A high-stability ternary positive electrode material and a preparation method thereof

Abstract

The application discloses a kind of high-stability ternary positive electrode materials and preparation method thereof, the material is prepared nickel cobalt manganese hydroxide precursor by coprecipitation reaction, then lithiumization and doped tungsten, zirconium double element to enhance crystal structure stability, again high-temperature sintering and surface passivation treatment, finally coated with alumina thin layer.Adopt the technical scheme of the application, can effectively inhibit the irreversible phase transition of layered structure, keep crystal structure integrity, significantly reduce capacity decay rate;Through the synergistic effect of tungsten, zirconium enhances grain boundary bonding force, effectively prevents grain boundary crack propagation, improves material mechanical stability;Surface passivation treatment forms stable passivation layer, significantly reduces interface side reaction;Alumina coating layer further enhances the thermal stability of material under high temperature or high voltage conditions, significantly reduces the risk of thermal runaway, improves the safety performance of lithium ion battery;The preparation method of the application is simple, and the parameters are controllable, suitable for large-scale industrial production.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion batteries, and in particular to a highly stable ternary cathode material and its preparation method. Background Technology

[0002] With the booming development of the new energy vehicle industry, the technological advancement of lithium-ion batteries, as core energy storage devices, is crucial to the industry's development. Cathode materials, as key components determining battery capacity and energy density in lithium-ion batteries, have always been a focus of attention for both the scientific research and industrial communities. Among them, ternary cathode materials, due to their high theoretical capacity and energy density, have become one of the mainstream choices in the power battery field.

[0003] Among them, ternary cathode materials typically refer to layered oxide materials composed of nickel, cobalt, and manganese in a specific ratio. These materials achieve a balance between capacity and stability by coordinating the synergistic effects of the different transition metals, and are therefore widely used in portable electronic devices and power batteries for new energy vehicles.

[0004] However, traditional ternary cathode materials face several technical challenges during long-term cycling. First, irreversible phase transitions in the crystal structure easily occur during charge-discharge cycles, leading to layered structure collapse and capacity decay. Second, while increasing nickel content can significantly improve material capacity, it also exacerbates interfacial side reactions and grain boundary cracks, resulting in a significant decrease in cycle stability. Furthermore, the thermal stability of ternary cathode materials remains a significant issue under high temperature or high voltage conditions, easily inducing thermal runaway risks and affecting battery safety. Existing modification methods, such as doping with a single element or controlling the thickness of the surface coating layer, are difficult to precisely control, making it difficult to fundamentally solve the synergistic coupling of these multiple technical challenges.

[0005] Therefore, a highly stable ternary cathode material and its preparation method are desired. Summary of the Invention

[0006] The purpose of this invention is to provide a highly stable ternary cathode material and its preparation method, thereby solving the problems mentioned in the background art.

[0007] This invention is achieved by providing a highly stable ternary cathode material and its preparation method, comprising the following specific steps: Step 1: Prepare a precursor mixture solution. Take nickel source compound, cobalt source compound, and manganese source compound, add them to deionized water according to the preset nickel-cobalt-manganese molar ratio, and stir until completely dissolved to obtain a homogeneous precursor mixture solution. Step 2: Synthesize the precursor using a co-precipitation reaction. Add the precursor mixture solution obtained in Step 1 and ammonia solution dropwise to a reaction vessel simultaneously. Perform a co-precipitation reaction under stirring conditions, controlling the reaction temperature and pH value within a preset range. After the reaction is complete, perform aging treatment, centrifuge, wash, and dry to obtain the nickel-cobalt-manganese hydroxide precursor. Step 3: Perform lithiation doping treatment. Mix the precursor obtained in Step 2 with a lithium source compound and a dopant compound. The dopants include tungsten source compounds and zirconium source compounds, which are prepared according to a preset doping ratio and mixed evenly to obtain a doped mixture; Step 4: High-temperature sintering is performed. The doped mixture obtained in Step 3 is placed in a high-temperature sintering furnace and sintered in stages under an oxygen atmosphere. The first stage is pre-sintering at a lower temperature, and the second stage is main sintering at a preset sintering temperature. After sintering, the mixture is cooled with the furnace to obtain the sintered product; Step 5: Surface passivation treatment is performed. The sintered product obtained in Step 4 is mixed with a passivating agent solution and surface passivation is performed under stirring conditions. The passivation temperature is controlled within a preset range. After treatment, the mixture is centrifuged, washed, and dried to obtain the final high-stability ternary cathode material.

