Electrochemical Lithium Insertion in Sol-gel Deposited LiNbO₃ Films

Inorganic LiNbO₃ ion conducting films were prepared by sol-gel process involving two alkoxides, lithium ethoxide and niobium ethoxide. The films were analyzed by ellipsometry, X-ray diffractometry, scanning electron microscopy and impedance spectroscopy. Impedance spectroscopy indicated that the Li⁺ conductivity values were in the range of 6-8 x 10^-7 S cm^-1. The morphology and thickness of these films played an important role in the insertion of lithium ions. Spectrophotometric investigation showed that LiNbO₃ films exhibit very weak cathodic coloration from 350 to 900 nm spectral region. The previous termelectrochemical and opticalnext term properties clearly indicate that sol-gel deposited LiNbO₃ films can be used as lithium ion conducting layers for electrochromic device application.