In Situ Transmission Electron Microscopy Studies of Electrochemical Reaction Mechanisms in Rechargeable Batteries

Rechargeable batteries dominate the energy storage market of portable electronics, electric vehicles and stationary grids, and corresponding performance advancements are closely related to the fundamental understanding of electrochemical reaction mechanisms and their correlation with structural and chemical evolutions of battery components. Through advancements in aberration-corrected transmission electron microscopy (TEM) techniques for significantly enhanced spatial resolution, in situ TEM techniques in which a nanobattery assembly is integrated into the system can allow for the direct real-time probing of structural and chemical evolutions of battery components under dynamic operating conditions. Here, open-cell in situ TEM configurations can provide the atomic resolution imaging of the intrinsic response of materials to ion insertion or extraction, whereas the development of sealed liquid cells can provide new avenues for the observation of electrochemical processes and electrode-electrolyte interface reactions that are relevant to real battery systems. And because of these recent developments in in situ TEM techniques, this review will present recent key progress in the utilization of in situ TEM to reveal new sciences in rechargeable batteries, including complex reaction mechanisms, structural and chemical evolutions of battery materials and their correlation with battery performances. In addition, scientific insights revealed by in situ TEM studies will be discussed to provide guiding principles for the design of better electrode materials for rechargeable batteries. And challenges and new opportunities will also be discussed.Graphical Abstract