Expanding the interlayer spacing of MXene through nanoarchitecture design

MXenes, a diverse class of two-dimensional transition metal carbides and nitrides with distinct surface chemistries, offer remarkable electrochemical and physicochemical properties. Yet, their performance can be hindered by the intrinsic restacking of layers, which restricts surface activity. This review outlines recent advances in interlayer spacing modulation strategies designed to overcome this limitation. A wide range of guest species–including mono- and polyatomic ions, small molecules, low-dimensional nanomaterials, and polymers–are discussed with respect to their intercalation mechanisms, structural effects, and capacity to introduce functional enhancements. These intercalating species interact with MXene via electrostatic forces, hydrogen bonding, redox reactions, or covalent linkages, resulting in stable, expanded nanoarchitectures. The influence of expanded spacing on capacitive behavior is briefly highlighted to illustrate its practical relevance. Although Ti3C2Tx is currently the most extensively investigated MXene, applying these interlayer engineering strategies to other MXene compositions will be essential for accessing a wider range of properties and functionalities.