Efficient synthesis of hierarchical NiO nanosheets for high-performance flexible all-solid-state supercapacitors

Hierarchical NiO nanosheets were successfully grown on flexible carbon fibers with pre-deposited ZnO nanoparticle films as the buffer layers, followed by the removal of the ZnO films. The as-grown NiO nanosheets with excellent flexibility exhibited a largest specific capacitance of 842 mF cm(-2) at a current density of 1 mA cm(-2). Configured as flexible symmetric all-solid-state supercapacitors, the device showed a specific capacitance of 20 mF cm(-2) at 0.1 mA cm(-2), excellent cyclability with a real capacitance of about 20 mF cm(-2) for over 10 000 cycles, and excellent mechanical flexibility and stability under different curvatures.