Solid oxide electrolysis cell (SOEC) technology potentially offers the most efficient means of clean H₂ production. Currently, the most critical issue is the delamination of the air electrode, but its fundamental cause has long been elusive. Using cutting-edge transmission electron microscopy techniques and density functional theory calculations, we reveal nanometer-scale interfacial degradation phenomena occurring in the early stages, clarifying the entire process of delamination and the origin thereof. During SOEC operation, oxygen ions accumulate at specific locations where they cannot be released as a gas. The annihilation of oxygen vacancies modifies the unit cell structure, causing anisotropic lattice strain; further injection of excess oxygen ions creates dislocations and segmented subgrains. Subsequently, these ions initiate the formation of nanopores, which eventually develop into cracks and delaminate the electrode. These previously undiscovered structural alterations contradict the long-held but unsubstantiated notion of gas pressure build-up, providing novel guidance for future development.

中文翻译：

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通过纳米级界面现象的直接成像揭示固体氧化物电解池的高温降解机制


固体氧化物电解池 (SOEC) 技术有可能提供最有效的清洁 H ₂ 生产方式。目前，最关键的问题是空气电极的分层，但其根本原因长期以来一直难以捉摸。利用尖端的透射电子显微镜技术和密度泛函理论计算，我们揭示了早期发生的纳米级界面退化现象，阐明了分层的整个过程及其起源。 SOEC 运行期间，氧离子会积聚在无法以气体形式释放的特定位置。氧空位的湮灭改变了晶胞结构，引起各向异性晶格应变；过量氧离子的进一步注入会产生位错和分段亚晶。随后，这些离子引发纳米孔的形成，最终发展成裂纹并使电极分层。这些先前未被发现的结构变化与长期以来但未经证实的气压积累概念相矛盾，为未来的发展提供了新的指导。