Planar type reversible solid oxide cells using LaGaO3 electrolyte thin-film prepared by dip-coating and co-sintering method

Planar type solid oxide reversible cells (SORCs) using 40 mu m thick La0.9Sr0.1Ga0.8Mg0.2O3-delta (LSGM) films on porous NiO-YSZ substrates were prepared via dip-coating and co-sintering. Ce0.6Mn0.3Fe0.1O2 (CMF) and TiO2Ce0.6La0.4O2 (Ti-LDC) served as buffer layers to prevent nickel diffusion, with Ba0.6La0.4CoO3 (BLC) as the air electrode. In SOFC mode, a typical cell exhibited maximum power densities of 0.584, 0.240, and 0.045 W/cm2 at 973, 873, and 773 K. In SOEC mode, the cell achieved the current densities of 2.21, 1.12, and 0.276 A/cm2 at 1.6 V on each temperature. Adding a porous LSGM functional layer increased performance, resulting in higher power densities of 0.873, 0.317, and 0.061 W/cm2 in SOFC mode and slightly higher current densities of 2.47, 1.30, and 0.311 A/cm2 at 1.6V in SOEC mode. This improvement is attributed to the reduced mass transport overpotential. Long-term stability tests at 973 K on cell with porous LSGM layer for 100 h showed degradation rates of 3.1 %/100 h (0.8 V, 0.75 A/cm2) and 5 %/100 h (1.2 V, 1 A/cm2), respectively. Post-characterization revealed no further Ni diffusion during operation; diffusion occurred mainly during co-sintering, which could be mitigated by shorter, higher-temperature sintering.