[0008] Preferably, the nickel source compound in step 1 is nickel nitrate, the cobalt source compound is cobalt nitrate, and the manganese source compound is manganese nitrate, and the preset nickel-cobalt-manganese molar ratio is nickel:cobalt:manganese equal to 8:1:1.

[0009] Preferably, the reaction temperature of the co-precipitation reaction in step 2 is 50 to 60 degrees Celsius, the reaction pH is 10.5 to 11.5, and the aging time is 2 to 4 hours.

[0010] Preferably, the lithium source compound in step 3 is lithium carbonate, and the total doping amount of tungsten source compound and zirconium source compound in the dopant is 1% to 3% of the total molar amount of the precursor, wherein the molar ratio of tungsten element to zirconium element is 1:1.

[0011] Preferably, in step 4, the first stage pre-sintering temperature is 450°C to 550°C, the pre-sintering time is 4 hours to 6 hours, the second stage main sintering temperature is 750°C to 850°C, the main sintering time is 10 hours to 15 hours, and the oxygen atmosphere flow rate is 1 liter to 2 liters per minute.

[0012] Preferably, the passivating agent in step 5 is an aluminum-based compound, the passivation temperature is 25 degrees Celsius to 35 degrees Celsius, and the passivation time is 1 hour to 3 hours.

[0013] Preferably, the high-stability ternary cathode material of the present invention further includes a coating layer, the coating layer material being alumina, and the coating layer thickness being 1 nanometer to 5 nanometers.

[0014] Preferably, the sintered product obtained in step 4 is further subjected to grinding and sieving before entering the surface passivation treatment in step 5. After grinding, the product is sieved through a sieve with a preset aperture to obtain sintered product powder with uniform particle size.

[0015] Preferably, the high-stability ternary cathode material of the present invention has a particle size distribution of 10 micrometers to 20 micrometers and a specific surface area of ​​0.5 square meters per gram to 1.5 square meters per gram.

[0016] Compared with existing technologies, this invention has the following advantages: By adopting a high-nickel formulation with a nickel-cobalt-manganese ratio of 8:1:1, the theoretical capacity and energy density of the material are significantly improved, meeting the high energy density requirements of power batteries for new energy vehicles; by simultaneously introducing tungsten and zirconium elements for dual-element doping during the lithiation process, the stabilizing effect of tungsten and zirconium in the crystal structure is utilized to effectively suppress the irreversible phase transition of the layered structure during charge-discharge cycles, maintaining the integrity of the crystal structure, thereby significantly reducing the capacity decay rate and extending the cycle life of the material; through the synergistic effect of tungsten and zirconium, the bonding force at the grain boundaries is enhanced, effectively preventing the propagation of grain boundary cracks and improving the mechanical stability of the material; through surface passivation treatment, a stable passivation layer is formed on the material surface, effectively blocking the direct contact between the electrolyte and the material surface, significantly reducing the occurrence of interfacial side reactions; by coating the material surface with a thin layer of alumina, the thermal stability of the material under high temperature or high voltage conditions is further enhanced, significantly reducing the risk of thermal runaway and improving the safety performance of the battery; the preparation method provided by this invention is simple in process and controllable in parameters, suitable for large-scale industrial production, and has good market application prospects. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall process flow architecture of the high-stability ternary cathode material preparation method according to the embodiments of this application; Figure 2 This is a schematic diagram illustrating the core principle framework of tungsten-zirconium dual-element synergistic doping and surface passivation treatment in a high-stability ternary cathode material according to an embodiment of this application. Detailed Implementation

[0018] Example 1 To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0019] This embodiment provides a highly stable ternary cathode material and its preparation method. The method includes the following five core steps, and each step is described in detail below.

