Aluminum-yttrium-boric acid coated high-nickel positive electrode material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of lithium ion battery positive electrode materials, in particular to an aluminum-yttrium-boric acid coated high-nickel positive electrode material and a preparation method and application thereof. The preparation method of the material comprises the following steps: synthesizing a doped and modified high-nickel ternary precursor from a mixed metal salt solution and a first aluminum source and / or a first yttrium source through a coprecipitation reaction; mixing the precursor with a lithium source, and performing first sintering treatment to obtain a base material; and mixing the base material with a solution containing boric acid, a second aluminum source and a second yttrium source, and carrying out solvent evaporation and second sintering treatment to obtain a final product. Through the synergistic effect of bulk phase doping and surface composite coating, generation of intragranular cracks and interface side reaction of the material in the circulation process are inhibited at the same time. The obtained positive electrode material successfully overcomes the technical problem that high capacity and long service life are difficult to consider at the same time, and the cycling stability is remarkably improved while the high specific capacity is kept.

Description

A high-nickel cathode material coated with aluminum-yttrium-boric acid, its preparation method and application Technical Field

[0001] This invention relates to the field of lithium-ion battery cathode material technology, specifically to an aluminum-yttrium-boric acid coated high-nickel cathode material, its preparation method, and its application. Background Technology

[0002] High-nickel layered ternary cathode materials (such as LiNi) x Co y Mn 1-x-y O2 (x≥0.5) is key to achieving high energy density lithium-ion batteries due to its high specific capacity. However, its commercial application is severely constrained by inherent technical challenges: during long-term cycling, the bulk structure of the material is prone to intracrystalline cracks, significantly increasing the side reaction interface with the electrolyte and accelerating the dissolution of transition metals and phase transitions. This leads to continuous consumption of active lithium and irreversible damage to the crystal structure, causing rapid capacity decay; on the other hand, the thick and unstable interface film formed at the cracks also increases ion transport impedance, impairing rate performance.

[0003] To address these challenges, existing technologies primarily employ bulk doping or surface coating strategies. While bulk doping can stabilize the crystal lattice to some extent, it struggles to effectively isolate the material surface and crack interior from electrolyte erosion. Surface coatings, while providing a physical barrier, may suffer from poor bonding with the matrix or low ionic conductivity, sacrificing initial capacity and kinetic performance while suppressing side reactions. Therefore, existing modification methods often compromise on one aspect while neglecting another, failing to simultaneously achieve a significant improvement in cycle life while maintaining high capacity. Summary of the Invention

[0004] This invention provides an aluminum-yttrium-boric acid coated high-nickel cathode material, its preparation method, and its application, in order to solve the problem that existing high-nickel ternary cathode materials cannot simultaneously achieve high capacity and long lifespan due to intracrystalline cracks and interfacial side reactions.

[0005] In a first aspect, the present invention provides a method for preparing an aluminum-yttrium-boric acid coated high-nickel cathode material, comprising the following steps: precursor doping: mixing a mixed metal salt solution with a first aluminum source and / or a first yttrium source for a co-precipitation reaction to obtain a doped and modified high-nickel ternary hydroxide precursor; lithiation sintering: mixing the doped and modified high-nickel ternary hydroxide precursor with a lithium source and performing a first sintering treatment to obtain a doped and modified high-nickel ternary cathode material matrix; surface coating: mixing the doped and modified high-nickel ternary cathode material matrix with a solution containing boric acid, a second aluminum source, and a second yttrium source, followed by solvent evaporation treatment and a second sintering treatment to obtain an aluminum-yttrium-boric acid coated high-nickel cathode material.

[0006] In one optional embodiment, the mixed metal salt solution comprises nickel salt, cobalt salt, and manganese salt or aluminum salt; when the mixed metal salt solution comprises manganese salt, a first aluminum source and a first yttrium source are added simultaneously in the precursor doping step; when the mixed metal salt solution comprises aluminum salt, only the first yttrium source is added in the precursor doping step; and / or, in the mixed metal salt solution, the molar amount of nickel accounts for 50% to 90% of the total molar amount of metal elements in the mixed metal salt solution, and the molar amount of cobalt accounts for 5% to 20% of the total molar amount of metal elements in the mixed metal salt solution; and / or, the molar concentration of the total metal elements in the mixed metal salt solution is 2 to 2.5 mol / L.

