Current understanding of electrochemical strain microscopy to visualize ion behavior on the nanoscale

Electrochemical Strain Microscopy (ESM) is a technique based on Atomic Force Microscopy and provides information about local ionic processes through electro-chemo-mechanical coupling. It is employed foremost in studying battery materials, from cathodes, and anodes to solid-state electrolytes. Based on this overlap we aim to connect the electrochemistry community further with those employing ESM, by providing the current understanding of ESM, starting with a thorough introduction to the technique. In the second section, typical applications and challenges identified in recent years are reviewed while in the third chapter new approaches to overcome these issues are presented. This includes the identification of various contributions to the ESM signal, the integration of ESM as part of a multi-modal characterization approach, and importantly, how to link local ESM results to the overall cell performance in batteries. Lastly, upcoming trends and new aspects are discussed, including the application of in-situ ESM directly in an electrochemical environment.