Computational Design and Experimental Validation of the Optimal Bimetal-Doped SrCoO_3−δ Perovskite as Solid Oxide Fuel Cell Cathode

Abstract

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.

An Efficient Steam‐Induced Heterostructured Air Electrode for Protonic Ceramic Electrochemical Cells

“…It has been reported that Nb-doped in B-site can enhance the stability of perovskite structure. [27,30,[59][60][61] The mapping results are also consistent with the aforementioned difference in the interplanar spacing between NPs and the backbone phase. The less amount of Nb cations (with enlarged ionic radius, e.g., r(Nb 5+ ) ≈64 pm > r(Co 3+ ) ≈54.5 pm) in the nanoparticles lead to the shrinkage of the unit cell and therefore demonstrate a smaller spacing when compared to Nb-rich PBCFN backbone.…”

“…To further enhance the stability of Co‐based perovskite, high‐valence cations, such as Nb and/or Ta, have been proposed to be incorporated in B‐site. [ 26,27 ] For example, SrSc 0.175 Nb 0.025 Co 0.8 O 3− δ and SrCo 0.8 Nb 0.1 Ta 0.1 O 3− δ air electrodes with excellent cells performance at relatively low temperatures has been reported. [ 28,29 ] Saccoccio et al.…”

“…To further enhance the stability of Co-based perovskite, high-valence cations, such as Nb and/or Ta, have been proposed to be incorporated in B-site. [26,27] For example, SrSc 0.175 Nb 0.025 Co 0.8 O 3−δ and SrCo 0.8 Nb 0.1 Ta 0.1 O 3−δ air electrodes with excellent cells performance at relatively low temperatures has been reported. [28,29] Saccoccio et al investigated the impact of Nb substitution in PrBaCo 2 O 5+δ (PBC) for SOFCs and concluded that the Nb-doped PBC demonstrated decent chemical compatibility with typical electrolyte material and good electrochemical performance.…”

Formation, Detection, and Function of Oxygen Vacancy in Metal Oxides for Solar Energy Conversion

“…The drifting of V O is an important pathway for oxygen ionic conductivity in the application of solid oxide fuel cells (SOFC). [8,96] Due to the presence of V O in MO-based compounds such as SrCoO 3 , [97] yttrium stabilized zirconia (YSZ), [98] the oxygen ions can hop forward to occupy the V O . The oxygen ionic drifting rate, determined largely by the V O , can influence the performance of SOFC.…”

Structural Engineering of Cobalt‐Free Perovskite Enables Efficient and Durable Oxygen Reduction in Solid Oxide Fuel Cells

“…Both ORR activity and durability are in close connection with a favorable crystal structure. [26,27] Among various structures, the cubic-phase perovskite is widely acknowledged as an ideal candidate for 3D oxygen ion diffusion. [28,29] Figure 1a showcases the Rietveld refinement results on the X-ray diffraction (XRD) pattern of BSFP sample with the corresponding crystallographic details listed in Table S1, Supporting Information.…”