[0007] In one optional embodiment, when both the first aluminum source and the first yttrium source are added simultaneously, the molar ratio of aluminum in the first aluminum source to the total metal elements in the mixed metal salt solution is (0.01~0.05):1, and the molar ratio of yttrium in the first yttrium source to the total metal elements in the mixed metal salt solution is (0.005~0.03):1; and / or, when only the first yttrium source is added, the molar ratio of yttrium in the first yttrium source to the total metal elements in the mixed metal salt solution is (0.005~0.03):1.

[0008] In one optional embodiment, the coprecipitation reaction is carried out in the presence of a complexing agent and a precipitant; optionally, the complexing agent includes at least one of ammonia water and ammonium salt, and the concentration of ammonium ions is controlled at 0.1~1.0 mol / L during the reaction; optionally, the precipitant includes at least one of sodium hydroxide, potassium hydroxide, and sodium carbonate, and the pH value of the reaction system is controlled in the range of 10.0~12.0; optionally, the temperature of the coprecipitation reaction is 50~70℃; optionally, the time of the coprecipitation reaction is 4~12h.

[0009] In one optional embodiment, in the surface coating step, the amount of boric acid added is 1.0% to 5.0% of the mass of the doped and modified high-nickel ternary cathode material matrix; optionally, the molar ratio of aluminum to boric acid in the second aluminum source is (0.05 to 0.5):1; optionally, the molar ratio of yttrium to boric acid in the second yttrium source is (0.015 to 0.35):1.

[0010] In one optional embodiment, the temperature of the first sintering treatment is 750°C to 850°C; and / or, the sintering time of the first sintering treatment is 8 to 15 hours; and / or, the first sintering treatment is carried out in an oxygen atmosphere or an air atmosphere; and / or, the heating rate of the first sintering treatment is 1 to 10°C / min.

[0011] In one optional embodiment, the temperature of the second sintering treatment is 300°C to 500°C; and / or, the sintering time of the second sintering treatment is 2 to 5 hours; and / or, the second sintering treatment is carried out in an oxygen atmosphere or an air atmosphere; and / or, the heating rate of the first sintering treatment is 1 to 10°C / min.

[0012] In one optional embodiment, in the surface coating step, the solvent of the solution containing boric acid, the second aluminum source, and the second yttrium source is water and / or alcohol; optionally, the alcohol includes ethylene glycol or glycerol; and / or, the solvent evaporation treatment temperature is 60°C to 90°C.

[0013] In one optional embodiment, the first aluminum source and / or the second aluminum source are each independently selected from at least one of aluminum nitrate, aluminum chloride, and aluminum isopropoxide; and / or, the first yttrium source and / or the second yttrium source are each independently selected from at least one of yttrium nitrate, yttrium chloride, and yttrium acetate; and / or, the lithium source includes at least one of lithium hydroxide, lithium carbonate, and lithium nitrate; and / or, the molar ratio of the metal element in the doped and modified high-nickel ternary hydroxide precursor to the lithium element in the lithium source is 1:(1.02~1.10).

[0014] Secondly, the present invention also provides an aluminum-yttrium-boric acid coated high-nickel cathode material, which is prepared by the above-mentioned method for preparing aluminum-yttrium-boric acid coated high-nickel cathode material.

[0015] Thirdly, the present invention also provides a lithium-ion battery, wherein the positive electrode comprises the above-mentioned aluminum-yttrium-boric acid coated high-nickel positive electrode material.

