New electropolymerized triphenylamine polymer films and excellent multifunctional electrochromic energy storage system materials with real-time monitoring of energy storage status

Multifunctional intelligent electrochromic energy storage with real-time monitoring of energy storage level by color change has become the extremely attractive researches for the development of electrochemical energy storage systems. Herein, three novel triphenylamine-based organic monomers with star-shaped donor-acceptor structure are designed and synthesized to successfully obtain the corresponding three polymer films with different and rich color switching by electrochemical polymerization via the coupling between peripheral tri-phenylamine groups. Based on these three polymer films as the electrodes, a fast switching electrochromic property with a large optical contrast of 80.5 % in the visible region and a high coloration efficiency of 277.21 cm2.C- 1, which are one of the best results among TPA-based electrochromic materials, is achieved for the polymer pPh-4TPA with the pyrazino[2,3-g]quinoxaline acceptor core. Meanwhile, pPh-4TPA also shows high specific capacitance of up to 423F.g(-1) (475F.cm(-3)), high capacity of 115.3 mAh.g(-1) and unparalleled rate performance. The assembled asymmetric electrochromic energy storage devices based on pPh-4TPA polymer films exhibited maximum energy density of 105.12 Wh.kg(-1) (107 mWh.cm(-3)) and power density of 45 kW.kg(-1) (45.9 W.cm(-3)), which are both the highest energy and power densities among the pure organic electrochromic pseudocapacitors ever reported, simultaneously accompanied by reversible color changes in appearance during charging and discharging process.