Review of Graphene Liquid Cell (In Situ TEM) for Battery Materials

The rapid development in power generation from renewable energy sources has led to the increased need for energy storage systems such as batteries, supercapacitors, and fuel cells. Consequently, extensive research and development are being conducted globally on these systems. However, to ensure the efficient performance of the energy storage systems, it is necessary to understand their associated complex electrochemical reactions and their failure mechanisms. In situ observation by liquid‐cell transmission electron microscopy (in situ TEM) has recently attracted significant attention from researchers as a material characterization technique. It allows observation and visualization of materials in liquid‐phase samples without the need to freeze or dry, which opens up the opportunity to analyze the materials in real time. In this review, we provide a comprehensive review of the recent application of in situ TEM in the characterization of energy storage materials using graphene liquid cells. We first describe the different steps and procedures involved in graphene liquid cell in situ TEM sample characterization, including sample preparation and probing, and how data are analyzed. We also discuss the challenges, opportunities, and future perspectives of the in situ graphene liquid‐cell TEM applications in energy storage systems.