Optimization of insertion compounds such as LiMn2O4 for Li-ion batteries

The spinel LiMn2O4, whose electrochemical activity with Li was discovered in the early 1980s, was put forth in the early 1990s as a possible alternative to LiCoO2 as a positive electrode material for Li-ion batteries. Ten years later, the Li-ion LiMn2O4/C cells are on the verge of entering the portable electronics and electric/hybrid vehicle market. This paper retraces the key steps of this decade that were necessary to master the intimate physical/electrochemical relationship of LiMn2O4, and that led to the development of rechargeable Li-ion LiMn2O4/C technology. During the long development period, the early supremacy of LiMn2O4 as the only alternative to LiCoO2 diminished with the development of positive electrode materials that present abundance and cost advantages. Despite the uncertainty of the future of the spinel, successfully translating a fundamental success into a commercial one, we stress that the long learning experience will benefit the scientific battery community aiming at rapidly optimizing the electrochemical performance of alternative materials, such as LiFePO4. (C) 2002 Telcordia Technologies.