High-nickel ternary positive electrode material and preparation method, secondary battery, battery module, battery pack and electrical apparatus thereof

A method for preparing a high-nickel ternary positive electrode material, comprising the following:

• S1:
• preparing a mixed metal salt solution of Ni, Co and M, as well as a magnesium salt solution and an yttrium salt solution;
• S2:
• adding water into a reaction kettle as a base liquid, adding an alkali solution and ammonia water to adjust a pH value and ammonia concentration of the base liquid, adding the mixed metal salt solution of Ni, Co and M, the alkali solution and ammonia water into the reaction kettle, keeping the pH value and ammonia concentration be constant and feeding an inert gas for protection, so as to obtain a high-nickel ternary precursor, stopping an addition of the mixed metal salt solution of Ni, Co and M, adding the magnesium salt solution, the yttrium salt solution, the alkali solution, and ammonia water into the reaction kettle, and keeping the pH value and ammonia concentration be constant, so as to obtain a high-nickel ternary precursor doped with an Mg and Y elements on a surface;
• S3:
• mixing and sintering a lithium-containing compound and the high-nickel ternary precursor doped with the Mg and Y elements on the surface to obtain a matrix of high-nickel ternary positive electrode material;
• and
• S4:
• mixing the matrix of high-nickel ternary positive electrode material with a boron-containing alloy in an inert atmosphere or air, and then sintering in an inert atmosphere or O2 to obtain the high-nickel ternary positive electrode material;
• wherein, the high-nickel ternary positive electrode material comprises:
• a matrix Li1+xNiaCobMgcYdM(1−a−b−c−d)O2±y, wherein M is selected from at least one of Mn, Zr, Al, B, Ta, Mo, W, Nb, Sb, and La, wherein:
• 0.8≤a<1.0, 0<b<0.2, 0<c≤0.005, 0<d≤0.01, a+b+c+d<1, −0.5<x<0.5, 0≤y<0.02, a surface of the matrix is provided with a cladding layer, and the cladding layer contains a boron-containing alloy.