The formation of nanoporous vanadium pentoxide by anodization for lithium ion battery

초록

In this study, nanoporous V2O5 is successfully synthesized via a facile electrochemical process. V2O5 is a metal oxide with a layered crystalline structure, which is considered as one of alternatives to cathode material of lithium ion battery, since it has much higher capacity than other traditional cathode materials (LiFePO4, LiCoO2 etc.), low cost, and simple synthesis route. There are many research works on synthesizing V2O5; hydrothermal, sol-gel method, chemical-synthesis routes. However, most works are focusing on the formation of V2O5 in the form of nanosized powders. Since binder and conducting agents are indispensably required in the powder-based electrode for the synthesis of a workable electrode, the loss of battery capacity due to inactive elements is expected. On the other hand, anodization method can produce thickness-adjustable nanoporous V2O5 which grows directly on the vanadium foil without no need of binders. As-prepared V2O5 with a thickness of more than 15 μm is analyzed by a high resolution electron scanning microscope (HR-SEM) and X-ray diffraction (XRD) to characterize surface/cross-sectional images and crystallinity. Electrochemical properties are measured by cyclic voltammetry (CV) and battery cycle test to determine performances of nanoporous V2O5 layer as cathode. All cells analyzed in this experimental are assembled in CR2032 coin half-cell. We found that the V2O5electrode prepared by anodization shows a high capacity of around 148 mAh/g and stable cycle performance without a significant drop of capacity.