MXene-based materials: Synthesis, structure and their application for advanced lithium-sulfur batteries

Lithium-sulfur (LiS) batteries, which possess high theoretical energy density, are extremely potential candidates for next-generation energy storage devices. However, the barriers of low conductivity for sulfur, shuttle effect of polysulfides, volume expansion of sulfur during the charging/discharging process, and uncontrollable dendrites growth, hinder the real-world applications of LiS batteries. Various advanced materials and strategies have been developed to overcome the above-mentioned problems. MXenes, as one of the emerging family of two-dimensional (2D) materials with laminar structure, admirable conductivity, excellent hydrophilicity, and tunable surface chemistry, have also been used to surmount these challenges. It has been found that MXene-based materials are generally employed as the substrates for sulfur hosts and interlayers between cathode and separator due to their satisfactory conductivity, strong adsorbability toward polysulfides, and catalytic effect for the conversion of polysulfides. Additionally, MXene-based materials with the ability to well regulate the lithium deposition behavior, are widely utilized to modify the lithium anode. To further facilitate effective and target-oriented research on MXene-based materials for advanced LiS batteries, a comprehensive summary of recent research progress is urgently needed. Herein, recent research progress in MXene-based materials for LiS batteries is summarized, from the perspectives of synthesis, structure and properties, and the state-of-the-art progress for LiS batteries. Finally, the challenges and perspectives for the MXene-based materials for the future development of advanced LiS batteries have also been proposed.