posted on 2021-06-18, 19:43authored byXin Mao, Zhiheng Li, Mengran Li, Xiaoyong Xu, Cheng Yan, Zhonghua Zhu, Aijun Du
Strontium
cobaltite-based perovskites (SrCoO3−δ) have
been widely studied as a promising cathode for the next-generation
solid-oxide fuel cell (SOFC). Here, we found a balance between oxygen
vacancy (VO) formation and its migration in designing SrCoO3−δ-based materials by using two activity descriptors,
i.e., radius and electronegativity. The ORR activity of these types
of perovskites is found to strongly rely on the two proposed descriptors,
and Nb- or Ta-doped SrCoO3−δ locates in the
promising zone as predicted with a moderate value of both VO formation energy and ion migration barrier. Then Sc–Ta co-doped
SrCoO3−δ (SSTC) and Sc–Nb co-doped
SrCoO3−δ (SSNC) are screened out to be the
best among 91 bimetal-doped SrCoO3−δ perovskites.
Further experiments have been carried out to synthesize the co-doped
SSTC and prove ultralow area-specific resistance values (0.071, 0.198,
and 0.701 Ω·cm2 at 550, 500, and 450 °C,
respectively), which is only one-third of that of benchmark materials
for the SOFC cathodes. Our results open a novel pathway in designing
SOFC cathodes with an optimal performance.