Influence of conductive polymer on a sandpaper-based flexible energy storage

The energy demand has grown explosively due to the changes in the world economy and the rapid development of society. Improving energy utilization and energy storage has thus become an essential area of science and technology development. Supercapacitors are necessary energy-storage devices, and their growth has become the goal of significant national efforts. We prepared a sandpaper-based composite electrode by mixing multiwalled carbon nanotubes (MWCNTs) and graphene with a conductive polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), with pseudocapacitance characteristics. The specific capacitance of the composite electrode was effectively increased from 55 to 124 F/g by 3% PEDOT addition. Furthermore, the internal resistance of the electrolyte was effectively reduced, and the electrode capacitance increased to 137 F/g by adding 1.0% MWCNTs to the phosphate gel electrolyte. The specific capacitance of the energy-storage device still retained 97% of its initial value after the charge–discharge cycle testing under constant current, which is an excellent cycling-life performance. The hybrid supercapacitor in this study has considerable development potential in flexible wearable devices and energy-storage component fields. Graphical Abstract