Characterization of thin-film electrolytes for all solid-state batteries

•We synthesized lithium thio-germanate thin-films.•The thin-films were characterized by XRD, Raman, SEM, XPS, and Impedance spectroscopy.•Ionic conductivities of the thin-films were higher than those of oxide thin-films.

In this study, amorphous lithium thio-germanate thin-films were prepared as electrolytes for solid-state lithium rechargeable batteries by using RF sputtering deposition in an Ar atmospheres. High quality lithium germanium sulfide, nLi2S + GeS2(n = 1, 2, and 3) thin-films have been successfully made by RF sputtering and synthesized as solid-state electrolytes. Although these materials are unstable in air the thin-films were thoroughly characterized by X-ray diffraction (XRD), Scanning electron spectroscopy (SEM), Raman spectroscopy, Infrared spectroscopy (IR), and impedance spectroscopy using special setups to prevent contamination. The ionic conductivities of the thin-films are ∼3 order magnitude higher than reported values for oxide thin-films. In this way, this work may provide a new way for developing new thin-film electrolytes for solid-state lithium ion batteries.