Mixtures of lithium manganese oxide spinel as cathode active material

摘要

A method of making lithium manganese oxide of spinel structure is disclosed. The method involves the step of prelithiating a manganese oxide by reacting it with lithium hydroxide or lithium salt and then reacting the prelithiated manganese oxide in a second step at elevated temperature, for example, with lithium carbonate to form a lithium manganese oxide spinel. The spinel product may be used advantageously in secondary (rechargeable) batteries. The spinel product may be admixed with a partially substituted nickelite, preferably, LiNixCo1-xO2 (0.1<x<0.9) or LiNixMg1-xO2 (0.85<x<0.97) and mixtures thereof to form the active material for the positive electrode of a rechargeable lithium ion cell. A preferred mixture for the positive electrode of lithium ion cells comprises lithium manganese oxide spinel and LiNixCo1-xO2 (0.1<x<0.9). The positive electrode for lithium ion cells may also be formed of a layer comprising active material of lithium manganese oxide spinel overlayed with a second layer comprising active material formed of a partially substituted nickelite, preferably LiNixCo1-xO2 (0.1<x<0.9) or LiNixMg1-xO2 (0.85<x<0.97) and mixtures thereof.