Positive electrode material and preparation method thereof, positive plate and battery

Abstract

The invention provides a positive electrode material and a preparation method thereof, a positive plate and a battery, and belongs to the technical field of batteries, the preparation method of the positive electrode material comprises the following steps: mixing a ternary precursor and a lithium source, and performing primary sintering to obtain a primary sintered product; adding the primary sintered product into an additive-containing aqueous solution for washing, filtering and drying to obtain a washed product, and the additive comprises a lithium-containing compound; and mixing the washed product with a coating agent, and carrying out secondary sintering to obtain the positive electrode material in which the molar percentage of nickel element is greater than or equal to 80%. The lithium-containing compound is added in the washing process when the sintered product is washed, so that the escape potential barrier of lithium ions in the crystal structure of the sintered product can be increased, the bond energy strength of Li-O-Ni can be enhanced, trivalent nickel is prevented from being disproportionated to generate NiO, an inactive layer is prevented from being formed on the crystal surface of the sintered product, and the service life of the sintered product is prolonged. Through mutual cooperation of primary sintering, unconventional water washing and secondary sintering, the performance of the positive electrode material prepared through three times of sintering is achieved, and the production cost is low.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a positive electrode material and its preparation method, a positive electrode sheet, and a battery. Background Technology

[0002] With the rapid development of electric vehicles, power tools, drones, and other fields, the market demand for high energy density, high power density, and fast charge / discharge performance of lithium-ion batteries is increasing. Therefore, the development of ternary cathode materials with high specific capacity, high rate performance, low impedance, and long cycle life has become a research hotspot.

[0003] High-nickel ternary cathode materials (Ni≥80%) have high energy density, ensuring long battery life. However, due to the high Ni content, the degree of irreversible H2-H3 phase transition increases, making them prone to structural collapse during battery charge and discharge cycles, leading to a sharp deterioration in battery cycle performance and impedance. Currently, researchers are improving the interfacial conductivity and stability of high-nickel ternary cathode materials through a third sintering process, in addition to the second sintering, thereby enhancing their power and cycle performance. However, the third sintering process is significantly more expensive than the second sintering process, making it uncompetitive in terms of cost for battery cell products. Summary of the Invention

[0004] This application provides a cathode material and its preparation method, cathode sheet, and battery. The obtained cathode material achieves cost reduction while taking into account high structural stability, high conductivity, long cycle life, high power density, and low interfacial impedance.

[0005] In a first aspect, embodiments of this application provide a method for preparing a cathode material, comprising: The ternary precursor and lithium source are mixed and sintered in one step to obtain a sintered product. A calcined product is added to an aqueous solution containing additives, washed with water, filtered, and dried to obtain a washed product. The additives include lithium-containing compounds. The washed product is mixed with a coating agent and sintered twice to obtain a cathode material, wherein the molar percentage of nickel in the cathode material is ≥80%.

[0006] This application involves mixing a ternary precursor and a lithium source and then sintering them once to construct the crystal structure framework of the cathode material through a solid-state reaction. Simultaneously, some divalent nickel ions are oxidized to trivalent nickel ions and embedded in the crystal structure framework, resulting in a sintered product. The sintered product is then washed with an aqueous solution containing a lithium compound. The presence of the lithium compound increases the escape barrier of lithium ions in the crystal structure of the sintered product, enhances the bond strength of Li-O-Ni, prevents trivalent nickel disproportionation to form NiO, and avoids the formation of an inactive layer on the crystal surface of the sintered product. During the initial sintering process, water washing removes residual alkaline substances and sintering byproducts from the surface of the sintered product, optimizing its crystal structure and yielding a washed product with a specific crystal form. The washed product is then mixed with a coating agent and subjected to a second sintering. This second sintering enhances the integrity of the crystal structure, and the coating agent forms a uniform protective layer on the surface of the washed product through solid-phase diffusion or melting, improving the material's structural and cycling stability. Ultimately, a cathode material with high structural stability, high conductivity, long cycling life, high power density, low interfacial impedance, and high nickel content is obtained. In other words, this application achieves the performance of a cathode material prepared through three sintering processes—primary sintering, unconventional water washing, and secondary sintering (i.e., high-temperature re-sintering)—while maintaining low production costs.

[0007] Optionally, the additives may also include metal oxides.

[0008] This application improves the structural stability and ionic conductivity of the cathode material by adding metal oxides as additives. During the water washing process, the metal oxides are uniformly adsorbed on the surface of the sintered product, and then uniform coating of the metal oxides is achieved through subsequent secondary sintering. At the same time, during the secondary sintering, the metal oxides can also react with the lithium element in the crystal structure of the water-washed product to form a stable lithium metal composite oxide.

[0009] Optionally, the mass ratio of lithium compound to metal oxide is 0.4 to 9:1; and / or, the amount of additive is 100 ppm to 5000 ppm.

[0010] This application, by rationally setting the mass ratio of lithium-containing compounds and metal oxides, not only enables the lithium-containing chemicals to effectively suppress the escape of lithium ions from the crystal structure of the calcined product during water washing, but also enables the metal oxides to achieve a uniform coating effect. By rationally setting the amount of additives, the appropriate amount of additives can not only give full play to the role of lithium-containing compounds and metal oxides to form a protective layer of suitable thickness on the crystal surface, but also avoid excessive deposition of additives on the crystal surface, thereby avoiding the formation of impurities and further improving the performance of the cathode material.

[0011] Optionally, the lithium-containing compound includes one or more of lithium hydroxide, lithium carbonate, lithium sulfate, lithium nitrate, and lithium chloride; and / or, the oxide includes at least one of aluminum oxide, zinc oxide, cobalt trioxide, tungsten trioxide, zirconium oxide, strontium oxide, niobium pentoxide, antimony pentoxide, and titanium dioxide.

[0012] In this application, by rationally setting the types of lithium-containing compounds, not only can different application scenarios be adapted according to the characteristics of different substances, but also the synergy of different substances can better suppress the escape of lithium ions in the crystal structure of the sintered product, optimize the crystal structure of the washed product, and thus obtain a cathode material with excellent crystal structure and high performance. By selecting appropriate types of metal oxides, a protective layer can be better formed on the crystal surface of the washed product through secondary sintering, thereby improving the stability of the cathode material. Moreover, the aforementioned metal oxides have a certain electronic conductivity or can react with lithium elements in the crystal structure to generate lithium metal composite oxides with ionic conductivity, thereby reducing interfacial impedance and improving the performance of the cathode material.

