Surface and structure engineering of MXenes for rechargeable batteries beyond lithium

With the rapid growth in renewable energy, researchers worldwide are trying to expand energy storage technologies. The development of beyond-lithium battery technologies has accelerated in recent years, amid concerns regarding the sustainability of battery materials. However, the absence of suitable highperformance materials has hampered the development of the next-generation battery systems. MXenes, a family of 2D transition metal carbides and/or nitrides, have drawn significant attention recently for electrochemical energy storage, owing to their unique physical and chemical properties. The extraordinary electronic conductivity, compositional diversity, expandable crystal structure, superior hydrophilicity, and rich surface chemistries make MXenes promising materials for electrode and other components in rechargeable batteries. This report especially focuses on the recent MXene applications as novel electrode materials and functional separator modifiers in rechargeable batteries beyond lithium. In particular, we highlight the recent advances of surface and structure engineering strategies for improving the electrochemical performance of the MXene-based materials, including surface termination modifications, heteroatom doping strategies, surface coating, interlayer space changes, nanostructure engineering, and heterostructures and secondary materials engineering. Finally, perspectives for building future sustainable rechargeable batteries with MXenes and MXene-based composite materials are presented based upon material design and a fundamental understanding of the reaction mechanisms. (c) 2023 The Authors. Published by Elsevier B.V. on behalf of The Chinese Ceramic Society. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).