Preparation of perovskite-type La1-xSrxMnO3 films by vapor-phase processes and their electrochemical properties

Dense and thin La1-xSrxMnO3 film electrodes were prepared on yttria-stabilized zirconia (YSZ) electrolyte by vapor phase processes. In order to construct the electrochemical system, the YSZ film was first deposited by a chemical va deposition-electrochemical vapor deposition method on porous La0.85Sr0.15MnO3 substrate. Then the La1-xSrxMnO3 film was deposited on the YSZ film by using a vapor mixture of LaCl3, SrCl2 and MnCl2 as metal sources and humidified oxygen gas as an oxygen source. The as-prepared La1-xSrxMnO3 thin films were uniform and pinhole-free, and adhered strongly to the YSZ film. The electrochemical conductivity of the La1-xSrxMnO3 thin film was comparable to that of sintered La1-xSrxMnO3. The electrode interface resistance of the deposited La1-xSrxMnO3 film, which was determined by ac impedance measurements, was proportional to the La1-xSrxMnO3 film thickness, and the inverse of the electrode interface resistance was proportional to the electrode surface area of the La1-xSrxMnO3 thin film. In the La1-xSrxMnO3 thin-film electrode, it was concluded that oxygen is reduced to oxide ions at the electrode surface and they are transported through the electrode thin film to the electrolyte.