A three-dimensional graphene/CNT/MnO₂ hybrid as supercapacitor electrode

Abstract

A novel nano δ-MnO2 with the flocculus structure was synthesized by the microemulsion approach. An original nano α-MnO2 with the sea urchin-like structure was synthesized by the hydrothermal approach. On this basis, the well dispersed graphene/CNT/MnO2 hybrids were prepared by the high energy ball milling. The specific capacitance of α-MnO2 is as high as 327.5 F/g, the specific capacitance retention rate of graphene/CNT/δ-MnO2 with the increase of scanning rate is 55.6% which is much higher than others. The conductivity and specific surface area of hybrid electrode materials have been greatly improved.