Effects of crystallinity and impurities on the electrical conductivity of Li-La-Zr-O thin films

摘要

We present a study of the fabrication of thin films from a Li_7La_3Zr_2O_(12) (LLZO) target using pulsed laser deposition. The effects of substrate temperatures and impurities on electrochemical properties of the films were investigated. The thin films of Li-La-Zr-O were deposited at room temperature and higher temperatures on a variety of substrates. Deposition above 600 ℃ resulted in a mixture of cubic and tetragonal phases of LLZO, as well as a La_2Zr_2O_7 impurity, and resulted in aluminum enrichment at the surface when Al-containing substrates were used. Films deposited at 600 ℃ exhibited the highest room temperature conductivity, 1.61 × 10~(-6) S/cm. The chemical stability toward metallic lithium was also studied using X-ray photoelectron spectroscopy, which showed that the oxidation state of zirconium remained at +4 following physical contact with heated lithium metal.