A Facile and Template-Free Hydrothermal Synthesis of Mn₃O₄ 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