Electrochromic/Electrofluorochromic Supercapacitor Based on a Network Polysiloxane Bearing Oligoaniline and Cyanophenethylene Groups

Electrochromic supercapacitors capable of indicating their energy levels by color changes have emerged as promising materials for use in a variety of next-generation devices and applications. However, a reflective indicating mode is less adventitious in applications and conditions with low ambient light, which inspires the exploration of emissive indicators. In this paper, we synthesized a network polysiloxane bearing fluorescence emissive cyanophenethylene groups and electroactive oligoaniline groups (PSZT) via an electrochemistry-assisted hydrolytic cross-linking reaction. The resulting PSZT exhibited high-performance electrochromic/electrofluorochromic behavior with a high optical contrast ratio (ΔT % of 52.5% varying from 71.0% to 18.5% at 700 nm), a marked fluorescence quenching ratio of 85%, and good switching durability. This PSZT was then incorporated into a smart symmetrical supercapacitor device integrating energy storage with the electrochromism/electrofluorochromism functions. Here, the energy status can be simultaneously indicated via tunable colors from transmissive green-yellow to dark green, along with a fluorescence on/off switch. This electrochromic/electrofluorochromic supercapacitor represents a direction toward smart energy storage systems.