In operando and in situ characterization tools for advanced rechargeable batteries: Effects of electrode origin and electrolyte

Abstract

Understanding the intricate interactions between electrodes and electrolytes during battery operation is critical for developing high-performance, long-lasting, and safe rechargeable batteries. Structural and chemical processes occurring within battery materials in real time can now be monitored using in situ and operando characterization techniques. In situ and operando electron microscopy and X-ray-based techniques are valuable because they directly reveal reaction pathways and degradation processes with high resolution across multiple length scales. This review first provides a detailed overview of these techniques, including the historical development of experimental setups, their working principles, and the specialized cell designs created for battery research. Recent studies are then discussed with a focus on Li-ion, Na-ion, all-solid-state, and aqueous battery systems. Special attention is given to how these techniques uncover ion insertion and transport processes, interfacial and side reactions, mechanical degradation, dendrite growth, and failure mechanisms. Ongoing efforts are expected in employing in situ and operando approaches to address critical research challenges, such as reaction inhomogeneity in commercial cathodes, fast charging, safe and reversible Li metal plating, and solid electrolyte interphase stabilization. A deeper understanding of component behavior across different battery chemistries is essential to improving current technologies and developing next-generation energy storage systems.