Characterization of Thin-Film Lithium Batteries with Stable Thin-Film Li3PO4 Solid Electrolytes Fabricated by ArF Excimer Laser Deposition

High quality Li3PO4 thin films have been prepared by pulsed laser deposition (PLD) as a solid electrolyte for thin-film batteries. The structure, composition, ionic conductivity, and electrochemical stability of the Li3PO4 thin films have been characterized. The Li3PO4 film exhibits a single lithium-ion conductor with an ionic conductivity of 4.0x10(-7) S cm(-1) at 25 degrees C and an activation energy of 0.58 eV. The Li3PO4 film is electrochemically stable in the potential range from 0 to 4.7 V vs Li/Li+. All-solid-state thin-film batteries, Li/Li3PO4/LiCoO2, have been fabricated by using PLD-grown Li3PO4 thin film. The thin-film battery shows excellent intercalation property and stability for long-term cycling in the potential range from 3.0 to 4.4 V.