Performance evaluation of lithium vanadium fluorophosphate in lithium metal and lithium-ion cells

In this study it is demonstrated that the lithium vanadium fluorophosphate, LiVPO4F phase, offers considerable promise as a viable cathode material for commercial lithium-ion batteries. The active material was synthesized using a reaction scheme based on carbothermal reduction. The LiVPO4F is isostructural with the known mineral ambygonite, LiAlPO4F, crystallizing with a triclinic structure (space group, Py). Performance evaluation of graphite//LiVPO4F lithium-ion cells indicates a reversible material utilization for the LiVPO4F of around 130 mAh/g and an average discharge voltage of 4.06 V. Long-term cycling (C/5 rate at 23 degrees C) of this lithium-ion configuration predicts a cycle life > 500 cycles to around 90% of the original discharge capacity. (c) 2005 The Electrochemical Society.