Electrochromic window with lithium conductive polymer electrolyte

Abstract

An electrochromic window was built using WO3 as the electrochromic material and V2O5 as the counterelectrode. Both were deposited onto ITO coated glass panes by vacuum evaporation and were amorphous to X-ray diffraction. The electrolyte was a lithium conducting polymer constituted by a Poly (ethylene oxide) - lithium salt complex. The electrochemical characterization of electrodes was realized by cyclic voltammetry, coulometric titration, and impedance spectroscopy, which allowed the determination of the chemical diffusion coefficients of lithium into WO3 and V2O5. Potentiostatic cycling of the complete transmissive cell yields a transmission variation from 41 to 13% at 633 nm with a response time of 10 seconds at room temperature.