the like.

[0095] The electrolyte solution of the present invention can be a variety of electrolyte solutions suitable for batteries. The electrolyte solution comprises an electrolyte and a solvent, wherein the electrolyte typically contains a lithium salt.

[0096] For example, the lithium salt may include, but is not limited to, at least one of the following lithium salts: lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalate borate (LiDFOB), lithium borate dioxylic acid (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorodioxylic acid phosphate (LiDFOP), and / or lithium tetrafluorooxalate phosphate (LiTFOP). The electrolyte concentration in the electrolyte solution can range from 0.5 to 5 mol / L.

[0097] In particular, the solvent may be at least one of, but is not limited to, ethylidene carbonate (EC), methyl ethyl carbonate (EMC), diethyl carbonate (DEC), propylidene carbonate (PC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methylenepropylene carbonate (MPC), ethylenepropylene carbonate (EPC), butylidene carbonate (BC), fluorinated ethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 4-butyrolactone (GBL), cyclobutane sulfone (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), and diethyl sulfone (ESE). The percentage by mass of the solvent in the electrolyte solution may be from 70% to 98%.

[0098] Furthermore, the electrolyte solution may optionally include an additive. For example, the additive may include a film-forming additive for the anode and a film-forming additive for the cathode, and may also include an additive that improves certain battery properties, such as an additive to improve the battery's overcharge performance, an additive to improve its high-temperature performance, an additive to improve its low-temperature performance, etc.

[0099] The battery may further include a separator. The separator is arranged between the cathode foil and the anode foil to keep the cathode foil and the anode foil apart and to prevent them from short-circuiting. The separator may be made of various materials suitable for use as insulating films for batteries according to the prior art. For example, the separator may include at least one of polypropylene and one of polyethylene. Power-consuming device

[0100] The present invention further provides a power-consuming device comprising a battery as described above. The battery serves as an energy source for the power-consuming device.

[0101] A power-consuming device is any device that can utilize electrical energy and convert it into one or more other formative energies such as mechanical energy, thermal energy, light energy, etc., such as an electric motor, an electric heater, an electric light source, and the like. Specifically, it can be a mobile device, an electric vehicle, an electric train, a ship, a satellite, an energy storage system, etc. A mobile device can be a mobile phone, a laptop, a drone, a robotic sweeper, an electronic cigarette, etc. An electric vehicle can be a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc.

[0102] The present invention will be explained in more detail below with reference to specific embodiments. It should be noted that, unless otherwise specified, the subsequent calcination takes place in an atmospheric environment. Example 1

[0103] One embodiment provides a lithium-ion battery which is manufactured as follows: (1) Production of the first lithium nickel manganese oxide particles

[0104] Mixing and dispersing Li2CO3, NiCO3 and MnO2 in a ball mill according to the stoichiometric ratios of Li, Ni and Mn in the chemical formula LiNi 0,5 Mn 1,5O4, to obtain a mixture; adding the obtained mixture to a muffle furnace to raise the temperature to T1°C, calcining for t1 hours, cooling to room temperature and transferring the material to a grinding machine, wherein zirconium dioxide grain was used for grinding, wherein the ratio of abrasive to material is S1:1, the grinding time is t1' hour, drying after grinding; coating an aluminum oxide coating layer on the surface of the material with an ALD instrument, wherein the thickness of each deposition round is 0.1 nm, to obtain aluminum oxide-coated lithium nickel manganese oxide, to obtain the first lithium nickel manganese oxide particles, wherein the thickness of the coating layer is C1 nm and the values ​​of T1, t1, S1, t1' and C1 are given in Table 1. (2) Production of the second lithium nickel manganese oxide particles

