Reduced graphene oxide/Mn3O4 nanohybrid for high-rate pseduocapacitive electrodes

Nanostructure Mn3O4 is a promising pseudocapacitive electrode material due to its low cost, environmental compatibility, and intrinsically high capacity. However, the poor electrical conductivity and low accessible active sites limit its performance. We report that one-dimensional (1D) nanoscale Mn3O4 has been coupled with reduced graphene oxide (RGO) to fabricate RGO/Mn3O4 nanohybrid (MORGO) as a pseudocapacitive electrode material with high capacitance. The selective reduction of graphene oxide (GO) in Mn3O4/graphene oxide (MOGO) to reduced graphene oxide (RGO) while sustaining the unchanged oxidation state of manganese is the key to obtain MORGO. Specific surface area of MORGO is 14 times higher than pure Mn3O4, and the charge transfer resistance decreases 3.2 times. These enhanced properties lead to excellent specific capacitance of 538 F g(-1) at the current density of 0.1 A g(-1), and of 472 F g(-1) at 10 A g(-1) in 1 M Na2SO4 aqueous electrolyte. The capacitance retained 89% after 2000 cycles, demonstrating its excellent long-term cycling stability. (C) 2017 Elsevier Inc. All rights reserved.