La_0.8Sr_0.2FeO_3−δ as Fuel Electrode for Solid Oxide Reversible Cells Using LaGaO₃-Based Oxide Electrolyte

Abstract

Activity of La 0.8 Sr 0.2 FeO 3 (LSF) to the fuel electrode reaction in solid oxide reversible cells (SORCs) was investigated by using La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3 (LSGM) and Ba 0.6 La 0.4 CoO 3 (BLC) as electrolyte and air electrode, respectively. In electrolysis mode (SOEC), the LSF electrode exhibited small overpotential under the atmosphere without H 2 cofeeding; the current densities reached −1.42, −0.92, and −0.36 A/cm 2 at 1.4 V at 900, 800, and 700 °C, respectively, and the H 2 formation rate is well agreed with that estimated by Faraday's law. On the other hand, in the SOEC−SOFC reversible mode with the gas composition of 20% steam/20%H 2 /60% Ar, the maximum power densities of 0.42, 0.28, and 0.11 W/cm 2 were achieved at 900, 800, and 700 °C, respectively. In addition, the cyclic reversible operation was also investigated at 800 °C, and it was found that the cell showed high stability over 30 cycles. DC polarization measurement suggests that the exchange current density of LSF is 14 mA/cm 2 at 700 °C, which is almost the same as that of Ni-YSZ reported. X-ray diffraction (XRD) measurement and scanning electron microscopy (SEM) observation after the reversible measurement suggest that LSF is highly stable under SOEC−SOFC cyclic operation conditions. Therefore, LSF is promising as the fuel electrode for SORCs, although the conductivity is not sufficiently high as an electrode.

Interface‐Engineered Intermediate Temperature Solid Oxide Electrolysis Cell

“…Figure 2a shows the polarization curves. The cell co-fired at 1350 C indicates the best electrolysis performance followed by the cells co-fired at 1400, 1300, and 1450 C. The current density reached as high as 0.86 A cm À2 at 1.3 V. As summarized in Figure 2d and Table S1, Supporting Information, our cell shows better performance than recently reported SOECs operated at 700 C. [16][17][18][19][20][21] All the cells can switch between SOEC and SOFC modes. The open-circuit voltages (OCVs) of all the cells were around 0.85 V at 700 C, which are higher than traditional SDC cell with Ni-SDC as hydrogen electrode (0.75 V at 700 C [22] ).…”

A Highly Efficient and Robust Perovskite Anode with Iron–Palladium Co‐exsolutions for Intermediate‐Temperature Solid‐Oxide Fuel Cells

“…The X‐ray diffraction (XRD) patterns of the as‐synthesized LSFN and LSFNP powders are shown in Figure . Before reduction, both LSFN and LSFNP exhibit a single‐phase orthorhombic perovskite structure with the Pbnm space group; this is consistent with previously reported La 0.8 Sr 0.2 FeO 3− δ (LSF) and LSFN . The positions of the main peaks of as‐prepared LSFN and LSFNP are identical and can be found at 2 θ =32.18°.…”

Co-electrolysis of CO2 and H2O in high-temperature solid oxide electrolysis cells: Recent advance in cathodes

“…Wang and Ishihara fabricated a (La,Sr)FeO 3 based SOEC with a configuration of La 0.6 Sr 0.4 FeO 3 −δ |LSGM|Ba 0.6 La 0.4 CoO 3 −δ (BLC) for CO 2 electrolysis, which delivered a current density of 240 mA/cm 2 at 800 °C with feed gas of 50% CO 2 + 1% CO + 49% Ar [74] . Subsequently, they prepared another SOEC with the similar configuration of La 0.8 Sr 0.2 FeO 3 −δ (L SF)|L SGM|BLC and compared its performance for H 2 O splitting with the Ni-cermet based SOEC (configuration of Ni-SDC|LSGM|BLC) [73] . The results are displayed in Fig.…”

“…(a) I -V curves of L SF|L SGM|BLC and Ni-SDC|L SGM|BLC cell for H 2 O electrolysis at different tem peratures with 20% H 2 O + 80% Ar and 20% H 2 O + 1% H 2 + 79% Ar as feed gas for LSF cathode and Ni-SDC cathode respectively; (b) Cyclic reversible operation of the cell using LSF fuel electrode at 800 °C. The cell voltages which were recorded at −0.82 and 0.51 A/cm 2 constant current applied were plotted as a function of cyclic numbers[73] . Reproduced from ref [73].…”

“…The cell voltages which were recorded at −0.82 and 0.51 A/cm 2 constant current applied were plotted as a function of cyclic numbers[73] . Reproduced from ref [73]. with permission from ACS publications, copyright 2016.…”