A novel solvothermal synthesis of Mn 3 O 4 /graphene composites for supercapacitors

Mn 3 O 4 /graphene (GM) composites were prepared via a simple solvothermal process by mixing Mn(AC) 2 ·4H 2 O and graphite oxide (GO) suspension in mixed ethanol/H 2 O. As characterized by scanning electron microscopy and transmission electron microscopy, Mn 3 O 4 nanoparticles with size of 37–50 nm are effectively anchored in graphene sheets. Cyclic voltammetry and galvanostatic charge–discharge measurements were adopted to investigate the electrochemical properties of GM composites in 1.0 M Na 2 SO 4 solution. In a potential window of −0.2 to 0.8 V vs. SCE, the composites deliver an initial specific capacitance of 161.0 F g −1 at 1 A g −1 and increase to 230 F g −1 after 1000 cycles, while significant capacitance fading for pure Mn 3 O 4. At a high current density of 5 A g −1, the specific capacitances of 116 F g −1, 22.5 F g −1 are exhibited for the Mn 3 O 4 /graphene composites and pure Mn 3 O 4, respectively, indicating that graphene greatly enhances the electrochemical performance of Mn 3 O 4.