A multi-chromic supercapacitor of high coloration efficiency integrating a MOF derived V2O5 electrode

Abstract

Modern technological trend in smart electronic devices demand more intelligent automation. Simultaneous integration of energy storage and multicolor electrochromism in a single device improve the user-device interfacing based on a salient human-readable output. In this work, primarily a metal organic framework (MOF) derived V2O5 was synthesized which as an electrochromic material, shows high optical modulation of 35% at 485 nm, with very fast switching speeds (2.9/3.4 sec for coloring/bleaching). The multiple coloration states of V2O5 electrode make it worthy for further integration as a smart negative electrode in a multicolored electrochromic asymmetric supercapacitor, where electrochromic polyaniline electrode served as the counter electrode. The device demonstrates a high coloration efficiency of 137.2 cm2/C and an areal capacitance of 12.27 mF/cm2 and an energy density of 2.21x10-3 mWh/cm2 at 0.05 mA/cm2 current density. By virtue of its different chromatic states during charging and discharging, smart visual tracking of the state of charge of the supercapacitor can be realized. Such a design of the energy storage devices will have promising practical application towards futuristic smart multifunctional electronic devices