Hydrothermally Tailored Three-Dimensional Ni-V Layered Double Hydroxide Nanosheets as High-Performance Hybrid Supercapacitor Applications

Here, we report a facile and easily scalable hydrothermal synthetic strategy to synthesize Ni-V layered double hydroxide (NiV LDH) nanosheets toward high-energy and high-power-density supercapacitor applications. NiV LDH nanosheets with varying Ni-to-V ratios were prepared. Three-dimensional curved nanosheets of Ni _0.80 V _0.20 LDH showed better electrochemical performance compared to other synthesized NiV LDHs. The electrode coated with Ni _0.80 V _0.20 LDH nanosheets in a three-electrode cell configuration showed excellent pseudocapacitive behavior, having a high specific capacity of 711 C g ^-1 (1581 F g ^-1 ) at a current density of 1 A g ^-1 in 2 M KOH. The material showed an excellent rate capability and retained the high specific capacity of 549 C g ^-1 (1220 F g ^-1 ) at a current density of 10 A g ^-1 and low internal resistances. Owing to its superior performance, Ni _0.80 V _0.20 LDH nanosheets were used as positive electrode and commercial activated carbon was used as negative electrode for constructing a hybrid supercapacitor (HSC) device, having a working voltage of 1.5 V. The HSC device exhibited a high specific capacitance of 98 F g ^-1 at a current density of 1 A g ^-1 . The HSC device showed a higher energy density of 30.6 Wh kg ^-1 at a power density of 0.78 kW kg ^-1 and maintained a high value of 24 Wh kg ^-1 when the power density was increased to 11.1 kW kg ^-1 . The performance of NiV LDHs nanosheets indicates their great potential as low-cost electrode material for future energy-storage devices.