[0020] In step 1, the precursor mixture solution is prepared. First, the required raw materials are prepared, including a nickel source compound, a cobalt source compound, and a manganese source compound. In this embodiment, nickel nitrate is used as the nickel source compound, cobalt nitrate as the cobalt source compound, and manganese nitrate as the manganese source compound. The above three raw materials are taken and mixed according to a preset nickel:cobalt:manganese molar ratio of 8:1:1. The weighed nickel, cobalt, and manganese source compounds are added to deionized water, ensuring that the three metal source compounds are completely dissolved to form a homogeneous mixture solution. After adding the deionized water, continuous stirring is performed using a magnetic stirrer or mechanical stirrer at a speed of 300 to 500 revolutions per minute for 30 to 60 minutes, ensuring that all solid raw materials are completely dissolved, the solution is clear and transparent, and free of suspended particles, ultimately yielding a homogeneous precursor mixture solution. The concentrations of nickel, cobalt, and manganese ions in the precursor mixture solution need to be precisely calculated based on the feed rate of the subsequent coprecipitation reaction to ensure that the precipitation rate of metal ions matches the addition rate of ammonia during the coprecipitation reaction.

[0021] In step 2, a co-precipitation reaction is used to synthesize the precursor. The precursor mixture obtained in step 1 and an ammonia solution are simultaneously added dropwise to a reaction vessel. The reaction vessel should be made of corrosion-resistant stainless steel or lined with polytetrafluoroethylene, and its volume is determined according to the production scale, typically 5 liters to 50 liters. The concentration of the ammonia solution is controlled between 0.5 mol / L and 2 mol / L. The flow rates of the precursor mixture and the ammonia solution are controlled by precision metering pumps, and the dropping rate is set according to the volume of the reaction vessel and the target yield. During the dropping process, a mechanical stirrer is installed in the reaction vessel, with a stirring speed set to 200 to 400 rpm to ensure uniform mixing of the reaction system. The reaction temperature of the co-precipitation reaction is precisely controlled by a heating jacket or heating coil, with a temperature setting range of 50°C to 60°C, and an optimal temperature of 55°C. The reaction pH is monitored in real time by an online pH sensor, and the pH is maintained within the range of 10.5 to 11.5 by adjusting the dropping rate of the ammonia solution, with an optimal pH of 11.0. After the reaction is complete, the feed pump is turned off, and stirring and aging are continued while maintaining the temperature. The aging time is set to 2 to 4 hours, with an optimal aging time of 3 hours. After aging, the reaction slurry is separated into solid and liquid components using a centrifuge. The centrifuge speed is set to 3000 to 5000 rpm, and the centrifugation time is 10 to 20 minutes. The separated solid product is washed multiple times with deionized water to remove residual ammonia and reaction byproducts. The number of washes is set to 3 to 5 times. After washing, the product is placed in a vacuum drying oven for drying. The drying temperature is set to 80 to 120 degrees Celsius, and the drying time is 12 to 24 hours, finally yielding a nickel-cobalt-manganese hydroxide precursor. This precursor is a blackish-gray powder with a particle size ranging from 1 to 5 micrometers and a specific surface area of ​​10 to 30 square meters per gram.

