Characterizing battery materials and electrodes via in situ/operando transmission electron microscopy

In situ transmission electron microscopy (TEM) research has enabled better understanding of various battery chemistries (Li-ion, Li–S, metal–O2, Li, and Na metal based, etc.), which fueled substantial developments in battery technologies. In this review, we highlight some of the recent developments shedding new light on battery materials and electrochemistry via TEM. Studying battery electrode processes depending on the type of electrolytes used and the nature of electrode–electrolyte interfaces established upon battery cycling conditions is key to further adoption of battery technologies. To this end, in situ/operando TEM methodologies would require accommodating alongside correlation microscopy tools to predict battery interface evolution, reactivity, and stability, for which the use of x-ray computed tomography and image process via machine learning providing complementary information is highlighted. Such combined approaches have potential to translate TEM-based battery results into more direct macroscopic relevance for the optimization of real-world batteries.