Evaluation of Mo-doped amorphous V2O5 films as a positive electrode for lithium batteries

Films of V0.9Mo0.1O2.55 were fabricated by spin-coating or casting technique using a solution of molybdenum-doped polyvanadate. Their lithium insertion/extraction performance was investigated in a LiClO4/propylene carbonate solution. A coated thin film (0.4 μm in thickness) showed the capacity of about 14 μA h/cm2 at the current density of 25 μA/cm2 between 3.5 and 2.2 V (vs. Li). This level of capacity was maintained through 100 times of discharge/charge cycles, performed with the cut-off voltages of 4.7 and 2.2 V. The capacity of cast films increased linearly with their thickness up to 18 μm (480 μA h/cm2 at this thickness) at the slope of 27 μA h/cm2/μm, which was almost comparable to the per-thickness capacity of far thinner coated films. Such cast films also showed good cyclic performance.