Lightweight, interconnected VO2 nanoflowers hydrothermally grown on 3D graphene networks for wide-voltage-window supercapacitors

Highly stable and interconnected VO2 nanoflowers were uniformly grown on flexible three dimensional graphene networks, which directly served as a lightweight and high conductivity supercapacitor electrode (VO2 NF@3DG). The uniform VO2 NF@3DG hybrid provided direct and stable pathways for rapid electron and ion transport. The hybrid produced an improved areal specific capacitance of 466 mF cm−2 and 283.2 mF cm−2 for the three- and the two-electrode configurations, respectively. A capacitance retention of 63.5% after 3000 cycles showed that the VO2 NF@3DG hybrid had a stable cycling performance at a high specific capacitance. A high energy density of 279.6 mW h m−2 and a high power density of 60 000 mW m−2 were achieved in symmetrical supercapacitors. The effective strategy could be applied to improve the performance of supercapacitors with high efficiency, wide potential windows and long life.