One‐Step Electrodeposition Method to Prepare Robust Flexible PEDOT‐Based Films for Ultra‐Stable Supercapacitors

Abstract Ultra‐long cycling stability is essential for conducting polymers (CPs) in the practical application of organic electronics. However, CPs usually exhibit poor cycling stability and fragile mechanical properties. Herein, through two alkyl‐bridged monomers, freestanding, flexible conducting P(EDOT‐ co ‐BEDTH) films based on the copolymerization of EDOT and 1,6‐bis((2,3‐dihydrothieno[3,4‐ b ][1,4]dioxin‐2‐yl)methoxy)hexane (BEDTH) are easily prepared through a one‐step electrodeposition process in CH 2 Cl 2 containing 0.1 M Bu 4 NBF 4 . Both the homopolymers and copolymers are characterized by using SEM, FTIR and UV/Vis spectroscopy, dynamic mechanical analysis (DMA), thermogravimetry (TG), and electrochemical methods. The results of DMA and TG indicate that the copolymer films show better mechanical flexibility and thermal stability than the corresponding homopolymers. Electrochemical results of P(EDOT‐ co ‐BEDTH) films with a capacitance of 23.6 mF cm −2 at 10 mV s −1 present ultra‐stable cycle life with a cycling capacitance retention of 99 % after 30 000 cycles. Furthermore, all‐solid‐state supercapacitors based on flexible P(EDOT‐ co ‐BEDTH) films exhibit the practical ability to light a red light‐emitting‐diode, demonstrating great promise in flexible energy‐storage devices.