Hierarchically Porous and Interconnected Ti 3 C 2 T x MXene Networks via Interface-Directed Functionalization for Lithium–Sulfur Batteries

Assembling 2D transition metal carbides/nitrides, MXenes, into a 3D network structure has emerged as a promising strategy for energy storage, leveraging their exceptional electrical properties and high surface area as well as redox active terminates. Nevertheless, while their porosity typically relies on sacrificial templates or assembly methods, the effects of the dispersion or wetting behavior of MXene have been largely neglected. We present 3D-interconnected, hierarchically porous Ti3C2Tx MXene networks, enabled by interface-directed functionalization and organized assembly at water-nonpolar heterointerface. Rational control of MXene flakes wettability through solution phase functionalization unfolds large tunability of MXene assembled structure, successfully addressing key design requirements for lithium-sulfur batteries. Interconnected hierarchical porosity facilitates electron/ion transport as well as polysulfide conversion, contributing to high sulfur utilization and excellent rate capability. In-depth microstructural characterization along with density functional theory simulations reveals that local lattice strain in the MXene plane enforced by nonplanar interfacial geometry boosts polysulfide adsorption. The proposed interface-directed functionalization strategy and the resulting hierarchical network structure offer a versatile framework for judicious microstructural tuning of MXene-based electrodes beyond typical energy storage applications.