[0105] Mixing and dispersing Li2CO3, NiCO3 and MnO2 in a ball mill according to the stoichiometric ratios of Li, Ni and Mn in the chemical formula LiNi 0,5 Mn 1,5O4, to obtain a mixture; adding the obtained mixture to a muffle furnace to raise the temperature to T2°C, calcining for t2 hours, cooling to room temperature and transferring the material to a grinding machine, wherein zirconium dioxide grain was used for grinding, wherein the ratio of abrasive to material is S2:1, the grinding time is t2' hour, drying after grinding; coating an aluminum oxide coating layer on the surface of the material with an ALD instrument, wherein the thickness of each deposition round is 0.1 nm, to obtain aluminum oxide-coated lithium nickel manganese oxide, to obtain the first lithium nickel manganese oxide particles, wherein the thickness of the coating layer is C2 nm and the values ​​of T2, t2, S2, t2' and C2 are given in Table 1. (3) Production of the cathode foil

[0106] Mixing the first lithium nickel manganese oxide particles as active cathode material with the conductive agent CNTs and the binder PVDF in a mass ratio of 97:1:2, adding the solvent NMP, stirring in a vacuum mixer and obtaining a first cathode slurry (to form the first active cathode substance layer);

[0107] Mixing the second lithium nickel manganese oxide particles as active cathode material with the conductive agent CNTs and the binder PVDF in a mass ratio of 97:1:2, adding the solvent NMP, stirring in a vacuum mixer and obtaining a second cathode slurry (to form the second active cathode substance layer);

[0108] Applying the first cathode slurry and the second cathode slurry to both sides of the aluminum foil of the cathode collector, coating the first cathode slurry on both sides of the cathode collector first, and applying the second cathode slurry to the surface of the first cathode slurry after the first cathode slurry has dried, and then obtaining the cathode foil after drying, cold pressing and cutting;

[0109] wherein a thickness fraction of the second active cathode substance layer, which is calculated on the basis of a total thickness of the first active cathode substance layer and the second active cathode substance layer, M b is, where the values ​​of M b are listed in Table 1. (4) Production of the anode foil

[0110] Mixing the active anode material (artificial graphite), the conductive agent (acetylene black), the thickening agent (CMC), and the binder (SBR) in a mass ratio of 96.4:1:1.2:1.4, adding the solvent (deionized water), and stirring in a vacuum mixer to obtain the anode slurry. Applying the anode slurry to both sides of the copper foil of the anode collector, followed by cold pressing and cutting of the anode foil. (5) Preparation of the electrolyte solution

[0111] Mixing ethylene carbonate (EC) and dimethyl carbonate (DMC) in a volume ratio of 1:1 to obtain an organic solvent, and dissolving the dried lithium salt LiPF6 in the obtained organic solvent to obtain an electrolyte solution with LiPF6 at a concentration of 1 mol / L. (6) Production of the lithium-ion battery

[0112] The cathode foil, separator (PE), and anode foil are stacked sequentially, with the separator positioned between the cathode and anode foils to act as insulation. These layers are then wound to form the bare electrical core. The bare electrical core is placed in the outer packaging, dried, and injected with the electrolyte solution. After vacuum encapsulation and a settling period, the formation process is carried out to create the lithium-ion battery. The formation process is as follows: the battery is charged to 4.8 V using the LAND system at a constant current of 0.33 C, then discharged to 3.5 V at a constant current of 0.33 C. This process is repeated for two cycles, after which the battery is removed from the charging system. Exemplary embodiments 2 to 27 and comparative examples 1 to 6

