SECONDARY BATTERIES – LITHIUM RECHARGEABLE SYSTEMS – LITHIUM-ION | Positive Electrode: Manganese Spinel Oxides

Abstract

Lithium manganese oxides derived from the spinel structure provide a broad variety of materials with different chemical compositions and electrochemical properties. The reversible lithium insertion/extraction reaction can occur at different potential regions, depending on the exact stoichiometry, the influence of partial exchange of manganese by other metals, and structural features. In general, lithium manganese oxides with spinel structure can be divided in three different groups of positive electrode materials for use in lithium ion batteries: 3-V, 4-V, and 5-V materials. Among these various materials the stoichiometric spinel LiMn 2 O 4 has been developed extensively. It presents advantages in terms of environmental benignity, low raw material costs compared to cobalt- or nickel-based positive electrode materials. In addition, lithium manganese oxide spinels are very attractive for high-power applications; they have excellent rate capability, due to their three-dimensional spinel framework, and offer better safety characteristics than the nickel or cobalt system in the charged state. However, complete cells with graphite anode and lithium manganese spinel suffer from capacity fading during extended cycling or prolonged storage at higher temperatures, which limits the commercial application of LiMn 2 O 4 .