[0016] The technical solution of this invention has the following advantages: A method for preparing an aluminum-yttrium-boric acid coated high-nickel cathode material includes the following steps: Precursor doping: mixing a mixed metal salt solution with a first aluminum source and / or a first yttrium source for a co-precipitation reaction to obtain a doped and modified high-nickel ternary hydroxide precursor; Lithification sintering: mixing the doped and modified high-nickel ternary hydroxide precursor with a lithium source and performing a first sintering treatment to obtain a doped and modified high-nickel ternary cathode material matrix; Surface coating: mixing the doped and modified high-nickel ternary cathode material matrix with a solution containing boric acid, a second aluminum source, and a second yttrium source, followed by solvent evaporation and a second sintering treatment to obtain an aluminum-yttrium-boric acid coated high-nickel cathode material. The preparation method provided by this invention effectively solves the technical problem of simultaneously achieving high capacity and long lifespan in high-nickel ternary cathode materials through the synergistic effect of bulk doping and surface composite coating. In the bulk doping stage, the introduction of aluminum and / or yttrium significantly enhances the crystal structure stability of the material, wherein Al 3+ As a structural support point to suppress lattice distortion, Y 3+ Effectively inhibit Li + / Ni2+ The mixed arrangement reduces the generation of intragranular cracks at the material bulk level. In the surface coating stage, an aluminum-yttrium-boric acid composite coating layer is constructed, which, after heat treatment, forms a dense and stable B2O3-based protective layer. This coating layer not only physically isolates the electrolyte from direct contact with the cathode material, effectively suppressing interfacial side reactions, but the aluminum and yttrium elements it contains also form an interfacial transition layer, promoting lithium-ion conduction and eliminating interfacial stress. This synergistic modification design from bulk to surface, by simultaneously suppressing the generation of intragranular cracks and the occurrence of interfacial side reactions, enables the resulting cathode material to maintain high specific capacity while significantly improving cycle life, effectively solving the problem of the difficulty in simultaneously achieving high capacity and long lifespan. Detailed Implementation

[0017] The following embodiments are provided to better understand the present invention, but the following embodiments do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the scope of protection of the present invention.

[0018] Unless otherwise specified, all experimental steps or conditions in the examples were performed according to conventional experimental procedures and conditions in the art. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0019] Example 1 This example provides a method for preparing an aluminum-yttrium-boric acid coated high-nickel cathode material. The specific steps are as follows: (1) Precursor doping: 0.8 mol nickel nitrate (Ni(NO3)2·6H2O), 0.1 mol cobalt nitrate (Co(NO3)2·6H2O), 0.1 mol manganese nitrate (Mn(NO3)2·4H2O), 0.03 mol aluminum nitrate (Al(NO3)3·9H2O), and 0.01 mol yttrium nitrate (Y(NO3)3·6H2O) are dissolved in 500 mL of deionized water to form a mixed metal salt solution; under constant temperature of 55℃, the mixed metal salt solution is mixed with 2 mol / L NaOH solution and 25% ammonia water were added to the reactor in parallel. The pH of the reaction system was controlled at 10.5 and the ammonium ion concentration was 0.5 mol / L. The reaction was stirred continuously for 6 hours. After filtration, washing and drying, an aluminum-yttrium co-doped ternary hydroxide precursor was obtained. (2) Lithification sintering: The metal element in the aluminum-yttrium co-doped ternary hydroxide precursor obtained in step (1) was mixed with the lithium element in lithium carbonate at a molar ratio of 1.05:1. The mixture was heated to 800℃ at 5℃ / min in an oxygen atmosphere for a first sintering treatment for 10 hours. After cooling with the furnace, aluminum was obtained. - Yttrium co-doped cathode material matrix; (3) Surface coating: 10g of the aluminum-yttrium co-doped cathode material matrix obtained in step (2) is dispersed in 100mL of 85℃ aqueous solution containing 0.002mol boric acid (approximately 0.12g), 0.001mol aluminum nitrate, 0.0005mol yttrium nitrate and 5mL ethylene glycol. The solution is stirred and evaporated to dryness at 65℃ to obtain the coating precursor. The coating precursor is heated to 350℃ at 3℃ / min in air atmosphere for a second sintering treatment for 3h to obtain aluminum-yttrium-boric acid coated high nickel cathode material.

