Composites of V₂O₅ aerogel and nickel fiber as high rate intercalation electrodes

Amorphous vanadium pentoxide (V₂O₅) has been investigated as an intercalation material for Li-ion batteries due to its high specific energy and high capacity for Li intercalation. However, the rate of insertion is typically limited by lithium diffusion in the host and by its modest conductivity. The present work demonstrates that high intercalation rates are possible if the host microstructure is modified to decrease the characteristic lithium diffusion distance and the characteristic conduction distance. Thin films of V₂O₅ were grown by preferential gelation on sintered nickel fibers via a sol-gel route. Electrochemical impedance measurements of the composite electrodes indicated that diffusion limitations in the host were successfully avoided. Constant current cycling and cyclic voltammetry were also used to characterize the composites. Specific powers, based on mass of active material, of almost 6 MW/kg were observed.