A Colorless to Multicolored Triphenylamine-Based Polymer for the Visualization of High-Performance Electrochromic Supercapacitor

Electrochromic supercapacitors (ECSCs) that combine electrochromism and energy storage characters enable visual monitoring of the energy storage state of the device. In this work, two triphenylamine-based polymers pTPACB and pTTPACB were prepared by electrochemical polymerization. Both polymers exhibit multi-step redox behavior due to the presence of multiple triphenylamine and carbazole units. Correspondingly, pTPACB and pTTPACB can be switched from neutral colorless state to multicolored changes at different potentials. Compared with pTPACB, pTTPACB presents faster switching time and higher optical contrast. It is more intriguing that pTTPACB shows much more outstanding pseudocapacitive behavior with ultrahigh areal specific capacitance (6.64 mF‧cm-2) at a current density of 0.05 mA‧cm-2 due to the smaller nanoparticles size and loose aggregated structure. In addition, the asymmetric electrochromic supercapacitor devices based on pTTPACB can light a display panel or blue LED for 30 s accompanied with color changes from blue-green to colorless in the process of power supply. Hence, this work achieves a novel triphenylamine-based polymer for high-performance electrochromic supercapacitors, which shows great potential in electronic tags and display devices.