High performance organic-inorganic hybrid material with multi-color change and high energy storage capacity for intelligent supercapacitor application

Abstract

As a kind of multifunctional supercapacitor, electrochromic-supercapacitor device (ESD) can be used to visually estimate the energy storage level of the device through the color change. Currently, low energy storage capacity limits the practical application of ESD. Here, WO3 with oblate shape morphology formed by the aggregation of nanoclusters is successfully prepared by hydrothermal synthesis. Then WO3-poly (5-cyanoindole) (P5ICN/WO3) hybrid material is obtained by electrochemical polymerization P5ICN on the surface of WO3. Due to the synergistic effect of P5ICN and WO3, P5ICN/WO3 hybrid material shows enhanced charge transfer rate, multi-colors change (blue-green, yellow and green) and good supercapacitive properties (specific capacitance is 89.2 mF cm−2). An asymmetric ESD is successfully constructed based on P5ICN/WO3, which also shows good electrochromic and supercapacitive properties, such as high specific capacitance, energy density and power density. The color of ESD can change between yellow and dark green during charge-discharge process. In practical application, the intelligent monitoring of the energy storage state of device is achieved by the color variations or transmittance change of this ESD. And the charged ESD also can power a LED, indicating the feasibility of practical application.