[0013] Optionally, the molecular formula of the ternary precursor is Ni x Co y Mn 1-x-y (OH)₂, where 0.8 ≤ x ≤ 0.98, 0.01 ≤ y ≤ 0.19; and / or, in the X-ray diffraction spectrum of the ternary precursor, the intensity of the 001 crystal plane diffraction peak I 001 With the diffraction peak intensity I of the 101 crystal plane 101 The ratio is 1.00~2.00; and / or, the D50 particle size of the ternary precursor is 2μm~14μm.

[0014] This application achieves a higher nickel content in the ternary material precursor by rationally setting its molecular formula, resulting in a high-nickel ternary cathode material and thus improving the battery's specific capacity and energy density. Furthermore, it improves the battery's specific capacity and energy density by rationally controlling the intensity of the 001 crystal plane diffraction peak I in the ternary precursor. 001 With the diffraction peak intensity I of the 101 crystal plane 101 The ratio of the two can balance the bulk diffusion of lithium ions, the interfacial intercalation reaction, and the side reactions, thereby enabling the cathode material to achieve the best electrochemical performance. By reasonably setting the D50 particle size of the ternary precursor, the ternary precursor with a suitable particle size is more likely to react with the lithium source and obtain a sintered product with excellent crystal structure. It can also ensure that the particle size of the cathode material obtained from the reaction is within a suitable range, thereby improving the compaction density and specific surface area of ​​the cathode material and thus improving the performance of the battery.

[0015] Optionally, the molar ratio of the ternary precursor to the lithium source is 1:1.02~1.06; and / or, the lithium source includes one or more of lithium hydroxide, lithium carbonate, lithium sulfate, lithium nitrate and lithium chloride.

[0016] This application improves the cycle stability of the battery by rationally setting the mass ratio of the ternary precursor and the lithium source. An appropriate excess of lithium source not only ensures that the transition metal in the ternary precursor reacts fully with lithium ions during the first sintering process, but also avoids excessive lithium source deposition on the surface of the cathode material, which would cause side reactions with the electrolyte. By rationally setting the type of lithium source, the lithium source can decompose into lithium ions during the first sintering process to participate in the high-temperature solid-phase reaction, while avoiding lithium source deposition on the surface of the sintered product, which would affect its structure and performance.

[0017] Optionally, the amount of coating agent added is 500ppm to 20000ppm; and / or, the coating agent includes at least one of cobalt oxide, cobalt hydroxide, tungsten oxide, tungsten hydroxide, aluminum oxide, and aluminum hydroxide.

[0018] This application achieves a uniform, dense, and appropriately thick coating layer on the surface of the cathode material by rationally setting the amount of coating agent added. This coating layer can protect the cathode material and prevent side reactions between the cathode material and the electrolyte. By rationally setting the type of coating agent, the stability of the coating layer formed on the surface of the cathode material is improved, resulting in better structural stability of the cathode material. At the same time, this type of coating agent can increase the interfacial conductivity of the cathode material and improve the electrochemical performance of the battery.

[0019] Secondly, embodiments of this application provide a cathode material prepared using the cathode material preparation method provided in the first aspect of this application.

[0020] This application prepares a cathode material through a specific preparation method, thereby giving the cathode material the advantages of high stability, high specific capacity, and low impedance.

[0021] Optionally, in the X-ray diffraction spectrum of the cathode material, the full width at half maximum (FWHM) of the 104 peak is 0.039~0.310, and the FWHM of the 003 peak is 0.100~0.280.

[0022] The small half-widths of the 104 and 003 peaks in the cathode material of this application indicate that the cathode material has a high degree of crystallinity and good crystal integrity. Furthermore, the cathode material has a moderate crystal size and number of grain boundaries, which can both disperse cyclic stress and shorten the diffusion path of lithium ions. At the same time, the interlayer arrangement of the cathode material is regular, and the lithium ion diffusion channels are unobstructed.

[0023] Thirdly, embodiments of this application provide a positive electrode sheet, including a positive electrode material prepared by the method for preparing positive electrode material provided in the first aspect of this application or a positive electrode material provided in the second aspect of this application.

[0024] The positive electrode sheet of this application includes the positive electrode material prepared by the method for preparing the positive electrode material provided in the first aspect of this application or the positive electrode material provided in the second aspect of this application, thereby enabling the positive electrode sheet to have the advantages of high cycle stability, high conductivity, high energy density, high rate performance and low impedance.

[0025] Fourthly, embodiments of this application provide a battery including the positive electrode provided in the third aspect of this application.

[0026] The battery of this application includes the positive electrode provided in the third aspect of this application, thereby enabling the battery to have the advantages of long cycle life, high energy density, high rate performance and low impedance. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a SEM image of the cathode material prepared in Example 2 of this application, with a scale bar of 5 μm; Figure 2 This is a SEM image of the cathode material prepared in Comparative Example 3 of this application, with a scale bar of 5 μm; Figure 3 This is the rate discharge capacity ratio curve of the batteries assembled in Example 2 and Comparative Example 3 of this application. Detailed Implementation

[0029] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0030] This application provides a positive electrode material and its preparation method, a positive electrode sheet, and a battery. These are described in detail below. It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of the embodiments. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any referenced number (fraction or integer) within the indicated range.

[0031] The technical solution of this application is as follows: Embodiments of this application provide a method for preparing a cathode material, comprising: The ternary precursor and lithium source are mixed and sintered in one step to obtain a sintered product. A calcined product is added to an aqueous solution containing additives, washed with water, filtered, and dried to obtain a washed product. The additives include lithium-containing compounds. The washed product is mixed with a coating agent and sintered twice to obtain a cathode material, in which the molar percentage of nickel is ≥80%.

