Highly Stable Poly(o-methoxyaniline)/WO3-Nanoflower Composite-Based Electrochromic Supercapacitors with Real-Time Charge Indication

Abstract

Polymer-based electrochromic supercapacitors (ECSs) are state-of-the-art innovations that use a color change to visually convey stored energy status in real time. However, the electrochemical instability of the polymers utilized in such devices limits their commercialization due to the difficulties in solution processability and short charge–discharge cyclic life. Herein, a simple and cost-effective chemical oxidative polymerization method is proposed for developing a highly stable and electrochromically active nanocomposite comprising poly(o-methoxyaniline) (PMOANI) and WO3 nanoflowers. The nanocomposite shows areal and specific capacitances of 83 mF/cm2 and 133.16 F/g, respectively. Moreover, the practical multifunctionality of the nanocomposite is demonstrated by developing an ECS device (5 × 5 cm2), which shows an energy density of 370 mWh/kg and power density of 4 W/kg with stable and prolonged charge–discharge cycles (>5000). Further, the ECS device is utilized to power a timer display (1.2 V) for >20 min using the energy stored in the charged state (blue color), which changes its color during discharge, demonstrating its capability as a power source with a real-time energy level indicator. It is expected that the polymer/metal oxide nanocomposite will certainly be a promising candidate to replace the traditional polymers in ECS technologies to achieve prolonged stability for their application in modern electronic gadgets and infrastructures.