Preparation of a Super Flexible Cu/Carbon Composite Nanofiber Film Electrode for High-Performance Flexible All-Solid-State Supercapacitors

A super flexible copper/carbon nanofiber film electrode is successfully synthesized through a calcination process wholly under nitrogen atmosphere. It is found that the heating rate in the calcination process plays a crucial role in achieving foldable super flexibility. The as-obtained film electrode exhibits mechanical super flexibility with a maximum specific capacitance of 608 F g(-1) at a current density of 1 A g(-1) and a capacity retention of 75.7% after 1000 cycles. Its flexible symmetric all-solid-state supercapacitor shows a superior areal capacitance of 88 mF cm(-2) at a current density of 0.2 mA cm(-2) and a high energy density of 41 mu Wh cm(-2) at a power density of 0.28 mW cm(-2).