[0022] In step 3, lithium doping is performed. The nickel-cobalt-manganese hydroxide precursor prepared in step 2 is mixed with the lithium source compound and the dopant compound. In this embodiment, lithium carbonate is used as the lithium source compound. The dopant includes a tungsten source compound and a zirconium source compound. The tungsten source compound can be ammonium metatungstate, and the zirconium source compound can be zirconium nitrate. The materials are prepared according to a preset doping ratio. The total amount of tungsten source compound and zirconium source compound in the dopant is 1% to 3% of the total molar amount of the precursor, with an optimal total doping amount of 2%. The molar ratio of tungsten to zirconium is 1:1. The precursor, lithium source compound, and dopant are weighed according to the calculated ratio and then placed in a ball mill for mixing. A zirconium oxide ball mill jar and zirconium oxide grinding balls are used in the ball mill to avoid introducing impurities. The ball mill speed is set to 200 to 300 revolutions per minute, and the ball milling time is 2 to 4 hours to ensure that the various raw materials are mixed evenly to form a homogeneous doped mixture. During the mixing process, the ball milling temperature must be controlled not to exceed 40 degrees Celsius to avoid overheating and causing pre-reaction of the raw materials. After mixing, the doped mixture is removed and stored in a drying oven for use in subsequent sintering processes.

[0023] In step 4, high-temperature sintering is performed. The doped mixture obtained in step 3 is placed in a high-temperature sintering furnace for segmented sintering. The high-temperature sintering furnace should have precise temperature control capabilities, with a temperature control accuracy of ±5 degrees Celsius, and be equipped with an oxygen intake system to provide the required oxygen atmosphere. The doped mixture is evenly spread in a sintering boat made of alumina or molybdenum, with the spread thickness controlled between 5 mm and 15 mm to ensure uniform heat conduction during sintering. The sintering process is divided into two stages. The first stage is the pre-sintering stage, in which the sintering furnace temperature is raised from room temperature to a range of 450°C to 550°C, with the optimal pre-sintering temperature being 500°C. The heating rate is set to 2°C to 5°C per minute. After reaching the preset temperature, this temperature is maintained for 4 to 6 hours, with the optimal holding time being 5 hours. The main function of the pre-sintering stage is to initially decompose the lithium source compound, producing lithium oxide which undergoes a preliminary solid-phase reaction with the precursor, while simultaneously removing crystal water and volatile impurities from the raw materials. The second stage is the main sintering stage, where the temperature is increased from the pre-sintering temperature to a range of 750°C to 850°C, with an optimal main sintering temperature of 800°C. The heating rate is also set at 2°C to 5°C per minute. After reaching the main sintering temperature, this temperature is maintained for 10 to 15 hours, with an optimal holding time of 12 hours. The main sintering stage is carried out in an oxygen atmosphere, with the oxygen flow rate controlled at 1 to 2 liters per minute, and an optimal flow rate of 1.5 liters per minute. The introduction of oxygen promotes the diffusion and embedding of lithium ions in the crystal structure, forming a complete layered structure, while suppressing the formation of low-valence nickel ions, thus improving the crystallinity and structural stability of the material. After the main sintering is completed, the heating system and oxygen supply are shut off, allowing the sintered product to cool to room temperature within the furnace. During the cooling process, a trace amount of inert or oxygen atmosphere must be maintained to prevent the product from being oxidized or reduced. After cooling to room temperature, the furnace door is opened and the sintered product is removed, yielding a sintered product powder. This sintered product is a black powder with a particle size ranging from 5 to 15 micrometers.

[0024] Preferably, before the sintered product obtained in step 4 enters the surface passivation treatment in step 5, a grinding and sieving process is also included. The sintered product is ground using a planetary ball mill for 30 to 60 minutes at a speed of 300 to 400 revolutions per minute. After grinding, it is sieved using a sieve. The sieve aperture is selected according to the target particle size, typically a sieve with an aperture of 20 to 30 micrometers. Sieving yields a sintered product powder with uniform particle size, narrowing the particle size distribution range to 10 to 20 micrometers, which is beneficial for the uniformity of the subsequent surface passivation treatment.