[0032] In this application, a ternary precursor and a lithium source are mixed and sintered once. The lithium ions generated by the decomposition of the lithium source react with the ternary precursor in a solid phase to construct the crystal structure framework of the cathode material. At the same time, some divalent nickel ions are oxidized to trivalent nickel ions and embedded in the crystal structure framework to obtain a sintered product. Next, the calcined product is washed with water in an aqueous solution containing lithium compounds. The presence of lithium compounds increases the escape barrier of lithium ions in the crystal structure of the calcined product, enhances the bond strength of Li-O-Ni, and prevents the disproportionation of trivalent nickel to form NiO. This avoids the formation of an inactive layer on the crystal surface of the calcined product and improves its activity (in the conventional water washing process without the addition of lithium compounds, lithium ions escape from the crystal lattice of the calcined product, and at the same time, high-valence nickel oxidizes water molecules to form NiO and LiOH, which not only reduces the lithium ion content in the crystal of the calcined product and reduces the lithium ion transport efficiency, but also causes NiO to adhere to the crystal surface of the calcined product to form an inactive layer, increasing the interfacial impedance). At the same time, water washing can remove residual alkaline substances and sintering byproducts and other impurities from the surface of the calcined product. The presence of lithium compounds can also regulate the distribution of lithium elements in the crystal structure of the calcined product, optimize the crystal structure of the calcined product, and obtain a water-washed product with a specific crystal form. Next, the washed material is mixed with a coating agent and then subjected to a second sintering. Firstly, the second sintering further eliminates internal defects in the crystal structure of the washed material, enhancing its integrity. Secondly, the coating agent modifies the crystal surface of the washed material, forming a uniform protective layer through solid-phase diffusion or melt coating, improving the material's structural and cycle stability. Furthermore, some of the coating agent reacts with lithium elements on the crystal surface of the washed material to generate highly conductive lithium metal composite oxides, while some of the metal elements in the coating agent are embedded in the crystal structure of the washed material, further optimizing its crystal structure. Ultimately, a cathode material with high structural stability, high conductivity, long cycle life, high power density, low interfacial impedance, and high nickel content is obtained. In other words, this application achieves the performance of a cathode material prepared by three sintering processes through the synergistic effect of primary sintering, unconventional washing, and secondary sintering, while also reducing production costs. Compared to three sintering processes, this application achieves cost reduction while maintaining the same electrochemical performance. This synthesis method is simple, efficient, and suitable for large-scale production.

[0033] For example, the sintering temperature for a single sintering is 750℃~850℃, and the sintering time is 18h~30h. For instance, the sintering temperature for a single sintering can be 750℃, 770℃, 790℃, 810℃, 830℃, 850℃, etc., and the sintering time can be 18h, 20h, 22h, 24h, 26h, 28h, 30h, etc. It is understood that by reasonably controlling the sintering temperature and sintering time of the single sintering, the ternary precursor and lithium source can react fully, and damage to the crystal structure can be avoided, resulting in a single-sintered product with excellent structure.

[0034] For example, the water washing temperature is 8℃~12℃ and the water washing time is 3~5min. For example, the water washing temperature can be 8℃, 9℃, 10℃, 11℃, 12℃, etc., and the water washing time can be 3min, 4min, 5min, etc.

[0035] For example, a product is washed with water in an aqueous solution containing additives, and in the filtration step, filtration refers to obtaining the washed product by pressure filtration.

[0036] For example, the sintering temperature for secondary sintering is 450℃~700℃, and the sintering time is 10h~14h. For instance, the sintering temperature for primary sintering can be 450℃, 500℃, 550℃, 600℃, 650℃, 700℃, etc., and the sintering time can be 10h, 11h, 12h, 13h, 14h, etc. It is understood that by reasonably controlling the sintering temperature and time of secondary sintering, internal defects in the crystal structure of the washed product can be effectively eliminated, the crystal structure optimized, and the coating agent can form a uniform protective layer on the surface of the washed product, thereby improving the structural stability and cycle stability of the material.

[0037] That is, this application achieves the performance of cathode materials prepared by three sintering processes through the synergistic effect of one sintering, unconventional water washing and high-temperature reheating.

[0038] For example, the preparation method of the cathode material further includes: after secondary sintering, crushing, sieving and demagnetizing the secondary sintering product.

[0039] In some embodiments, the additive also includes metal oxides.

[0040] In this application, by including metal oxides as additives, specifically by adding metal oxides to the aqueous solution during the washing process, the metal oxides are uniformly dispersed in the aqueous solution to form a suspension. During the washing process, the metal oxides are uniformly adsorbed onto the surface of the sintered product, i.e., the metal oxides are uniformly adsorbed onto the surface of the sintered product through wet coating, and then uniform coating of the metal oxides is achieved through subsequent secondary sintering. Simultaneously, during the secondary sintering, the metal oxides can also react with lithium elements in the crystal structure of the washed product to form a stable lithium metal composite oxide, thereby improving the structural stability and ionic conductivity of the cathode material. In other words, this application optimizes the crystal structure and obtains a high-performance cathode material through the synergistic effect of wet coating during the washing process and solid-phase coating by the coating agent.

[0041] In some embodiments, the mass ratio of lithium compound to metal oxide is 0.4 to 9:1, for example, it can be 0.4:1, 1:1, 3:1, 5:1, 7:1, 9:1, etc.

[0042] In this application, by setting the mass ratio of lithium-containing compound to metal oxide to 0.4~9:1, not only can the lithium-containing compound effectively suppress the escape of lithium ions from the crystal structure of the calcined product during the water washing process, thus preventing the formation of an inactive layer on the crystal surface of the calcined product, but the metal oxide can also achieve a uniform coating effect. At the same time, the appropriate ratio of lithium-containing compound and metal oxide can also regulate the reaction between the metal oxide and the lithium element in the crystal structure of the water-washed product, thereby forming a stable lithium metal composite oxide, and thus obtaining a cathode material with a specific structure.

[0043] In some embodiments, the amount of additive added is 100ppm to 5000ppm, that is, the amount of additive added accounts for 0.01% to 0.5% of the mass of a calcined product. For example, the amount of additive added can be 100ppm, 500ppm, 1000ppm, 1500ppm, 2000ppm, 2500ppm, 3000ppm, 3500ppm, 4000ppm, 4500ppm, 5000ppm, etc.

[0044] Understandably, by setting the amount of additives to 100ppm~5000ppm, the appropriate amount of additives can not only give full play to the role of lithium compounds and metal oxides, repair defects in the crystal structure, optimize the crystal structure, and form a protective layer of appropriate thickness on the crystal surface; but also avoid excessive deposition of additives on the crystal surface, thereby avoiding the formation of impurities and further improving the performance of the cathode material.

[0045] In some embodiments, the lithium-containing compound includes one or more of lithium hydroxide, lithium carbonate, lithium sulfate, lithium nitrate, and lithium chloride.

