The effect of anode support on the electrochemical performance of microtubular solid oxide fuel cells fabricated by gel-casting

Different cell configurations of anode-supported microtubular solid oxide fuel cells (mT-SOFCs) using samaria-doped ceria (SDC) as the electrolyte were fabricated. Several cells were processed varying the porosity and wall thickness (outer diameter) of NiO-SDC tubular supports. Suitable aqueous slurry formulations of NiO-SDC for gel-casting were prepared using agarose, as a gelling agent, and sucrose, as a pore former. The subsequent NiO-SDC anode functional layer (AFL), the SDC electrolyte and the La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ-SDC cathode were deposited by spray-coating. Pre-sintering temperatures of the supports were optimized from linear shrinkage curves, thus obtaining after co-sintering, a dense electrolyte without anode-electrolyte delamination. Electrochemical characterization of mT-SOFC cells fabricated by agarose gel-casting is reported by the first time. The cell with a support of 2.6 mm diameter, 380 μm wall thickness, an active area of 1 cm² and added porosity, using 10 wt% sucrose, achieved a maximum power density of about 400 mW cm^-2 at 650°C.