Synthesis, structural and electrochemical properties of V(4)O(9) cathode for lithium batteries

Single-phase three-dimensional vanadium oxide (V(4)O(9)) was synthesized by reduction of V(2)O(5) using a gas stream of ammonia/argon (NH(3)/Ar). The as-synthesized oxide, prepared by this simple gas reduction method was subsequently electrochemically transformed into a disordered rock salt type-“Li3.7V4O9” phase while cycling over the voltage window 3.5 to 1.8 V versus Li. The Li-deficient phase delivers an initial reversible capacity of ∼260 mAhg(−1) at an average voltage of 2.5 V vs. Li(+)/Li(0). Further cycling to 50 cycles yields a steady 225 mAhg(−1). Ex situ X-ray diffraction studies confirmed that (de) intercalation phenomena follows a solid-solution electrochemical reaction mechanism. As demonstrated, the reversibility and capacity utilization of this V(4)O(9) is found to be superior to battery grade, micron-sized V(2)O(5) cathodes in lithium cells.