Study of a Novel Electrochromic Device with Crystalline WO3 and Gel Electrolyte

Abstract

Most ECDs are coated with an electrochromic material on the transparent conductive oxide (TCO) substrate. A novel electrochromic device (ECD), having a variable optical performance, was prepared by using tungsten foil as a substrate in this study. It was found that the WO3 discoloration layer, having a monoclinic phase crystalline structure made of 600◦ C calcined, had optimum charge transmission performance with PADA gel polymer electrolyte. Ionic conductivity of PADA gel polymer electrolyte was 2.3 × 10−3 S cm−1 at −20◦ C, and it was possible to help Li+ to implement embedding and extraction from WO3 even in low-temperature conditions. The colored time (tc ) and the bleached time (tb ) of the electrochromic device were 15 s and 26 s, and it showed yellowish-brown in the colored state and navy blue in the bleached state. The ECD (WO3-600) exhibited good cycle stability reach at least 150 times.