Preparation of amorphous TiS _x thin film electrodes by the PLD method and their application to all-solid-state lithium secondary batteries

Titanium sulfide thin film electrodes were prepared by the pulsed laser deposition method using a KrF excimer laser. Thin films of various compositions were prepared under several deposition conditions such as Ar gas pressure, laser fluence, and target-substrate distance. The thickness of the titanium sulfide thin film prepared under Ar gas pressure of 0.01 Pa, the pulse energy of 200 mJ/pulse, and the distance of 5 cm between the target and the substrate was ca. 400 nm. The films prepared at room temperature showed no peaks in the XRD pattern and no periodic lattice fringe in high-resolution transmission electron microscopic images, suggesting that they were amorphous. An all-solid-state cell using a TiS_4.0 thin film electrode formed on a pelletized Li₂S–P₂S₅ glass–ceramic electrolyte showed the reversible capacity of 543 mAh g⁻¹, which was higher than that of a cell using a TiS_1.7 film. The former solid-state cell retained higher capacity for 20 cycles at room temperature.