Construction of hierarchical graphene/polyaniline@polyaniline electrodes by chemical and electrochemical polymerization for high-energy supercapacitors

In this study, we present the construction of the hierarchical graphene/polyaniline (PANI) supercapacitor electrode composites through a two-step PANI deposition approach of in-situ chemical and electrochemical polymerization. The graphene oxide (GO)/PANI colloid synthesized by chemical method undergoes the water evaporation and GO reduction to form the hydrated reduced GO (rGO)/PANI films on carbon cloth (CC) substrates. The resulting integrated rGO/PANI/CC films could be directly used as the electrodes to electrodeposit supplemental PANI on the subsurface/surface to obtain the rGO/PANI@PANI/CC electrodes with PANI distribution gradient. Benefited from the hierarchical PANI loading on the porous graphene scaffold with efficient PANI utilization in the electrochemical process, the as-prepared electrode can deliver a superior capacitance of 1131.6 F g−1 at 2 A g−1 with a high retention of 87.7% at 40 A g–1. Meanwhile the all-solid-state symmetric device achieves a large energy density of 52.6 Wh kg−1 and prominent cyclic stability. The excellent electrochemical performances of the electrodes manifest the feasibility of this reported strategy designing new carbon-based composites towards high energy-storing system with promising application prospect.