[0046] In this application, by setting the types of lithium-containing compounds to include one or more of lithium hydroxide, lithium carbonate, lithium sulfate, lithium nitrate and lithium chloride, and selecting lithium-containing compounds with different water solubility and different activities, it is possible not only to adapt to different application scenarios according to the characteristics of different substances, but also to better suppress lithium ion escape in the crystal structure of the calcined product through the synergy of different substances, optimize the crystal structure of the washed product, and thus obtain a cathode material with excellent crystal structure and high performance.

[0047] In some embodiments, the oxide includes at least one of aluminum oxide (Al2O3), zinc oxide (ZnO), cobalt trioxide (Co2O3), tungsten trioxide (WO3), zirconium oxide (ZrO2), strontium oxide (SrO2), niobium pentoxide (Nb2O5), antimony pentoxide (Sb2O5), and titanium dioxide (TiO2).

[0048] It is understandable that by selecting appropriate types of metal oxides, on the one hand, a protective layer can be better formed on the crystal surface of the washed product through secondary sintering, thereby improving the stability of the cathode material; on the other hand, the metal ions in the aforementioned metal oxides can enter the crystal lattice of the washed product during secondary sintering, thereby improving the stability of the crystal structure through lattice doping and suppressing the distortion of the crystal structure during cycling; at the same time, the aforementioned metal oxides have a certain electronic conductivity or can react with lithium elements in the crystal structure to generate lithium metal composite oxides with ionic conductivity, thereby reducing interfacial impedance and improving the performance of the cathode material.

[0049] In some embodiments, the molecular formula of the ternary material precursor is Ni x Co y Mn 1-x-y (OH)2, where 0.8≤x≤0.98, 0.01≤y≤0.19.

[0050] In this application, the molecular formula of the ternary material precursor is set to Ni x Co y Mn 1-x-y (OH)2, and ensuring 0.8≤x≤0.98, so that the nickel content in the ternary material precursor is relatively high, thus making the cathode material obtained by the reaction a high-nickel ternary cathode material, improving the specific capacity and energy density of the battery; reasonably setting the cobalt content improves the stability and electronic conductivity of the obtained cathode material; reasonably setting the manganese content appropriately expands the interlayer spacing of the cathode material crystal structure, optimizes the lithium ion transport channel, and improves the lithium ion transport efficiency.

[0051] For example, the preparation method of the ternary material precursor includes: mixing a nickel sulfate solution, a manganese sulfate solution, a cobalt sulfate solution, and a sodium hydroxide solution; adding an ammonia complexing agent; adjusting the pH of the solution to 11.0~12.0; reacting under stirring conditions for 60h~72h; washing and drying the solid formed after co-precipitation to obtain the ternary material precursor. The concentrations of the nickel sulfate solution, manganese sulfate solution, and cobalt sulfate solution are 1.00mol / L~2.50mol / L, 1.00mol / L~2.50mol / L, and 1.00mol / L~2.50mol / L, respectively. The molar ratio of hydroxide ions in sodium hydroxide, nickel ions in nickel sulfate, manganese ions in manganese sulfate, and cobalt ions in cobalt sulfate is 2.01:1~2.05:0.1~0.55:0.1~0.55.

[0052] For example, the molecular formula of the sintered product obtained after one sintering is LiNi. x Co y Mn 1-x-y O2, where 0.8≤x≤0.98, 0.01≤y≤0.19.

[0053] In some embodiments, in the X-ray diffraction spectrum of the ternary precursor, the intensity I of the 001 crystal plane diffraction peak is... 001 With the diffraction peak intensity I of the 101 crystal plane 101 The ratio is 1.00~2.00.

[0054] Understandably, by designing the ternary precursor with a high peak intensity ratio, the ternary precursor inherits the high crystallinity characteristics during a single sintering process, allowing the crystal to grow along the 001 crystal plane, increasing the C-axis spacing, and enabling smoother diffusion of lithium ions in the two-dimensional plane. A suitable peak intensity ratio results in crystals growing along the 101 crystal plane having finer primary grains and a looser surface structure, thus achieving a suitable surface porosity for the resulting cathode material. This not only enhances the interfacial transport dynamics of lithium ions but also reduces the extent of side reactions between the cathode material and the electrolyte. In other words, this is achieved by rationally controlling the diffraction peak intensity I of the 001 crystal plane of the ternary precursor. 001 With the diffraction peak intensity I of the 101 crystal plane 101 The ratio of these factors can balance the bulk diffusion of lithium ions, the interfacial intercalation reaction, and the side reactions, thereby enabling the cathode material to achieve optimal electrochemical performance.

[0055] In some embodiments, the D50 particle size of the ternary precursor is 2 μm to 14 μm.

[0056] Understandably, by setting the D50 particle size of the ternary precursor to 2μm~14μm, firstly, the ternary precursor with a suitable particle size reacts more easily with the lithium source, resulting in a sintered product with excellent crystal structure; secondly, the ternary precursor with a suitable particle size ensures that the particle size of the resulting cathode material is within a suitable range, increasing the compaction density and specific surface area of ​​the cathode material, thereby improving battery performance. In other words, this application synthesizes a high-capacity, high-power, long-cycle, high-nickel-content ternary cathode material through the design of the ternary precursor structure, the synergy of unconventional water washing and two sintering processes, giving it the performance advantages of cathode materials synthesized through three-stage sintering.

[0057] In some embodiments, the mass ratio of the ternary precursor to the lithium source is 1:1.02~1.06.

[0058] In this application, by setting the mass ratio of ternary precursor to lithium source to 1:1.02~1.06, an appropriate excess of lithium source can not only ensure that the transition metal in the ternary precursor reacts fully with lithium ions during the first sintering process, so that lithium is fully embedded in the crystal structure framework of the cathode material, but also avoid excessive lithium source depositing on the surface of the cathode material and causing side reactions with the electrolyte, thereby improving the cycle stability of the battery.

[0059] In some embodiments, the lithium source includes one or more of lithium hydroxide, lithium carbonate, lithium sulfate, lithium nitrate, and lithium chloride.

[0060] It is understandable that by reasonably setting the type of lithium source, lithium ions can be decomposed and participate in high-temperature solid-phase reaction during the first sintering process, while avoiding the deposition of lithium source on the surface of the sintered product, which would affect its structure and performance.

[0061] In some embodiments, the amount of coating agent added is 500ppm to 20000ppm, that is, the amount of coating agent added accounts for 0.05% to 2% of the water washing mass. For example, the amount of coating agent added can be 500ppm, 1000ppm, 3000ppm, 5000ppm, 7000ppm, 9000ppm, 10000ppm, 12000ppm, 14000ppm, 16000ppm, 18000ppm, 20000ppm, etc.