[0113] The embodiments and the comparative examples all provide a lithium-ion battery, and the manufacturing process is similar to that of embodiment 1, with the following difference: (a) In step (1) the values ​​of T1, t1, S1, t1' and C1 are given in Table 1; (b) In step (2) the values ​​of T2, t2, S2, t2' and C2 are given in Table 1; (c) In step (3), the total thickness of the first cathode substance layer and the second cathode substance layer remains unchanged, and the values ​​of M b are listed in Table 1. Table 1 T1 T2 t1 t2 S1 S2 t1' t2' C1 C2 MB Example 1 850 650 16 14 15 10 12 12 25 25 0,65 Example 2 850 650 16 14 15 10 13,6 12,5 26 26 0,66 Example 3 800 650 16 14 15 10 14,2 11 24 24 0,65 Example 4 860 680 16 14 15 10 11 10 20 20 0,64 Example 5 850 650 16 14 15 10 12,8 10 28 28 0,63 Execution b el 6 850 650 16 14 15 10 12 12 25 25 0,60 Example 7 850 650 16 14 15 10 12 12 25 25 0,70 Example 8 880 650 16 14 15 10 12 10,5 22 22 0,64 Example 9 850 650 16 14 15 10 13,8 10 21 21 0,65 Example 10 850 650 16 14 15 10 11,3 15 27 27 0,66 Example 11 850 650 16 14 15 10 14,8 18 35 35 0,65 Example 12 780 700 16 14 15 10 9,6 8 15 15 0,66 Example 13 850 650 16 14 15 10 19,7 12,8 27 27 0,64 Example 14 850 650 16 14 15 10 12,4 18 34 34 0,66 Example 15 850 650 16 14 20 8 9 8 18 18 0,65 Example 16 900 650 16 14 10 15 10 4 14 14 0,67 Example 17 900 650 16 14 15 10 5,5 10,4 18 18 0,66 Example 18 850 650 16 14 15 10 12 12 27 27 0,51 Example 19 850 650 16 14 15 10 12 12 23 23 0,78 Example 20 850 650 16 14 15 10 12 12 17 17 0,60 Example 21 850 650 16 14 15 10 12 12 45 45 0,78 Example 22 850 650 16 14 15 10 12 12 22 22 0,52 Example 23 850 650 16 14 15 10 12 12 19 19 0,53 Example 24 850 650 16 14 15 10 12 12 50 50 0,78 Example 25 850 750 16 16 15 10 12 12 25 25 0,66 Example 26 700 650 18 14 15 10 12 12 25 25 0,67 Example 27 700 750 18 16 15 10 12 12 25 25 0,65 Comparison example 1 800 650 16 14 15 10 14,2 11 50 50 0,66 Comparison example 2 850 750 16 14 15 10 12 3,5 10 10 0,65 Comparison example game 3 800 650 16 14 15 10 28 19 28 28 0,67 Comparison example 4 950 650 16 14 15 10 3 3 22 22 0,66 Comparison example 5 850 650 16 14 15 10 12 12 26 26 0,40 Comparison example 6 850 650 16 14 15 10 12 12 21 21 0,90

[0114] The particle size Dn50 (a µm) of the first lithium nickel manganese oxide particles, the particle size Dn50 (b µm) of the second lithium nickel manganese oxide particles, the thickness fraction (M bThe ratio of the second active cathode layer to the total thickness of the first active cathode layer and the second active cathode layer, the amount (k%) of transition metal ions released from the cathode foil after 200 cycles at 25°C, and the crystal structures of the first lithium nickel manganese oxide particles and the second lithium nickel manganese oxide particles are shown in Table 1 or Table 2:

[0115] Partial size of the first and second lithium nickel manganese oxide particles: Take an empty battery and disassemble it to obtain the cathode foil, which is then subjected to CP sectioning; observation and measurement using SEM with the magnification set to 5 Kx. The upper, middle, and lower regions of each active substance layer were selected and photographed; the particle size distribution of all particles in these three regions was measured, and an average particle size Dn50 was determined for 50% of the number distribution in these three regions; the average value of Dn50 in these three regions was calculated to obtain the average particle size Dn50 of each active substance layer, i.e., the particle size Dn50(a) of the first lithium nickel manganese oxide particles and the particle size Dn50(b) of the second lithium nickel manganese oxide particles.

[0116] Thickness fraction of the second active cathode substance layer: Take an empty battery and disassemble it to obtain the cathode foil; the cathode foil is then subjected to CP sectioning; using SEM (scanning electron microscopy), the thickness of the first active cathode substance layer and the thickness of the second active cathode substance layer are determined in cross-section and then calculated to determine the thickness fraction (M). b ) to obtain the second active cathode substance layer.

[0117] Transition metal ion release after 200 cycles at 25°C: Take an empty battery and disassemble it to obtain the cathode foil. Immerse the cathode foil in DMC (dimethyl carbonate) at 25°C for 1 hour to remove the electrolyte solution. Remove and dry. Scrape the cathode material from the collector surface and, after the cathode material has dissolved, use ICP (inductively coupled plasma) to measure the total mass of Ni and Mn. The sum of the two is M1, where 5 parallel samples (i.e., 5 batteries were used for the test) were measured, and the average value of M1 was calculated and recorded.

