Multicolor electrochromic polymers based on butterfly-shaped monomers for the visualization of energy storage

Electrochromic supercapacitors (ECSCs) enable visual indication of their energy storage, thus effectively preventing them from being overcharged or insufficient energy. The current studies mainly focus on improving its specific capacitance and cycling stability. Herein, two butterfly-shaped triphenylamine-thiophene derivatives with twisted molecular structures were designed and synthesized featuring an EDOT unit as the central core. Then, two conjugated polymers pBTTPAE and pETPAE were prepared through electrochemical polymerization. Both polymers exhibit distinct multicolor display behavior, faster response time and excellent cycling stability. GCD tests show that pBTTPAE exhibited a higher volumetric specific capacitance (324.4 F·cm−3) and GCD stability due to its high specific area. The prototype device based on pBTTPAE is remarkable for its impressive energy density of 17.94 mWh·cm−3 and power density of 6.32 W·cm−3, which can be switched reversibly from yellow to yellow-green and blue when the potential changes from -0.4 V to 1.5 V. The high-performance electrochromic supercapacitor materials demonstrate their extensive utilizations for intelligent energy-storage devices.