[0062] In this application, by setting the amount of coating agent added to 500ppm~20000ppm, a uniform, dense coating layer with appropriate thickness is formed on the surface of the cathode material. This not only protects the cathode material and prevents side reactions between the cathode material and the electrolyte, but also prevents the dissolution of transition metal elements during battery charging and discharging, thereby improving the stability of the cathode material, without affecting the transport of lithium ions.

[0063] In some embodiments, the coating agent includes at least one of cobalt oxide, cobalt hydroxide, tungsten oxide, tungsten hydroxide, aluminum oxide, and aluminum hydroxide.

[0064] It is understandable that by setting the coating agent to include at least one of cobalt oxide, cobalt hydroxide, tungsten oxide, tungsten hydroxide, aluminum oxide, and aluminum hydroxide, the coating layer formed on the surface of the cathode material by the coating agent has better stability, resulting in better structural stability of the cathode material. At the same time, this type of coating agent can increase the interfacial conductivity of the cathode material and improve the electrochemical performance of the battery.

[0065] Secondly, embodiments of this application provide a cathode material prepared using the cathode material preparation method provided in the first aspect of this application.

[0066] In this application, a cathode material is prepared by a specific preparation method, thereby giving the cathode material the advantages of high stability, high specific capacity, and low impedance.

[0067] In some embodiments, the half-width at half-maximum (FWHM) of the 104 peak in the X-ray diffraction spectrum of the cathode material is 0.039 to 0.310, and the half-width at half-maximum (FWHM) of the 003 peak is 0.100 to 0.280.

[0068] Understandably, the half-width at half-maximum (WHM) of the 104 peak in this cathode material is 0.039–0.310. This relatively small WHM indicates high crystallinity and good crystal integrity, suggesting that the crystal size and number of grain boundaries are appropriate, effectively dispersing cyclic stress and shortening the lithium-ion diffusion path. Furthermore, the WHM of the 003 peak is 0.100–0.280, further indicating high crystallinity and good crystal integrity, along with regular interlayer arrangement and unobstructed lithium-ion diffusion channels.

[0069] For example, the D10 particle size of the cathode material is 1.0 μm to 10.0 μm, the D50 particle size is 1.5 μm to 13.5 μm, and the D90 particle size is 12.5 μm to 20.0 μm; the particle size distribution width of the cathode material is Span((D90-D10) / D50) and it is 0.25 to 2.00; the primary particle size of the cathode material is 100 nm to 2000 nm.

[0070] For example, the specific surface area of ​​the cathode material is 0.30 m². 2 / g~1.50m 2 / g.

[0071] For example, the compaction density of the cathode material is 2.70 g / cc to 3.50 g / cc.

[0072] Thirdly, embodiments of this application provide a positive electrode sheet, including a positive electrode material prepared by the method for preparing positive electrode material provided in the first aspect of this application or a ternary positive electrode material provided in the second aspect of this application.

[0073] In this application, by applying ternary cathode materials to the cathode sheet, the cathode sheet can have the advantages of high cycle stability, high conductivity, high energy density, high rate performance, and low impedance.

[0074] For example, the positive electrode sheet includes a positive electrode material, a conductive agent, and a binder, wherein the mass ratio of the ternary positive electrode material in the positive electrode sheet is 80% to 98%; and the particle size distribution width Span((D90-D10) / D50) of the ternary positive electrode material, conductive agent, and binder is 0.25 to 2.50.

[0075] Fourthly, embodiments of this application provide a battery including the positive electrode provided in the third aspect of this application.

[0076] In this application, by applying the positive electrode sheet provided in the third aspect of this application to the battery, the battery can have the advantages of long cycle life, high energy density, high rate performance and low impedance.

[0077] The present application will be specifically described below through specific embodiments. These embodiments are only some embodiments of the present application and are not intended to limit the present application. Unless otherwise specified, the raw materials used in the following embodiments are all commercially available products.

[0078] Example 1 This embodiment provides a method for preparing a cathode material, including: (1) The ternary precursor Ni 0.9 Co 0.05 Mn 0.05 (OH)₂ and lithium hydroxide are mixed and added to a roller kiln for a single sintering process to obtain a sintered product. The X-ray diffraction spectrum of the ternary precursor shows that the 001 crystal plane diffraction peak intensity I... 001 With the diffraction peak intensity I of the 101 crystal plane 101 The ratio of the ternary precursor to lithium hydroxide is 1.35, the D50 particle size of the ternary precursor is 10 μm, the molar ratio of the ternary precursor to lithium hydroxide is 1:1.04, the sintering temperature of the first sintering is 800℃, and the sintering time is 24h.

[0079] Ternary precursor Ni 0.9 Co 0.05 Mn 0.05 The preparation method of (OH)₂ includes: mixing nickel sulfate solution, manganese sulfate solution, cobalt sulfate solution, and sodium hydroxide solution; adding ammonia as a complexing agent; adjusting the pH of the solution to 11.0-12.0; reacting under stirring for 65 hours; washing and drying the solid formed after co-precipitation to obtain the ternary material precursor. The concentrations of the nickel sulfate solution, manganese sulfate solution, and cobalt sulfate solution are all 1.50 mol / L. The molar ratios of hydroxide ions in sodium hydroxide, nickel ions in nickel sulfate, manganese ions in manganese sulfate, and cobalt ions in cobalt sulfate are 2.01:0.9:0.05:0.05.

[0080] (2) The calcined product was added to an aqueous solution containing lithium carbonate, washed with water, filtered under pressure, and dried to obtain the washed product. The amount of lithium carbonate added was 500 ppm, that is, the amount of lithium carbonate added accounted for 0.05% of the mass of the calcined product; the water washing temperature was 10℃ and the water washing time was 4 min.

[0081] (3) The washed product is mixed with aluminum oxide and cobalt oxide, and added to a roller kiln for secondary sintering to obtain the cathode material. The amount of aluminum oxide added is 1000 ppm and the amount of cobalt oxide added is 3000 ppm, that is, the amount of aluminum oxide added accounts for 0.1% of the mass of the washed product and the amount of cobalt oxide added accounts for 0.3% of the mass of the washed product; the sintering temperature of the secondary sintering is 600℃ and the sintering time is 12h; after the reaction is completed, the secondary sintering product is crushed, sieved and demagnetized.

