A self-bleaching electrochromic mirror based on metal organic frameworks

Abstract

Metal-organic frameworks (MOFs) are considered to be the most promising positive anode materials to store charge for electrochromic devices. Nevertheless, a detailed mechanism of the electrochemical and ions storage process has not yet been revealed. Herein, the electrochemical mechanism of the highly porous ZIF-67 films and the electrochromic performance of electrochromic mirrors constructed from ZIF-67 and WO3 electrodes were investigated. The mechanism of the charge storage was revealed in the kinetic analysis of the Li-ion behavior based on the cyclic voltammetry curves and electrochemical impedance spectra. Impressively, the electrochromic mirrors with the self-bleaching effect and self-discharge behavior showed a unique electrochromic performance, such as a high coloration efficiency of 16.47 cm2 C−1 and a maximum reflectance modulation of 30.10% at 650 nm. This work provides a fundamental understanding of MOFs for applications in electrochromic devices and can also promote the exploration of novel electrode materials for high-performance reflective electrochromic devices.