Electroactivity of natural and synthetic triphylite

The electrochemical behavior of three triphylite (LiFePO4) ores from different mining localities has been investigated. Two Of them show clearly an activity corresponding to the triphylite phase. A discharge capacity of 85 mAh g(-1) was obtained. The benefit of heat treatment that allows to deposit the electronically conductive carbon-based coating on the particles is reported for both natural and Synthetic LiFePO4 samples, Discharge capacity, kinetics and Stability upon cycling were all improved after the heating process. The best results Were obtained with carbon coatings coming from the decomposition of a modified polycyclic aromatic. In this case, for synthetic samples, the whole capacity was reversibly exchanged and less than 1% of the initial capacity was lost after 10 cycles. (C) 2001 Elsevier Science B.V. All rights reserved.