Different-layered Ni(OH) nanoflakes/3D graphene composites for flexible supercapacitor electrodes.

Monolayer and multilayer Ni(OH) nanoflakes/3D graphene composites were successfully prepared by modulating the seed layer of Ni(OH) in a hydrothermal synthesis. An important advantage is that no other inactive binder is required to be utilized in the composite electrode to produce a flexible supercapacitor. It is found that the 3D graphene grown via CVD has a limited contribution to the overall capacitance when solely utilized as a current collector, while Ni(OH) nanoflakes have been determined to be the primary contributor to the overall capacitance of the device. The electrochemical properties of monolayer Ni(OH) nanoflakes/3D graphene are significantly enhanced relative to multilayer Ni(OH) nanoflakes/3D graphene. At 10 A/g current density, a high specific capacitance of 1606 F/g (per total mass of electrodes) is obtained for monolayer Ni(OH) nanoflakes/3D graphene composites. After 1000 cycles of charge/discharge, cycling performance shows 96 % capacitance retention at 10 A/g current density. [ABSTRACT FROM AUTHOR]