La and Ca-doped A-site deficient strontium titanates anode for electrolyte supported direct methane solid oxide fuel cell

Nickel-yttria stabilized zirconia (Ni-YSZ) cermet anodes for solid oxide fuel cells (SOFC) possesses excellent catalytic properties and stability for H₂ oxidation but not for hydrocarbons as it results in fast carbon deposition in absence of excess steam. In the present work, A-site deficient porous LSCT_A- (La_0.2Sr_0.25Ca_0.45TiO₃) anode has been fabricated using the environment friendly, aqueous tape casting method followed by the same procedure for the dense YSZ electrolyte and YSZ porous scaffold as cathode matrix. The anode, electrolyte, and porous cathode matrix have been laminated together and sintered up to 1350°C. After sintering, nitrate precursors of La, Sr, Co and Fe are infiltrated inside the porous YSZ cathode matrix to form the perovskite phases of La_0.8Sr_0.2CoO₃ (LSC) and La_0.8Sr_0.2FeO₃ (LSF). The as fabricated electrolyte supported SOFCs have been tested in H₂ and CH₄ fuel at 800°C. The electrolyte supported cell 15%LSF-5% LSC-YSZ/YSZ/4%Ni-6%CeO₂-LSCT_A- gives maximum power density of 328 mW cm⁻² for 3 h in H₂, but in CH₄ the performance decreased to 165 mW cm⁻² even though a sustained open circuit voltage of ∼1 V obtained during H₂ and CH₄ operation. The morphology of the anode before and after cell testing has been analyzed using scanning electron microscope followed by X-ray diffraction studies to understand phase changes during fabrication and testing.