Hydrothermal synthesis of Ni(OH)2 nanoflakes on 3D graphene foam for high-performance supercapacitors

Ni(OH)2 nanoflakes were successfully synthesized with a facile hydrothermal method on 3D (three-dimensional) graphene grown by atmospheric pressure chemical vapor deposition (APCVD). The hydrothermal temperature and time were optimized to improve the performance of the composite as a binder-free supercapacitor electrode. The Ni(OH)2/3D graphene composite synthesized at 180 °C for 3 h shows high specific capacitance of 1450 F/g at a current density of 5 A/g. Even when the discharge current density increases to 60 A/g, a specific capacitance of 1196 F/g is still retained, highlighting the remarkable rate capability of our composite electrode. It also shows good capacity retention of 78 % after 1000 charge-discharge cycles, presenting the excellent cycle stability. These impressive results suggest that the composite is a promising electrode material for high-performance supercapacitors.