Film-based liquid cell transmission electron microscopy (TEM) has opened a new frontier in direct, atomic-scale visualization of nanocrystals within liquid environments. Ultrathin and flexible films supported on TEM grids, generally free from microfabrication, function simultaneously as electron-transparent windows and liquid encapsulation layers, enabling sub-nanometer spatial resolution for dynamic imaging of processes in solution. This technique enables real-time tracking of nucleation, growth, and etching at atomic resolution, revealing fundamental mechanisms underlying nanoscale transformations. This review examines the evolution of liquid cell architectures, analyzes key considerations including electron beam–sample interactions, solid–liquid–gas interface dynamics, and resolution limits, while highlighting the unique capabilities and emerging applications of film-based liquid cells. Particular emphasis is placed on breakthrough discoveries in elucidating metal nanocrystal structural evolution and in establishing structure–dynamics–function relationships. Looking forward, advances in diverse membrane materials, multi-field integration, and high-throughput analytical methods are expected to further enhance the versatility of film-based liquid cell TEM. These developments will deepen mechanistic insights into nanoscale dynamics in realistic liquid-phase reactions and accelerate the predictive design of compositionally and structurally complex metallic nanomaterials.

The solid-electrolyte-based memristors have attracted tremendous attention for the next-generation nonvolatile memory for both logic and neuromorphic applications. However, they encounter variability performance challenges which originated from the random ionic transport and conductive filaments formation. Evidently, the electrochemical metallized mechanism associated with ion transport has been elucidated. Nonetheless, the failure mechanism caused by ion transport during cycles is rarely reported. Hereafter, the five stages of failure in the Ag/Ag₁₀Ge₁₅Te₇₅/W memristor are elucidated through ex-situ current−voltage measurements combined with in-situ transmission electron microscopy characteristics. Our investigation reveals that the migration and enrichment of Ag ions result in the precipitation of Ag₂Te. The formation of Ag₂Te hinders the device's ability to maintain its bipolar characteristics and also decreases the resistance value of the high resistance state, thereby reducing the device's switching ratio. The promising results provide important guidance for the future design of structures and the manipulation of ion transport for high-performance memristors.

Combining multiple metal elements into one nanostructure merits untold application potential but is still a challenge for the traditional bottom-up synthesis method. Herein, we propose a eutectic-directed self-templating strategy to prepare two multi-component nanostructured alloys (PtPdRhIrNi (D-SN) and NiPtPdRhIrAl (D-SS)) through the combination of rapid solidification with dealloying. The PtPdRhIrNi nanoporous nanowires (NPNWs) represent a new family of high-entropy alloys (HEAs) containing delicate hierarchical nanostructure with ultrafine ligament sizes of ~ 2 nm in addition to one-dimensional (1D) morphology. Moreover, the PtPdRhIrNi NPNWs display excellent electrocatalytic activity and stability toward hydrogen evolution reaction, with the low overpotential of 22 and 55 mV to afford a current density of 10 mA·cm⁻² in 0.5 M H₂SO₄ and 1.0 M KOH electrolytes, respectively. The enhanced electrocatalytic performance can be attributed to the high-entropy effect favoring the surface electronic structure for the optimized activity, the promotion impact of Ni, 1D morphology facilitating the electron transport, and the nanoporous structure promoting the electrolyte diffusion.

The thermal stability of CeO₂ nanomaterials can directly impact both the uniformity of the supported catalysts and the catalytic behavior of CeO₂ itself. However, knowledge about the thermal stability of CeO₂ is still deficient. Here, we conduct in-situ transmission electron microscopy experiments and theoretical calculations to elucidate the thermal stability of CeO₂ nanomaterials under different environments. A sinter (< 700 ℃) and a structural decomposition (> 700 ℃) are observed within CeO₂ nanoflowers under O₂. The sinter firstly occurs among the nanoflowers' monomers and then the sintered nanoparticles structurally decompose to tiny nanoparticles from the strain interface. Under a vacuum environment, the CeO₂ nanoflowers firstly undergo a transition from cubic fluorite CeO₂ to hexagonal Ce₂O₃, accompanied by the oxygen release. The Ce₂O₃ nanoparticles further atomically sublimate from the edges to the center under high temperatures. Theoretical calculation results reveal a considerably lower energy barrier for the structural decomposition under O₂ and for the sublimation under vacuum. This work provides a perspective on the structural design and performance optimization of CeO₂-based catalysts.