Sn and Y co-doped BaCo0.6Fe0.4O3- cathodes with enhanced oxygen reduction activity and CO2 tolerance for solid oxide fuel cells

Applying mixed oxygen ionic and electronic conducting (MIEC) oxides as the cathode offers a promising solution to enhance the performance of solid oxide fuel cells (SOFCs). However, the phase instability in CO 2 -containing air and sluggish oxygen reduction activity of MIEC cathodes remain a long-term challenge for optimizing the electrochemical performance of SOFCs. Herein, a heterovalent co-doping strategy is proposed to enhance the oxygen reduction activity and CO 2 tolerance of SOFCs cathodes, which can be demonstrated by developing a novel BaCo 0.6 Fe 0.4 O 3- δ (BCF)-based MIEC oxide, BaCo 0.6 Fe 0.2 Sn 0.1 Y 0.1 O 3- δ (BCFSY). In addition to improving the stability of BCF-based perovskites, this strategy achieves an optimized balance of ionic mobility and oxygen vacancies due to the synergies between the effects of the co-dopants. Compared with single-doped materials, BCFSY exhibits improved CO 2 tolerance and considerably higher ORR activity, which is reflected in a significantly lower polarization resistance of 0.15 Ω cm 2 at 600 °C. The results of this work provide an efficient tactic for designing electrode materials for SOFCs. BaCo 0.6 Fe 0.2 Sn 0.1 Y 0.1 O 3- δ (BCFSY), heterovalent co-doping by Sn and Y, enhance the CO 2 tolerance and ORR catalytic activity, achieving an optimized balance of ionic mobility and oxygen vacancies due to the synergistic effect.