Al3+ based solid electrolytes for electrochromic applications

Abstract

The solid-state electrolytes have attractive properties for electrochromic (EC) devices and battery industries. Li+ ion is the most applied and investigated carrier ion in this field together with less commonly ions Mg2+, Na+ H+ and Al3+. In this study, we have investigated Al3+ solid electrolytes for WO3 based EC devices as alternative to Li+ ions. We have fabricated a series of AlSiOx thin films by applying different target powers of 0-15 W by magnetron sputtering method. The resulting films were characterized by Grazing incidence X-ray diffraction, atomic force microscopy, scanning electron microscopy, energy disperse spectroscopy, ultraviolet-visible-infrared spectrophotometer, X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy (EIS). All samples showed high transparency in the visible range (similar to 90%) while the transparency decreased about 10% in the near infrared region. Analysis of EIS data by Kramers-Kronig and Voigt models showed that some of the films have good ionic conductivity. The ionic conductivities of films grown with 10 W, 13 W and 15 W Al target powers were 1.54x10(-6), 5.68x10(-7) and 2.72x10(-8) S/cm, respectively. The results indicate that AlSiOx solid electrolytes are promising for EC applications.