Precursors and methods for preparing Ni-based Li transition metal oxide cathodes for rechargeable batteries

摘要

A crystalline precursor compound for producing a lithium transition metal-based oxide powder that can be used as a positive electrode active material in a lithium ion battery, wherein the precursor is represented by the general formula Li1-a ((Niz (Ni1 / 2Mn1 / 2) yCox) 1-kAk) 1 + aO2 where x + y + z = 1, 0.1 ≦ x ≦ 0.4, 0.25 ≦ z ≦ 0.55, A is a dopant, 0 ≦ k ≦ 0.1 and 0.04 ≦ a ≦ 0.50), the precursor has a crystallite size L represented by um, and 77− (67 * z) ≦ L ≦ A crystalline precursor compound which is 97- (67 * z). The crystalline precursor compound is sintered in an oxidizing atmosphere at a temperature T of 800-1000 ° C. for a time t of 6-36 hours, to give a general formula Li1-a ′ ((Niz (Ni1 / 2Mn1 / 2) yCox ) 1-kAk) 1 + a′O 2 (where x + y + z = 1, 0.1 ≦ x ≦ 0.4, 0.25 ≦ z ≦ 0.55, A is a dopant, 0 ≦ A method for producing a positive electrode material having k ≦ 0.1 and 0.01 ≦ a ′ ≦ 0.10 is also described.