[0082] Example 2 This embodiment provides a method for preparing a positive electrode material. Compared with Example 1, the only difference is that in step (2), a calcined product is added to an aqueous solution containing lithium carbonate and aluminum oxide, washed with water, filtered under pressure, and dried to obtain a washed product. The amount of lithium carbonate added is 500 ppm, the amount of aluminum oxide added is 500 ppm, and the rest is the same as in Example 1, which will not be repeated here.

[0083] Example 3 This embodiment provides a method for preparing a positive electrode material. Compared with Example 2, the only difference is that in step (2), the amount of lithium carbonate added is 50 ppm and the amount of aluminum oxide added is 50 ppm. The other steps are the same as in Example 2 and will not be repeated here.

[0084] Example 4 This embodiment provides a method for preparing a cathode material. Compared with Example 2, the only difference is that in step (2), the amount of lithium carbonate added is 2500 ppm and the amount of aluminum oxide added is 2500 ppm. The other steps are the same as in Example 2 and will not be repeated here.

[0085] Example 5 This embodiment provides a method for preparing a cathode material. Compared with Example 2, the only difference is that in step (2), the amount of lithium carbonate added is 285 ppm and the amount of aluminum oxide added is 715 ppm, that is, the mass ratio of lithium carbonate to aluminum oxide is 0.4:1. The rest is the same as in Example 2, and will not be repeated here.

[0086] Example 6 This embodiment provides a method for preparing a positive electrode material. Compared with Example 2, the only difference is that in step (2), the amount of lithium carbonate added is 900 ppm and the amount of aluminum oxide added is 100 ppm, that is, the mass ratio of lithium carbonate to aluminum oxide is 9:1. The rest is the same as in Example 2, and will not be repeated here.

[0087] Example 7 This embodiment provides a method for preparing a cathode material. Compared with Embodiment 2, the only difference is that in step (1), the chemical formula of the ternary precursor is Ni. 0.97 Co 0.01 Mn 0.02 In the X-ray diffraction pattern of the (OH)₂ ternary precursor, the intensity of the diffraction peak on the 001 crystal plane is I. 001 With the diffraction peak intensity I of the 101 crystal plane 101 The ratio is 1.35, and the ternary precursor Ni 0.97 Co0.01 Mn 0.02 The preparation method of (OH)₂ includes: mixing nickel sulfate solution, manganese sulfate solution, cobalt sulfate solution and sodium hydroxide solution, adding ammonia complexing agent, adjusting the pH of the solution to 11.0~12.0, reacting under stirring for 65 h, washing and drying the solid formed after co-precipitation to obtain the ternary material precursor. The concentrations of the nickel sulfate solution, manganese sulfate solution and cobalt sulfate solution are 1.50 mol / L, and the molar ratios of hydroxide ions in sodium hydroxide, nickel ions in nickel sulfate, manganese ions in manganese sulfate and cobalt ions in cobalt sulfate are 2.01:0.97:0.02:0.01. Other aspects are consistent with Example 2 and will not be repeated here.

[0088] Example 8 This embodiment provides a method for preparing a cathode material. Compared with Embodiment 2, the only difference is that in step (3), the washed product is mixed with aluminum oxide and cobalt oxide, added to a roller kiln, and sintered twice to obtain the cathode material. The amount of aluminum oxide added is 5000 ppm, and the amount of cobalt oxide added is 15000 ppm.

[0089] Example 9 This embodiment provides a method for preparing a cathode material. Compared with Embodiment 2, the only difference is that in step (3), the washed product is mixed with aluminum oxide and cobalt oxide, added to a roller kiln, and sintered twice to obtain the cathode material. The amount of aluminum oxide added is 100 ppm, and the amount of cobalt oxide added is 400 ppm.

[0090] Comparative Example 1 This comparative example provides a method for preparing a positive electrode material. The only difference from Example 1 is that in step (2), a calcined product is added to pure water for washing, i.e., there are no additives in the water. The product is then filtered, dried, and washed to obtain the washed product. The rest is consistent with Example 1 and will not be repeated here.

[0091] Comparative Example 2 This comparative example provides a method for preparing a positive electrode material. The only difference from Example 1 is that in step (2), a calcined product is added to an aqueous solution containing aluminum oxide for washing, filtration, and drying to obtain a washed product. The amount of aluminum oxide added is 500 ppm, that is, lithium carbonate in step (2) is replaced with aluminum oxide. The rest is the same as in Example 1 and will not be repeated here.

[0092] Comparative Example 3 This comparative example provides a method for preparing a cathode material, including: (1) The ternary precursor Ni0.9 Co 0.05 Mn 0.05 (OH)₂ and lithium hydroxide are mixed and added to a roller kiln for a single sintering process to obtain a sintered product. The X-ray diffraction spectrum of the ternary precursor shows that the 001 crystal plane diffraction peak intensity I... 001 With the diffraction peak intensity I of the 101 crystal plane 101 The ratio of the ternary precursor to lithium hydroxide is 1.35, the D50 particle size of the ternary precursor is 10 μm, the mass ratio of the ternary precursor to lithium hydroxide is 1:1.04, the sintering temperature of the first sintering is 800℃, and the sintering time is 24h.

[0093] (2) Add a calcined product to pure water for washing, filter under pressure, and dry to obtain a washed product. The washing temperature is 10℃ and the washing time is 4min.

[0094] (3) The washed product is mixed with aluminum oxide and cobalt oxide, and added to a roller kiln for secondary sintering to obtain a second-fired product. The amount of aluminum oxide added is 1000 ppm and the amount of cobalt oxide added is 3000 ppm, that is, the amount of aluminum oxide added accounts for 0.1% of the mass of the washed product and the amount of cobalt oxide added accounts for 0.3% of the mass of the washed product; the sintering temperature of the secondary sintering is 600℃ and the sintering time is 12h.

[0095] (4) The second sintered product is added to a roller kiln for a third sintering process to obtain the cathode material. The sintering temperature for the third sintering is 300℃ and the sintering time is 12h. After the reaction is completed, the second sintered product is crushed, sieved and demagnetized.

[0096] The cathode materials prepared in Examples 1-9 and Comparative Examples 1-3 were subjected to performance tests, and the results are shown in Table 1.

[0097] The specific capacity is detected by charging at a constant current and constant voltage of 4.25~2.5V and 0.2C to 4.25V, cutting off at 0.02C, letting it stand for 10 minutes, and then discharging it to 2.5V under a current density of 0.2C.

