Fast charging LiFePO4

An excellent fast charging ability for olivine LiFePO4 is demonstrated with respect to its advantageous open-circuit voltage of 3.4 V vs. Li/Li+ with an appropriately large overvoltage margin to the electrolyte oxidation, structural integrity under the nonequilibrium state induced by the large overpotential, and moderate electrochemical activity easily enhanced to the practical level by efficient nanocomposite formation. The current relaxation to the applied stepwise voltage of 4.2 V vs. Li/ Li+ for the LixFePO(4) was fast enough to consume most of the theoretical capacity within 10-20 min and the speed is competitive with that of the conventional electrode composite of LixMn2O4, while the capacity consumption of LixMnPO4 under the identical experimental conditions was almost null. (C) 2004 The Electrochemical Society.