Lithium-Anode Protection in Lithium–Sulfur Batteries

Lithium–sulfur (Li–S) batteries show significant promise as next-generation energy-storage devices due to their high energy density (2600 Wh kg^-1). However, the severe shuttling of polysulfide intermediates and low Coulombic efficiency during operation induce rapid capacity loss, hindering their practical applications. Although sulfur coin cells can reach 1000 cycles, sulfur pouch cells reach only dozens of cycles before the lithium-metal anode is damaged by the electrolyte and/or polysulfides. Therefore, lithium-metal protection is an important issue in realizing long lifespans of Li–S pouch cells. In this review, we highlight recent progress on lithium-metal protection, including altering the solvation structure of lithium ions in the liquid electrolyte, designing an artificial solid electrolyte interphase (SEI), employing solid-state electrolytes, and adopting micro/nanostructured hosts.