Sn and Y co-doped BaCo_(0.6)Fe_(0.4)O_(3)-δcathodes with enhanced oxygen reduction activity and CO_(2) tolerance for solid oxide fuel cells

Applying mixed oxygen ionic and electronic conducting(MIEC)oxides as the cathode offers a promis-ing 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 chal-lenge 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 opti-mized 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 consider-ably higher ORR activity,which is reflected in a significantly lower polarization resistance of 0.15Ωcm^(2) at 600℃.The results of this work provide an efficient tactic for designing electrode materials for SOFCs.