The interfacial resistances of La1-xSrxCo1-yFeyO3-δ (denoted LSCF(10(1-x)/10x/10(1-y)/10y)) cathodes, and the catalytic activities of a Ni-Ce0.85Y0.15O1.925 (Ni-YDC) anode and an LSCF(2/8/8/2) cathode of a single-chamber solid oxide fuel cells (SOFCs) were investigated. LSCF cathodes with high oxide ion conductivities gave low interfacial resistances. LSCF cathodes with suitable thermal expansion coefficients formed favorable interfacial structures with a ceria-based electrolyte. Ni-YDC showed a higher conversion efficiency for CH4 and a lower selectivity for CO2 than LSCF(2/8/8/2). The single-chamber SOFC based on the Sm-doped ceria electrolyte with the Ni-YDC anode and LSCF(2/8/8/2) cathode showed a maximum power density of 186 mW/cm2 at 800°C.