Increase in Discharge Capacity of Li Battery Assembled with Electrochemically Prepared V₂O₅/polypyrrole-composite-film Cathode

摘要

Flexible composite films of V2O5 and conductive polypyrrole (V2O5/PPy) were grown by facile electrochemical polymerization, wherein an anodization potential was applied to the substrate electrode in an electrolyte solution containing pyrrole monomer and dispersed V2O5 particles. The coating of polypyrrole (PPy) on the surface of V2O5 particles was induced by the oxidative catalytic action of V2O5 during the electrochemical polymerization of pyrrole. PPy in the composite film connects the isolated V2O5 particles. This results in the formation of conductive networks in the composite film cathode, thereby enhancing the Li+ ion diffusion to the surface of the isolated V2O5 particles and thus increasing the accessibility of the Li+ ions. The specific capacity tests of the Li rechargeable batteries revealed that the discharge capacity of this composite film cathode was higher, i.e., 497 mAhg-1, than that of V2O5/PPy powder or pristine V2O5.