• In-situ TEM techniques enable real-time, atomic-scale visualization of interfacial nanostructures in electrochemical energy storage systems, providing critical insights into ion transport and structural evolution.
• Advanced imaging modalities such as electron holography and differential phase contrast imaging allow mapping of strain fields and ionic valence states, linking nanoscale phenomena to macroscopic battery performance.
• The review highlights how in-situ TEM reveals dynamic processes at electrode/electrolyte interfaces, informing the design of high-performance batteries and other energy storage devices.
• Future developments in in-situ TEM, including improved spatial and temporal resolution and integration with other characterization tools, are essential for addressing challenges in next-generation energy storage technologies.