High-nickel ternary positive electrode material, preparation method thereof and lithium ion battery

Abstract

The application provides a high-nickel ternary positive electrode material and a preparation method and a lithium ion battery thereof, and the preparation method of the high-nickel ternary positive electrode material comprises the following steps: mixing a high-nickel ternary precursor and a lithium source, and then pre-sintering in a protective atmosphere to obtain an intermediate; and then calcining the obtained intermediate in an air atmosphere to obtain the high-nickel ternary positive electrode material; the pre-sintering is performed in two stages, the temperature of the first-stage pre-sintering is 280 DEG C to 300 DEG C, and the temperature of the second-stage pre-sintering is 310 DEG C to 320 DEG C. The preparation method of the high-nickel ternary positive electrode material provided by the application gradually dehydrates, decomposes and preliminarily lithiates the precursor and the lithium source in the protective atmosphere through two-stage pre-sintering, reduces the violent reaction in the initial stage of subsequent high-temperature calcination, and is beneficial to the formation of oxygen vacancies, in-situ protective layers and layered-spinel dual-phase interfaces, so as to inhibit the excessive oxidation of the surface, the release of lattice oxygen and the cation mixing, and improve the high-voltage cycle stability and rate performance of the positive electrode material.

Description

Technical Field

[0001] This invention belongs to the field of battery technology, and relates to a high-nickel ternary cathode material, and more particularly to a high-nickel ternary cathode material, its preparation method, and a lithium-ion battery. Background Technology

[0002] With the increasing demands for energy density from electric vehicles, large-scale energy storage, and portable electronic devices, higher requirements are being placed on the energy density, cycle life, and safety performance of lithium-ion batteries. As a key component determining the energy density and electrochemical performance of lithium-ion batteries, developing cathode materials that combine high specific capacity, high operating voltage, and good cycle stability has become an important direction in the lithium-ion battery field.

[0003] Layered nickel-cobalt-manganese ternary cathode materials possess high reversible specific capacity, high operating voltage, and relatively low raw material costs, thus finding widespread application in power batteries and energy storage batteries. Among them, layered high-nickel ternary materials (LiNi) x Co y Mn z O2 (x≥0.8, x+y+z=1) is considered a key material for achieving battery energy densities of over 300Wh / kg due to its advantages such as high reversible specific capacity (>200mAh / g) and relatively low cost.

[0004] However, the existing high-nickel ternary cathode material preparation process generally uses high-temperature sintering in an air or oxygen atmosphere. During the calcination process at 600℃~900℃, problems such as overcharging, lattice oxygen release, and cation mixing can easily occur on the material surface, resulting in poor cycle stability and severe rate performance degradation of the high-nickel ternary cathode material at high voltage (≥4.3V).

[0005] For example, CN115286055A discloses a ternary cathode material and its preparation method, a cathode, and a lithium-ion battery, relating to the field of lithium-ion battery technology. The preparation method of the ternary cathode material includes: high-pressure low-temperature pretreatment: a mixture obtained by mixing a nickel-cobalt-manganese ternary precursor with a lithium source is placed in an inert atmosphere at a pressure greater than or equal to 0.5 MPa, and the mixture is reacted at a high-pressure environment temperature of 200℃~250℃ for 4h~8h to obtain an intermediate material; high-temperature treatment: the intermediate material is placed in an environment at a temperature of 750℃~980℃ in an air or oxygen atmosphere for 4h~8h. The ternary cathode material is prepared using the above-mentioned preparation method. The cathode of a lithium-ion battery includes the above-mentioned ternary cathode material, and the lithium-ion battery includes the above-mentioned cathode.

[0006] CN107528064A discloses a high-voltage type quasi-single-crystal ternary cathode material and its preparation method. The preparation method of this invention includes the following steps: mixing and reacting nickel salt, cobalt salt, manganese salt, ammonia complexing agent and ammonium oxalate precipitant in water to obtain a precursor; mixing with a lithium source and ball milling at 100 rpm to 400 rpm for 3 to 6 hours; in an atmosphere furnace, under air or oxygen atmosphere, heating to 450°C to 750°C at 1°C to 10°C, sintering for 4 to 10 hours and then cooling to room temperature; ball milling at 400 rpm to 750 rpm for 5 to 8 hours; mixing with a lithium source and ball milling at 100 rpm to 400 rpm for 1 to 4 hours; in an atmosphere furnace, under oxygen atmosphere, heating to 450°C to 600°C at 3°C / min to 10°C / min, calcining for 2 to 6 hours, heating to 750°C to 950°C at 1°C / min to 750°C to 950°C, calcining for 8 to 12 hours and then cooling to room temperature; and finally crushing, pulverizing and sieving to obtain a high-voltage type quasi-single-crystal ternary cathode material.

[0007] In addition, emerging application scenarios such as drones, robots, and eVTOL have placed higher demands on battery energy density, and the traditional pure air atmosphere sintering process can no longer meet the development needs of high-activity, high-energy-density cathode materials.

[0008] In summary, the existing methods for preparing high-nickel ternary cathode materials all have certain drawbacks. When sintering in a high-temperature air or oxygen atmosphere during the preparation process, excessive oxidation of the material surface, decreased lattice oxygen stability, and intensified cation mixing can easily occur, resulting in insufficient cycle stability and rate performance under high voltage. Therefore, the development and design of a new type of high-nickel ternary cathode material and its preparation method are crucial for lithium-ion batteries. Summary of the Invention

[0009] To address the shortcomings of existing technologies, the present invention aims to provide a high-nickel ternary cathode material, its preparation method, and a lithium-ion battery. The preparation method of the high-nickel ternary cathode material provided by the present invention involves two-stage pre-calcination in a protective atmosphere, which gradually dehydrates, decomposes, and initially lithiates the precursor and lithium source, reducing the violent reaction in the initial stage of subsequent high-temperature calcination. This method also facilitates the formation of oxygen vacancies, an in-situ protective layer, and a layered-spinel dual-phase interface, thereby suppressing excessive surface oxidation, lattice oxygen release, and cation mixing, and improving the high-voltage cycle stability and rate performance of the cathode material.

