Sr(La)TiO3 Anode Substrate for Low Ni Diffusion in Sr- and Mg-Doped LaGaO3 Film Prepared with Co-Sintering Method for Intermediate Temperature Tubular Type Solid Oxide Fuel Cells

Abstract

Tubular type Solid Oxide Fuel Cells (SOFCs) using La0.9Sr0.1Ga0.8Mg0.2O3−δ film was prepared by dip coating and co-sintering method. Although it is known that LaGaO3 doped with Sr and Mg denoted as LSGM has reactivity with NiO in substrate and nickel diffusion into LSGM film was occurred during co-sintering. Nickel diffusion can be decreased by using Ce0.6La0.4O2-TiO2 (Ti-LDC) and Ce0.6Mn0.3Fe0.1O2 (CMF) buffer bilayer. In this study, LSGM/Ti-LDC/CMF film was prepared on NiO-Sr0.55La0.3TiO3 (SLT) substrate. Since nickel is reacted with Ti4+ in substrate, nickel diffusion was significantly suppressed by using SLT for anode substrate and the cell using LSGM film with suppressed amount of Ni diffusion shows reasonable high open circuit potential and power density. The single SOFC using NiO-SLT substrate shows the maximum power density of 0.412, 0.165 and 0.065 W/cm2 at 973, 873, and 773 K, respectively. Although anodic overpotential is almost the same with that of the cell prepared on NiO-Ce0.8Gd0.2O2 (GDC) substrate, anodic IR loss became much smaller on NiO-GDC at low temperature and this may be assigned to the high conductivity of GDC at low temperature. However, at high temperature, because of small overpotential, the cell using LSGM film on NiO-SLT anode substrate shows higher power density than that of NiO-GDC cell.