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, γ ­ LiV 2 O 5 and Li 3 V 2 ( PO 4 ) 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 → CO 2 and C → CO which facilitate controlled transition metal reduction while also allowing lithium ion incorporation. Electrochemical performance evaluation indicates that the CTR γ ­ LiV 2 O 5 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 Li 3 V 2 ( PO 4 ) 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.