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Corrosion degrades metals through complex microscopic processes that traditional methods often fail to capture. In-situ transmission electron microscopy (TEM) bridges this gap by providing real-time atomic-scale imaging of oxidation and corrosion dynamics. Gas-phase TEM uncovers critical oxidation mechanisms like oxide nucleation and alloying effects, while liquid-phase TEM tracks corrosion initiation. Coupled with emerging techniques like ultrafast direct electron detection cameras, these advancements promise unprecedented resolution in understanding material degradation.

All solid-state batteries (ASSBs) with ceramic electrolytes and alkali metal anodes are a potential future energy storage technology for vehicle electrification and smart grids. However, uncontrollable dendrite growth toward ultimate short circuiting in solid electrolytes (SEs) has become a serious concern in the design of long-cycle, safe ASSBs, and the underlying mechanism has remained unclear. Here through multiscale imaging and morphodynamic tracking we show that Na dendrites grow in β''-Al₂O₃ SEs through an alternating sequence of Na deposition and crack propagation. Atomic-scale imaging evidenced that electrochemical cycling causes massive delamination cracking along the Na⁺ conduction planes, accompanied by the closuremore » of neighboring conduction channels. In situ SEM observations revealed a dynamic interplay between Na deposition and crack propagation: Na deposition accumulates mechanical stress that induces cracking; cracking releases the local stress, which promotes further Na deposition. Thus, Na deposition and cracking alternatingly proceed until short circuits take place. A multiscale phase-field model is developed to recapitulate the morphodynamics of Na dendrite growth, predicting the tree-like fractal morphology of the growing dendrites. Importantly, our findings suggest that decoupling between Na deposition and cracking represents an important route to mitigate uncontrollable dendrite growth in ASSBs.« less

The high-temperature oxidation of NiAl is studied with dry oxygen and water vapor. The oxidation in H₂O results in a thicker Al₂O₃ oxide scale than that in O₂. The oxide scale formed initially is a single layer of γ-Al₂O₃ that subsequently transforms into a α-Al₂O₃/γ-Al₂O₃ bilayer structure, in which the inner α-Al2O3 layer formed in H2O has a higher porosity than that in O₂. Finally, further density functional theory calculations show that H protons derived from H₂O molecules penetrate into the oxide lattice and boost the formation of lattice vacancies in both α-Al₂O₃ and γ-Al₂O₃, thus enhancing the oxide scalemore » growth.« less