Synthesis of CU-doped vanadium oxide/graphene hybrid material for high performance electrochemical capacitor

Vanadium oxides have attracted great concern in the research of electrode materials for electrochemical capacitors because of their high theoretical specific capacitance, wide range of sources and low prices. On the other hand, as one of the most promising 2D materials, graphene also gathers much attention during the last decade. In the present work, the vanadium oxide/graphene electrode material for electrochemical capacitors has been successfully synthesized by one-step simultaneous hydrothermal reduction technology, and the Cu-doped modified electrode material has also been prepared by adding cupric nitrate with the same progress. With the investigation of X-ray diffraction pattern (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and electrochemical measurements, the vanadium oxide/graphene and Cu-doped modified electrode materials both exhibit remarkable electrochemical performance with the starfruit-like structure of vanadium oxide particles in the electrochemical capacitors. High specific capacitances of 193.23F·g^-1 and 221.90F·g^-1 have been achieved for vanadium oxide/graphene hybrid material and Cu-doped electrode material respectively in 0.5mol·L^-1 K2SO4 electrolyte at a current density of 0.25A·g^-1. Moreover, with the modification of the electrode material, the capacitance retention of the hybrid electrode material has increased from 56.27% to 71.79% after a cycling stability test at a current density of 1.0A·g^-1, showing a good application prospect.