▎ 摘　　要

Highly conductive polypyrrole/graphene/manganese dioxide (PPy/graphene/MnO2) composites are fabricated via ultrasonic irradiation using p-toluenesulfonic acid as a dopant. The microstructures of PPy/graphene/MnO2 are evidenced by the SEM and TEM examinations. The effects of the graphene and MnO2 loading on the electrical conductivity are investigated. The maximum conductivity of PPy/graphene/MnO2 composites about 17.15 S/cm found with 3wt% graphene and 48.7wt% MnO2 at room temperature. Such uniform structure together with the observed high conductivities afforded high specific capacitance. A specific capacitance of as high as 258 F/g at a current density of 1 A/g was achieved over the PPy/graphene/MnO2 composite.