Coral-like PEDOT Nanotube Arrays on Carbon Fibers as High-Rate Flexible Supercapacitor Electrodes

Integration of conductive polymers with flexible substrate to construct an electronically conductive and mechanically flexible electrode is of great significance for a flexible energy storage device. This work reports a facile method to prepare coral-like poly(3,4-ethylenedioxythiophene) (PEDOT) nanotube arrays on textile carbon fibers (TCs) for high-rate supercapacitor application. The ZnO nanowires grown on TCs serve as a sacrificial template. Electrochemical polymerization of 3,4-ethylenedioxythiophene followed by template removal of ZnO nanowires yields a hybrid composed of PEDOT nanotubes vertically grown on TC (TC@PEDOT). The strong interfacial interactions between nanotubes and substrate afford the hybrid with superior mechanical flexibility and high conductivity (790 S m–1). More importantly, the tubular structure enables ∼88% PEDOT to be involved in the reversible redox reaction, delivering a specific capacitance 184 F g–1 in 1.0 M H2SO4 electrolyte with 88% capacitance retention after 10 000 cycles. A solid-state TC@PEDOT-based supercapacitor with PVA-H2SO4 as gel electrode exhibits a high-rate capability with a relaxation time constant (τ0 = 0.96 s) very close to that in aqueous H2SO4 electrolyte (τ0 = 0.87 s). Moreover, it can withstand various bending and twisting tests without notable performance loss, giving the TC@PEDOT hybrid great promise as a high-rate electrode for flexible energy storage devices.