Facile synthesis of porous graphene as binder-free electrode for supercapacitor application

Here, porous grapheme oxide (GO) gel deposited on nickel foam was prepared by using polystyrene (PS) colloidal particles as spacers for use as electrodes in high rate supercapacitors, then reduced by Vitamin C aqueous solution in ambient condition. The PS particles were surrounded by reduced graphene oxide (rGO) sheets, forming crinkles and rough textures. When PS particles were selectively removed, rGO gel coated on the skeleton of Ni foam can formed an open porous structure, which prevents elf aggregation and restacking of graphene sheets. The porous rGO-based supercapacitors exhibit excellent electrochemical performances such as a specific capacitance of 152 F g(-1) at 1 A g(-1), high rate capability of 53% capacitance retention upon a current increase to 100 A g(-1) and good cycle stability, due to effective rapid and short pathways for ionic and electronic transport provided by the sub-micrometer structure of rGO gel and 3D interconnected network of Ni foam. (C) 2016 Elsevier B.V. All rights reserved.