High-performance electrochromic supercapacitor based on a new EDOT-triphenylamine conjugated polymer

Abstract

Despite the rapid advancement of electrochromic capacitive energy storage, there are still challenges in simultaneously improving electrochemical kinetics and cycling stability. Here we synthesize a new conjugated polymer bearing twisted EDOT-triphenylamine (TPA) dual-redox centers through facile electropolymerization. Benefiting from the multiple electroactive segments, the resultant polymer electrode reveals remarkable multicolor electrochromism (from yellow to green and blue) and concurrently good capacitive energy storage (high capacitance of 39 mF cm−2). The twisted alignment of the TPA structure facilitates ions diffusion and electrochemical reaction kinetics. Coupled with vanadium pentoxide ion-storage material, an assembled asymmetric electrochromic supercapacitor device (AESD) displays a high optical contrast of 71.37%, a wide voltage window of 2 V, the desirable energy density of 20.2 μWh cm−2, and outstanding cycling durability (87% capacitance after 6000 cycles at 0.2 mA cm−2). This method and knowledge offered by density functional theory (DFT) provide another path toward improving electrochromic and capacitive performance in a synergetic manner.