Improved overall properties in La1–x Ca x Fe0.8Cr0.2O3–δ as cathode for intermediate temperature solid oxide fuel cells

Property evaluation of Sm 1‐x Sr x Fe 0.7 Cr 0.3 O 3‐δ perovskites as cathodes for intermediate temperature solid oxide fuel cells

“…We have surveyed the electrical conducting, thermal expansion, and electrocatalytic properties of La 1‐x Ca x Fe 1‐y Cr y O 3‐δ (x = 0.5‐0.7, y = 0.1‐0.3, LCFCr) perovskites, in which the Sr 2+ at the A‐site of LSFCr was replaced with smaller Ca 2+ . It has turned out that LCFCr showed substantially reduced TECs while retaining good electrical conductivity and electrocatalytic activity . This preliminary result validates our expectation on the effect of A‐site size modulation, which in turn warrants further attempts towards rare‐earth replacement engineering.…”

“…It has turned out that LCFCr showed substantially reduced TECs while retaining good electrical conductivity and electrocatalytic activity. 23,24 This preliminary result validates our expectation on the effect of A-site size modulation, which in turn warrants further attempts towards rare-earth replacement engineering. Efforts in this direction may offer an alternative approach for modifying the overall properties of LSFCr perovskites.…”

“…These electrical conductivities are inferior to those (75 to 110 S·cm −1 ) of La 0.3 Sr 0.7 Fe 0.7 Cr 0.3 O 3‐δ in the same temperature range . Fortunately, the electrical conductivities of SmSFCr specimens (ie, several tens S·cm −1 in the range 600°C to 800°C) are still within the limits of acceptable level for cathode materials …”

“…This situation causes a dilemma for composition selection. Similar problem has been encountered for LSFCr and LCFCr perovskites . It has been proposed that a rational selection of cathode materials should be done based on a holistic appraisement of required properties, emphasizing a compromise between various properties .…”

“…The TECs of SmSFCr ceramic specimens were calculated in different temperature ranges. The results are summarized in [21][22][23] The TECs of SmSFCr specimens averaged within the (GDC, 12.5 × 10 −6 K −1 ), 20 with the TEC difference between these cathode and electrolyte materials satisfying the criterion (approximately less than 15%) required for achieving thermodynamically compatibility. 37 The TECs of SmSFCr specimens in low temperature range are associated with the intrinsic lattice expansion, while those in high temperature range are assigned to the co-contribution of the intrinsic and extrinsic lattice expansions.…”