[0020] Example 2 This example provides a method for preparing an aluminum-yttrium-boric acid coated high-nickel cathode material. The specific steps are as follows: (1) Precursor doping: 0.85 mol nickel nitrate, 0.1 mol cobalt nitrate, 0.05 mol aluminum nitrate, and 0.005 mol yttrium nitrate are dissolved in 400 mL of deionized water to form a mixed metal salt solution; under constant temperature of 60°C, the mixed metal salt solution is added to the reactor in parallel with 2 mol / L NaOH solution and 25% ammonia water, the pH of the reaction system is controlled to be 11.0, the ammonium ion concentration is 0.3 mol / L, and the reaction is continuously stirred for 5 h. After filtration, washing, and drying, yttrium-doped ternary hydroxide precursor is obtained; (2) Lithification sintering: The precursor obtained in step (1) is mixed with lithium carbonate at a total molar ratio of lithium to transition metal of 1.04:1, and the mixture is heated to 850°C at 5°C / min in an oxygen atmosphere for a first sintering treatment for 8 h. After cooling in the furnace, yttrium-doped precursor is obtained. (2) Surface coating: 8g of the matrix material obtained in step (2) is dispersed in an 80mL, 90℃ aqueous solution containing 0.016mol boric acid (approximately 0.10g), 0.0008mol aluminum nitrate, and 0.0003mol yttrium nitrate. The solution is stirred and evaporated to dryness at 70℃ to obtain a coating precursor. The coating precursor is heated to 400℃ at 5℃ / min in an air atmosphere for a second sintering treatment for 2h to obtain aluminum-yttrium-boric acid coated high-nickel cathode material.

[0021] Example 3 This example provides a method for preparing an aluminum-yttrium-boric acid coated high-nickel cathode material. The specific steps are as follows: (1) Precursor doping: 0.5 mol nickel nitrate, 0.2 mol cobalt nitrate, 0.3 mol manganese nitrate, 0.025 mol aluminum nitrate, and 0.015 mol yttrium nitrate are dissolved in 500 mL of deionized water to form a mixed metal salt solution; under constant temperature of 50 °C, the mixed metal salt solution is mixed with 2 mol / L NaOH solution and 25% ammonia water were added to the reactor in parallel. The pH of the reaction system was controlled at 11.0 and the ammonium ion concentration was 1.0 mol / L. The reaction was stirred continuously for 8 hours. After filtration, washing and drying, an aluminum-yttrium co-doped ternary hydroxide precursor was obtained. (2) Lithification sintering: The precursor obtained in step (1) was mixed with lithium hydroxide at a total molar ratio of lithium to transition metal of 1.02:1. The mixture was heated to 750°C at 10°C / min in an air atmosphere for a first sintering treatment for 15 hours. After cooling with the furnace, an aluminum-yttrium co-doped precursor was obtained. (2) Surface coating: 10g of the matrix material obtained in step (2) is dispersed in 50mL of 70℃ aqueous solution containing 0.0016mol boric acid (about 0.10g by mass), 0.0001mol aluminum nitrate, 0.00005mol yttrium nitrate and 3mL glycerol. The solution is stirred and evaporated to dryness at 60℃ to obtain the coating precursor. The coating precursor is heated to 300℃ in air atmosphere for a second sintering treatment for 5h to obtain aluminum-yttrium-boric acid coated high nickel cathode material.

[0022] Example 4 This example provides a method for preparing an aluminum-yttrium-boric acid coated high-nickel cathode material. The specific steps are as follows: (1) Precursor doping: 0.9 mol nickel nitrate, 0.05 mol cobalt nitrate, 0.05 mol aluminum nitrate, and 0.027 mol yttrium nitrate are dissolved in 500 mL of deionized water to form a mixed metal salt solution; under constant temperature of 65°C, the mixed metal salt solution is added to the reactor in parallel with 2 mol / L NaOH solution and 25% ammonia water, the pH of the reaction system is controlled to be 10.5, the ammonium ion concentration is 0.1 mol / L, and the reaction is continuously stirred for 4 h. After filtration, washing, and drying, a yttrium-doped ternary hydroxide precursor is obtained; (2) Lithification sintering: The precursor obtained in step (1) is mixed with lithium carbonate at a total molar ratio of lithium to transition metal of 1.07:1, and the mixture is heated to 850°C at 3°C / min in an oxygen atmosphere for a first sintering treatment for 8 h. After cooling in the furnace, a yttrium-doped cathode is obtained. (3) Surface coating: 10g of the matrix material obtained in step (2) is dispersed in 100mL of 95℃ aqueous solution containing 0.0081mol boric acid (about 0.5g), 0.0005mol aluminum isopropoxide and 0.00025mol yttrium acetate. The solution is stirred and evaporated to dryness at 90℃ to obtain the coating precursor. The coating precursor is heated to 500℃ at 8℃ / min in an oxygen atmosphere for a second sintering treatment for 2h to obtain aluminum-yttrium-boric acid coated high nickel cathode material.

