Li---V---Si---O thin film electrolyte for all-solid-state Li-ion battery

Ultraviolet (355 nm) reactive pulsed laser deposition (PLD) using a mixture of Li2CO3, V2O5 and SiO2 as a target was employed to prepare Li---V---Si---O thin film electrolyte in O2 gas ambient for all-solid-state Li-ion battery. The morphology and structure of Li---V---Si---O thin films were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques, and the properties of thin films strongly depend on the substrate temperature. A dense and smooth Li---V---Si---O thin film without pinholes and cracks was obtained at substrate temperature of 300 °C. The ionic conductivity of this thin film electrolyte was determined by AC impedance measurement, and an ionic conductivity was estimated to be 3.98×10−7 S/cm at 25 °C with conductivity activation energy of 0.55 eV. In addition, the ionic transference number was measured by Wagner’s DC polarization technique and the cyclic voltammetric measurement was performed to investigate the electrochemical stability of the thin film electrolyte.