Systematic evaluation of cobalt-free Ln0.5Sr0·5Fe0·8Cu0·2O3−δ (Ln = La, Pr, and Nd) as cathode materials for intermediate-temperature solid oxide fuel cells

Structures and Properties of LaFe0.8Cu0.2O3−δ and BaFe0.8Cu0.2O3−δ as Cobalt‐Free Perovskite‐Type Cathode Materials for the Oxygen Reduction Reaction

“…In contrast, LFCuO showed an almost linear expansion curve similar to other Fe–Cu‐based perovskite oxides, giving rise to a much smaller TEC value of 12.0×10 −6 °C −1 at 25–900 °C. This TEC value is remarkably small compared to the TECs (>20×10 −6 °C −1 ) of cobalt‐based perovskite oxides; and it is even smaller than the TEC results of Fe–Cu‐based perovskite oxides such as La 0.5 Sr 0.5 Fe 0.8 Cu 0.2 O 3− δ (17.7×10 −6 °C −1 at 25–900 °C), Nd 0.5 Sr 0.5 Fe 0.8 Cu 0.2 O 3− δ (14.7×10 −6 °C −1 at 25–800 °C), and Ln 0.5 Sr 0.5 Fe 0.8 Cu 0.2 O 3− δ (Ln=La, Pr and Nd, TEC≈16×10 −6 °C −1 at 30–850 °C) . Most significantly, this TEC value matches perfectly with the TECs of electrolytes Ce 0.8 Sm 0.2 O 1.9 (SDC) and Ce 0.8 Gd 0.2 O 1.9 (GDC).…”

“…This weight loss was attributed to thermal‐driven release of the lattice oxygen; therefore, a gradual decrease in oxygen content and increase in oxygen deficiency with higher temperatures followed (Figures b and c) and the oxygen deficiency in LFCuO is 0.087 at 800 °C. In the case of BFCuO, however, a different TG curve was obtained (Figure a): a slight weight gain (0.15 wt %) first occurred in the low‐temperature range of 340–460 °C, which could be ascribed to an oxygen‐adsorption process as found in other perovskite oxides . This process happened in BFCuO, but not in LFCuO, possibly because the as‐synthesized BFCuO had a very large oxygen deficiency.…”

“…The obtained ASR results were inserted in Figure a and are shown in the Arrhenius plot in Figure b. According to the slope of the Arrhenius plot, the reaction activation energy ( E a ) of the LFCuO cathode was calculated to be 1.65 eV, which is similar to E a values of other Fe–Cu‐based perovskite cathodes . The ASR values of the LFCuO cathode are 0.09 Ω cm 2 at 800 °C, 0.20 Ω cm 2 at 750 °C, 0.55 Ω cm 2 at 700 °C, and 1.6 Ω cm 2 at 650 °C.…”

“…BaFe 0.8 Cu 0.2 O 3− δ (BFCuO) and LaFe 0.8 Cu 0.2 O 3− δ (LFCuO) powders were synthesized with an ethylene diamine tetraacetic acid (EDTA) complex sol‐gel method, as described in our previous work . All the reagents used are of analytical reagent (AR) degree.…”

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

“…Extensive efforts have been done to explore cobalt‐free cathode materials with improved overall properties . Recently, La 0.3 Sr 0.7 Fe 1‐y Cr y O 3‐δ (y = 0.1‐0.3, LSFCr) perovskites have emerged as promising candidate materials for IT‐SOFC cathode due to a variety of attractive properties .…”