All-polymer ultrathin flexible supercapacitors for electronic skin

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2021-02, Vol.405, p.126915, Article 126915
• Main Authors: Gao, Fengxian, Song, Jingyao, Teng, He, Luo, Xiliang, Ma, Mingming
• Format: Article
• Language: English
• Subjects: Conducting polymer; Electronic skin; Flexible supercapacitors; Robustness; Ultrathin supercapacitors
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2020.126915

[Display omitted] •Designed dynamic network structure enables strong and robust PEG-PPy films.•Optimized PEG-PPy film shows both high conductivity and specific capacitance.•All-polymer ultrathin flexible supercapacitors (UF-SC) are made of PEG-PPy films.•The UF-SC exhibits high capacitance, mechanical and electrochemical robustness. Ultrathin flexible supercapacitors (UF-SCs) are highly desired for powering electronic skin devices. Most of current UF-SCs require electrochemically inactive substrates and binders to load electro-active materials, which limit the volumetric capacitance and stability of these UF-SCs. Herein, we report an all-polymer UF-SC based on conductive polypyrrole (PPy) film, which is constructed by the dynamic network formed by rigid PPy (~90 wt%) and soft polyethylene glycol (PEG, only 10 wt%) through supramolecular interactions. The network structure can effectively dissipate the destructive energy during mechanical or electrochemical deformation, making the PPy film strong and robust; and also helps to maximize the utilization of PPy, enabling the PPy film better electric conductivity and electrochemical capacitance than conventional PPy materials. After systematic optimization, we found the PEG600-PPy as the optimal electrode material, which can serve as electroactive material, current collector, and mechanical support simultaneously. Therefore, without using any substrate or current collector, these high-performance PEG600-PPy films can be directly used as electrodes for making all-polymer UF-SC. With high volumetric capacitance (547 F/cm3), outstanding mechanical and electrochemical stability, our all-polymer UF-SC (~80 μm in thickness, thinner than a piece of A4 paper) is a promising power device for electronic skin devices.