Interlayer design based on carbon materials for lithium–sulfur batteries: a review

Abstract

Lithium–sulfur batteries were extensively investigated during the past two decades for their extremely high theoretical specific energy (2600 W h kg⁻¹) and volumetric energy density (2800 W h L⁻¹). However, their industrialization has been restrained due to the insulating nature of sulfur, volume expansion of sulfur cathodes, formation of lithium dendrites, and terrible shuttle effect of soluble lithium polysulfides (Li₂S_x, 3 ≤ x ≤ 8). Many researchers have been struggling with the design of interlayers having remarkable conductivity and polysulfide-trapping capability so that these persistent drawbacks can be overcome. This review summarizes recently developed Li–S batteries with novel interlayers based on carbon materials, such as graphene, carbon nanotubes, carbon fibers, and nanofibers. The electrochemical properties of Li–S batteries with various interlayers are systematically compared. In particular, the enhancing mechanisms of Li–S batteries after the insertion of these interlayers are highlighted. Existing challenges and future development strategies with regard to high-energy Li–S batteries having carbon interlayers have also been summarized, and a prospective has been provided.