[0010] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for preparing a high-nickel ternary cathode material, the method comprising: After mixing the high-nickel ternary precursor and the lithium source, the mixture is pre-calcined in a protective atmosphere to obtain an intermediate; the intermediate is then calcined in an air atmosphere to obtain the high-nickel ternary cathode material. The pre-firing is carried out in two stages. The temperature of the first stage of pre-firing is 280℃~300℃, and the temperature of the second stage of pre-firing is 310℃~320℃.

[0011] In this invention, the temperature of the first pre-firing stage is 280℃~300℃, for example, it can be 280℃, 285℃, 290℃, 295℃ or 300℃, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0012] In this invention, the preheating temperature of the second stage is 310℃~320℃, for example, it can be 310℃, 311℃, 312℃, 313℃, 314℃, 315℃, 316℃, 317℃, 318℃, 319℃ or 320℃, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0013] The method for preparing high-nickel ternary cathode material provided by this invention involves two-stage pre-calcination in a protective atmosphere, with the temperatures of the first and second stages controlled within the ranges of 280℃~300℃ and 310℃~320℃, respectively. This allows the high-nickel ternary precursor and lithium source to gradually undergo dehydration, decomposition, and preliminary lithiation reactions, reducing the risk of excessively vigorous initial reactions during subsequent high-temperature calcination in air atmosphere. It also facilitates the control of the surface structure of the resulting high-nickel ternary cathode material. Furthermore, the two-stage pre-calcination under a protective atmosphere introduces oxygen vacancies onto the material surface and forms a protective layer in situ, thereby inhibiting excessive oxidation and lattice oxygen release, improving the lattice oxygen stability of the material, and forming a layered-spinel dual-phase interface within the material. This layered-spinel dual-phase interface blocks Ni... 2+ Migration to the lithium layer reduces Ni 2+ / Li + The degree of cation mixing. Therefore, the high-nickel ternary cathode material prepared by the preparation method provided by the present invention exhibits excellent cycle stability (capacity retention ≥94.8% after 200 cycles in the high-voltage charge-discharge range of 2.8V~4.6V) and rate performance (1C discharge specific capacity ≥210mAh / g) under high voltage. In addition, the preparation method provided by the present invention can be directly implemented using existing production lines, with low modification costs, and is suitable for large-scale mass production.

[0014] Preferably, the protective atmosphere includes nitrogen and / or an inert gas.

[0015] Preferably, the gas pressure during pre-firing is 90 kPa to 110 kPa, for example, it can be 90 kPa, 92 kPa, 94 kPa, 96 kPa, 98 kPa, 100 kPa, 102 kPa, 104 kPa, 106 kPa, 108 kPa or 110 kPa, but it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0016] In the preparation method provided by the present invention, when the gas pressure during pre-calcination is 90kPa~110kPa, it is beneficial to maintain the stability of the protective atmosphere, reduce the entry of external oxygen into the pre-calcination system, and promote the discharge of gaseous products generated during the pre-calcination process. This ensures that the high-nickel ternary precursor and the lithium source undergo uniform dehydration, decomposition, and preliminary lithiation reactions, reduces local over-oxidation and uneven reaction of the material, and is beneficial to improving the structural stability of the obtained high-nickel ternary cathode material.

[0017] Preferably, the pre-burning time for the first stage is 2h to 3h, for example, it can be 2.0h, 2.1h, 2.2h, 2.3h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h or 3.0h, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0018] Preferably, in the pre-firing process, the pre-firing time of the second stage is 2h to 3h, for example, it can be 2.0h, 2.1h, 2.2h, 2.3h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h or 3.0h, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0019] Preferably, in the pre-firing process, the first pre-firing stage is further divided into two stages, where the temperature is increased from the temperature of the first pre-firing stage to the temperature of the second pre-firing stage at a rate of 1℃ / min to 3℃ / min. The heating rate can be, for example, 1.0℃ / min, 1.2℃ / min, 1.4℃ / min, 1.6℃ / min, 1.8℃ / min, 2.0℃ / min, 2.2℃ / min, 2.4℃ / min, 2.6℃ / min, 2.8℃ / min, or 3.0℃ / min, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0020] In the preparation method provided by the present invention, by controlling the time of the first pre-calcination and the second pre-calcination and the heating rate between the two pre-calcinations to 1℃ / min~3℃ / min, the low-temperature reaction between the high-nickel ternary precursor and the lithium source can proceed gradually and uniformly, reducing the uneven local reaction caused by excessive heating or insufficient reaction time, which is beneficial to forming an intermediate with relatively stable composition and structure.

[0021] Preferably, exhaust gas is continuously discharged during the pre-burning process.

[0022] In the preparation method provided by the present invention, nitrogen and / or inert gas are used for protection during the pre-calcination process, and the exhaust gas is continuously discharged, which can reduce the impact of the oxidizing atmosphere on the material surface.

[0023] Preferably, the calcination includes sequential heating and holding, wherein the holding temperature is 760℃~800℃ and the holding time is 9h~12h.

