A Facile and Template-Free Hydrothermal Synthesis of Mn 3 O 4 Nanorods on Graphene Sheets for Supercapacitor Electrodes with Long Cycle Stability

Graphene/Mn3O4 composites were prepared by a simple hydrothermal process from KMnO4 using ethylene glycol as a reducing agent. Mn3O4 nanorods of 100 nm to 1 μm length were observed to be well-dispersed on graphene sheets. To assess the properties of these materials for use in supercapacitors, cyclic voltammetry and galvanostatic charging–discharging measurements were performed. Graphene/Mn3O4 composites could be charged and discharged faster and had higher capacitance than free Mn3O4 nanorods. The capacitance of the composites was 100% retained after 10 000 cycles at a charging rate of 5 A/g.