[0025] In step 5, surface passivation is performed. The sintered product obtained in step 4 is mixed with a passivating agent solution for surface passivation. In this embodiment, the passivating agent is an aluminum-based compound, such as aluminum nitrate or aluminum sulfate. When preparing the passivating agent solution, the aluminum-based compound is dissolved in deionized water to prepare a solution with a concentration of 0.01 mol / L to 0.1 mol / L. The sintered product powder is added to the passivating agent solution, with a solid-liquid ratio of 10 mL to 50 mL of solution per gram of product. Continuous stirring is performed using a magnetic stirrer or mechanical stirrer at a speed of 200 to 400 rpm. The passivation treatment temperature is controlled within the range of 25°C to 35°C, with an optimal treatment temperature of 30°C. The passivation treatment time is set to 1 hour to 3 hours, with an optimal treatment time of 2 hours. Under stirring and heating conditions, the active sites on the surface of the sintered product react with the passivating agent, forming a dense passivation layer on the particle surface. This passivation layer effectively prevents direct contact between the electrolyte and the material surface, reducing interfacial side reactions. After passivation, the slurry is centrifuged at 3000-5000 rpm for 10-15 minutes. The resulting solid product is washed with deionized water to remove unreacted passivating agent and reaction byproducts, 2-3 times. After washing, the product is dried in a vacuum drying oven at 80-100°C for 8-12 hours. This yields a highly stable ternary cathode material product.

[0026] Further preferably, the high-stability ternary cathode material of the present invention also includes a coating layer, the coating layer material being alumina. After the surface passivation treatment in step 5 is completed, an alumina coating treatment can be further performed. Specifically, the passivated product is redispersed in deionized water, an appropriate amount of aluminum source compound is added as a coating agent, and the coating treatment is carried out under stirring conditions. The coating temperature is controlled at 60°C to 80°C, and the coating time is 1 hour to 2 hours. After the coating reaction is completed, the material is filtered, washed, and dried to obtain a ternary cathode material with a thin alumina coating layer on its surface. The thickness of the alumina coating layer is controlled in the range of 1 nanometer to 5 nanometers, with an optimal coating thickness of 3 nanometers. This alumina coating layer can further improve the thermal stability of the material, effectively inhibiting the oxidative decomposition of the electrolyte under high temperature or high voltage conditions, and significantly reducing the risk of thermal runaway.

[0027] The finally prepared high-stability ternary cathode material has the following characteristic parameters: particle size distribution of 10 to 20 micrometers, specific surface area of ​​0.5 m² / g to 1.5 m² / g, and tap density of 2.0 g / cm³ to 2.5 g / cm³. The material exhibits a typical layered structure with lattice parameters of approximately 2.87 Å on the a-axis and 14.41 Å on the c-axis. The intensity ratio of the (003) peak to the (104) peak in the X-ray diffraction pattern is greater than 1.2, indicating that the material has good layered structural order. In charge-discharge tests, the material achieves a discharge capacity of 180 to 200 mAh / g at 1C rate, and retains over 90% of its capacity after 100 cycles, demonstrating excellent cycle stability.

[0028] The preparation method in this embodiment is simple, with controllable parameters and mild reaction conditions in each step, making it easy to achieve large-scale industrial production. By using a high-nickel ternary material, the theoretical capacity and energy density of the material are improved; the dual-element doping of tungsten and zirconium effectively stabilizes the crystal structure and suppresses phase transitions and structural collapse during charge and discharge; surface passivation treatment and alumina coating significantly improve the interfacial stability and thermal stability of the material. The resulting high-stability ternary cathode material can meet the requirements of new energy vehicle power batteries for high energy density, high safety, and long cycle life.

[0029] Example 2 To further verify the technical solution of the present invention, a second specific embodiment of the present invention is provided below.

