Controllable fabrication of NiV2O6 nanosphere as a high-performance flexible all-solid-state electrode material for supercapacitors

Flexible high-performance electrochemical capacitors have aroused much attention with their prospect applications in future wearable electronic devices. Herein, a new strategy for fabrication the NiV2O6 nanosphere by hydrothermal combined with subsequent room temperature liquid phase synthesis method was investigated. The introduced NH4+ during the preparation is benefit to attain the NiV2O6 architectures with high electrical conductivity, large surface area, and exclusive porous networks. When applied as active electrode materials for electrochemical energy storage device, NiV2O6 gives rise to superior specific capacity (565.5 C/g at 1 A/g) and cyclic stability (84.6% of initial capacity retention after 3000 cycles). An asymmetric supercapacitor device can reach voltagewindow of 1.6 V and supply an energy density of 24.3 Wh kg-1 at the power density 800 W kg-1 in an aqueous electrolyte and 7.8 W h kg-1 at the power density of 850 W kg-1 in a solid state gel electrolyte. The cyclic stability of flexible asymmetric supercapacitor has provided 74% capacitance retention over 3000 charge-discharge cycles. Thus, the NiV2O6 nanosphere electrode presents a great potential for flexible and transparent energy storage devices.