[0023] Comparative Example 1 This comparative example provides a method for preparing an aluminum-yttrium-boric acid coated high-nickel cathode material. The only difference between this method and Example 1 is that aluminum nitrate and yttrium nitrate are not added in the precursor doping step (1). All other conditions are exactly the same as in Example 1.

[0024] Comparative Example 2 This comparative example provides a method for preparing an aluminum-yttrium-boric acid coated high-nickel cathode material. The only difference between it and Example 1 is that step (3) surface coating is not performed, while all other conditions are exactly the same as in Example 1.

[0025] Comparative Example 3 provides a method for preparing an aluminum-yttrium-boric acid coated high-nickel cathode material. The only difference between this method and Example 1 is that aluminum nitrate and yttrium nitrate are not added in the surface coating step (3). All other conditions are exactly the same as in Example 1.

[0026] Comparative Example 4 provides a method for preparing an aluminum-yttrium-boric acid coated high-nickel cathode material. The only difference between this method and Example 1 is that in step (3) surface coating, after mixing the coating precursor and the matrix material, solvent evaporation is not performed. Instead, the material is directly filtered, dried, and subjected to a second sintering process. All other conditions are exactly the same as in Example 1.

[0027] The test example used the ternary cathode materials prepared in Examples 1-4 and Comparative Examples 1-4 to prepare lithium-ion batteries (CR2032 type button half-cells). The specific method is as follows: In an argon atmosphere in a glove box, a Celgard 2500 type separator was used, with lithium metal sheets as the negative electrode and LBC3021C011 type electrolyte. The positive electrode was prepared by coating an aluminum foil current collector with a mixture of active material, conductive carbon black (SuperP), and polyvinylidene fluoride (PVDF) in a weight ratio of 90:5:5, with the active material surface loading being 10 mg / cm². 2 The battery is assembled in the following order: negative electrode, electrolyte, separator, electrolyte, and positive electrode.

[0028] Electrochemical performance testing: The battery was placed in the Blue Electric testing system for electrochemical performance testing. At 25°C, it was charged to 4.3V at a rate of 0.2C, and then discharged to 2.75V at a rate of 0.2C. This constitutes one cycle. The discharge capacity of this cycle is the first-cycle discharge specific capacity, and the first-cycle charge / discharge specific capacity ratio is the first-cycle coulombic efficiency. After two cycles, it was charged and discharged at 1C for 100 cycles. The charge / discharge capacity of the third cycle and the charge / discharge capacity of the 102nd cycle were recorded. The retention rate is the ratio of the discharge capacity of the 102nd cycle to that of the third cycle. The test results are shown in Table 1.

[0029] Table 1

[0030] Based on the above test results, the overall electrochemical performance of Examples 1 to 4 of this invention is significantly better than that of the comparative examples. Specifically, the cycle retention rate of Comparative Example 1 (without any bulk doping) was only 80.46%, demonstrating that the absence of the precursor doping step resulted in severely insufficient crystal structure stability, making it more prone to intracrystalline cracks during cycling and leading to rapid capacity decay. The cycle retention rate of Comparative Example 2 (without surface coating) was 80.55%, indicating that the absence of the composite coating layer resulted in direct contact between the material surface and the electrolyte, exacerbating side reactions and failing to effectively maintain a long cycle life. While Comparative Example 3 (without aluminum and yttrium sources in the coating layer) showed a slight improvement in cycle retention rate (81.32%), it was still far lower than that of Examples 1 to 4, indicating that the simple boric acid coating layer has defects in terms of density, bonding strength, and ionic conductivity, failing to achieve optimal interface protection. The cycle retention rate (80.66%) of Comparative Example 4 (without solvent evaporation in the coating process) was close to that of Comparative Example 2, confirming that "solvent evaporation" is a key step in forming a uniform and complete coating layer, and its absence will lead to the failure of the coating effect.

