Crystalline phases and oxygen permeation properties of mixed conductive (La, Ca)FeO3-

Oxide Ion Conduction and Surface Exchange Reactions of Mixed Conductive La0.65Ca0.35FeO3−δ Based on Oxygen Permeation Study

“…5 The t el for LCF6535 is close to unity because the total conductivity of the LCF exceeds 100 S cm −1 over the 800−1000 °C range investigated in the previous study. 17 The ion conductivities (σ i ) of the LCF6535 ranged from 0.035 to 0.29 S cm −1 in the 800−1000 °C range, as presented in Figure 5. In this case, t el i σ approximates σ i , and consequently, the L c is the only uncertain value in eq 10.…”

“…15−17 Particularly, we proposed that La 1−x Ca x FeO 3−δ (LCF) is a good mixed conductive oxide candidate and also reported that the oxygen permeation flux (J O 2 ) of LCF in the x = 0.3−0.4 range is much higher than that of others in the LCF series. 17 Notably, the J O 2 of the sample with x = 0.35 at 1000 °C is approximately twice higher than that of LSCF. Therefore, La 0.65 Ca 0.35 FeO 3−δ (LCF6535) possesses strong potential as an alternative to LSCF for use in next-generation SOFC cathodes and oxygen separation membranes.…”

“…The obtained sample of La 0.65 Ca 0.35 FeO 3−δ was confirmed to be a single phase with an orthorhombic perovskite (Pnma) structure, as described in the literature. 17 The sintered pellet samples were polished with a waterproof abrasive lapping film (3000 mesh size). Pellet samples with a thickness of 0.6 and 1.2 mm were prepared to investigate the effect of thickness on the oxygen permeation and surface exchange reaction.…”

Oxygen permeation simulation of La0.8Ca0.2Fe0.95O3−δ‐Ag hollow fiber membrane at different modes and flow configurations

“…Their high fluxes are nonetheless traded‐off by the low structure stability and permeation flux durability between 750°C and 900°C given their high Sr and Co content 4 . The current drive to develop more robust membranes having both high oxygen permeability and high structure stability has led to the development of Sr and Co‐free membranes 5 . La 1− x Ca x FeO 3−δ (LCF, 0.2 ≤ x ≤ 1.0) represents such a membrane that displayed high structure stability in reducing atmosphere especially at lower Ca content ( x ≤ 0.4) while exhibiting comparable oxygen permeation fluxes to that of LSCF 5,6 .…”

“…The current drive to develop more robust membranes having both high oxygen permeability and high structure stability has led to the development of Sr and Co‐free membranes 5 . La 1− x Ca x FeO 3−δ (LCF, 0.2 ≤ x ≤ 1.0) represents such a membrane that displayed high structure stability in reducing atmosphere especially at lower Ca content ( x ≤ 0.4) while exhibiting comparable oxygen permeation fluxes to that of LSCF 5,6 . Further modification on LCF membranes such as incorporating silver (Ag) during the powder preparation stage was recently demonstrated to improve the oxygen permeation fluxes; in particular, the La 0.8 Ca 0.2 Fe 0.95 O 3−δ ‐Ag (LCF‐Ag) hollow fiber displayed up to 2.24‐fold higher oxygen permeation flux at 950°C relative to that of LCF hollow fiber membrane under an air feed flow rate of 100 ml/min and a He sweep gas flow rate of 180 ml/min 7 .…”