Precursors and Methods for the Preparation of Ni-Based Li Transition Metal Oxide Cathodes for Rechargeable Batteries

摘要

A crystalline precursor compound for preparing a lithium transition metal oxide powder usable as a positive electrode active material in a lithium-ion battery is disclosed, and the precursor is represented by the general formula Li _1-a ((Ni _z (Ni _½ Mn _½ ) _y Co _x ) _{1 -k} A _k ) _{1 + a} O ₂ (wherein 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, and the precursor has a crystal size L expressed in nm and 77- (67 * z) ≦ L ≦ 97- (67 * z). The general formula Li _{1-a '} ((Ni _z (Ni _1/2 Mn ₁ ) by sintering the crystalline precursor compound at a temperature T of 800 to 1000 ° C. in an oxidizing atmosphere for a time t of 6 to 36 hours. _{/ 2} ) _y Co _x ) _1-k A _k ) _{1 + a ′} 0 ₂ (where x + y + z = 1, 0.1 ≦ x ≦ 0.4, 0.25 ≦ z ≦ 0.55, A is a dopant, Also disclosed is a method of making a positive electrode material having 0 ≦ k ≦ 0.1 and 0.01 ≦ a ′ ≦ 0.10.