Fabrication of solid-state thin-film batteries using LiMnPO4 thin films deposited by pulsed laser deposition

Solid-state thin-film batteries using LiMnPO 4 thin films as positive electrodes were fabricated and the electrochemical properties were characterized. The LiMnPO 4 thin films were deposited on Pt coated glass substrates by pulsed laser deposition . In-plane X-ray diffraction revealed that the LiMnPO 4 thin films were well crystallized and may have a texture with a (020) orientation. The deposition conditions were optimized; the substrate temperature was 600 °C and the argon pressure was 100 Pa. The electrochemical measurements indicate that the LiMnPO 4 films show charge and discharge peaks at 4.3 V and 4.1 V, respectively. The electrical conductivity of the LiMnPO 4 film was measured by impedance spectroscopy to be 2 × 10 − 11 S cm − 1 at room temperature. The solid-state thin-film batteries that show excellent cycle stability were fabricated using the LiMnPO 4 thin film . Moreover, the chemical diffusion of the LiMnPO 4 thin film was studied by cyclic voltammetry . The chemical diffusion coefficient of the LiMnPO 4 thin film is estimated to be 3.0 × 10 − 17 cm 2 s − 1 , which is approximately four orders magnitude smaller than the LiFePO 4 thin films, and the capacity of the thin-film battery was gradually increased for 500 cycles.