Interface in Focus: Opportunities and Challenges of Nanopipette Dynamic Microscopy

Electrochemical liquid-phase transmission electron microscopy (EC-LP-TEM) offers an unprecedented view of the dynamic solid-liquid interfaces that regulate electrochemical processes. Although mainstream planar or microfluidic EC-LP-TEM cells have uncovered important nanoscale transformations, there is a spatial discrepancy between the imaging area and the detected electrochemical signal. Recent advances in nanopipette-based structures─inspired by ultramicroelectrode electrochemistry─allow for the colocalization of imaging and electrochemical regions within highly confined geometries, attaining both nanometer-scale visualization and picoampere-to-nanoampere current detectability. In this perspective, we follow the development of EC-LP-TEM from conventional designs to emerging nanopipette-based setups, examine the conceptual shift toward interface-resolved imaging, and outline major technical challenges in geometry optimization, signal synchronization, and multimodal data correlative analysis. We also emphasize the potential of nanopipette-enabled EC-LP-TEM to directly observe electric double layer dynamics and nanoscale reaction heterogeneity─revolutionizing our ability to investigate electrochemical interfaces from ensemble averages to spatiotemporally resolved events.