A promising Nb-doped La0.5Sr0.5Co0.8Cu0.2O3–δ cathode materials for intermediate temperature solid oxide fuel cells

Cobalt-based perovskites are widely used as cathode materials for intermediate temperature solid oxide fuel cells (IT-SOFCs) due to their excellent catalytic activities. In this paper, a series of Nb-doped La 0.5 Sr 0.5 Co 0.8 Cu 0.2- x Nb x O 3–δ (LSCCu 0.2- x Nb x O 3-δ , x  = 0.00 ≤  x  ≤ 0.075) cathode materials with excellent electrochemical performance are prepared by a Pechini method, and the critical Nb-doping effect is studied in detail. In the new cathode material, the surface oxygen content increases with the Nb doping, while the segregation of Sr and the coefficient of thermal expansion (TEC) is reduced. The optimum LSCCu 0.15 Nb 0.05 O 3-δ shows the highest surface oxygen content, the lowest surface Sr content, and the highest oxygen reduced reaction (ORR) catalytic activity. At 700 °C, the polarization resistance (Rp) is 0.065 Ω cm 2 , and the peak power density (PPD) of single cells supported by the electrolyte is 518 mW cm −2 , which are promising for the IT-SOFCs. Therefore, the LSCCu 0.15 Nb 0.05 O 3-δ should be a promising cathode material for the high-performance IT-SOFCs.