Phase-tuned nanoporous vanadium pentoxide as binder-free cathode for lithium ion battery

Abstract

Phase-controlled nanoporous vanadium pentoxide (V2O5) was prepared by electrochemical oxidation of vanadium foil as a binder-free cathode with high capacity and good cycling stability for lithium ion batteries. Increasing the annealing temperature led to the formation of a V2O5 film with preferential growth along the (001) plane on the as-prepared anodic film, resulting in enhanced Li ion diffusion and electronic conductivity. Thermal reduction of V2O5, depending on the annealing temperature, generated V3O7 and VO2 (R), which affect both the cell capacity and stability. Appropriate development of the (001) plane and intermediate phases (such as V3O7 and VO2) by thermal decomposition of the V2O5 lattice, determined by the annealing temperature, are key parameters for achieving high performance of the vanadium oxide cathode for Li ion batteries. The anodic V2O5 film annealed at 400 °C shows the highest discharge capacity of 170.1 mAh g−1 at fast charge/discharge rate (1.5 C) and good cycling stability for 100 cycles with a capacity retention of 91.4 %.