Sol-Gel Lithium Silicate Electrolyte Thin Films

Abstract

ABSTRACTFor more than a decade, the sol-gel process has been used to prepare lithium silicate gels that have potential applications as solid electrolytes in lithium batteries and electrochromic windows. The interest in these Li2O-SiC2 materials is their fast and stable ionic conductivity from room temperature up to 350°C. Typically these materials have been prepared with 15 mole % Li2O in bulk samples, but rarely in thin films. This work was undertaken to prepare chemically stable lithium silicate thin films with up to 30 mole % Li2O. Lithium nitrate was used as the lithium precursor. Solutions were evaluated for gelling time and homogeneity. Thin films were made by dip coating. After heat treatment at 200, 250 and 300°C, films were characterized for surface quality, thickness and microstructure using electron microscopy, x-ray diffraction analysis and profilometry. Transparency was investigated in the visible range (350–800 nm).