[0030] The main difference between this embodiment and Embodiment 1 lies in the optimization and adjustment of the dopant content and sintering process parameters. In the lithiation doping treatment in step 3, the total dopant content of the tungsten source compound and zirconium source compound in the dopant is adjusted to 1.5% of the total molar amount of the precursor, while the molar ratio of tungsten to zirconium remains at 1:1. The amount of lithium carbonate added is calculated based on the total molar amount of nickel, cobalt, and manganese, and the molar ratio of lithium to transition metal is set to 1.05:1 to ensure that the excess lithium source partially compensates for lithium loss during the sintering process.

[0031] In the high-temperature sintering process of step 4, the pre-sintering temperature in the first stage is adjusted to 480 degrees Celsius, and the holding time is adjusted to 5 hours. The main sintering temperature in the second stage is adjusted to 820 degrees Celsius, and the holding time is adjusted to 12 hours. The oxygen atmosphere flow rate is adjusted to 1.2 liters per minute. Other step parameters are consistent with those in Example 1.

[0032] The high-stability ternary cathode material prepared according to the process parameters of this embodiment has a particle size distribution of 12 to 18 micrometers and a specific surface area of ​​0.8 m² / g to 1.2 m² / g. Under the same charge-discharge test conditions, the discharge capacity of this material is 185 mAh / g to 195 mAh / g, and the capacity retention rate is over 92% after 100 cycles and still over 85% after 200 cycles. Compared with Example 1, the material prepared in this embodiment exhibits superior cycle stability, which is attributed to the optimized content of doping elements and the precise control of sintering temperature, resulting in a more uniform distribution of tungsten and zirconium elements in the crystal structure and forming a more stable crystal structure.

[0033] Example 3 To expand the application scope of the present invention and the universality of the verification process, a third specific embodiment of the present invention is provided below.

[0034] The difference between this embodiment and Embodiment 1 lies in the adjustment of the precursor formulation and the improvement of the coating process. In the preparation of the precursor mixed solution in step 1, the molar ratio of nickel, cobalt, and manganese is adjusted to nickel:cobalt:manganese = 6:2:2, i.e., a ternary material with a medium-nickel formulation is used. Although the theoretical capacity of this formulation is slightly lower than that of the high-nickel formulation, it has better cycle stability and safety, making it suitable for applications with higher safety performance requirements.

[0035] In the coprecipitation reaction of step 2, the reaction temperature was adjusted to 55 degrees Celsius, the reaction pH was adjusted to 10.8, and the aging time was adjusted to 3 hours. Other parameters remained the same as in Example 1.

[0036] In step 3, the total content of doping elements is adjusted to 2.5% of the total molar amount of the precursor, with the molar ratio of tungsten to zirconium adjusted to 2:1. This adjustment of the doping ratio aims to enhance the stabilizing effect of tungsten on the crystal structure, while appropriately reducing the zirconium content to optimize the rate performance of the material.

[0037] In the high-temperature sintering process of step 4, the pre-sintering temperature of the first stage is adjusted to 520 degrees Celsius, and the holding time is adjusted to 4 hours. The main sintering temperature of the second stage is adjusted to 780 degrees Celsius, and the holding time is adjusted to 14 hours. The oxygen atmosphere flow rate is adjusted to 1.8 liters per minute.

[0038] In step 5, the surface passivation treatment temperature was adjusted to 32 degrees Celsius, and the passivation time was adjusted to 2.5 hours. The passivating agent solution concentration was adjusted to 0.05 mol / L.

[0039] In terms of coating process, the thickness of the alumina coating layer is adjusted to 2 to 4 nanometers, the coating temperature is controlled at 70 degrees Celsius, and the coating time is 1.5 hours.

