Increased Energy Density with Conjugated Polymer-Based Composite Electrode without Power Density Sacrifice

The joint of capacitance and diffusion contribution in electrode materials of supercapacitors is effective to achieve high energy density without power density sacrifice. Therefore, a series of donor–acceptor type conductive polymers with benzidine as the donor and other monomers having different aromaticity as the acceptor have been designed and synthesized. In this study, after the binary flexible electrode from the thiophene ring-containing polymer on carbon cloth was modified with the Prussian blue analogue CoFePBA, a flexible ternary composite electrode with integrated capacitance and diffusion capabilities was prepared. Its specific capacitance was up to 1135.72 F/g at 0.5 A/g with a retention ratio of 98.45% after 10,000 cycles. Its electrochemical performance remained basically unchanged after 1000 times of bending. When the energy density of a two-electrode supercapacitor device assembled with the as-made electrode reached up to 13.8 W h/kg, it is at a high power density of 745.9 W/kg, and it shows 6.7 W h/kg even at maximum power density of 5010.1 W/kg.