Preparation method of double-shell spherical lithium-rich layered oxide positive electrode material with radially arranged crystal grains

[0033] Example 1

[0034] Prepare solution A, molar ratio Mn:Ni:Co=4:1:1 Weigh manganese sulfate, nickel sulfate, cobalt sulfate, and dissolve in deionized water to prepare 2mol / L A solution; prepare B solution, weigh a certain amount A large amount of precipitating agent and complexing agent are dissolved in deionized water, where the precipitating agent is sodium carbonate, the concentration of sodium carbonate solution is 2mol / L, the complexing agent is ammonia, and the concentration of ammonia is 0.1mol / L; dissolve polyvinylpyrrolidone Stir evenly in deionized water to prepare a 0.1g / L polyvinylpyrrolidone solution. Co-precipitation is carried out in four stages: stage one, add solution A, solution B, and polyvinylpyrrolidone solution dropwise to the deionized water solution, control the pH of the reaction system to 8.0, the stirring rate to 800 rpm, and the solution temperature to 50°C , Reaction for 12h; stage two, stop adding polyvinylpyrrolidone solution, other cond

[0038] Example 2

[0039] Prepare solution A, weigh manganese nitrate, nickel nitrate, and cobalt nitrate by molar ratio Mn:Ni:Co=5:1:1, and dissolve them in deionized water to prepare 0.1mol / L solution A; prepare solution B and weigh A certain amount of precipitating agent and complexing agent are dissolved in deionized water, where the precipitating agent is sodium bicarbonate, the concentration of sodium bicarbonate solution is 0.1 mol / L, the complexing agent is ammonium bicarbonate, the concentration is 0.01 mol / L; The polyvinylpyrrolidone is dissolved in deionized water and stirred evenly to prepare a 0.5g / L polyvinylpyrrolidone solution. Co-precipitation is carried out in four stages: stage one, add solution A, solution B, and polyvinylpyrrolidone solution dropwise to the deionized water solution, control the pH of the reaction system to 6.0, the stirring rate to 300 rpm, and the solution temperature to 20°C , Reaction for 40h; stage two, stop adding polyvinylpyrrolid

[0042] Example 3

[0043] Prepare solution A, massage the molar ratio Mn:Ni:Co=4:1:1. Weigh manganese formate, nickel formate, and cobalt formate, and dissolve them in deionized water to prepare 1mol / L A solution; prepare B solution, weigh a certain amount A large amount of precipitant and complexing agent are dissolved in deionized water, where the precipitating agent is potassium carbonate, the potassium carbonate solution concentration is 1 mol / L, the complexing agent is ammonium carbonate, the concentration is 0.05 mol / L; dissolve polyvinylpyrrolidone Stir well in deionized water to prepare 5.0g / L polyvinylpyrrolidone solution. Co-precipitation is carried out in four stages: stage one, add solution A, solution B, and polyvinylpyrrolidone solution dropwise to the deionized water solution, control the pH of the reaction system to 9.0, the stirring rate to 3000 rpm, and the solution temperature to 60°C , Reaction for 2h; stage two, stop adding polyvinylpyrrolidone solution