PPy/graphene nanosheets/rare earth ions: A new composite electrode material for supercapacitor

Highly conductive PPy/graphene nanosheets/rare earth ions (PPy/GNS/RE3+) composites were prepared via in situ polymerization with p-toluenesulfonic acid as a dopant and FeCl3 as an oxidant. The effects of GNS and RE3+ on the electrical conductivity of the composites were investigated. The results showed that the GNS as a filler had effect on the conductivity of PPy/GNS/RE3+ composites, which played an important role in forming a conducting network in PPy matrix. The microstructures of GNS and PPy/GNS/RE3+ were characterized by the SEM and TEM examinations. It was found that GNS and PPy nanospheres formed a uniform composite with the PPy nanospheres absorbed on the GNS surface and/or filled between the GNS. Such uniform structure together with the observed high conductivities afforded high specific capacitance when used as supercapacitor electrodes. A specific capacitance of as high as 238 F/g at a current density of 1 A/g was achieved over the PPy/GNS/Eu3+ composite.