Ultralight and flexible supercapacitor electrodes made from Ni(OH)2 nanosheets doped with Ag nanoparticle/3D graphene composite

Abstract

A composite of Ni(OH)₂ nanosheets doped with Ag nanoparticle/3D graphene (Ag/Ni(OH)₂/3DG) was synthesized by a combination of chemical vapor deposition and a hydrothermal process. The Ag/Ni(OH)₂/3DG composite is light, flexible and has a high conductivity. It can be utilized directly for supercapacitor electrodes (including current collectors) without using binder materials or conductive agents. Doping the Ni(OH)₂ nanosheets with Ag nanoparticles can improve the conductivity, which enhances the specific capacitance of the hybrid electrode accordingly. Electrochemical tests show a high specific capacitance of 2167 F g⁻¹ scaled to the total mass of the electrodes at 10 A g⁻¹ current density, a good rate capability and an excellent cycling performance of 98% capacitance retention over 1000 cycles at 25 A g⁻¹ current.