[0118] Take an empty battery and disassemble it to obtain the cathode and anode foils. Mix the obtained cathode and anode foils with the electrolyte solution (ethylene carbonate (EC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC)) in a volume ratio of 1:1:1 to obtain an organic solvent. Dissolve the completely dried lithium salt LiPF6 in the mixed organic solvent to obtain an electrolyte solution with LiPF6 at a concentration of 1 mol / L. Determine the capacity at 25°C for 2 cycles and then at 25°C for 200 cycles at a rate of 1C. Then disassemble it to obtain the anode foil. Immerse the anode foil in DMC (dimethyl carbonate) at 25°C for 1 hour to remove the electrolyte solution. Remove and dry.Scraping off the anode material on the surface of the collector and measuring the total mass M2 of Ni and Mn using ICP after the anode material has dissolved, using 5 parallel samples (i.e., 5 batteries were used for the test), and calculating the average value of M2, which is considered as... M2¯ is being recorded.

[0119] Calculates to obtain k, k%=M2¯ / M1¯×100%;

[0120] The dissolution procedure is as follows: Disperse the cathode material or the anode material in 20 mL of water, add 10 mL of nitric acid (66% HNO3 mass content), disperse and heat until the cathode material or the anode material is completely dissolved, then make up the mixture with water to 100 mL to obtain the solution to be tested, and then perform an ICP test with the solution to be tested;

[0121] The operating conditions of the ICP instrument are as follows: gas flow rate 0.5 L / min, power 1150 W;

[0122] The procedure for determining the capacity is as follows: charging with 0.33C constant current and constant voltage to 4.75V, where the cut-off current at constant voltage ≤ 0.05C, discharging with 0.33C constant current to 3.5V, and repeating the charging and discharging process twice;

[0123] The cycle procedure is as follows: charging with constant current and constant voltage at a rate of 1C up to an upper limit voltage of 4.75V, charging with constant voltage at this voltage until the current is less than or equal to 0.05C; and then discharging at 1C down to a lower limit voltage of 3.5V and repeating the above charging and discharging process 200 times.

[0124] Determination of the crystal structure of the first and second lithium nickel manganese oxides: Conformational analysis of the prepared materials was performed using a confocal microscopic Raman spectrometer, RM2000, manufactured by Renishaw, UK. Test conditions: The laser wavelength is 514 nm, and the Raman shift interval is 100 cm⁻¹. -1 up to 2000 cm -1 The A1g peak is at 638.8 cm -1 and the F 2g(1) Peaks at 594.7 and 611.3 cm -1 corresponded to the symmetrical stretching vibration of the Mn-O bond in the Raman test pattern. Meanwhile, the Eg peak at 408.4 cm⁻¹ corresponds to -1 and the F 2g(1) -Peak at 498.4 cm -1 of the stretching vibration of the Ni-O bond. The intensities of the peaks at 638.8 cm⁻¹ -1 498.4 cm -1 and 408.4 cm -1 are significantly lower in the sample with disordered structure than in the sample with ordered structure. Furthermore, the F 2g(1)-Peak at 594.7 cm -1 In the sample with disordered structure, a more pronounced cleavage is observed, which is mainly due to the increase in the degree of disorder of Ni / Mn, leading to the structural transition from the ordered P4332 structure to the disordered Fd-3m structure.

[0125] The lithium-ion batteries obtained from the above embodiments and comparative examples were tested as follows:

[0126] Battery capacity retention rate after 100 cycles at 45°C and DCR growth rate after 100 cycles at 45°C: After being left to stand, the battery was charged to 4.8 V at a constant current rate of 0.33C using a Blue Power (LAND) system, and then discharged to 3.5 V at a constant current rate of 0.33C, performing two cycles. At the end of each cycle, the battery was removed from the charging device and left for use (the activation process). After battery activation, the battery is charged at 45°C at a constant current rate of 1C to 4.8 V, and then charged at a constant voltage until the current is less than 0.05C. Then the battery is discharged and charged at a rate of 1C until the voltage reaches 3.5V, and a complete charge and discharge process is performed as one cycle, repeated for 100 cycles.Calculate the capacity maintenance rate using the following formula: Capacity maintenance rate = Discharge capacity of the 100th cycle / Discharge capacity of the first cycle * 100%.

