Single crystal multi-element cathode material, preparation method of the same, and lithium-ion battery

A lithium-ion battery, comprising a single crystal multi-element cathode material, wherein the single crystal multi-element cathode material comprises quasi single crystal particles each consisting of a plurality of crystal grains, element G being present at grain boundaries between the plurality of crystal grains, wherein:

• a concentration of the element G at a g-site of the grain boundaries gradually decreases with an increase in a distance between the g-site and a surface of the quasi single crystal particles;
• and
• the element G is selected from at least one of Ni, Co, Mn, Ta, Cr, Mo, W, La, Al, Y, Ti, Zr, V, Nb, Ce, Er, and B,
• the single crystal multi-element cathode material comprises a matrix and a coating layer coated on the matrix, wherein:
• the matrix has a composition represented by Formula III:
• Li1+a(NixCoyMezMw)O2, Formula III,
• where:
• −0.1≤a≤0.1, 0<x<1, 0<y≤0.4, 0<z≤0.6, 0≤w≤0.2;
• Me is selected from Mn and/or Al;
• and M is at least one element of Ta, Cr, Mo, W, La, Al, Y, Ti, Zr, V, Nb, Ce, Er, Mg, Sr, and Ba;
• and
• the coating layer is selected from a lithium oxide compound of the element G and/or oxide of the element G;
• a molar ratio of the coating layer, based on n (G), to the matrix, based on [n(Ni)+n(Co)+n(Me)+n(M)], ranges from 0.001 to 0.05.