[0098] The particle size was measured using a laser particle size analyzer with the instrument's refractive index set to 1.692 and absorption rate set to 1.0. Internal and external ultrasonic testing were not required.

[0099] The powder impedance was tested using a powder electronic instrument with a 16mm four-probe mold, with a sample addition of about 2g, a test pressure of 195mPa, and a holding time of 10s. The compaction density was tested using a compaction density meter with a 16mm four-probe mold, a sample addition of approximately 2g, a testing pressure of 195mPa, and a holding time of 10s.

[0100] The specific surface area was measured using a specific surface area analyzer, which was degassed at 200°C for 2 hours, with nitrogen as the working gas.

[0101] The XRD-FWHM detection method is as follows: take the prepared cathode material and test the half-peak width of the powder on an X-ray diffractometer.

[0102] The primary particle size detection method is as follows: After scraping the powder, the positive electrode sheet is photographed under a scanning electron microscope at 10K magnification. Then, the grayscale image is optimized using Avizo software, and the average particle size of each particle image is calculated by an automatic algorithm. The normal distribution map of particle size of all particles in the region is obtained, thereby analyzing and determining the primary particle size of the sample.

[0103] Table 1

[0104] As can be seen from the data in Table 1 of Examples 1-9 and Comparative Example 3, the specific capacity, particle size distribution, primary particle size, half-maximum width at half maximum (WHM) of the 104 peak and the half-maximum width at half maximum (WHM) of the 003 peak of the cathode materials prepared in Examples 1-9 are basically the same as those of Comparative Example 3. The compaction density and specific surface area of ​​the cathode materials prepared in Examples 1-9 are improved compared with those of Comparative Example 3, and the powder impedance is significantly reduced. This indicates that the cathode materials prepared by the preparation method of this application can reach or even exceed the cathode materials obtained by traditional three-stage sintering. This shows that the preparation method of this application reduces the production cost while maintaining the high performance of the cathode materials.

[0105] At the same time, by Figure 1 and Figure 2 It can be seen that the morphology of the cathode material obtained in Example 2 is similar to that of the cathode material obtained in Comparative Example 3, and the structure of the cathode material in Example 2 is more orderly than that in Comparative Example 3.

[0106] As can be seen from the data in Examples 2-6, when the amount of lithium carbonate and aluminum oxide added during the water washing process is changed or the ratio of lithium carbonate and aluminum oxide added during the water washing process is changed, the specific capacity and powder impedance of the obtained cathode material change to a certain extent. This may be because changing the amount or ratio of lithium carbonate and aluminum oxide added during the water washing process will affect the distribution of lithium element in the crystal structure of the calcined product and the distribution of aluminum oxide on the surface of the calcined product, thereby affecting the structure and performance of the obtained cathode material.

[0107] As can be seen from the data of Example 7, when the chemical formula of the ternary precursor is changed, the performance of the resulting cathode material remains basically unchanged, indicating that the ternary precursor used in Example 7 can also achieve better results.

[0108] As can be seen from the data of Examples 2 and 8-9, changing the amount of aluminum oxide and cobalt oxide in the coating agent will affect the distribution of oxides on the surface of the calcined product and the interaction between oxides, thereby affecting the structure of the coating layer on the surface of the obtained cathode material and its performance.

[0109] The data from Comparative Example 1 and Example 1 show that when lithium carbonate is not added during the water washing process, the specific capacity of the obtained cathode material decreases, the particle size distribution deviates, and the powder impedance increases significantly. This is mainly because when lithium carbonate is not added during the water washing process, lithium ions escape from the crystal lattice of the sintered product, and at the same time, high-valence nickel elements oxidize water molecules, forming an inactive layer on the surface of the sintered product crystal, which increases the powder impedance.

[0110] As can be seen from the data of Comparative Example 2 and Example 1, when lithium carbonate in the water washing process is replaced with aluminum oxide, the specific capacity of the obtained cathode material decreases. However, as can be seen from the data of Comparative Examples 1-2 and Examples 1-2, adding lithium carbonate in the water washing process can significantly improve the specific capacity of the cathode material. Furthermore, the performance of the cathode material can be improved through the synergistic effect of unconventional water washing (i.e., adding lithium carbonate in the water washing process), wet coating (i.e., adding aluminum oxide in the water washing process), and solid-phase coating (i.e., adding aluminum oxide and cobalt oxide before secondary sintering).

[0111] The cathode materials prepared in Examples 1-9 and Comparative Examples 1-3 were assembled into batteries and their performance was tested. The results are shown in Table 2.

[0112] The battery assembly method is as follows: Positive electrode material, SuperP conductive agent, carbon nanotubes (CNTs), and polyvinylidene fluoride (PVDF) binder are weighed in a mass ratio of 97.8:0.5:0.5:1.2, and an organic solvent is added to prepare a slurry. The slurry is coated onto aluminum foil and dried to obtain the positive electrode sheet. Graphite, sodium carboxymethyl cellulose (CMC), polyacrylic acid (PAA), styrene-butadiene rubber (SBR), and carbon nanotubes (CNTs) are weighed in a mass ratio of 96.7:0.4:1.0:0.7:1.2, and an organic solvent is added to prepare a slurry. The slurry is coated onto copper foil and dried to obtain the negative electrode sheet. Through cutting, stacking, casing, electrolyte injection, formation, and sealing, a soft-pack battery is formed.

[0113] The method for detecting the total specific capacity is as follows: charge the battery at a constant current and constant voltage of 4.25~2.5V and 0.2C to 4.25V, cut off at 0.02C, let it stand for 10 minutes, and then discharge it at a constant current to 2.5V. Divide the obtained specific capacity by the mass of the positive electrode material in the electrode sheet to obtain the total specific capacity of the battery.

[0114] The impedance detection method is as follows: Take the cell after capacity testing and write it at 0.33C for 3 cycles under 4.25~2.5V conditions, charge it to 50% SOC (50% battery state of charge), discharge it at a current density of 2C for 10s, take the voltage before discharge and after 10s discharge, divide it by the current, and you will get the impedance under 50% SOC conditions. The rate discharge retention test involves charging at 0.5C constant current and voltage to 4.25V, with a cutoff at 0.02C, and then discharging at 0.2C, 0.5C, 1.0C, 2.0C, and 3.0C to 2.5V. For example, 0.5C / 0.2C refers to the ratio of the capacity of the same battery at a 0.5C discharge rate to its capacity at a 0.2C discharge rate.

