Controllable fabrication of NiV₂O₆ nanosphere as a high-performance flexibleall-solid-stateelectrode material for...

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.