2023-12-09 20:10:00
Observation at the nanometric scale of the evolution of the microstructure of the components of a fuel cell during operation is now a reality. This achievement, made possible thanks to a unique transmission electron microscopy experiment, is a crucial step in optimizing the lifespan and efficiency of these energy converters.
Energy conversion devices, such as batteries, electrolyzers or fuel cells, are complex systems composed of several different materials. During their use, the microstructure of these materials can evolve under the effect of sometimes extreme conditions, often leading to a reduction in performance or even security of the system. It is therefore essential to characterize and quantify these developments to better understand the mechanisms at play and optimize their performance.
Solid Oxide Fuel Cells (SOFC)
Solid oxide fuel cells (SOFC) are devices that produce an electric current by consuming dihydrogen (H2), one of the vectors of the energy transition. With water as the only reaction product, SOFCs are expected to play an important role in the decarbonization of energy.
Their microstructure evolves over time due to high operating temperatures, the presence of reducing and oxidizing gases, and strong electrical polarization. These reaction conditions are particularly difficult to reproduce within conventional microstructural characterization equipment.
Experimental device placed in the chamber of an environmental TEM and which makes it possible to observe at the nanometric scale the evolution of the microstructure of the components of a fuel cell during its operation. © Matthieu Bugnet & Thierry Epicier
An innovative approach for observing PACs
Scientists from French, Swiss and Asian laboratories, in collaboration with two European companies, have implemented an innovative approach which makes it possible to observe at the nanometric scale the evolution of the microstructure of the components of these batteries during their operation. Their strategy combines the realization of a model experiment in the chamber of an electron microscope in environmental transmission, with validation tests on the macroscopic scale.
By bringing into contact a cathode-electrolyte-anode cell and a micro-electromechanical system (MEMS) heating and polarization in the microscope chamber, they were able to establish a direct correlation between the environmental conditions (pressure and nature of the gas mixture, temperature), the electrical voltage of the cell and the microstructural evolution, on the scale nanometric.
Promising results
These results provide valuable information on the impact of the oxidation state of the anode and its morphology on the electrical properties of the cell. In particular, they make it possible to monitor the state of the nickel catalyst on the surface of the anode, an essential component for the cell’s performance, during its exposure to oxygen and hydrogen.
Synthetic
This study, published in the journal Nature Communications, opens a new field of possibilities for studying the degradation pathways that affect these energy conversion devices. It marks an important step in understanding the mechanisms that govern the operation of fuel cells and might contribute to optimizing their lifespan and efficiency.
For a better understanding
1. What is a solid oxide fuel cell (SOFC)?
A solid oxide fuel cell (SOFC) is an energy conversion device that produces electrical current by consuming dihydrogen (H2). It is composed of a cathode, an anode and a solid electrolyte. SOFCs are considered a promising solution for energy decarbonization, because their only reaction product is water.
2. What are the challenges related to the study of fuel cells?
Fuel cells are complex systems composed of several materials whose microstructure evolves under the effect of extreme conditions, such as high temperatures, the presence of reducing and oxidizing gases, and strong electrical polarization. It is difficult to reproduce these reaction conditions in conventional microstructural characterization equipment.
3. What is the innovative approach used to observe fuel cells?
Scientists have developed an innovative approach that makes it possible to observe at the nanometric scale the evolution of the microstructure of fuel cell components during their operation. This approach combines the performance of a model experiment in the chamber of an environmental transmission electron microscope, with validation tests on the macroscopic scale.
4. What are the results obtained using this approach?
The results make it possible to monitor the state of the nickel catalyst on the surface of the anode, an essential component for cell performance, during its exposure to oxygen and hydrogen. They also provide valuable information on the impact of the oxidation state of the anode and its morphology on the electrical properties of the cell.
5. What are the implications of this study for the future of fuel cells?
This study opens a new field of possibilities to study the degradation pathways that affect energy conversion devices. It might contribute to optimizing the lifespan and efficiency of fuel cells by allowing a better understanding of the mechanisms that govern their operation.
Main lessons
TeachingSolid oxide fuel cells (SOFCs) are promising energy conversion devices for energy decarbonization. The study of fuel cells is complex due to the evolution of the microstructure of materials under extreme conditions. An approach innovative method combining electron microscopy and macroscopic validation tests makes it possible to observe fuel cells in operation. The results obtained provide valuable information on the impact of the oxidation state of the anode and its morphology on the electrical properties of the cell. The study makes it possible to monitor the state of the nickel catalyst on the surface of the anode during its exposure to oxygen and hydrogen. This is the first proof of the concept that a fuel cell can be analyzed under operando conditions in an environmental transmission electron microscope. This study opens a new field of possibilities for studying the degradation pathways that affect energy conversion devices. Understanding the mechanisms that govern the operation of batteries fuel might contribute to optimizing their lifespan and efficiency. The scientists involved in this study come from French, Swiss and Asian laboratories, in collaboration with two European companies. The study was published in the journal Nature Communications.
References
Operando analysis of a solid oxide fuel cell by environmental transmission electron microscopy : Q. Jeangros, M. Bugnet, T. Epicier, C. Frantz, S. Diethelm, D. Montinaro, E. Tyukalova, Y. Pivak, J. Van herle, A. Hessler-Wyser, M. Duchamp.
Nature Communications 2023
https://doi.org/10.1038/s41467-023-43683-4
Article adapted from the content of the author AVR / source: CNRS
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