[0024] In this invention, the insulation temperature is 760℃~800℃, for example, it can be 760℃, 762℃, 764℃, 766℃, 768℃, 770℃, 772℃, 774℃, 776℃, 778℃, 780℃, 782℃, 784℃, 786℃, 788℃, 790℃, 792℃, 794℃, 796℃, 798℃ or 800℃, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0025] In this invention, the heat preservation time is 9h to 12h, for example, it can be 9.0h, 9.2h, 9.4h, 9.6h, 9.8h, 10.0h, 10.2h, 10.4h, 10.6h, 10.8h, 11.0h, 11.2h, 11.4h, 11.6h, 11.8h or 12.0h, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0026] In the preparation method provided by the present invention, calcination at 760℃~800℃ in an air atmosphere is beneficial to complete the lithiation reaction and form a layered crystal structure. By controlling the holding temperature and holding time, the crystal integrity and structural stability of the material can be taken into account.

[0027] Preferably, the heating rate is 3℃ / min to 5℃ / min, for example, it can be 3.0℃ / min, 3.2℃ / min, 3.4℃ / min, 3.6℃ / min, 3.8℃ / min, 4.0℃ / min, 4.2℃ / min, 4.4℃ / min, 4.6℃ / min, 4.8℃ / min or 5.0℃ / min, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0028] Preferably, the preparation method further includes cooling after calcination, wherein the final temperature of the cooling is 5℃~40℃, for example, it can be 5℃, 6℃, 9℃, 10℃, 13℃, 14℃, 15℃, 16℃, 17℃, 18℃, 19℃, 20℃, 21℃, 25℃, 26℃, 28℃, 29℃, 32℃, 36℃, 37℃, 38℃, 39℃ or 40℃, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0029] Preferably, the preparation method further includes washing and drying the high-nickel ternary precursor before mixing.

[0030] Preferably, the washing process includes sequential alkaline washing and water washing.

[0031] In the preparation method provided by the present invention, the high-nickel ternary precursor is subjected to alkali washing and water washing in sequence, which helps to remove residual alkaline substances and other impurities on the surface of the precursor.

[0032] Preferably, the alkaline solution used in the alkaline washing includes a sodium hydroxide solution with a concentration of 0.2 mol / L to 0.8 mol / L, for example, it can be 0.2 mol / L, 0.25 mol / L, 0.3 mol / L, 0.35 mol / L, 0.4 mol / L, 0.45 mol / L, 0.5 mol / L, 0.55 mol / L, 0.6 mol / L, 0.65 mol / L, 0.7 mol / L, 0.75 mol / L or 0.8 mol / L, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0033] Preferably, the water used in the washing process includes permeate water.

[0034] Preferably, the drying is carried out in a protective atmosphere.

[0035] Preferably, the drying temperature is 100℃~180℃ and the drying time is 8h~16h.

[0036] In this invention, the drying temperature is 100℃~180℃, for example, it can be 100℃, 105℃, 110℃, 115℃, 120℃, 125℃, 130℃, 135℃, 140℃, 145℃, 150℃, 155℃, 160℃, 165℃, 170℃, 175℃ or 180℃, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0037] In this invention, the drying time is 8h to 16h, for example, it can be 8h, 8.5h, 9h, 9.5h, 10h, 10.5h, 11h, 11.5h, 12h, 12.5h, 13h, 13.5h, 14h, 14.5h, 15h, 15.5h or 16h, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0038] Preferably, the moisture content in the dried high-nickel ternary precursor obtained after drying is not higher than 0.5 wt%, for example, it can be 0.5 wt%, 0.45 wt%, 0.4 wt%, 0.35 wt%, 0.3 wt%, 0.25 wt%, 0.2 wt%, 0.15 wt%, 0.1 wt%, or 0.05 wt%, but it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0039] Preferably, the high-nickel ternary precursor is prepared by a co-precipitation method, wherein the co-precipitation method includes: A ternary mixed salt solution, a liquid alkali solution, and an ammonia solution are simultaneously and concurrently added to a reactor containing a base liquid. A co-precipitation reaction is carried out under stirring conditions. The particle size of the particles in the reaction system is continuously monitored. When the D50 particle size of the particles reaches 1μm~50μm, the feeding is stopped, and the reaction continues until the material is completely reacted to obtain the high-nickel ternary precursor.

[0040] Preferably, the concentration of the ternary mixed salt solution is 80 g / L to 120 g / L, and the feed rate is 1 L / h to 10 L / h.

[0041] In this invention, the concentration of the ternary mixed salt solution is 80 g / L to 120 g / L (that is, the total concentration of metal salts in the ternary mixed salt solution is 80 g / L to 120 g / L), for example, it can be 80 g / L, 85 g / L, 90 g / L, 95 g / L, 100 g / L, 105 g / L, 110 g / L, 115 g / L or 120 g / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0042] In this invention, the feed rate of the ternary mixed salt solution is 1L / h to 10L / h, for example, it can be 1L / h, 1.5L / h, 2L / h, 2.5L / h, 3L / h, 3.5L / h, 4L / h, 4.5L / h, 5L / h, 5.5L / h, 6L / h, 6.5L / h, 7L / h, 7.5L / h, 8L / h, 8.5L / h, 9L / h, 9.5L / h, or 10L / h, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0043] Preferably, the mass concentration of the liquid alkali solution is 10wt%~30wt%, and the feed rate is 1L / h~7L / h.

[0044] In this invention, the mass concentration of the liquid alkali solution is 10wt% to 30wt%, for example, it can be 10wt%, 12wt%, 14wt%, 16wt%, 18wt%, 20wt%, 22wt%, 24wt%, 26wt%, 28wt% or 30wt%, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0045] In this invention, the feed rate of the liquid alkali solution is 1L / h to 7L / h, for example, it can be 1L / h, 1.5L / h, 2L / h, 2.5L / h, 3L / h, 3.5L / h, 4L / h, 4.5L / h, 5L / h, 5.5L / h, 6L / h, 6.5L / h or 7L / h, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0046] Preferably, the mass concentration of the ammonia solution is 10wt%~20wt%, and the feed rate is 0.1L / h~1L / h.