[0127] The DCR value after 100 cycles at 45°C is recorded as R1, and the initial DCR value before the cycle is recorded as R0; then the DCR growth rate after 100 cycles is = (R1-R0) / R0*100%.

[0128] The DCR test condition for the battery is at 50% SOC; the specific DCR test procedure is as follows: A1. Leave the battery at room temperature (25°C) for 10 minutes; A2. Charging the battery with constant current and constant voltage, at a constant current rate of 0.33C, voltage of 4.80V, charging at constant voltage up to a current of ≤ 0.05C and discharging at constant current up to 3.5V, at a rate of 0.33C; A3. Repeat steps A1 to A2 three times. In the last step A2, the discharge capacity is recorded as C1; A4. Repeat steps A1 to A2 until the battery is fully charged; A5. Discharge with constant current until the capacity is 0.5C1, the discharge rate is 0.33C. At this point, the battery is in a 50% state of charge (SOC). A6. Leave the battery for 120 minutes and record the voltage as V0 at the end of the standby time; A7. Discharge with constant current for 18 seconds, the rate is 1C, recording the voltage at the end of the discharge as V1. Table 2 a b away k k / M b Structure of the first lithium nickel manganese oxide particles Structure of the second lithium nickel manganese oxide particle Capacity maintenance rate after 100 cycles at 45°C DCR growth rate after 100 cycles at 45°C Example 1 2,51 6,53 0,384 0,10 0,15 disordered Fd-3m structure orderedP4332 structure 98,00% 1,23% Example 2 2,02 6,24 0,324 0,09 0,14 disordered Fd-3m structure orderedP4332 structure 96,00% 1,47% Example 3 2,01 6,64 0,303 0,12 0,18 disordered Fd-3m structure orderedP4332 structure 95,00% 1,65% Example 4 2,77 6,96 0,398 0,10 0,16 disordered Fd-3m structure orderedP4332 structure 94,50% 2,11% Example 5 2,24 6,00 0,373 0,11 0,17 disordered Fd-3m structure orderedP4332 structure 96,00% 1,46% Example 6 2,50 6,54 0,382 0,11 0,18 disordered Fd-3m structure orderedP4332 structure 97,10% 1,25% Example 7 2,52 6,52 0,387 0,10 0,14 disordered Fd-3m structure orderedP4332 structure 96,30% 1,24% Example 8 2,98 6,81 0,438 0,11 0,17 disordered Fd-3m structure orderedP4332 structure 93,00% 2,15% Example 9 2,01 6,96 0,289 0,13 0,20 disordered Fd-3m structure orderedP4332 structure 92,50% 2,48% Example 10 2,78 6,01 0,463 0,10 0,15 disordered Fd-3m structure orderedP4332 structure 92,80% 2,47% Example 11 1,58 5,03 0,314 0,11 0,17 disordered Fd-3m structure orderedP4332 structure 87,10% 2,46% Example 12 3,17 7,96 0,398 0,11 0,17 disordered Fd-3m structure orderedP4332 structure 89,00% 3,21% Example 13 1,03 6,20 0,166 0,16 0,25 disordered Fd-3m structure orderedP4332 structure 86,50% 2,77% Example 14 2,33 5,02 0,464 0,09 0,14 disordered Fd-3m structure orderedP4332 structure 89,20% 2,87% Example 15 1,01 7,97 0,127 0,17 0,26 disordered Fd-3m structure orderedP4332 structure 87,40% 4,51% Example 16 3,98 7,98 0,499 0,09 0,13 disordered Fd-3m structure orderedP4332 structure 90,60% 4,55% Example 17 3,98 6,83 0,583 0,10 0,15 disordered Fd-3m structure orderedP4332 structure 88,20% 3,50% Example 18 2,50 6,53 0,383 0,08 0,16 disordered Fd-3m structure orderedP4332 structure 92,10% 2,66% Example 19 2,52 6,52 0,387 0,12 0,15 disordered Fd-3m structure orderedP4332 structure 91,10% 2,52% Example 20 2,49 6,54 0,381 0,18 0,30 disordered Fd-3m structure orderedP4332 structure 93,70% 2,12% Example 21 2,53 6,52 0,388 0,05 0,06 disordered Fd-3m structure orderedP4332 structure 90,80% 2,75% Example 22 2,52 6,54 0,385 0,14 0,27 disordered Fd-3m structure orderedP4332 structure 91,30% 3,01% Example 23 2,53 6,53 0,387 0,22 0,42 disordered Fd-3m structure orderedP4332 structure 90,10% 4,44% Example 24 2,50 6,52 0,383 0,03 0,04 disordered Fd-3m structure orderedP4332 structure 89,80% 3,81% Example 25 2,51 6,57 0,382 0,11 0,17 disordered Fd-3m structure disordered Fd-3m structure 92,30% 2,52% Example 26 2,49 6,53 0,381 0,12 0,18 orderedP4332 structure orderedP4332 structure 94,70% 3,88% Example 27 2,49 6,55 0,380 0,10 0,15 orderedP4332 structure disordered Fd-3m structure 91,90% 4,01% Comparative example 1 2,01 4,50 0,447 0,11 0,17 disordered Fd-3m structure orderedP4332 structure 74,40% 5,76% Comparative example 2 2,51 10,00 0,251 0,12 0,18 disordered Fd-3m structure orderedP4332 structure 80,50% 8,33% Comparative example 3 0,70 5,03 0,139 0,09 0,13 disordered Fd-3m structure orderedP4332 structure 72,70% 5,89% Comparative example 4 4,20 7,95 0,528 0,11 0,17 disordered Fd-3m structure orderedP4332 structure 82,40% 8,12% Comparative example 5 2,50 6,55 0,382 0,10 0,25 disordered Fd-3m structure orderedP4332 structure 74,30% 5,14% Comparative example 6 2,51 6,54 0,384 0,10 0,11 disordered Fd-3m structure orderedP4332 structure 83,20% 9,35%

