Mixed ionic-electronic conduction as an interfacial paradigm in lithium-based batteries

초록

Mixed ionic-electronic conductors (MIECs) have emerged as important functional materials for lithium-based batteries, including lithium-ion batteries (LIBs) and all-solid-state batteries (ASSBs). In both systems, performance is increasingly limited by discontinuities in ionic and electronic transport at heterogeneous interfaces, which lead to local polarization, unstable interphases, non-uniform lithium (Li) deposition, and impedance growth during cycling. MIECs offer a promising strategy to mitigate these problems by enabling coupled ionic and electronic transport within material phases or engineered interfacial architectures. As interlayers, coatings, binders, and composite frameworks, they can regulate interfacial flux, improve charge transfer kinetics, mitigate dendrite growth, and enhance electrochemical stability. This review examines the fundamental transport characteristics of MIECs, material design strategies for transport regulation, and their applications in Li metal and silicon (Si) anodes, high-voltage cathodes, and solid-state battery interfaces. In addition to summarizing recent progress, the review discusses key challenges for practical implementation, including chemical compatibility, structural design, realistic testing conditions, and scalable processing. Overall, the article highlights how MIECbased architectures can contribute to the development of more stable and high-performance Li-based batteries.

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