Preparation and Electrochemical Properties of Graphene/MnO₂Nanocomposites for Supercapacitors

Abstract

In the present work, we demonstrated a facile process to prepare graphene/MnO 2 composites via a simple hydrothermal method at 120 °C using KMnO 4 and graphene oxide as raw materials followed by reduction with or without hydrazine. The electrochemical performance of the graphene/MnO 2 composites were investigated in a neutral electrolyte of Na 2 SO 4 . Among these samples, the sample rGM 3 prepared without hydrazine show uniform morphology and the best electrochemical performance. The specific capacitance of rGM 3 is 169 F g -1 at a specific current of 0.2 A g -1 . It exhibits a maintenance of 75.5 % of the initial capacitance after 1000 cycles. The results manifest that the graphene/MnO 2 composites can be potentially applied in supercapacitors.