Contact interfaces in anodes with large volume strain for high-performance lithium-ion storage

Silicon, germanium, tin, phosphorus, metal oxides, and their related compounds have emerged as promising anode materials for lithium-ion batteries owing to their high theoretical capacities. However, their practical application is severely hindered by large volume changes during lithiation and delithiation, which lead to electrode pulverization and rapid capacity fading. In addition, their intrinsically low electrical conductivity limits rate performance. To mitigate these issues, composite strategies—such as incorporating buffering matrices and conductive carbon—are widely employed, resulting in complex contact interfaces within the electrode. Nevertheless, the static and dynamic understanding of these interfaces remains insufficient. Under substantial volume strain, these contact interfaces undergo continuous evolution: point contacts may transform into surface contacts, while established interfaces may delaminate, ultimately governing electrode failure mechanisms. In this review, we systematically examine the nature and impact of contact interfaces in anodes undergoing significant volume strain. Contact interfaces are categorized into geometric types as well as physical and chemical interfaces, with particular emphasis on their operando evolution and coupling with solid electrolyte interphase chemistry. We critically evaluate advanced characterization techniques, including operando X-ray/neutron imaging and cryogenic electron microscopy, and present a comparative matrix outlining their respective capabilities. Furthermore, we bridge the gap between qualitative understanding and quantitative design principles by highlighting emerging advances in multiscale simulations as well as AI-assisted and data-driven interface engineering. Finally, we propose a roadmap linking laboratory-scale strategies to industrial scalability, offering a forward-looking framework for the rational design of next-generation Li^+ storage systems.