Flexible quasi-solid-state dual-ion asymmetric supercapacitor based on Ni(OH)2 and Nb2O5 nanosheet arrays

摘要

cqvip:Increasing the energy density, power density as well as widening the operation voltage are essential to electrochemical capacitors to meet the practical energy demands. Herein, a novel flexible quasi-solid-state dual-ion asymmetric supercapacitor(ASC) with Ni(OH)2 and Nb2O5 nanosheets directly grown on stainless steel mesh is developed. In the dual-ion ASC, Nb2O5 negative and Ni(OH)2 positive electrodes react with Li+ and OH- respectively in alkaline gel electrolyte to store energy, which is quite different from conventional alkali metal ion SCs and alkaline SCs. The as-assembled flexible device has an extended working voltage of 1.7 V and delivers a capacity of 5.37 mAh cm-2, a maximum energy density and power density of 0.52 mWh cm-3 and 170 mW cm-3 , respectively. The device maintains around 60% capacity retention after long cycling up to 1000 cycles. Moreover, our device can light up a LED light efficiently upon fast charging. The proposed quasi-solid-state dual-ion ASC has potential applications in future portable electronics and flexible energy storage devices.