Electrochemical Processes and Reactions In Rechargeable Battery Materials Revealed via In Situ Transmission Electron Microscopy

Abstract Rechargeable batteries that make renewable energy resources feasible for electrification technologies have been extensively investigated. Their corresponding performance is strongly dependent on the structural characteristics and chemical dynamics of internal electrode and electrolyte materials under operating conditions. To enhance battery performance and lifetime, a comprehensive understanding of the structure‐dynamics‐performance correlation of such materials under different working conditions is of great significance. Fortunately, in situ transmission electron microscopy (TEM) encompassing high‐resolution imaging, diffraction, and spectroscopic analysis, offers unprecedented insights into the nano/atomic scale structural changes and degradation pathways of rechargeable battery materials under operational conditions. Such insights are pivotal for a deep‐rooted understanding of reaction mechanisms and the structure‐activity interplay within battery materials. This work, therefore, highlights the advances in in situ TEM's utility in unveiling dynamic chemical and physical changes in real‐time within battery materials of rechargeable batteries. Electrochemical processes and degradation mechanisms are systematically explored and summarized. Moreover, the technical progress, challenges, and valuable insights provided by in situ TEM techniques for addressing critical issues in battery materials are underscored. The work concludes with a discussion of emerging research directions that hold the potential to revolutionize the renewable energy field in the near future.