Synthesis of SWCNT–GO/MnO2 nanocomposites for use as electrodes of electrochemical capacitors by microwave and hydrothermal methods

Abstract

HNO3-oxidized single-wall carbon nanotubes (SWCNTs) and graphene oxide (GO) were ultrasonically dispersed in water to which potassium permanganate was added, and the resulting mixtures were treated under microwave radiation at 100 °C for 1 h or hydrothermal conditions at 100 °C for 1, 5 and 10 h to prepare SWCNT–GO/MnO2 composites as electrode materials of electrochemical capacitors. Results indicate that the composite prepared using the microwave method has a higher specific capacitance (173 F/g at 0.2 A/g), lower pseudo-charge transfer resistance (1.425 Ω ) and longer cyclic stability (3.74% capacitance loss after 1000 cycles at the scan rate of 20 mV/s) than the ones prepared using the hydrothermal method. Moreover, the microwave method has the advantages of simplicity of operation and shorter heating time. [New Carbon Materials 2015, 30(3): 214–221]