Real Time Electron Microscopy Observations of Electrode Materials for Li-Ion Batteries

Transmission electron microscopy (TEM) has played a vital role in providing nano- and atomic-scale insights into the morphology, microstructure, and chemical properties of Li-ion batteries at both anode and cathode materials. Moreover, improvements of in-situ capabilities, as enabled by specialized biasing TEM sample holders, offers an exciting opportunity to monitor the changes taking place in the electrode materials under external stimuli at an unparalleled resolution, enabling a deeper understanding of how the materials behave under various operating conditions. In-situ capability is also applicable to investigate structural changes of electrode materials during lithium removal or insertion under biasing conditions. Such operando characterization of the electrode materials is critical for gaining a fundamental understanding of how lithium-ion batteries function and degrade.<br/>My presentation will focus on real-time TEM observations of the phase transformations that take place in electrode materials during lithium migration. A dry-cell setup was developed inside the TEM column based on the Nanofactory STM-TEM sample holder, and lithium movement was controlled by applying bias to the samples. A multi-step lithium insertion reactions within tin sulfide will be presented as a proof-of-concept, and the nanoscale structural evolutions in these solid-state-cells will be further discussed. My talk will illustrate that dynamic investigations of electrode materials not only enhance our understanding of the structural changes induced by lithium but also provide intriguing insights into the underlying origins of battery performances.