[0047] In this invention, the mass concentration of the ammonia solution is 10wt% to 20wt%, for example, it can be 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, or 20wt%, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0048] In this invention, the feed rate of the ammonia solution is 0.1 L / h to 1 L / h, for example, it can be 0.1 L / h, 0.15 L / h, 0.2 L / h, 0.25 L / h, 0.3 L / h, 0.35 L / h, 0.4 L / h, 0.45 L / h, 0.5 L / h, 0.55 L / h, 0.6 L / h, 0.65 L / h, 0.7 L / h, 0.75 L / h, 0.8 L / h, 0.85 L / h, 0.9 L / h, 0.95 L / h or 1 L / h, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0049] Preferably, the temperature of the base liquid is 20℃~80℃, the ammonia concentration is 0g / L~10g / L, and the pH value is 8.0~12.0.

[0050] In this invention, the temperature of the base liquid is 20℃~80℃, for example, it can be 20℃, 25℃, 30℃, 35℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃ or 80℃, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0051] In this invention, the ammonia concentration of the base liquid is 0 g / L to 10 g / L, for example, it can be 0 g / L, 1 g / L, 2 g / L, 3 g / L, 4 g / L, 5 g / L, 6 g / L, 7 g / L, 8 g / L, 9 g / L or 10 g / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0052] In this invention, the pH value of the base solution is 8.0~12.0, for example, it can be 8.0, 8.2, 8.6, 8.8, 9.0, 9.2, 9.4, 9.6, 10.2, 10.4, 10.8, 11.0, 11.4, 11.8 or 12.0, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0053] Preferably, the stirring rate during the coprecipitation reaction is 100 r / min to 400 r / min, for example, it can be 100 r / min, 140 r / min, 160 r / min, 180 r / min, 220 r / min, 240 r / min, 260 r / min, 300 r / min, 340 r / min, 360 r / min, 380 r / min or 400 r / min, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0054] Preferably, during the coprecipitation reaction, the pH of the reaction system is 8.0~12.5, the ammonia concentration is 0g / L~13g / L, and the temperature is 20℃~80℃.

[0055] In this invention, during the coprecipitation reaction, the pH value of the reaction system is 8.0~12.5, for example, it can be 8.0, 8.2, 8.8, 9.0, 9.2, 9.4, 10.2, 10.4, 10.6, 10.8, 11.0, 11.6, 11.8, 12.2, 12.4 or 12.5, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0056] In this invention, during the coprecipitation reaction, the ammonia concentration of the reaction system is 0 g / L to 13 g / L, for example, it can be 0 g / L, 1 g / L, 2 g / L, 3 g / L, 4 g / L, 5 g / L, 6 g / L, 7 g / L, 8 g / L, 9 g / L, 10 g / L, 11 g / L, 12 g / L or 13 g / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0057] In this invention, during the coprecipitation reaction, the temperature of the reaction system is 20℃~80℃, for example, it can be 20℃, 25℃, 30℃, 35℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃ or 80℃, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0058] Preferably, during the coprecipitation reaction, before the D50 particle size of the particles reaches 1μm~50μm, the particles are collected using a thickening device, and the collected particles are returned to the reaction vessel to continue the coprecipitation reaction.

[0059] In this invention, the particle size is defined as before the D50 particle size reaches 1μm to 50μm, for example, before 1μm, 2μm, 5μm, 8μm, 10μm, 12μm, 15μm, 18μm, 20μm, 22μm, 25μm, 28μm, 30μm, 32μm, 35μm, 38μm, 40μm, 42μm, 45μm, 48μm or 50μm.

[0060] Preferably, the high-nickel ternary precursor comprises a nickel-cobalt-manganese hydroxide precursor, wherein the chemical formula of the nickel-cobalt-manganese hydroxide precursor is Ni. x Co y Mn z (OH)2, where 0.8≤x<1, y>0, z>0, and x+y+z=1.

[0061] In this invention, 0.8 ≤ x < 1, and can be, for example, 0.80, 0.81, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.90, 0.93, 0.94, 0.97, 0.98 or 0.99, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0062] In this invention, y>0, for example, can be 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, or 0.19, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0063] In this invention, z>0, and can be, for example, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, or 0.19, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0064] Preferably, the lithium source includes any one or a combination of at least two of lithium hydroxide, lithium carbonate, lithium nitrate, or lithium acetate. Typical but non-limiting combinations include combinations of lithium hydroxide and lithium carbonate, combinations of lithium nitrate and lithium acetate, combinations of lithium carbonate and lithium nitrate, combinations of lithium hydroxide, lithium carbonate, and lithium nitrate, or combinations of lithium carbonate, lithium nitrate, and lithium acetate.

[0065] Preferably, the molar ratio of the high-nickel ternary precursor to the molar ratio of the lithium source is 1:(1.01~1.08), for example, it can be 1:1.01, 1:1.02, 1:1.03, 1:1.04, 1:1.05, 1:1.06, 1:1.07 or 1:1.08, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0066] Secondly, the present invention provides a high-nickel ternary cathode material, wherein the high-nickel ternary cathode material is obtained by the preparation method described in the first aspect.

[0067] Preferably, the chemical formula of the high-nickel ternary cathode material is LiNi. x Co y Mn z O2, where 0.8≤x<1, y>0, z>0, and x+y+z=1.

[0068] In this invention, 0.8 ≤ x < 1, and can be, for example, 0.80, 0.81, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.90, 0.93, 0.94, 0.97, 0.98 or 0.99, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0069] In this invention, y>0, for example, can be 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, or 0.19, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0070] In this invention, z>0, and can be, for example, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, or 0.19, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0071] Thirdly, the present invention provides a lithium-ion battery, the lithium-ion battery comprising the high-nickel ternary cathode material described in the second aspect.

