Flexible thermoelectric (TE) materials have received significant attention for their key role in developing renewable energy. Polypyrrole (PPy) film, as a promising TE material, shows poor flexibility and electrical conductivity by common oxidation polymerization due to π-conjugated rigid molecules. However, the dynamic conductive network formed between soft and rigid conductive polymers can dissipate mechanical energy while maintaining the integrity of the π-conjugation structure, enabling flexible and conductive thin films. To obtain a flexible freestranding PPy film, pentaerythritol ethoxylate (PEE)-borate was introduced into the PPy matrix to form a dynamic composite network (PPy/PEE) and enhance the elongation at the break (∼5.4%) due to the strong intermolecular interaction between PPy and PEE with the dopant anions (BF 3 − ). The as-prepared PPy films obtained at the PEE concentration of 0.07 M have achieved an enhanced electrical conductivity as high as 132.30 S cm −1 and a power factor of 0.33 μW m −1 K −2 . After the electrochemical treatment at 0.8 V, the electrical conductivity and power factor are further improved to 177.83 S cm −1 and 0.54 μW m −1 K −2 , respectively. The Seebeck coefficient dramatically increased up to 17.27 μV K −1 in the dedoped state. The PPy/PEE composite film still exhibits good flexibility after electrochemical dedoping, which makes it a promising way to optimize TE for flexible PPy films.

The rapid development of current wearable electronics motivates the promotion of energy storage devices. Supercapacitor with flexible, lightweight, highly efficient, and long cycling life is one of the potential and glittering candidates. Here, the composite film of carboxylated graphene (CG) and commercially available poly (3, 4-ethylene dioxythiophene): poly (styrene sulfonate) (PEDOT:PSS) are prepared as electrodes for flexible electrochemical capacitors by ultrasonication and vacuum filtration. The CG/PEDOT:PSS films were roundly characterized by SEM, XPS, FTIR, XRD and Raman spectrometer. The as-prepared free-standing films exhibited high specific capacitance (192.7 F g-1 at 0.5 A g-1), excellent rate capability (up to 80.4% from 0.5 to 20 A g-1), and good electrochemical stability (95.5% of specific capacitance retention after 50000 cycles). Surprisingly, the post treated free-standing films by Dimethyl Formamide (DMF) shows better capacitive properties than those of the pristine electrode, such as higher specific capacitance (204.3 F g-1 at 0.5 A g-1), and ultralong-cycling stability (104.6% retention at a high current density of 20 A g-1 after 50000 cycles). It is expected that the free-standing CG/PEDOT:PSS films can be used as flexible electrodes for various wearable energy storage devices.