Development of Electrochromic Devices Working with Hydrophobic Lithium Electrolyte

Abstract

This manuscript report on a new lithium electrolyte, allowing the manufacturing of electrochemical systems, such as electrochromic devices, in ambient atmosphere. It is based on lithiumbis-trifluoromethane sulfonimide dissolved in the following hydrophobic salt, which was first prepared by M. Grätzelet al.: 1-ethyl. 3-methyllimidazoliumbis-trifluoromethane sulfonimide. We have also successfully tested the compatibility of this electrolyte with WO3and TiO2-CeO2films acting respectively as efficient electrochromic electrode and counter electrode for smart-window working with Li+ions.

Grafting Mechanism of Electrochromic PAA–WO3Composite Film

“…depends on its microstructure (2), and that the porous and amorphous films can exhibit a better electrochromic property of fast and strong coloration (2). We have recently developed a new solution route to prepare uniform and hybrid tungsten oxide film by successive coatings of polyacrylic acid (PAA) and WO solutions (3)(4)(5)(6). From transmission electron microscopy, the resulting PAA-WO To whom correspondence should be addressed.…”

New Solution Route to Electrochromic Poly(acrylic acid)/WO3 Hybrid Film

“…For the working electrode, each film was processed to have an active area of 1.2 cm 2 , and the Pt wire and Ag/AgCl with Luggin capillary were used as counter and reference electrodes, respectively. The lithium electrolyte was prepared by mixing 10 wt % of Li(CF 3 SO 2 ) 2 N (LiTFSI) with the hydrophobic molten salt, 1,3-EtMeIm(CF 3 SO 2 ) 2 N (EtMeImTFSI), , in the N 2 -filled drybox. Cyclic voltammetry for PAA/WO 3 film was performed in the potential ( E ) range −0.8 to ca.…”