Synthesis of Mn3O4-encapsulated graphene sheet nanocomposites via a facile, fast microwave hydrothermal method and their supercapacitive behaviour

Well-crystallized Mn3O4-anchored reduced graphene oxide (rGO) nanocomposites have been successfully

synthesized via a facile, effective, energy-saving, and scalable microwave hydrothermal technique

for potential application as supercapacitor material. Integrating these nanostructures resulted in a strong

synergistic effect between the two materials, consequently leading to a hybrid composite with higher

specific capacitance compared to the bare Mn3O4 nanoparticles. The results from different sorts of characterization

indicate that the Mn3O4 particles were deposited and anchored on graphene sheets. The

capacitance value of the rGO(31.6%)–Mn3O4 nanocomposite reached 153 F/g, much higher than that of

the bare Mn3O4 (87 F/g) at a scan rate of 5 mV/s in the potential range from

−0.1 V to 0.8 V. More importantly, a 200% increase in capacitance was observed for the nanocomposite with cycling at 10 mV/s due

to electrochemical activation and the oxidization of Mn(II,III) to Mn(IV) during cycling, as verified by Xray

photoelectron spectroscopy. There is no observable capacitance fading up to 1000 cycles. The facile

synthesis method and good electrochemical properties indicate that the nanocomposite could be an

electrode candidate for supercapacitors.