Three-dimensional Co2V2O7·nH2O superstructures assembled by nanosheets for electrochemical energy storage

ABSTRACT Hierarchical superstructures assembled by nanosheets can effectively prevent aggregation of nanosheets and improve performance in energy storage. Therefore, we proposed a facile hydrothermal method to obtain three-dimensional (3D) superstructure assembled by nanosheets. We found that the ratio of Co2+/HMTA affected the morphology of the samples, and the 3D hierarchical structures of are obtained while the ratio of Co2+/HMTA is 12:25. The hierarchical structures with sufficient interior space preserves the original sheet-like dimensional components and results in sufficient active sites and efficient mass diffusion. Hence, the 3D Co2V2O7·nH2O hierarchical structure exhibits good rate capability and high stability while as electrode materials. Meanwhile, when power density is 745.13 W/kg, the assembled CVO-2//AC shows an energy density of 47.7 Wh/kg. The work displays a facile method for fabrication of 3D superstructure assembled by 2D nanosheets that can be applied in energy storage.