A cytocompatible conductive polydopamine towards electrochromic energy storage device

Polydopamine (PDA), a quinone containing bioinspired material, is attractive for environmental and human-friendly energy storage systems because of its fast and reversible proton-involved redox activity. Herein, we describe a multifunctional porous double-network polymer based on tetraaniline and PDA. This material can take advantage of the redox activity and wettability from PDA, as well as the electronic conductivity and electrochromic capability provided by tetraaniline. It does not show cytotoxic effects as evidenced by conventional cell viability and imaging assays. An electrochromic battery-type device based on this material delivers a considerable capacity of 160 mAh g⁻¹ together with a high coloring efficiency of 270 cm²/C and a large optical contrast of up to 37% at 700 nm. The device is capable of storing energy while indicating the energy status visually. This multifunctional porous conductive PDA material is promising for versatile energy storage applications.