MXenes for Boosting Potassium Ion Storage: Structure‐Property Relationships, Interface Science, Microscopic Mechanisms, and Application Perspectives

Abstract

Potassium‐ion batteries (PIBs) have attracted significant attention owing to the abundance and low cost of potassium resources. However, their practical development remains hindered by anode‐related challenges, including sluggish kinetics and pronounced volume variation during cycling. MXenes provide a promising platform for addressing these issues because of their two‐dimensional layered architecture, high electrical conductivity, and tunable surface chemistry. This Review provides a critical overview of recent advances in MXene‐based anodes for PIBs, with emphasis on interlayer spacing expansion, surface termination regulation, and heterostructure design. It also examines the underlying potassium‐storage mechanisms, including intercalation, pseudocapacitive storage, conversion reactions, and alloying‐related processes. The discussion examines how interfacial charge transfer, defect engineering, and the “trapping‐conversion” mechanism contribute to improved electrochemical performance. Finally, this review discusses key challenges associated with MXene‐based PIB anodes, including interfacial instability, full‐cell compatibility, and performance verification under practical operating conditions. Future perspectives are proposed for advancing MXene‐based potassium storage materials through multidimensional structural regulation, interfacial engineering, and mechanism‐guided material design.