Preparation of oxygen ion conducting doped LaGaO3 thin films on porous substrates by pulsed laser deposition

Recently, LaGaO₃ based perovskite material of La_1-xSr_xGa_1-y-zMg_yCo_zO_3-(x+y+z) (LSGMCO) has been considered as one of promising candidates for an electrolyte of solid oxide fuel cell (SOFC) due to its high oxygen ion conductivity. LSGMCO electrolyte films were deposited on porous anode of Ni and NiO+Ce_0.8Sm_0.2O_1.9 by pulsed laser deposition method. The LSGMCO film deposited at the substrate temperature of 800 °C and the oxygen pressure of 20 Pa (72000 laser pulses) had columnar crystallized structures with large boundaries. The LSGMCO film had the high oxygen ion conductivity of 0.7 S/cm at a measurement temperature of 800 °C. Open circuit voltage could be measured from our tube type SOFC unit cell utilizing the LSGMCO electrolyte film, however the value was smaller than theoretical one. We found that control of grain size by adjusting the oxygen pressure was needed for the lower temperature operating anode - support SOFC.