A binder-free porous graphene/functionalized multiwalled carbon nanotubes composite containing nickel hydroxide as a supercapacitor electrode

In this paper, porous graphene (PG)/functionalized multiwalled carbon nanotubes (f-MWNTs) composite was first synthesized through a catalytic chemical vapor deposition (CCVD) followed by hydrothermal procedure. The prepared f-MWNTs/PG composite was then embedded into Ni foam (NF) via direct electrophoretic deposition, and Ni(OH)(2) nanoplates were simultaneously deposited on the surfaces of both porous graphene and f-MWNTs through a simple electrochemical deposition. The obtained Ni(OH)(2)@f-MWNTs-PG deposit was characterized through XRD, FT-IR, Raman, DSC-TGA, BET, FE-SEM, and TEM techniques. These analyses results verified that beta-Ni(OH)(2) nanoplates uniformly anchored onto both components of the electrodeposited composite. The charge storage ability of the fabricated Ni(OH)(2)@f-MWNTs-NPG/NF was tested as a binder-free supercapacitor electrode through cyclic voltammetry, continuous charge-discharge cycling, and AC impedance techniques, and compared with pristine Ni(OH)(2)/Ni foam electrode. The specific capacities as high as 374.5 mAh g(- 1) and 277 mAh g(- 1) at the current loads of 0.5 and 10 A g(-1) were respectively achieved for the prepared composite/NF electrode. Also, the cycling abilities of 94.8% and 77.8% were obtained after 5000 continuous charge-discharge cycles at 2 and 6 A g(-1), respectively. The outstanding capacitive capability of the fabricated composite electrode was assigned to the synergetic contributions between the Ni(OH)(2) nanoplates and porous graphene/functionalized MWNTs and their rational architecture in the composite matrix.