[0072] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0073] Compared with the prior art, the present invention has the following beneficial effects: The method for preparing high-nickel ternary cathode material provided by this invention involves two-stage pre-calcination in a protective atmosphere, with the temperatures of the first and second stages controlled within the ranges of 280℃~300℃ and 310℃~320℃, respectively. This allows the high-nickel ternary precursor and lithium source to gradually undergo dehydration, decomposition, and preliminary lithiation reactions, reducing the risk of excessively vigorous initial reactions during subsequent high-temperature calcination in air atmosphere. It also facilitates the control of the surface structure of the resulting high-nickel ternary cathode material. Furthermore, the two-stage pre-calcination under a protective atmosphere introduces oxygen vacancies onto the material surface and forms a protective layer in situ, thereby inhibiting excessive oxidation and lattice oxygen release, improving the lattice oxygen stability of the material, and forming a layered-spinel dual-phase interface within the material. This layered-spinel dual-phase interface blocks Ni... 2+ Migration to the lithium layer reduces Ni 2+ / Li +The degree of cation mixing. Therefore, the high-nickel ternary cathode material prepared by the preparation method provided by the present invention exhibits excellent cycle stability (capacity retention ≥94.8% after 200 cycles in the high-voltage charge-discharge range of 2.8V~4.6V) and rate performance (1C discharge specific capacity ≥210mAh / g) under high voltage. In addition, the preparation method provided by the present invention can be directly implemented using existing production lines, with low modification costs, and is suitable for large-scale mass production. Detailed Implementation

[0074] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0075] The "range" disclosed in this invention can be defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the specific range. This type of range definition can include or exclude endpoints; any endpoint can be independently included or excluded, and they can be arbitrarily combined, meaning any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for specific parameters, it is understood that ranges of 60~110 and 80~120 are also expected. Furthermore, if minimum range values ​​1 and 2 are listed, and maximum range values ​​3, 4, and 5 are also listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this invention, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0" and "5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is described as an integer ≥2, it is equivalent to listing integers such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For instance, when a parameter is described as an integer selected from "2~10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0076] In this invention, "a combination of at least two" refers to a quantity greater than or equal to two, unless otherwise specified. For example, "any combination of one or at least two" means one or more or more items. It can be understood that when referring to "a combination of at least two," it refers to any suitable combination of multiple items, that is, a combination of "at least two" items carried out in a manner that does not conflict with and enables the implementation of this invention.

[0077] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0078] The term "embodiment" as used in this invention means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this invention can be combined with other embodiments.

[0079] Those skilled in the art will understand that the order in which the steps are written in the methods of the various embodiments does not imply a strict execution order. The detailed execution order of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps of the present invention may be performed sequentially or randomly, but are preferably performed sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), meaning that step (c) can be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0080] In this invention, open-ended technical features or solutions described using terms such as "comprising" do not exclude additional members beyond those listed unless otherwise specified. They can be considered as providing both closed-ended features or solutions comprised of the listed members and open-ended features or solutions that include additional members beyond the listed members. For example, A includes a1, a2, and a3. Unless otherwise specified, it may also include other members or exclude additional members. This can be considered as providing both technical features or solutions where "A is composed of a1, a2, and a3" or "A is selected from a1, a2, and a3," and technical features or solutions where "A includes not only a1, a2, and a3, but also other members."

[0081] In this invention, unless otherwise specified, the features or solutions corresponding to "and / or" include any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" represents a group consisting of A, B, and "a combination of A and B". "Containing A and / or B" can mean "containing A, containing B, and containing A and B", or "containing A, containing B, or containing A and B", and can be appropriately understood according to the context.

[0082] In this invention, the terms "first aspect," "second aspect," "third aspect," "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," "fourth," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on the quantity.

[0083] Example 1 This embodiment provides a high-nickel ternary cathode material, the chemical formula of which is LiNi. 0.90 Co 0.05 Mn 0.05 O2; The preparation method of the high-nickel ternary cathode material is as follows: (1) Preparation of high-nickel ternary precursors: A ternary mixed salt solution (100 g / L, i.e., the total concentration of metal salts in the ternary mixed salt solution is 100 g / L, with a molar ratio of Ni ions, Co ions, and Mn ions of 0.90:0.05:0.05), a 20 wt% liquid alkali solution (sodium hydroxide solution), and a 15 wt% ammonia solution were added concurrently to a reaction vessel containing a base liquid at 50°C, an ammonia concentration of 5 g / L, and a pH of 10.0. The mixture was stirred at 250 r / min. A coprecipitation reaction was carried out at a controlled rate, with the pH of the reaction system maintained at 10.0, the ammonia concentration at 6 g / L, and the temperature at 50 °C. The particle size of the particles in the reaction system was continuously monitored. Before the D50 particle size reached 25 μm, a high-efficiency thickener was used to collect all the particles and return them to the reactor for continued reaction and growth. When the D50 particle size reached 25 μm, the feed was stopped, and the reaction continued until the material was completely reacted, yielding a high-nickel ternary precursor (chemical formula Ni). 0.90 Co 0.05 Mn 0.05 (OH)2) slurry; (2) Washing and drying in an inert atmosphere: The slurry containing high-nickel ternary precursor obtained in step (1) was subjected to centrifugal alkaline washing (using 0.5 mol / L NaOH solution) and water washing (using permeable water as the washing solution) twice in sequence, and then sent to a drying oven and dried in a nitrogen atmosphere at 150°C for 12 hours to obtain a dried high-nickel ternary precursor with a moisture content of no more than 0.5 wt%. (3) Lithium-based mixing and low-temperature segmented pre-firing: A high-nickel ternary precursor with a molar ratio of 1:1.05 was mixed with a lithium source (lithium hydroxide) and placed in a tube furnace. In an argon atmosphere with a pressure of 100 kPa, the temperature was increased from 25°C to 290°C at a rate of 2°C / min. The first stage of pre-calcination was carried out at 290°C for 2.5 h. Then, the temperature was increased to 315°C at a rate of 2°C / min. The second stage of pre-calcination was carried out at 315°C for 2.5 h. The mixture was then cooled to 25°C with the furnace to obtain an intermediate. Throughout the process, exhaust gas was continuously discharged. (4) High-temperature air calcination: The intermediate obtained in step (3) was transferred to an air atmosphere box furnace, heated to 780°C at a rate of 4°C / min in air atmosphere and held for 10 hours, and then naturally cooled to 25°C to obtain a high-nickel ternary cathode material.

