Gradient single-crystalline cathode material, preparation method and application

Abstract

The present invention discloses a gradient single-crystal cathode material, and the chemical formula of the single-crystal cathode material is LiNi x Co y A 1-x-y O2@mLi a Z b O c where 0 < x < 1, 0 < y < 1, 0 < x + y < 1, 0 < m < 0.05, 0.3 < a ≤ 10, 1 ≤ b < 4, 1 ≤ c < 15. A is at least one of Mn, Zr, Sr, Ba, W, Ti, Al, Mg, Y, Nb, and Z is at least one of B, Al, Co, W, Ti, Zr, Si. The atomic ratio of Co content on the particle surface of the single-crystal cathode material to Ni + Co + A on the surface is greater than 0.4 and less than 0.8. The atomic ratio of Co at a position 10% of the radius depth from the particle surface of the single-crystal cathode material is 0.3 or more. The particles of the single-crystal cathode material have a roundness of > 0.4 and no sharp edges and corners. And the preparation method and application of the above gradient single-crystal material are provided.