Effects of Pr-deficiency on thermal expansion and electrochemical properties in Pr1−BaCo2O5+ cathodes for IT-SOFCs

Enhanced Electrochemical Properties of Non-stoichiometric Layered Perovskites, Sm1−xBaCo2O5+d, for IT-SOFC Cathodes

“…However, in the composition of SBCO_0.85 with an increased nonstoichiometric condition, the ASR value measured at 600 • C was 0.179 Ω • cm 2 , which is relatively higher than the ASR values of SBCO_0.95 and SBCO_0.90 measured at 600 • C. That is, from the non-stoichiometric compositions of Sm 1−x BaCo 2 O 5+d , the characteristics of the percolation composition showing the lowest ASR value in the chemical composition of Sm 0.90 BaCo 2 O 5+d can be found. This tendency can also be confirmed in the layered perovskite composition of LnBaCo 2 O 5+d in which Pr was substituted into the A / -site of the layered perovskite (Zhang et al, 2016;Idrees et al, 2019).…”

“…For example, according to the literature on ASR characteristics caused by non-stoichiometric composition of Pr 1−x BaCo 2 O 5+d (x = 0-0.1), PrBaCo 2 O 5+d (PBCO) and P 0.92 BaCo 2 O 5+d (PBCO_0.92) exhibit ASR values of about 0.097 and 0.081 Ω •cm 2 at 700 • C (Zhang et al, 2016). In the case of electrochemical properties related to the non-stoichiometric composition that reduce the amount of Pr in Pr 1−x BaCo 2 O 5+d oxide systems, when the degree of non-stoichiometry of the A / -site increased, the ASR tended to decrease; at the same time, the percolation composition was also exhibited.…”

“…As another example, the oxygen content of PrBaCo 2 O 5+d was 5.74 and the value of Pr 0.92 BaCo 2 O 5+d was reduced to 5.62 when the amount of Pr removed increased. In addition, Pr 0.92 BaCo 2 O 5+d was found to have excellent ASR values of 0.081 and 0.041 Ω•cm 2 at 700 and 750 • C (Zhang et al, 2016). Therefore, in the case of the non-stoichiometric composition of the layered perovskite, excellent electrochemical properties can be obtained when the lanthanide element is controlled.…”

“…Recently, to replace existing IT-SOFC cathode materials, many research groups have investigated new concept-based cathode materials with a chemical composition of layered perovskite, because this structure yields superior oxide ionic diffusivity, excellent oxygen surface exchange coefficients, high oxygen transport properties, and higher electronic conductivity (Kim et al, 2010;Joung et al, 2013;Zhang et al, 2016). In this new perovskite structure (A / A // B 2 O 5+d chemical composition), various lanthanide atoms such as La, Pr, Nd, and Sm can be substituted into the A / -site; Ba can be replaced in the A // -site; and transition metal ions of Co, Mn, and Fe can be located at the B-site.…”

Characterization of B‐Site Niobium‐Doped Pr0.4Sr0.6 (Co0.3Fe0.6)1‐xNbxO3‐δ (x=0, 0.05, 0.1, 0.2) Perovskites as Cathode Materials for Solid Oxide Fuel Cells

“…In recent years, numerous cobalt‐based perovskite materials such as Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3‐δ , SrCo 1‐y Nb y O 3‐δ , GdBa 0.5 Sr 0.5 Co 2 O 5+δ , PrBa 0.5 Sr 0.5 Co 2‐x Fe x O 5+δ and Pr 1‐x BaCo 2 O 5+δ were developed as cathode materials in IT‐SOFCs because of their high electro‐catalytic activity for the ORR, which attributes to high diffusion of oxygen ions and surface exchange kinetics. However, cobalt‐rich cathodes have some disadvantages including high thermal expansion coefficient (TEC), easy evaporation of cobalt element, and high cost.…”