Operando microscopy to provide significant insights in battery chemistry

Abstract

Operando analyses have provided several breakthroughs in the construction of high-performance materials and devices, including energy storage systems. However, despite the advances in electrode engineering, the formidable issues of lithium intercalation and deintercalation kinetics cannot be investigated via planar observations. In situ optical and transmission electron microscopy (OM and TEM) on lithium-ion batteries has offered diverse opportunities for monitoring the dynamic processes of electrodes during electrochemical reaction at both spatial and temporal resolution. In this talk, I will introduce side-view operando OM and TEM studies on anodes, for example graphite, silicon, and lithium metal that suffer lithium plating by overpotential, anomalous volumetric changes, fracture, or dendritic formation during lithiation process. Since the graphite color varies according to the optical energy gap during lithiation and delithiation, we could study the corresponding charge/discharge kinetics; in addition, our cell configuration uses liquid electrolytes similarly to commercial cells, allowing practical applications. Furthermore, this side-view observation has showed that microscale spatial variations in rate and composition control the insertion and desertion, revealing the kinetics through the whole electrode. The results of this study could enhance the fundamental understanding of the kinetics of battery materials.