| Nov 18, 2024 |
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(Nanowerk News) Dr. Hye Jung Chang and Dr. Kyung Joong Yoon of the Hydrogen Energy Materials Research Center at the Korea Institute of Science and Technology (KIST) have announced that they have elucidated the mechanism of the initial degradation phenomenon that triggers the performance drop of high-temperature solid oxide electrolysis cell systems, using advanced transmission electron microscopy.
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Unlike previous studies, which analyzed the final stages of degradation at the micrometer scale (1 µm, one-millionth of a meter), this study successfully verified the initial changes in electrolysis cell materials at the nanometer scale (1 nm, one-billionth of a meter).
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The research is published in Energy & Environmental Science (“Unveiling the high-temperature degradation mechanism of solid oxide electrolysis cells through direct imaging of nanoscale interfacial phenomena”).
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| Solid oxide electrolysis cell (SOEC) technology is one of the most efficient methods for producing clean hydrogen. However, electrode delamination remains a significant issue. To identify the causes of electrode delamination, recent studies have employed advanced transmission electron microscopy (TEM) and density functional theory (DFT) to discover nanoscale interface degradation. (Image: KIST)
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The research team identified the degradation mechanism occurring between the air electrode and electrolyte of the electrolysis cell through TEM diffraction analysis and theoretical calculations. The observations revealed that oxygen ions accumulated at the interface of the electrolyte, known as Yttria Stabilized Zirconia (YSZ), during the oxygen injection process that that drives the electrolysis reaction.
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Consequently, the atomic structure of the interfacial YSZ is compressed, leading to the formation of nanoscale defects and, eventually, cracks between the air electrode and the electrolyte, which in turn caused the deterioration of the cell’s performance. Furthermore, by visually verifying the stress and defects formed at the interface, the team succeeded in elucidating the correlation between ions, atoms, nanoscale defects, pores, and cracks occurring in the early stages of degradation.
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This research achievement marks the first study to elucidate the degradation mechanism at the nanoscale, providing guidelines to address the performance decline of high-temperature electrolysis cells during long-term operation. Specifically, it could enable the development of materials that can operate stably above 600°C for extended periods, significantly enhancing the durability of commercial electrolysis cells. The nanoscale analytical technology using advanced TEM in this study can be applied to solve degradation issues in various energy devices.
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The research team plans to accelerate the commercialization of high-temperature electrolysis cells by collaborating with manufacturers to establish automated production processes for mass production. Additionally, they are conducting research to develop new materials that can suppress the accumulation of oxygen ions in specific areas of the electrolysis cell, aiming to increase production efficiency and reduce production costs, ultimately lowering the cost of clean hydrogen production.
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Dr. Chang from KIST stated, “Using advanced transmission electron microscopy, we were able to identify the causes of previously unknown degradation phenomena at the early stages. Based on this, we aim to present strategies to improve the durability and production efficiency of high-temperature electrolysis cells, contributing to the economic viability of clean hydrogen production.”
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