[0084] Example 2 This embodiment provides a high-nickel ternary cathode material, the chemical formula of which is LiNi. 0.88 Co 0.06 Mn 0.06 O2; The preparation method of the high-nickel ternary cathode material is as follows: (1) Preparation of high-nickel ternary precursors: A ternary mixed salt solution (80 g / L, i.e., the total concentration of metal salts in the ternary mixed salt solution is 80 g / L, with a molar ratio of Ni ions, Co ions, and Mn ions of 0.88:0.06:0.06), a 30 wt% liquid alkali solution (sodium hydroxide solution), and a 10 wt% ammonia solution were added concurrently to a reactor containing a base solution at 80°C, 0 g / L ammonia, and pH 12.0. A co-precipitation reaction was carried out at a stirring rate of 400 r / min. During the reaction, the pH of the reaction system was controlled at 12.5, the ammonia concentration at 3 g / L, and the temperature at 80°C. Particle size was continuously monitored. Before the D50 particle size reached 10 μm, a high-efficiency thickener was used to collect all particles and return them to the reactor for continued reaction and growth. When the D50 particle size reached 10 μm, the feed was stopped, and the reaction continued until the material was completely reacted, yielding a high-nickel ternary precursor (chemical formula Ni).0.88 Co 0.06 Mn 0.06 (OH)2) slurry; (2) Washing and drying in an inert atmosphere: The slurry containing high-nickel ternary precursor obtained in step (1) was subjected to centrifugal alkaline washing (using 0.5 mol / L NaOH solution) and water washing (using permeable water as the washing solution) twice in sequence, and then sent to a drying oven and dried in a nitrogen atmosphere at 150°C for 12 hours to obtain a dried high-nickel ternary precursor with a moisture content of no more than 0.5 wt%. (3) Lithium-based mixing and low-temperature segmented pre-firing: A high-nickel ternary precursor with a molar ratio of 1:1.04 was mixed with a lithium source (lithium hydroxide) and placed in a tube furnace. Under a nitrogen atmosphere with a pressure of 90 kPa, the temperature was increased from 25°C to 300°C at a rate of 3°C / min. The first stage of pre-calcination was carried out at 300°C for 2 hours. Then, the temperature was increased to 320°C at a rate of 3°C / min. The second stage of pre-calcination was carried out at 320°C for 2 hours. The mixture was then cooled to 25°C with the furnace to obtain an intermediate. Throughout the process, exhaust gas was continuously discharged. (4) High-temperature air calcination: The intermediate obtained in step (3) was transferred to an air atmosphere box furnace, heated to 760°C at a rate of 3°C / min in air atmosphere and held for 12 hours, and then naturally cooled to 25°C to obtain a high-nickel ternary cathode material.

[0085] Example 3 This embodiment provides a high-nickel ternary cathode material, the chemical formula of which is LiNi. 0.92 Co 0.04 Mn 0.04 O2; The preparation method of the high-nickel ternary cathode material is as follows: (1) Preparation of high-nickel ternary precursors: A ternary mixed salt solution (120 g / L, i.e., the total concentration of metal salts in the ternary mixed salt solution is 120 g / L, with a molar ratio of Ni ions, Co ions, and Mn ions of 0.92:0.04:0.04), a 10 wt% liquid alkali solution, and a 20 wt% ammonia solution were added concurrently to a reactor containing a base solution at 20°C, an ammonia concentration of 10 g / L, and a pH of 8.0. A co-precipitation reaction was carried out at a stirring rate of 100 r / min. During the reaction, the pH of the reaction system was controlled at 8.0, the ammonia concentration at 13 g / L, and the temperature at 20°C. Particle size was continuously monitored. Before the D50 particle size reached 50 μm, a high-efficiency thickener was used to collect all particles and return them to the reactor for continued reaction and growth. When the D50 particle size reached 50 μm, the feed was stopped, and the reaction continued until the material was completely reacted, yielding a high-nickel ternary precursor (chemical formula Ni). 0.92 Co 0.04 Mn 0.04 (OH)2) slurry; (2) Washing and drying in an inert atmosphere: The slurry containing high-nickel ternary precursor obtained in step (1) was subjected to centrifugal alkaline washing (using 0.5 mol / L NaOH solution) and water washing (using permeable water as the washing solution) twice in sequence, and then sent to a drying oven and dried in a nitrogen atmosphere at 150°C for 12 hours to obtain a dried high-nickel ternary precursor with a moisture content of no more than 0.5 wt%. (3) Lithium-based mixing and low-temperature segmented pre-firing: A high-nickel ternary precursor with a molar ratio of 1:1.08 was mixed with a lithium source (lithium hydroxide) and placed in a tube furnace. Under a protective atmosphere with a pressure of 110 kPa, the temperature was increased from 25°C to 280°C at a rate of 1°C / min. The first stage of pre-calcination was carried out at 280°C for 3 hours. Then, the temperature was increased to 310°C at a rate of 1°C / min. The second stage of pre-calcination was carried out at 310°C for 3 hours. The mixture was then cooled to 25°C with the furnace to obtain an intermediate. Throughout the process, exhaust gas was continuously discharged. (4) High-temperature air calcination: The intermediate obtained in step (3) was transferred to an air-atmosphere box furnace and heated to 800°C at a rate of 5°C / min in the air atmosphere. After holding at the temperature for 9 hours, it was naturally cooled to 25°C to obtain a high-nickel ternary cathode material.