[0129] For the batteries produced in each embodiment of the present invention, the capacity retention rate after 100 cycles at 45°C at a rate of 1C is ≥85%, and the DCR growth rate after 100 cycles at 45°C at a rate of 1C is ≤4.6%, so that it can be seen that the batteries comprising the cathode foil of the present invention exhibit excellent kinetic performance and cycle performance at high temperature.

[0130] As can be seen from embodiments 1 to 7 in comparison to embodiments 11 to 12, from embodiment 13 in comparison to embodiment 15 and from embodiment 14 in comparison to embodiment 16, the kinetic performance and the cycle performance at high temperature of the battery are relatively better when the values ​​of the particle size Dn50 of the first lithium nickel manganese oxide particles and the second lithium nickel manganese oxide particles correspond to the preferred ranges described in the present invention.

[0131] As can be seen from embodiments 1 to 7 in comparison to embodiments 8 to 10, the kinetic power and cycle power at high battery temperature are relatively better when the cathode foil meets 0.3 ≤ a / b ≤ 0.4.

[0132] As can be seen from embodiments 1 and 6 to 7 in comparison to embodiments 18 to 19, and from embodiment 20 in comparison to embodiments 21 to 22, the kinetic power and the cycle power at high battery temperatures are relatively better when the values ​​of the thickness fraction M b the second active cathode substance layer corresponds to the preferred areas described in the present invention.

[0133] As can be seen from embodiment 15 compared to embodiment 16, from embodiments 1 to 7 compared to embodiment 20, and from embodiments 18 to 19 compared to embodiments 21 to 22, the kinetic power and cycle power at high battery temperature are relatively better when the cathode foil has a density of 0.1 ≤ k / M b ≤ 0.2 is fulfilled.

