A high performance PEDOT/PEDOT symmetric supercapacitor by facile in-situ hydrothermal polymerization of PEDOT nanostructures on flexible carbon fibre cloth electrodes

Achievement of conducting polymer based symmetric supercapacitor with high specific capacitance and long cyclic stability is a very challenging and a complicated approach. Generally, the specific capacitance and stability of the conducting polymer system have been improved by forming composite with metal oxides or carbon based nanomaterials. In this present work, we demonstrated a simple and straightforward strategy for the deposition of bare PEDOT nanostructures on flexible 3D carbon fibre cloth (CFC) via in situ hydrothermal polymerization technique. The hydrothermally polymerized electrodes were easily assembled into PEDOT/PEDOT symmetrical supercapacitor without using any organic binders and conductive additives. This symmetric supercapacitor exhibited significantly high specific capacitance of 203 F g⁻¹ at 5 mV s⁻¹ scan rate with high energy density of 4.4 W h kg⁻¹ and power density of 40.25 kW kg⁻¹ in 1 M H₂SO₄ electrolyte, which is highest value reported for this material as a symmetric device. More importantly, the formation of 3D PEDOT nanostructure with flexible carbon cloth affords an efficient and stable electrode for facile electron transfer in symmetrical supercapacitor and delivered a long device stability with capacitance retention of ∼86% after 12,000 charge/discharge cycles.