Tuning of metal–electrolyte interface structure via electrolyte doping and its role on carbon deposition during internal CH4 reforming in solid oxide fuel cells

The internal reforming and carbon deposition of Ni/ScSZ, Ni/YSZ, and Ni/LaYSZ anodes for solid oxide fuel cells (SOFCs) and the effect of electrolyte doping on the metal–electrolyte interface structure were investigated in a CH 4 /H 2 O environment. Although the SOFC performance of Ni/LaYSZ was almost identical to that of Ni/YSZ, the La-doped anode showed superior carbon deposition tolerance to that of Ni/ScSZ and Ni/YSZ. Density functional theory calculations on C 2 H 2 formation were performed to examine the carbon deposition tolerance. Electrolyte doping allows controlling the work of adhesion between the Ni metal and the electrolyte ( X SZ, X = Y, Sc, La), which is in accord with C 2 H 2 stability on Ni/XSZ. Specifically, owing to its large size, the La dopant decreased the metal–electrolyte interface stability after C 2 H 2 formation on Ni/XSZ, leading to lower C 2 H 2 stability relative to Ni/YSZ and Ni/ScSZ. This low C 2 H 2 stability can explain the carbon deposition tolerance of Ni/LaYSZ. • Carbon deposition of Ni/ScSZ, Ni/YSZ, and Ni/LaYSZ anodes were studied in SOFC. • La-doped anode showed superior carbon deposition tolerance. • La dopant decreased the metal–electrolyte interface stability after C 2 H 2 formation. • The lower C 2 H 2 stability in Ni/LaYSZ accounts for carbon deposition tolerance.