Lithium nickel cobalt manganese oxide positive active material having concentration gradient of nickel, cobalt, and manganese and precursor thereof and preparation methods

摘要

A precursor of a modified ternary material for a lithium ion battery positive material belongs to the technical field of application of lithium ion battery positive materials. A molecular formula of the precursor is: (Ni_1/3Co_1/3Mn_1/3)(OH)₂, and the precursor consists of three layers. An inner layer of the precursor is a ternary material with the Co content of more than ⅓ and equal Ni and Mn content, and the molecular formula of the inner layer of the precursor is: (Ni_1/3−xCol/_3+2xMn_1/3−x(OH)₂, where 0x⅓. An outer layer of the precursor is a ternary material with the Co content of greater than 0 to ⅓ and equal Ni and Mn content, and the molecular formula of the outer layer of the precursor is: (Ni_0.5−yCo_2yMn_0.5−y)(OH)₂, where 0y⅙. An intermediate layer of the precursor is a concentration gradient composite material of the two materials of the inner layer and the outer layer of the precursor. The modified ternary material containing the precursor has the chemical formula of Li(Ni_1/3Co_1/3Mn_1/3)O₂. The inside of each microscopic particle of the ternary material consists of three parts, namely, an inner layer, an intermediate layer and an outer layer. The present invention effectively improves the cyclic stability, thermal stability and compacted density, and has a high cost-performance advantage.