X-ray Micro-Computed Tomography: A Powerful Device to Analyze the 3D Microstructure of Anode-Electrolyte in BaZr0.8Y0.2O3 Protonic Ceramic Electrochemical Cells and the Reduction Behavior

Abstract

New advanced fuel cell technologies are moving towards high-temperature proton conductors (HTPCs) to meet environmental issues. Their elaboration remains a challenge and micro-computed tomography (µCT) is an innovative way to control their quality. NiO-BZY anodic supports of a protonic ceramic electrochemical cell (PCEC), elaborated by co-tape casting and co-sintered at 1350 °C, were coated with a BZY20 electrolyte layer by DC magnetron sputtering. The µCT allowed to observe defects inside the volume of these PCEC half-cells and to show their evolution after an annealing treatment at 1000 °C and reduction under hydrogen. This technique consists in obtaining a 3D reconstruction of all the cross-sectional images of the whole sample, slice by slice. This allows seeing inside the sample at any desired depth. The resolution of 0.35 µm is perfectly adapted to this type of problem considering the thickness of the different layers of the sample and the size of the defects. Defects were detected, and their interpretation was possible thanks to the 3D view, such as the phenomenon of NiO grain enlargement explaining defects in the electrolyte, the effect of NiO reduction, and finally, some anomalies due to the shaping process. Ways to anticipate these defects were then proposed.

Reactive Magnetron Sputtering for Y-Doped Barium Zirconate Electrolyte Deposition in a Complete Protonic Ceramic Fuel Cell

“…8 Y 0 . 2 (purity 99.9%, Ø 50 mm × 6 mm) targets as described in previous work [56]. The reactor is a 90 L cylinder Alcatel 604 SCM (CIT Alcatel, Annecy, France) pumped down via a turbomolecular pump system that permitted a residual vacuum below 10 −4 Pa.…”

Modeling, Degradation Study, Failures Diagnosis and Faulty Operating Management of Electrolyzers

“…As a result of this Special Issue proposal, five research papers [12][13][14][15][16] from four different countries have been published. Researchers at academic institutions and the French National Centre for Scientific Research (CNRS) from France [12,13,15], Mexico [15], Germany [14], and Taiwan [16] contributed to this work. It is important to point out that the research reported in Ref.…”

“…Moreover, all the published papers reported experiments performed on electrolyzers that demonstrate the relevance of the papers and the significance of using experimental data for investigation purposes. Hence, the published papers reported on new contributions compared to the current literature, including an investigation of the effects of current ripple from power electronics on the performance of PEM electrolyzers [12]; the use of X-ray micro-computed tomography to examine the 3D microstructure of the anode-electrolytes of electrolyzers [13]; the development of a mathematical model to evaluate the cell polarization, current density distribution and water flow paths inside a cell under low stoichiometry conditions [14]; the analysis of the decrease in the open-circuit voltage of the PEM electrolyzer during shutdown operation and its modeling [15]; and the application of micro-electro-mechanical systems to monitor, in real-time, the state-of-health of a PEM electrolyzer [16].…”