[0086] Example 4 This embodiment provides a high-nickel ternary cathode material. Except for the gas pressure during pre-calcination in step (3) of the preparation method being 60 kPa, the rest is the same as in Example 1.

[0087] Example 5 This embodiment provides a high-nickel ternary cathode material, except that the gas pressure during pre-calcination in step (3) of the preparation method is 140 kPa, and the rest is the same as in Example 1.

[0088] Example 6 This embodiment provides a high-nickel ternary cathode material. Except for step (3) of the preparation method, in which the first stage of pre-firing time is 1 hour, the rest is the same as in Example 1.

[0089] Example 7 This embodiment provides a high-nickel ternary cathode material. Except for step (3) of the preparation method, in which the first stage of pre-calcination time is 5 hours, the rest is the same as in Example 1.

[0090] Example 8 This embodiment provides a high-nickel ternary cathode material. Except for step (3) of the preparation method, in which the second stage of pre-calcination time is 1 hour, the rest is the same as in Example 1.

[0091] Example 9 This embodiment provides a high-nickel ternary cathode material. Except for step (3) of the preparation method, in which the second stage of pre-calcination time is 5 hours, the rest is the same as in Example 1.

[0092] Comparative Example 1 This comparative example provides a high-nickel ternary cathode material. Except for step (3) of the preparation method, in which the temperature is raised to 260°C and then the first stage of pre-calcination is carried out at 260°C, the rest is the same as in Example 1.

[0093] Comparative Example 2 This comparative example provides a high-nickel ternary cathode material. Except for step (3) of the preparation method, in which the temperature is raised to 310°C and then the first stage of pre-calcination is carried out at 310°C, the rest is the same as in Example 1.

[0094] Comparative Example 3 This comparative example provides a high-nickel ternary cathode material. Except for step (3) of the preparation method, in which the temperature is raised to 300°C and then a second pre-calcination is performed at 300°C, the rest is the same as in Example 1.

[0095] Comparative Example 4 This comparative example provides a high-nickel ternary cathode material. Except for step (3) of the preparation method, in which the temperature is raised to 340°C and then a second pre-calcination is performed at 340°C, the rest is the same as in Example 1.

[0096] Comparative Example 5 This comparative example provides a high-nickel ternary cathode material. Except for omitting the second pre-calcination step (3) of the preparation method and extending the first pre-calcination time to 5 hours, the rest is the same as in Example 1.

[0097] Comparative Example 6 This comparative example provides a high-nickel ternary cathode material. Except for omitting the first pre-calcination step (3) of the preparation method and extending the second pre-calcination time to 5 hours, the rest is the same as in Example 1.

[0098] Comparative Example 7 This comparative example provides a high-nickel ternary cathode material, except that the argon atmosphere with a pressure of 100 kPa in step (3) of the preparation method is replaced with an air atmosphere with a pressure of 100 kPa, and the rest is the same as in Example 1.

[0099] Comparative Example 8 This comparative example provides a high-nickel ternary cathode material. Except for omitting step (3) of the preparation method, which involves placing the material in a tube furnace, heating it from 25°C to 290°C at a rate of 2°C / min in an argon atmosphere with a pressure of 100 kPa, performing a first-stage pre-calcination at 290°C for 2.5 h, then heating it to 315°C at a rate of 2°C / min, performing a second-stage pre-calcination at 315°C for 2.5 h, and then cooling it to 25°C with the furnace to obtain an intermediate, with the exhaust gas continuously discharged throughout the process, the material is the same as in Example 1 except that the mixed high-nickel ternary precursor and the lithium source are directly placed in an air atmosphere box furnace for calcination.

[0100] The high-nickel ternary cathode material provided in the above embodiments and comparative examples was used to prepare an ion battery. The preparation method was as follows: the high-nickel ternary cathode material, acetylene black conductive agent, and polyvinylidene fluoride binder were mixed in a mass ratio of 8:1:1. N-methylpyrrolidone was added and the mixture was thoroughly ground to form a uniform slurry. The slurry was uniformly coated on the surface of an aluminum foil current collector. After vacuum drying at 120°C for 12 hours, the slurry was rolled to a thickness of about 100 μm and punched into a cathode sheet with a diameter of 14 mm. Then, a lithium metal sheet was used as the negative electrode, and a Celgard 2400 separator and a 1 mol / L LiPF6 carbonate electrolyte were used to assemble a CR2032 type coin cell lithium-ion battery in an argon glove box.

[0101] The obtained lithium-ion batteries were subjected to cycle performance and rate performance tests. The test method was as follows: the Blue Electric CT2001A battery test system was used for testing at 25℃. During the cycle performance test, constant current charge and discharge was performed at a 1C rate in the voltage range of 2.8V~4.6V. After 200 consecutive cycles, the capacity retention rate was calculated. During the rate performance test, charge and discharge were performed sequentially at 0.1C, 1C and 5C rates, and the discharge specific capacity at each rate was recorded. The capacity retention rate after 200 cycles in the high voltage charge and discharge range of 2.8V~4.6V is shown in Table 1, and the discharge specific capacity at 1C is shown in Table 1.

[0102] Table 1 From Table 1, we can obtain: (1) The high-nickel ternary cathode material prepared by the preparation method provided in Examples 1 to 3 of the present invention exhibits excellent cycle stability (capacity retention ≥ 97% after 200 cycles in the high voltage charge-discharge range of 2.8V to 4.6V) and rate performance (1C discharge specific capacity ≥ 213mAh / g) under high voltage.

