MXene and MXene-based materials for lithium-sulfur batteries

Lithium-sulfur (Li–S) batteries are regarded as potential alternatives to lithium-ion batteries due to their extremely high theoretical energy density. Nevertheless, Li–S batteries still suffer from low coulombic efficiency, low sulfur utilization, and poor cycling life, which hinder their further applications. To obtain ideal Li–S cells, intensive work has been dedicated to improve the conductivity of the electrode, inhibiting the shuttle of lithium polysulfides, and promoting the redox of sulfur. Two-dimensional transition metal carbides, nitrides or carbonitrides, also known as MXenes, attracting significant research interest in Li–S batteries due to their high conductivity, abundant active sites, layered structure and adjustable surface chemistry. In this review, we summarize the partial etching methods of MXenes with different surface terminations, the role of MXenes in Li–S batteries and MXene-based composites designed for Li–S batteries based on interfacial chemistry and interlayer structure. In the end, we also propose the perspectives of MXenes for Li–S batteries.