Novel Lithium-Ion Cathode Materials Based on Layered Manganese Oxides

Lithium manganese oxides with a two-dimensional layered crystal structure are of high fundamental and technological interest as cathode materials for rechargeable lithium-ion batteries, due to the safety, low cost, and low toxicity of manganese-based materials. However, basic problems such as the collapse of the layer structure during cycling of the battery have proven difficult to solve. This collapse usually leads to poor rate performance and to evolution of steps in the voltage profile, both of which are undesirable for practical applications. This article highlights important recent work on stabilization of the layered crystal structure of lithium manganese oxide. In particular we focus on the use of layered manganese oxide as a base for developing novel complex solid–solution cathode materials with improved capacity, cycling stability, and safety.