Yuanbo Lin

Co-Firing of Anode-Supported SOFCs with Thin La0.9Sr0.1Ga0.8Mg0.2O3 − δ Electrolytes

Anode-supported solid oxide fuel cells (SOFCs) with thin La 0.9 Sr 0.01 Ga 0.8 Mg 0.2 O 3-δ (LSGM) electrolytes and (Ce 0.6 La 0.4 )O 2-δ (LDC) barrier layers were studied. The cells were fabricated by first colloidally depositing an LDC/LSGM/LDC tri-layer on a NiO-LDC anode support and co-firing. Cathodes consisting of LSCF-LSGM (LSCF = La 0.6 Sr 0.4 Fe 0.8 Co 0.2 O 3-δ ) were then deposited and fired. Cell tests in air and humidified hydrogen showed maximum power densities of 0.91 W/cm 2 at 700°C and 0.60 W/cm 2 at 650°C. The relatively good performance indicated that the LDC layers were effective in minimizing interdiffusion and reaction. However, the open-circuit voltage of these cells was ∼0.1 V lower than the Nernst potential; observations of electrolyte microstructure and composition indicated that this was due to electronic conductivity in the LSGM layer, resulting from Ni impurities that entered during co-firing with the NiO-LDC anode. While the LDC layers were necessary, impedance measurements indicated that they substantially increased the cell ohmic resistance.