Thermal cycling durability improved by doping fluorine to PrBaCo2O5+δ as oxygen reduction reaction electrocatalyst in intermediate-temperature solid oxide fuel cells

La-doped Ba0.5Sr0.5Co0.8Fe0.2O3- d as Cathode for Protonic-Conducting Solid Oxide Fuel Cells with Enhanced Structure Stability

“…As we previously reported, the oxygen chemical bulk diffusion coefficient, Dchem, and chemical oxygen surface exchange coefficient, kchem, of BSCF at 700  C are 2*10 -5 cm 2 S -1 and 4*10 -4 cm S -1 , respectively (12). Both the bulk diffusion coefficient and the surface exchange coefficient of BSCF are about one order of magnitude higher than those of classic electrocatalyst La0.6Sr0.4Co0.8Fe0.2O3- (LSCF) at the same temperature: 6.4*10 -6 cm 2 S -1 for kchem and 1.3*10 -5 cm S -1 for Dchem, respectively (13), and are comparable with those of PrBaCo2O5+ which is the state-of-the-art electrocatalyst for PCFCs cathodes (1*10 -5 cm -2 S -1 for Dchem and 1*10 -4 cm S -1 for kchem, respectively) (2,14). Therefore, BSCF is an excellent ORR electrocatalyst.…”

“…Figure 3b is the result of CO2-TPD. Due to the decrease in barium concentration, La0.1BSCF presents lower alkalinity, and thus a reduced CO2 desorption at lower temperature (14,27).…”

“…Large thermal mismatch between the electrode and electrolyte will cause serious performance degradation. Especially, cobalt-based perovskites often suffer from high thermal expansion coefficient (TEC) due to change of cobalt electronic structure and formation of oxygen vacancies (14). Before preparing single cells, dilatometry experiments with strip samples were conducted to evaluate the thermal expansion behavior of BSCF and La0.1BSCF (Figure 5a).…”

Enhanced oxygen reduction kinetics of IT-SOFC cathode with PrBaCo2O5+δ/Gd0.1Ce1.9O2−δ coherent interface

“…In addition, cobalt-containing A-site cation-ordered perovskites usually have higher thermal expansion coefficients (TECs), for example, 24.0 × 10 −6 K −1 for PBC 16 and 23.1 × 10 −6 K −1 for NdBaCo 2 O 5+ δ , 17 which are not compatible with conventional electrolytes, e.g. , gadolinium-doped ceria (GDC, 12.5 × 10 −6 K −1 ) and strontium and magnesium-doped lanthanum gallate (LSGM, 10.5 × 10 −6 K −1 ).…”

A Durable Ruddlesden‐Popper Cathode for Protonic Ceramic Fuel Cells

“…The average linear expansion coefficient C TE can be also calculated from the volumetric thermal expansion coefficient ( C TE, V ) from the relation ( C TE, V =3 C TE ), and the results are exhibited in Figure b. For 3‐SEFC 0.0 , C TE is 14.83×10 −6 K −1 , which is much lower than some typical perovskites and double‐perovskites (e. g., 20.62×10 −6 K −1 for La 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3− δ , 23.19×10 −6 K −1 for Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3− δ , and 26.52×10 −6 K −1 for PrBaCo 2 O 5+ δ ) . However, C TE increases with Co increasing content and reaches 17.07×10 −6 K −1 for 3‐SEFC 1.5 , larger than that for BaZr 0.1 Ce 0.7 Y 0.2 O 3− δ (10.2×10 −6 K −1 ) …”