VO(B) nanobelts/reduced graphene oxide composites for high-performance flexible all-solid-state supercapacitors.

Vanadium oxide has attracted extensive attention for electrochemical capacitors due to its wide range of versatility. However, due to the relative poor conductivity and chemical stability of vanadium oxide, severe losses of capacitance often occur during charge and discharge processes. Herein, a free-standing vanadium dioxide (VO(B)) nanobelts/reduced graphene oxide (VO/rGO) composite film was fabricated by assembly of VO(B) nanobelts and rGO for supercapacitors. The flexible rGO sheets and VO(B) nanobelts intertwined together to form a porous framework, which delivered a 353 F g specific capacitance at 1 A g, and after 500 cycles, the specific capacitance retention rate was 80% due to the enhanced conductivity of the VO(B) nanobelts by rGO and increased transport of ions and electrons by the porous structures. An all-solid-state symmetrical supercapacitor was assembled from the VO/rGO composites, which exhibited good energy storage performance with a maximum voltage of 1.6 V. The maximum power density is 7152 W kg at the energy density of 3.13 W h kg, ranking as one of the highest power densities for reported materials. In addition, after 10000 cycles, it still has a specific capacitance retention rate of 78% at 10 A g.