Polymer-free gel electrolyte and its application in TiO2-based electrochromic devices

Electrochromic devices based on polymer-free gel electrolytes (PFGEs) offer several advantages over polymer electrolytes. The preparation and characterization of a novel fumed silica-based PFGE and its applications in TiO2 electrochromic devices (ECD) were the main aims of the present study. First, a series of liquid electrolytes were prepared by mixing lithium chloride (LiCl) and ethylene Glycol (EG) with different molar ratios and their ionic conductivities were measured to get an idea about the highest ionic conductivity composition. The total oxygen atoms of EG to lithium ions of LiCl molar ratio (O:Li+) was altered from 5:1 to 80:1. The highest ionic conductivity was observed for 15: 1 molar ratio with the value being the 1.28 × 10− 2 S cm− 1. This optimized composition was selected for preparing PFGE. In order to prepare PFGE, 10 wt