This study presents a performance evaluation platform for sputtered thin-film electrodes used in biogas-driven, low-temperature solid oxide fuel cells (SOFCs). The design considerations include electrolyte material composition and thickness, anode material composition and thickness, anode fuel composition, and cathode composition and thickness, all derived from a review of existing literature. For the electrolyte, we propose a thickness of 100 μm for the main electrolyte made of gadolinium-doped ceria (GDC) and 0.1 μm for the auxiliary electrolyte made of scandia-stabilized zirconia. In terms of anode fabrication, we suggest a material composition of Ru/Ni-Cu-GDC, with thicknesses of 1 μm for Ni-Cu-GDC and a few nanometers for Ru in the nanoporous anode. For the anode fuel supply, we recommend mole ratios of 45% to 75% CH₄ and 25% to 55% CO₂ to assess the impact of biogas composition on power performance. Lastly, for the cathode, we propose a material composition of Pt-Ti-samarium-doped ceria with a thickness of 100 nm for the nanoporous structure.

In this study, we fabricated thin film solid oxide fuel cells on nanoporous anodic aluminum oxide (AAO) substrate for low-temperature operation using the all-through sputtering method. To deposit up to a three-micrometer thick anode with both porosity and electrical conductivity, we used the glancing angle deposition and co-sputtering methods. For the anode materials, we used nickel gadolinium-doped-ceria (Ni-GDC) mixed ionic and electronic conductor (MIEC), which improved hydrogen oxidation reaction reactivity at the anode side. TF-SOFCs were successfully operated at 500℃, and 223.6 mW/cm² was their highest measured maximum power density. We conducted structural and electrochemical analyses to figure out cells’ unique resistant characteristics; ohmic resistance through the anode thin film and polarization resistance of reaction area near the narrowed anode pores. We found how the anode thin film thickness affects the current collecting performance and the anode reactivity, and their effects were qualitatively and quantitatively compared.