Tough Hydrogen Bonding Crosslinked Poly(3-fluorothiophene)Network via Electrosynthesis for High-performance Electrochromic Supercapacitors

As a type of bi-functional device,electrochromic supercapacitors(EC-SCs)have attracted extensive attention in diverse applications such as flexible electronics.However,despite recent encouraging progress,rational design and development of high-performance EC-SC materials with desirable stability remain challenging for practical applications.Here,we propose a fluorination strategy to develop high-performance EC-SC materials with tough hydrogen bonding cross-linked intermolecular polymer network by one-step electrosynthesis of 3-fluorothiophene.The electrosynthesized free-standing poly(3-fluorothiophene)(PFT)films simultaneously achieve high electrochromic performance(optical contrast 42%at 560 nm with reversible color changes between purple and blue),and good capacitance property(290 F·g^(-1),1 A·g^(-1)),as well as outstanding cyclic stability(<2%reduction after 20000 cycles).We further demonstrate the fabrication of PFT-based flexible electrochromic supercapacitor devices(FESDs),and the resultant devices can be used to visually monitor the energy storage state in real-time and maintain outstanding stability under mechanical distortion like bending.Such a tough fluorination hydrogen bonding cross-linking strategy may provide a new design concept for high-performance EC-SC materials and reliable FESDs toward practical applications.