[0115] The method for detecting power discharge at 25℃ involves charging the battery to different states of charge (SOC), then pulse-discharging it at a constant power for 10 seconds. The voltage at the last second of the discharge is taken as the power discharge result. For example, 63W@5%SOC refers to the voltage after discharging the battery at a constant power of 63W for 30 seconds when the battery is in a low-charge state with only 5% of its rated capacity remaining, and the ambient temperature is maintained at 25℃.

[0116] The voltage range for capacity retention at 0.5C / 1C cycle@500cls and 6A / 104W cycle@500cls is 4.25~2.5V. 0.5C / 1C cycle@500cls refers to the capacity retention after 500 cycles of charging at 0.5C and discharging at 1C; 6A / 104W cycle@500cls refers to the capacity retention after 500 cycles of charging at a constant current of 6A and discharging at a constant power of 104W.

[0117] Table 2

[0118] As can be seen from the data of Examples 1-9 and Comparative Example 3 in Table 2, when the cathode materials prepared in Examples 1-9 are applied to batteries, (1) the total capacity of the battery is improved compared with Comparative Example 3; (2) the impedance of the battery is significantly reduced compared with Comparative Example 3; (3) the rate discharge retention rates of 0.5C / 0.2C, 1C / 0.2C, 2C / 0.2C and 3C / 0.2C are basically the same as those of Comparative Example 3, and the rate discharge retention rates are generally higher, indicating that the capacity decay of the battery assembled with the cathode material of this application is relatively small. The less the current, the more stable the discharge performance under different currents; (4) The voltage value of 63W@5%SOC is basically the same as that of Comparative Example 3, while the voltage values ​​of 300W@30%SOC, 335W@50%SOC and 781W@60%SOC are higher than those of Comparative Example 3, indicating that the impedance of the battery in this application is relatively smaller; (5) The capacity retention rate of 0.5C / 1C cycle@500cls and 6A / 104W cycle@500cls is generally good, further indicating that the battery in this application has good stability. It can be seen that the battery assembled by the positive electrode material prepared by the preparation method of this application can achieve the same performance as the battery assembled by the positive electrode material obtained by traditional three-time sintering. This is mainly because the positive electrode material prepared by this application has excellent structure, which makes the battery perform better.

[0119] At the same time, by Figure 3 A comparison of the rate discharge capacity ratio (corresponding to the rate discharge retention rate in Table 2) shows that the performance of the battery in Example 2 is basically the same as that of the battery in Comparative Example 3, and the battery capacity retention rate is relatively high during cycling.

[0120] The data from Comparative Example 1 and Example 1 show that when lithium carbonate is not added during the water washing process, the performance of the battery assembled from the obtained cathode material decreases in all aspects. This is mainly because the crystal structure of the obtained cathode material is different at this time, which affects the performance of the battery.

[0121] The data from Comparative Example 2 and Example 1 show that when lithium carbonate is replaced with aluminum oxide in the water washing process, the performance of the battery assembled from the obtained cathode material decreases. The data from Comparative Examples 1-2 and Examples 1-2 further illustrate that adding lithium carbonate in the water washing process can significantly improve the performance of the battery.

[0122] The foregoing has provided a detailed description of a positive electrode material, its preparation method, the positive electrode sheet, and the battery provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for preparing a positive electrode material, characterized in that, include: The ternary precursor and lithium source are mixed and sintered in one step to obtain a sintered product. The calcined product is added to an aqueous solution containing additives, washed with water, filtered, and dried to obtain a washed product, wherein the additives include lithium-containing compounds; The washed product is mixed with a coating agent and sintered twice to obtain a positive electrode material, wherein the molar percentage of nickel in the positive electrode material is ≥80%.

2. The method for preparing the cathode material according to claim 1, characterized in that, The additives also include metal oxides.

3. The method for preparing the cathode material according to claim 2, characterized in that, The mass ratio of the lithium-containing compound to the metal oxide is 0.4 to 9:1; and / or, The amount of the additive added is 100ppm to 5000ppm.

4. The method for preparing the cathode material according to claim 2, characterized in that, The lithium-containing compound includes one or more of lithium hydroxide, lithium carbonate, lithium sulfate, lithium nitrate, and lithium chloride; and / or, The metal oxide includes at least one of aluminum oxide, zinc oxide, cobalt trioxide, tungsten trioxide, zirconium oxide, strontium oxide, niobium pentoxide, antimony pentoxide, and titanium dioxide.

5. The method for preparing the cathode material according to any one of claims 1 to 4, characterized in that, The molecular formula of the ternary precursor is Ni x Co y Mn 1-x-y (OH)₂, where 0.8 ≤ x ≤ 0.98, 0.01 ≤ y ≤ 0.19; and / or, In the X-ray diffraction spectrum of the ternary precursor, the diffraction peak intensity I of the 001 crystal plane is... 001 With the diffraction peak intensity I of the 101 crystal plane 101 The ratio is 1.00 to 2.00; and / or, The D50 particle size of the ternary precursor is 2μm~14μm.

6. The method for preparing the cathode material according to any one of claims 1 to 5, characterized in that, The molar ratio of the ternary precursor to the lithium source is 1:1.02~1.06; and / or, The lithium source includes one or more of lithium hydroxide, lithium carbonate, lithium sulfate, lithium nitrate, and lithium chloride.

7. The method for preparing the cathode material according to any one of claims 1 to 6, characterized in that, The amount of the coating agent added is 500ppm to 20000ppm; and / or, The coating agent includes at least one of cobalt oxide, cobalt hydroxide, tungsten oxide, tungsten hydroxide, aluminum oxide, and aluminum hydroxide.

8. A positive electrode material, characterized in that, It is prepared by the method for preparing the cathode material as described in any one of claims 1 to 7.

9. The cathode material according to claim 8, characterized in that, In the X-ray diffraction spectrum of the cathode material, the full width at half maximum (FWHM) of the 104 peak is 0.039~0.310, and the FWHM of the 003 peak is 0.100~0.

280.

10. A positive electrode plate, characterized in that, The cathode material includes the cathode material prepared by the method of any one of claims 1 to 7, and / or the cathode material according to any one of claims 8 to 9.

11. A battery, characterized in that, Includes the positive electrode sheet as described in claim 10.

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