Reduced Thermal Expansion and Enhanced Redox Reversibility of La_0.5Sr_1.5Fe_1.5Mo_0.5O_6−δAnode Material for Solid Oxide Fuel Cells

Abstract

High performance anode materials with suitable thermal and chemical expansions are highly desirable for solid oxide fuel cells. In this work, we report a promising anode material La0.5Sr1.5Fe1.5Mo0.5O6‑δ (LSFM) synthesized in nitrogen at 1050 °C. Its phase stability, mechanical behavior, redox stability, and electrochemical performance were studied. The electrical conductivity of LSFM reaches 23 S cm–1 in 5% H2–95% N2 at 800 °C with excellent reversibility over three redox cycles. After lanthanum doping, the coefficient of thermal expansion (CTE) is reduced from 17.12 × 10–6 K–1 (SF1.5M) to 15.01 × 10–6 K–1 (LSFM), and this value can be lowered further with a higher lanthanum content. Dilatometry testing at 800 °C shows that the chemical expansion behavior of LSFM is highly reversible during the oxidation–reduction cycling. These results indicate that the thermal and chemical expansion of the crystal lattice can be reduced by a stronger metal–oxygen (M–O) bond strength, leading to an improvement in redox reversibility. The polarization resistance of the LSFM symmetrical cell at 800 °C in humidified hydrogen is 0.16 Ω cm2, and the active region is ∼4.5 μm. The half-tear-drop-shaped impedance spectroscopy indicates an oxygen bulk diffusion and surface reaction colimited process. The maximum power density of the LSFM single cell reaches 1156 mW cm–2 at 800 °C within humidified H2. The new ceramic material LSFM is a promising anode for high performance solid oxide fuel cells.

Low-temperature water electrolysis: fundamentals, progress, and new strategies

“…83 At temperatures beyond the boiling point of water, steam electrolysis is performed using some modified high-temperature PEM water electrolysers (100–200 °C), 84 or intermediate-temperature (400–600 °C) or high-temperature (700–900 °C) solid oxide electrolysis cells (SOEC). 85–89 Generally, these high-temperature water electrolysers are more efficient due to the decreased internal resistance losses and improved HER and OER kinetics. Detailed discussion on high-temperature water electrolysis is beyond the scope of this review.…”

Unlocking the Potential of A-Site Ca-Doped LaCo0.2Fe0.8O3−δ: A Redox-Stable Cathode Material Enabling High Current Density in Direct CO2 Electrolysis

“…Specifically, after obtaining the conductivity in air, the atmosphere was changed to CO 2 , and the conductivity was measured, which was defined as one cycle. Figure d indicates that the conductivity of LCCF64 is almost reversible between air and CO 2 , suggesting that LCCF64 exhibits good structural stability and compatibility with CO 2 …”

“…Figure 6d indicates that the conductivity of LCCF64 is almost reversible between air and CO 2 , suggesting that LCCF64 exhibits good structural stability and compatibility with CO 2 . 48 3.6. Polarization Resistance.…”

Positive Effects of H2O on the Hydrogen Oxidation Reaction on Sr2Fe1.5Mo0.5O6−δ-Based Perovskite Anodes for Solid Oxide Fuel Cells

“…The synthetic details can be found in our previous report. 30 For the synthesis of SF1.5M, the stoichiometric amounts of Sr(NO 3 ) 2 (Alfa Aesar), Fe(NO 3 ) 3 •9H 2 O (Alfa Aesar) and (NH 4 ) 6 Mo 7 O 24 •4H 2 O (Alfa Aesar) were dissolved in deionized water. When those metal nitrates were completely dissolved, the ethylenediaminetetraacetic acid (EDTA) (Alfa Aesar) and citric acid (Alfa Aesar) were dissolved in this solution sequentially.…”

“…Sr 2 Fe 1.5 Mo 0.5 O 6−δ (SF1.5M) and related perovskite materials were synthesized with the Pechini method. The synthetic details can be found in our previous report . For the synthesis of SF1.5M, the stoichiometric amounts of Sr­(NO 3 ) 2 (Alfa Aesar), Fe­(NO 3 ) 3 ·9H 2 O (Alfa Aesar) and (NH 4 ) 6 Mo 7 O 24 ·4H 2 O (Alfa Aesar) were dissolved in deionized water.…”