Nanoflower-like Ag adhered NiMo(OH)x composite arrays on nickel foam for high-performance supercapacitor

Abstract

As the core component of supercapacitors, the choice of electrode material is critical in determining the energy and power density of the supercapacitors. To date, transition metal materials have been widely employed as electrodes in supercapacitors. In this study, we successfully designed and fabricated nanoflower-like Ag-NiMo(OH)x composite materials on a nickel foam base using a combination of hydrothermal and calcination techniques. NiMoOx flower-like nanosheets grown on NF increase the overall specific surface area of the electrode material and improve charge transport, provide mechanical stability, and supporting template for Ag nanoparticles attachment in the next step. With the solvothermal method, we are able to generate Ag nanoparticles onto NiMoOx nanosheets to obtain Ag-NiMo(OH)x. Utilizing the Ag-NiMo(OH)x composite as the cathode which displayed distinguished electrochemical performance with a specific capacity of 3548 mF cm−2 at 2 mA cm−2. We also construct solid-state asymmetric supercapacitors (ASCs) with Ag-NiMo(OH)x/NF electrode as the cathode and activated carbon electrode as the anode. The two-electrode system was analyzed, and the energy density achieved is 80.21 Wh kg−1 under 717.98 W kg−1. Furthermore, 84.66 % of the original capacity is left over after 10,000 charge-discharge cycles, indicating good cycling stability of the material.