Abstract:To address the challenge of insufficient oxygen vacancies in proton-conducting solid oxide fuel cells (H-SOFC), transition metal elements were doped into the B site of lanthanum ferrite perovskite (ABO₃) to enhance its catalytic activity further. The Mo-doped La_0.6Sr_0.4Fe_0.9-xNi_0.1Mo_xO_3-δ (LSFNM_x, x=0.05, 0.1) powder was synthesized via the sol-gel method, and its crystal structure, conductivity, defect chemistry, and electrochemical performance as an H-SOFC cathode were investigated. The prepared material exhibited a hexagonal structure with the R-3c space group and demonstrates good chemical stability under simulated working conditions. Mo doping increased the surface concentration of oxygen vacancies, leading to the accelerated oxygen transportation. Consequently, the polarization resistance (R_pol) and activation energy (E_a) are reduced. Specifically, LSFNM_0.05 showed the lowest polarization resistance (approximately 0.26 Ω·cm²) at 700 °C. LSFNM_0.05 achieved a maximum power density of 484 mW/cm² at this temperature, outperforming those of LSFN (353 mW/cm²) and LSFNM_0.1 (365 mW/cm²).

Key words: proton-conducting solid oxide fuel cells; proton transmission; air electrode; doping engineering; electrochemical properties; oxygen vacancy