MXenes-based separators with nanoconfined two-dimensional channels for high-performance lithium–sulfur battery

Lithium–sulfur (Li–S) batteries with high energy density and capacity have garnered significant research attention among various energy storage devices. However, the shuttle effect of polysulfides (LiPSs) remains a major challenge for their practical application. The design of battery separators has become a key aspect in addressing the challenge. MXenes, a promising two-dimensional (2D) material, offer exceptional conductivity, large surface area, high mechanical strength, and active sites for surface reactions. When assembled into layered films, MXenes form highly tunable two-dimensional channels ranging from a few angstroms to over 1 nm. These nanoconfined channels are instrumental in facilitating lithium-ion transport while effectively impeding the shuttle effect of LiPSs, which are essential for improving the specific capacity and cyclic stability of Li–S batteries. Substantial progress has been made in developing MXenes-based separators for Li–S batteries, yet there remains a research gap in summarizing advancements from the perspective of interlayer engineering. This entails maintaining the 2D nanochannels of layered MXenes-based separators while modulating the physicochemical environment within the MXenes interlayers through targeted modifications. This review highlights advancements in in situ modification of MXenes and their integration with 0D, 1D, and 2D materials to construct laminated nanocomposite separators for Li–S batteries. The future development directions of MXenes-based materials in Li–S energy storage devices are also outlined, to drive further advancements in MXenes for Li–S battery separators.

Graphical Abstract