High-performance electrochromic supercapacitor based on an electroactive polyimide containing pentaaniline

Attributed to their obvious color transition, good electrochemical reversibility, and high theoretical capacitance, polyaniline-based electrochromic supercapacitors have recently garnered significant attention in wearable devices, intelligent power supplies, and smart windows. However, its limited processability as well as poor electrochemical endurability have severely hampered polyaniline's practical application in this regard. Herein, a new electroactive polyimide containing pentaaniline in the main chain has been facilely designed and synthesized using oxidative coupling polymerization followed by thermal imidization. Rational matched with vanadium pentoxide ion-storage counter electrode, a quasi-solid-state electrochromic supercapacitor device (QSES) is manufactured with desirable simultaneous optical change and energy storage performance of high optical contrast of 68%, fast switching speed of 1.29/1.58 s, good open circuit memory (1.28% decay after power off for 3600 s), wide voltage window of 2 V, large capacitance of 41.53 mF/cm2, and outstanding cycling durability (85% capacitance and 96% optical modulation retention after 10000 cycles at 0.2 mA/cm2). This study provides a feasible approach of molecular designing for achieving processable electroactive polymer and shows the promising potential of the resultant electrochromic supercapacitor in smart power supply devices with energy level indication functionality.