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.