[0040] The high-stability ternary cathode material prepared according to the process parameters of this embodiment has a particle size distribution of 11 to 19 micrometers and a specific surface area of ​​0.7 m² / g to 1.3 m² / g. In charge-discharge tests, the material exhibits a discharge capacity of 170 mAh / g to 185 mAh / g at a 1C rate, retains over 93% of its capacity after 100 cycles, and still retains over 80% after 300 cycles. This material demonstrates extremely excellent cycle stability and is suitable for high-end energy storage systems and aerospace applications where material reliability is extremely important. The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A highly stable ternary cathode material and its preparation method, characterized in that, Includes the following steps: A precursor mixture solution was prepared by adding nickel, cobalt, and manganese source compounds to deionized water according to a preset nickel-cobalt-manganese molar ratio and stirring until completely dissolved to obtain a homogeneous precursor mixture solution. The precursor was synthesized by co-precipitation reaction by simultaneously adding the precursor mixture solution and ammonia solution to a reaction vessel and carrying out the co-precipitation reaction under stirring conditions. The reaction temperature and pH were controlled within a preset range. After the reaction was completed, the precursor was aged, centrifuged, washed, and dried to obtain a nickel-cobalt-manganese hydroxide precursor. Lithium doping was then performed by mixing the precursor with a lithium source compound and a dopant compound, wherein the dopant included a tungsten source compound and a zirconium source compound, according to a preset doping ratio. After homogeneous mixing, a doped mixture was obtained. High-temperature sintering was then performed by placing the doped mixture in a high-temperature sintering furnace and sintering in stages under an oxygen atmosphere. The first stage involved pre-sintering at a lower temperature, and the second stage involved main sintering at a preset sintering temperature. After sintering, the mixture was cooled with the furnace to obtain the sintered product. Surface passivation treatment is performed by mixing the sintered product with a passivating agent solution and performing surface passivation treatment under stirring conditions. The passivation temperature is controlled within a preset range. After the treatment is completed, the product is centrifuged, washed, and dried to obtain the final high-stability ternary cathode material.

2. The high-stability ternary cathode material and its preparation method according to claim 1, characterized in that, In the step of preparing the precursor mixed solution, the nickel source compound is nickel nitrate, the cobalt source compound is cobalt nitrate, the manganese source compound is manganese nitrate, and the preset nickel-cobalt-manganese molar ratio is nickel:cobalt:manganese equal to 8:1:

1.

3. The high-stability ternary cathode material and its preparation method according to claim 1, characterized in that, In the coprecipitation reaction precursor synthesis step, the reaction temperature is 50°C to 60°C, the reaction pH is 10.5 to 11.5, and the aging time is 2 hours to 4 hours.

4. The high-stability ternary cathode material and its preparation method according to claim 1, characterized in that, In the lithiation doping step, the lithium source compound is lithium carbonate, and the total doping amount of the tungsten source compound and zirconium source compound in the dopant is 1% to 3% of the total molar amount of the precursor, wherein the molar ratio of tungsten to zirconium is 1:

1.

5. The high-stability ternary cathode material and its preparation method according to claim 1, characterized in that, In the high-temperature sintering step, the first stage pre-sintering temperature is 450 degrees Celsius to 550 degrees Celsius, and the pre-sintering time is 4 hours to 6 hours. The second stage main sintering temperature is 750 degrees Celsius to 850 degrees Celsius, and the main sintering time is 10 hours to 15 hours. The oxygen atmosphere flow rate is 1 liter to 2 liters per minute.

6. The high-stability ternary cathode material and its preparation method according to claim 1, characterized in that, In the surface passivation treatment step, the passivating agent is an aluminum-based compound, the passivation treatment temperature is 25 degrees Celsius to 35 degrees Celsius, and the passivation treatment time is 1 hour to 3 hours.

7. A highly stable ternary cathode material and its preparation method according to any one of claims 1 to 6, characterized in that, The process also includes a coating layer formation step. After the surface passivation treatment is completed, the product is mixed with an aluminum source compound coating agent, and an alumina coating treatment is performed under stirring conditions. The coating temperature is controlled at 60 degrees Celsius to 80 degrees Celsius, and the coating time is 1 hour to 2 hours, to obtain a ternary cathode material with a thin alumina layer on the surface. The thickness of the alumina coating layer is 1 nanometer to 5 nanometers.

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