[0031] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing an aluminum-yttrium-boric acid coated high-nickel cathode material, characterized in that, Includes the following steps: precursor Doping: A mixed metal salt solution is mixed with a first aluminum source and / or a first yttrium source to carry out a co-precipitation reaction to obtain a doped and modified high-nickel ternary hydroxide precursor; Lithification sintering: The doped and modified high-nickel ternary hydroxide precursor is mixed with a lithium source and subjected to a first sintering treatment to obtain a doped and modified high-nickel ternary cathode material matrix; Surface coating: The doped and modified high-nickel ternary cathode material matrix is ​​mixed with a solution containing boric acid, a second aluminum source, and a second yttrium source, and subjected to solvent evaporation treatment and a second sintering treatment to obtain an aluminum-yttrium-boric acid coated high-nickel cathode material.

2. The preparation method according to claim 1, characterized in that, The mixed metal salt solution comprises nickel salt, cobalt salt, and manganese salt or aluminum salt; when the mixed metal salt solution comprises manganese salt, a first aluminum source and a first yttrium source are added simultaneously in the precursor doping step; when the mixed metal salt solution comprises aluminum salt, only the first yttrium source is added in the precursor doping step; and / or, in the mixed metal salt solution, the molar amount of nickel accounts for 50% to 90% of the total molar amount of metal elements in the mixed metal salt solution, and the molar amount of cobalt accounts for 5% to 20% of the total molar amount of metal elements in the mixed metal salt solution; and / or, the molar concentration of the total metal elements in the mixed metal salt solution is 2 to 2.5 mol / L.

3. The preparation method according to claim 2, characterized in that, When both the first aluminum source and the first yttrium source are added simultaneously, the molar ratio of aluminum in the first aluminum source to the total metal elements in the mixed metal salt solution is (0.01~0.05):1, and the molar ratio of yttrium in the first yttrium source to the total metal elements in the mixed metal salt solution is (0.005~0.03):1; and / or, when only the first yttrium source is added, the molar ratio of yttrium in the first yttrium source to the total metal elements in the mixed metal salt solution is (0.005~0.03):

1.

4. The preparation method according to claim 1 or 2, characterized in that, In the surface coating step, the amount of boric acid added is 1.0% to 5.0% of the mass of the doped and modified high-nickel ternary cathode material matrix; optionally, the molar ratio of aluminum to boric acid in the second aluminum source is (0.05 to 0.5):1; optionally, the molar ratio of yttrium to boric acid in the second yttrium source is (0.015 to 0.35):

1.

5. The preparation method according to claim 1 or 2, characterized in that, The temperature of the first sintering treatment is 750℃~850℃; and / or, the sintering time of the first sintering treatment is 8~15 hours; and / or, the first sintering treatment is carried out in an oxygen atmosphere or an air atmosphere.

6. The preparation method according to claim 1 or 2, characterized in that, The temperature of the second sintering treatment is 300℃~500℃; and / or the sintering time of the second sintering treatment is 2~5 hours; and / or the second sintering treatment is carried out in an oxygen atmosphere or an air atmosphere.

7. The preparation method according to claim 1 or 2, characterized in that, In the surface coating step, the solvent of the solution containing boric acid, the second aluminum source, and the second yttrium source is water and / or alcohol; optionally, the alcohol includes ethylene glycol or glycerol; and / or, the solvent evaporation treatment temperature is 60°C to 90°C.

8. The preparation method according to claim 1 or 2, characterized in that, The first aluminum source and / or the second aluminum source are each independently selected from at least one of aluminum nitrate, aluminum chloride, and aluminum isopropoxide; and / or, the first yttrium source and / or the second yttrium source are each independently selected from at least one of yttrium nitrate, yttrium chloride, and yttrium acetate; and / or, the lithium source includes at least one of lithium hydroxide, lithium carbonate, and lithium nitrate; and / or, the molar ratio of the metal element in the doped and modified high-nickel ternary hydroxide precursor to the lithium element in the lithium source is 1:(1.02~1.10).

9. An aluminum-yttrium-boric acid coated high-nickel cathode material, characterized in that, It is prepared by the method for preparing aluminum-yttrium-boric acid coated high-nickel cathode material as described in any one of claims 1 to 8.

10. A lithium-ion battery, wherein the positive electrode comprises the aluminum-yttrium-boric acid coated high-nickel positive electrode material as described in claim 9.

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