A carbothermal reduction method for the preparation of electroactive materials for lithium ion applications

A novel preparative method based on a carbothermal reduction (CTR) process is described for the synthesis of the representative electroactive materials, gamma-LiV2O5 and Li3V2(PO4)(3). In the CTR procedure a high surface area carbon is mixed intimately with appropriate precursor compounds and the mixture heated in an inert atmosphere. Use is then made of the two carbon oxidation reactions, namely, C --> CO2 and C --> CO which facilitate controlled transition metal reduction while also allowing lithium ion incorporation. Electrochemical performance evaluation indicates that the CTR gamma-LiV2O5 is capable of cycling at a material utilization of 130 mAh/g, a figure that compares favorably with the theoretical specific capacity of 142 mAh/g. The insertion behavior of the lithium vanadium phosphate shows a specific capacity equivalent to the reversible cycling of two lithium ions per Li3V2(PO4)(3) formula unit. In summary, we believe the CTR method to be an energy-efficient, economical, and convenient process to produce a wide range of electroactive compounds. It appears ideally suited to preparation of active materials for use in lithium ion applications. (C) 2003 The Electrochemical Society.