[0103] (2) By comparing Example 1 with Examples 4 and 5, it can be seen that in the preparation method provided by the present invention, when the gas pressure during pre-burning is 90kPa~110kPa, the high-nickel ternary cathode material prepared has better comprehensive performance. This is because the gas pressure range can maintain a stable protective atmosphere, ensure the smooth discharge of tail gas while avoiding air infiltration, balance the reaction uniformity and surface structure regulation effect, and reduce internal defects of particles.

[0104] (3) By comparing Example 1 with Examples 6 and 7, it can be seen that the preparation method provided by the present invention, when the first stage of pre-calcination time is 2h~3h, the high-nickel ternary cathode material prepared has better comprehensive performance. This is because when the first stage of pre-calcination time is within this range, the dehydration and the initial decomposition process of the lithium source can be carried out smoothly, avoiding incomplete reaction or degradation of the precursor structure, and providing a uniform reaction basis for the subsequent lithiation reaction.

[0105] (4) By comparing Example 1 with Examples 8 and 9, it can be seen that the preparation method provided by the present invention, when the second stage of pre-calcination time is 2h~3h, the high-nickel ternary cathode material prepared has better comprehensive performance. This is because when the second stage of pre-calcination time is within this range, it can promote the uniform construction of the in-situ protective layer and the two-phase interface, which can not only ensure the structural regulation effect, but also avoid the aggravation of cation mixing caused by excessive time, thus taking into account both cycle performance and rate performance.

[0106] (5) By comparing Example 1 with Comparative Examples 1 to 8, it can be seen that the preparation method of the high-nickel ternary cathode material provided by the present invention, through two-stage pre-calcination in a protective atmosphere, and controlling the temperatures of the first and second stages of pre-calcination within the ranges of 280℃~300℃ and 310℃~320℃ respectively, allows the high-nickel ternary precursor and lithium source to gradually undergo dehydration, decomposition, and preliminary lithiation reactions, reducing the risk of excessively vigorous initial reactions during subsequent high-temperature calcination in air atmosphere, and is beneficial for controlling the surface structure of the obtained high-nickel ternary cathode material; in addition, the two-stage pre-calcination under a protective atmosphere can introduce oxygen vacancies on the material surface and form a protective layer in situ, thereby inhibiting excessive oxidation and lattice oxygen release on the material surface, improving the lattice oxygen stability of the material, and also forming a layered-spinel dual-phase interface in the material, using the layered-spinel dual-phase interface to block Ni 2+ Migration to the lithium layer reduces Ni 2+ / Li + The degree of cation mixing. Therefore, the high-nickel ternary cathode material prepared by the preparation method provided by the present invention exhibits excellent cycle stability (capacity retention ≥94.8% after 200 cycles in the high-voltage charge-discharge range of 2.8V~4.6V) and rate performance (1C discharge specific capacity ≥210mAh / g) under high voltage. In addition, the preparation method provided by the present invention can be directly implemented using existing production lines, with low modification costs, and is suitable for large-scale mass production.

[0107] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing a high-nickel ternary cathode material, characterized in that, The preparation method includes: After mixing the high-nickel ternary precursor and the lithium source, the mixture is pre-calcined in a protective atmosphere to obtain an intermediate; the intermediate is then calcined in an air atmosphere to obtain the high-nickel ternary cathode material. The pre-firing is carried out in two stages. The temperature of the first stage of pre-firing is 280℃~300℃, and the temperature of the second stage of pre-firing is 310℃~320℃.

2. The preparation method according to claim 1, characterized in that, The protective atmosphere includes nitrogen and / or an inert gas; And / or, the gas pressure during pre-firing is 90 kPa to 110 kPa.

3. The preparation method according to claim 1, characterized in that, In the pre-firing process, the first stage of pre-firing takes 2 to 3 hours. And / or, in the pre-firing process, the second pre-firing time is 2h~3h.

4. The preparation method according to claim 1, characterized in that, The calcination includes sequential heating and holding, with the holding temperature being 760℃~800℃ and the time being 9h~12h.

5. The preparation method according to claim 1, characterized in that, The high-nickel ternary precursor is prepared by a co-precipitation method, which includes: A ternary mixed salt solution, a liquid alkali solution, and an ammonia solution are simultaneously and concurrently added to a reactor containing a base liquid. A co-precipitation reaction is carried out under stirring conditions. The particle size of the particles in the reaction system is continuously monitored. When the D50 particle size of the particles reaches 1μm~50μm, the feeding is stopped, and the reaction continues until the material is completely reacted to obtain the high-nickel ternary precursor.

6. The preparation method according to claim 1, characterized in that, The high-nickel ternary precursor includes a nickel-cobalt-manganese hydroxide precursor, the chemical formula of which is Ni. x Co y Mn z (OH)2, where 0.8≤x<1, y>0, z>0, and x+y+z=1; And / or, the lithium source includes any one or a combination of at least two of lithium hydroxide, lithium carbonate, lithium nitrate, or lithium acetate.

7. The preparation method according to any one of claims 1 to 6, characterized in that, The molar ratio of the high-nickel ternary precursor to the molar ratio of the lithium source is 1:(1.01~1.08).

8. A high-nickel ternary cathode material, characterized in that, The high-nickel ternary cathode material is obtained by the preparation method according to any one of claims 1 to 7.

9. The high-nickel ternary cathode material according to claim 8, characterized in that, The chemical formula of the high-nickel ternary cathode material is LiNi. x Co y Mn z O2, where 0.8≤x<1, y>0, z>0, and x+y+z=1.

10. A lithium-ion battery, characterized in that, The lithium-ion battery includes the high-nickel ternary cathode material as described in claim 8 or 9.

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