An Intermediate Temperature Solid Oxide Fuel Cell Using a La(Sr)Ga(Mg)O₃ Thin Film Prepared by Pulsed Laser Deposition as Electrolyte

Abstract

A dense La_0.9Sr_0.1Ga_0.8Mg_0.2O_3–δ (LSGM, 5μm in thickness)/Ce_0.8Sm_0.2O_2–δ (SDC, 400 nm in thickness) bi-layer film was fabricated on a dense NiO (Fe₃O₄)-SDC anode substrate by a pulsed laser deposition method. After in-situ reduction, the substrate turned to be porous by the reduction of NiO and Fe₃O₄ to Ni and Fe, and the porosity reached to 13.6 vol%. Stoichiometric composition of LSGM film was successfully prepared by optimizing the deposition parameters and the target composition. When Sm_0.6Sr_0.4CoO_3–δ (SSC) was used as cathode material, extremely high power density was achieved at relatively low temperature. The maximum power density reached to 3270, 1951, 612 and 80 mW/cm² at 973, 873, 773 and 673 K, respectively. Detail analysis by current interruption method revealed that IR drop was still dominant internal resistance at low temperature and the overpotential of the anode and the cathode was not significant even at 673 K. Therefore, SOFC can be operated at temperature lower than 773 K by using LSGM thin film.