▎ 摘　　要

A binder-free novel three-dimensional assembly comprising graphene, carbon nanoparticles and nickel hydroxide is presented as a supercapacitor electrode. The combined effect of three-dimensional graphene for excellent charge conduction and nickel hydroxide coating on carbon nanoparticles for high surface area was exploited to obtain excellent supercapacitance. The resulting structure presented an ultrahigh 4667 F g(-1) specific capacitance at a 2 A g(-1) discharge rate with 98.6% high charge retention for more than 1000 charge-discharge cycles. In addition, the presented assembly demonstrated very high power and energy densities.