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| Home > Publications database > Fabrication and electrochemical performance of an air electrode BaCo0.4Fe0.4Zr0.2O3- δ composite in proton-conducting electrolysis cells |
| Home > Publications database > Fabrication and electrochemical performance of an air electrode BaCo0.4Fe0.4Zr0.2O3- δ composite in proton-conducting electrolysis cells |
| Conference Presentation (After Call) | FZJ-2022-05571 |
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2022
Abstract: Proton conducting fuel and electrolysis cells (PCF/ECs) emerge as a technology energy conversion (gas to power) and reliable large-scale electricity storage in the form of hydrogen gas (power to gas). The fabrication of proton conducting electrolysis cells is associated with numerous constraints arising during the fabrication and operation, such as electrode layer cracking, delamination, and warpage due to thermo-chemical mismatching. According to Løken, this mismatch should not exceed 50% to avoid thermal stress leading to cracks and delamination [1]. Forming a cer-cer or a cer-met composite of the electrode and the electrolyte is a common way to address these issues. Hence, in the present work we focus on the development and the electrochemical characterization of an air electrode cer-cer composite by direct mixing of BaCo0.4Fe0.4Zr0.2O3-δ (BCFZ442) and BaZr0.7Ce0.2Y0.1O3-δ (BZCY721) powders in various ratios (50:50, 70:30, and 90:10 wt % , respectively). We examined their chemical compatibility at various sintering temperatures through X-ray diffraction analysis. We then screen-printed the so-prepared air electrode composite pastes on both sides of sintered BZCY721 pellets serving as the electrolyte, thus forming symmetric cells after sintering the electrodes. The cross-sectional scanning electron microscopic (SEM) views collected on the symmetrical cell before and after the operation/measurements showed a good adherence between the electrolyte and the electrode and an electrode/electrolyte interface with a porous structure, availing the accessible path for gas diffusion. The electrochemical impedance of the symmetrical cells was measured from 400-700 oC at 50 oC intervals by Impedance spectroscopy with wet air (3% H2O) in the frequency range of 0.1 Hz to 1 MHz. The total cell resistance, which represents the polarization and ohmic resistance, decreases as expected with the temperature increases and it was studied as a function of the electrode composition as well.[1] Løken Andreas, Ricote Sandrine, Wachowski Sebastian, Thermal and chemical expansion in proton ceramic electrolytes and compatible electrodes, Crystals, 8(9), 365 (2018)
Keyword(s): Energy (1st) ; Materials Science (2nd)
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