Recent advances in li metal anode protection for high performance lithium-sulfur batteries

Abstract

Lithium-sulfur batteries (LSBs) have garnered significant attention as a promising next-generation rechargeable battery, offering superior energy density and cost-effectiveness. However, the commercialization of LSBs faces several challenges, including the ionic/electronic insulating nature of the active materials, lithium polysulfide (LiPS) shuttle effect, volume expansion/contraction of the cathode, and issues with Li metal anode. Despite numerous efforts to address these challenges, previous studies have predominantly been conducted under mild conditions such as high electrolyte-to-sulfur (E/S) ratio, low sulfur loading, and excess Li metal, which cover issues related to Li metal anode. However, for realizing high-energy–density LSBs, practical conditions such as low E/S ratio, high sulfur loading, and limited Li metal are essential. Under these conditions, the increased current on Li metal and higher LiPS concentration exacerbate issues with Li metal anode such as dendrite growth, dead Li, high reactivity with electrolyte, and high reactivity with LiPSs. These problems lead to rapid failure of Li metal, significantly impacting the electrochemical performance of LSBs. Consequently, protecting Li metal anode is crucial for the practical LSBs. This paper introduces the challenges associated with Li metal anode in LSBs and reviews research focused on protecting Li metal anode in each battery component: anode, electrolyte, cathode, and separator/interlayer. Finally, we discuss future research directions of each component towards practical LSBs. Graphical Abstract