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Abstract Conversion‐type materials have been considered as potentially high‐energy‐density alternatives to commercially dominant intercalation‐based electrodes for rechargeable ion batteries and have attracted tremendous research effort to meet the performance for viable energy‐storage technologies. In situ transmission electron microscopy (TEM) has been extensively employed to provide mechanistic insights into understanding the behavior of battery materials. Noticeably, a great portion of previous in situ TEM studies has been focused on conversion‐type materials, but a dedicated review for this group of materials is missing in the literature. Herein, recent developments of in situ TEM techniques for investigation of dynamic phase transformation and associated structural, morphological, and chemical evolutions during conversion reactions with alkali ions in secondary batteries are comprehensively summarized. The materials of interest broadly cover metal oxides, chalcogenides, fluorides, phosphides, nitrides, and silicates with specific emphasis on spinel metal oxides and recently emerged 2D metal chalcogenides. Special focus is placed on the scientific findings that are uniquely obtained by in situ TEM to address fundamental questions and practical issues regarding phase transformation, structural evolution, electrochemical redox, reaction mechanism, kinetics, and degradation. Critical challenges and perspectives are discussed for advancing new knowledge that can bridge the gap between prototype materials and real‐world applications.
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This content will become publicly available on November 22, 2025
(Invited) Advanced Insitu Electron Microscopy for Batteries: Insights for Lithium-Ion and Beyond
Rechargeable batteries are crucial for energy storage across consumer electronics and automobile propulsion applications, facilitating the transition towards carbon neutrality and advancing clean energy technologies. Despite great success of Li-ion batteries (LIBs) in the commercial market, alternative technologies based on beyond-Li chemistry are highly demanded for large-scale and power-intensive applications necessitating enhanced energy density, lifetime, and safety, where fundamental understanding of the structure-property relationship of novel battery materials is critically needed. Transmission electron microscopy (TEM) is an indispensable method to characterize materials structures and compositions at the atomic scale, which is of particular importance for battery research to investigate crystal lattices, defects, as well as microstructural and chemical heterogeneities within materials used in electrodes, electrolytes, and their interfaces. Further, with rapid technical development, in-situ TEM has enabled real-time observations of various dynamical phenomena and chemical processes during battery cycling and phase transformations. Leveraging advanced in-situ TEM techniques, our collaborative endeavors with Dr. Marca Doeff have enabled us to conduct comparative analyses of Li and Na reactions within battery electrodes, offering unique insights into in early-stage beyond-Li chemistry. Herein, we present a systematic exploration of in-situ TEM studies for LIBs and beyond, focusing on electrode materials through intercalation, alloying, and conversion reaction mechanisms. By direct comparison between electrochemical reactions with Li and Na, we found substantial differences in reaction mechanisms, pathways, and kinetics between lithiation and sodiation processes, which are fundamentally related to various factors, such as ionic diffusion barrier, electrochemically induced stress, and geometric constraints. This concept has been demonstrated in multiple case studies that allows us to enhance the sodiation kinetics by tuning the overall reaction energetics through nanostructure optimization and interfacial engineering. We envision that the knowledge learned from in-situ TEM will provide valuable insights into understanding the alkali-ion electrochemistry and kinetics, thereby serving as foundational principles guiding the advancement of beyond Li-ion battery technologies.
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- Award ID(s):
- 2239598
- PAR ID:
- 10573975
- Publisher / Repository:
- IOP Publishing
- Date Published:
- Journal Name:
- ECS Meeting Abstracts
- Volume:
- MA2024-02
- Issue:
- 2
- ISSN:
- 2151-2043
- Page Range / eLocation ID:
- 210
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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