Intelligent electrochromic-supercapacitor based on effective energy level matching poly(indole-6-carboxylicacid)/WO3 nanocomposites

Abstract

Poly(indole-6-carboxylicacid) (P6ICA)/WO₃ nanocomposites with a core–shell nanorod structure are prepared using two continuous steps, including hydrothermal synthesis and electrodeposition. These novel nanocomposites display multi-color changes (dark green, yellow, and yellow-green) and their specific capacitance is up to 33.8 mF cm⁻². After 5000 cycles of charge and discharge, P6ICA/WO₃ nanocomposites can maintain 87% of their initial capacitance value. A P6ICA/WO₃//PEDOT asymmetric electrochromic-supercapacitor is constructed using P6ICA/WO₃ as the positive electrode and poly(3,4-ethylenedioxythiophene) (PEDOT) as the negative electrode. This electrochromic-supercapacitor under a discharged state exhibits a large optical modulation of 62% at 625 nm with yellow-green color. The device also exhibits a blue-black color when transmittance modulation decreases to a minimum of 7% under the fully charged state. These results demonstrate that the energy storage state of the electrochromic-supercapacitor can be monitored by the light transmittance or color change. The coloring efficiency of the device is up to 763 cm² C⁻¹ and the specific capacitance of the device is 13.69 mF cm⁻², indicating a good energy storage capacity. This study shows that the constructed P6ICA/WO₃//PEDOT electrochromic-supercapacitor is of great significance in energy storage and sustainable utilization, as well as intelligent applications in the future.