The ultralong cycle life of solid flexible asymmetric supercapacitors based on nickel vanadium sulfide nanospheres†
Abstract
The increasing development of portable devices for intelligent living promotes explorations into solid flexible energy storage systems. However, obtaining high-performance energy equipment with high-efficiency fabrication processes is still a serious challenge. Herein, a new strategy for the design of high energy flexible solid-state supercapacitors possessing a superior specific capacitance is reported. The electrodes of hierarchical porous nickel vanadium sulfide nanospheres optimized with triethanolamine show an attractive capacitance of 697.4 C g−1 at a current density of 1 A g−1 and an outstanding cycling ability of 86.1% after cycling at 10 A g−1 3000 times. The asymmetric solid flexible supercapacitor (ASC) equipment delivers a high energy density of 12 W h kg−1 at a power density of 900 W kg−1 and gives rise to a robust superior cycling stability with 100% capacitance maintained over 7000 charge–discharge cycles. This research shows that ternary nickel vanadium sulfide nanospheres show great potential for applications in future flexible electronic devices.