A new composite cathode for intermediate temperature solid oxide fuel cells with zirconia-based electrolytes

Abstract

Improving the electrocatalytic activity of electrode materials is vitally important to achieve practically meaningful performance for intermediate temperature solid oxide fuel cells (IT-SOFCs). The present work develops a composite cathode consisting of an electronic conductor Sr-doped LaMnO 3 (LSM) and an ionic conductor Y-and Ce-co-doped Bi 2 O 3 (BYC7). BYC7 is an excellent oxide-ion conductor, exhibiting a high and stable ionic conductivity of 0.008 S cm-1 at 500 o C. The polarization resistance of LSM-BYC7 cathode in a symmetrical cell with doped ZrO 2 as electrolyte varies from 5.76 at 500 o C to 0.25 Ω cm 2 at 650 o C. The surface diffusion and charge transfer at the triple phase boundaries are the rate determining steps based on the dependence of polarization resistance on partial pressure of oxygen. The maximum power density of a ZrO 2-based anode-supported cell with LSM-BYC7 composite cathode is 56.4, 154.6, 327.9, and 451.0 mW cm-2 at 500, 550, 600, and 650 o C respectively. AC impedance analysis reveals that the performance of IT-SOFC prepared in this study is actually limited by the anode, not by LSM-BYC7 cathode.

Nanointegrated, High-Performing Cobalt-Free Bismuth-Based Composite Cathode for Low-Temperature Solid Oxide Fuel Cells

“…The compositions and electrolytes for each bismuth-based SOFC are listed in the caption. Our current work using LSM-i-ESB/GDC with an electrolyte thickness of 24 μm shows the highest performance among cobalt-free SOFCs that has yet been reported. − Compared to other bismuth-based SOFCs, as listed with average PPD values of 0.2 and 0.3 W/cm 2 , − our current work shows 3–4 times higher performance, clearly demonstrating the high activity of nanointegrated LSM–ESB composite.…”

“…Here, we demonstrate the high-performance cobalt-free LT-SOFC with high stability reaches a peak power density (PPD) of 1.2 W/cm 2 at 600 °C, doubled the highest performance of reported bismuth-based SOFCs at low temperatures, − through the nanostructured composite design enabled by lowering the heat treatment temperature of infiltrates. In this study, a precursor solution of La 0.85 Sr 0.15 MnO 3±δ (LSM), an electrocatalyst with high stability and activity, ,− was coated on the backbone of a pure ionic conductor (Bi 0.8 Er 0.2 ) 2 O 3 (ESB), the oxide that has the high ionic conductivity among solid electrolytes.…”

Enhanced oxygen reduction kinetics of IT-SOFC cathode with PrBaCo2O5+δ/Gd0.1Ce1.9O2−δ coherent interface

“…The relationship between the polarization resistance and oxygen partial pressure can be described as R p = k ( p O 2 ) − m , where parameter m is used for differentiating the sub-reaction. 46–49 The entire oxygen reduction reaction can be summarized as the following eqn (1),but it is actually complicated and made up of a battery of sub-steps. Fig.…”

Nano-CeO2-Modified Cathodes for Direct Electrochemical CO2 Reduction in Solid Oxide Electrolysis Cells

“…Electrochemical impedance spectroscopy (EIS) at open circuit voltage (OCV) and 1.4 V for the cells is shown in Figure a,b, respectively. From Figure a, all of the cells have a similar ohmic resistance (the first intersection of the X axis (Z′′ = 0)), which consists of the ohmic resistance of the electrolyte, electrodes, leads, and the interfacial contact resistance (mainly resulting from the O 2– transportation between electrode and electrolyte). − At OCV, the decrease in R p (the distance between the second intersection and the first intersection of the X axis) after the impregnation of CeO 2 nanoparticles reflects the fact that the impregnated cathode has a stronger ability to adsorb CO 2 , as shown by the results of CO 2 -TPD. In Figure b, the total resistance values (the second intersection of the X axis, R tot ) of the cells after the impregnation of CeO 2 nanoparticles are smaller than for the conventional cathode.…”