Freeze-drying method to synthesize V2O5/graphene composites toward enhanced sodium ion storage

Abstract V2O5 nanowires/Graphene composite was successfully constructed through a delicate method. SEM, TEM, XRD and Raman spectra were utilized to investigate the morphology and phase structure of as-obtained samples. When being compared with bare V2O5 nanowires, the as-obtained composite presented an enhanced performance of sodium ion storage. The results illustrated that the composite electrode can render a discharge specific capacity of 154 mA h g−1 during the first cycle, whereas it was 100 mA h g−1 for bare V2O5 nanowires electrode. It was worth noting that the method here to decorate graphene sheets with V2O5 nanowires was crucial to achieve the optimal electrochemical property. EIS and CV cures (at different scanning rate) indicated that the introduction of graphene sheets can enhance the electrical conductivity of as-obtained composite and facilitate the surface-controlled electrochemical reaction process of electrode. Finally, the enhanced sodium ion storage performance can be expected.