[0134] As can be seen from embodiment 1 in comparison to examples 25 to 27, the kinetic performance and the cycle performance at high temperature of the battery are relatively better when the first lithium nickel manganese oxide particles have a disordered Fd-3m structure and the second lithium nickel manganese oxide particles have an ordered P4332 structure.

[0135] According to comparative examples 1 to 6, the kinetic power and cycle power at high battery temperatures are relatively poor if the particle size Dn50 of the first lithium nickel manganese oxide particles, the particle size Dn50 of the second lithium nickel manganese oxide particles, or the thickness fraction M b the second active cathode substance layer may assume a value that is too high or too low.

[0136] Finally, it should be noted that the above-mentioned embodiments are used only to illustrate the technical solutions of the present invention and not to limit the scope of protection of the present invention. Although the present invention is described in detail with reference to the preferred embodiments, a person with ordinary technical knowledge in the field should understand that the technical solutions of the present invention can be modified or replaced with equivalent solutions without departing from the substance and scope of the technical solutions of the present invention.

[0137] The present invention relates to a cathode foil, a battery, and a power-consuming device comprising the cathode foil, and pertains to the technical field of batteries. The present invention enables a layered distribution of lithium nickel manganese oxide according to a specific particle size Dn50, with the thickness ratio between the layers being maintained within an optimal range. This ensures that the lithium nickel manganese oxide exhibits high kinetic performance while simultaneously reducing side reactions with the electrolyte solution. It improves the packing density and the uniformity of the pore size within the cathode foil, thereby effectively enhancing both the kinetic and cycle performance of the cathode foil.

Claims

Cathode foil, characterized in that it comprises: a cathode collector; a first active cathode substance layer provided on at least one surface of the cathode collector, wherein the first active cathode substance layer comprises lithium nickel manganese oxide particles, wherein a particle size Dn50 of the lithium nickel manganese oxide particles is a µm, where a is in a range of 1 ≤ a ≤ 4; and a second active cathode substance layer provided on a surface of the first active cathode substance layer facing away from the cathode collector, wherein the second active cathode substance layer comprises lithium nickel manganese oxide particles, wherein a particle size Dn50 of the lithium nickel manganese oxide particles is b µm, where b is in a range of 5 ≤ b ≤ 8;and wherein a thickness fraction of the second active cathode substance layer, calculated on the basis of a total thickness of the first active cathode substance layer and the second active cathode substance layer, Mbist, where Mbin is in a range of 0.5 to 0.8.; Cathode foil according to claim 1, characterized in that a and b satisfy the following relation formula: 0.125 ≤ a / b ≤ 0.

5. Cathode foil according to claim 2, characterized in that a and b satisfy the following relation formula: 0.3 ≤ a / b ≤ 0.

4. Cathode foil according to claim 1, characterized in that a is in a range of 2 µm to 3 µm; and / or that b is in a range of 6 µm to 7 µm; and / or that M is in a range of 0.6 to 0.

7. Cathode foil according to claim 1, characterized in that the emission amount of transition metal ions after 200 cycles at 25°C is k%, wherein the cathode foil fulfills the following: 0.06 ≤ k / Mb ≤ 0.

3. Cathode foil according to claim 5, characterized in that the cathode foil fulfills the following: 0.1≤ k / Mb≤ 0.

2. Cathode foil according to claim 5, characterized in that k lies in a range of 0.05 ≤ k ≤ 0.

2. Cathode foil according to claim 1, characterized in that the lithium nickel manganese oxide particles in the first active cathode substance layer have a disordered Fd-3m structure, wherein the lithium nickel manganese oxide particles in the second active cathode substance layer have an ordered P4332 structure. Battery characterized in that it comprises a cathode foil according to one of claims 1 to 8. Battery according to claim 9, characterized in that it further comprises an anode foil, wherein the transition metal elements in the anode foil comprise a nickel element and a manganese element; wherein the content of the nickel element in the anode foil is in the range of 50 ppm to 200 ppm, and the content of the manganese element is in the range of 500 ppm to 1500 ppm. Power-consuming device, characterized in that it comprises a battery according to claim 9 or 10.