Advances in the Catalytic Mechanism of Metal Oxides for Lithium–Sulfur Batteries

Lithium-sulfur (Li-S) batteries are one of the promising next-generation energy storage/conversion devices, considering their high energy density and low cost. However, the shuttle of polysulfides hinders the practical application of Li-S batteries, which leads to reduced cycling stability. Although chemical adsorption strategies have made significant progress in improving the cycling stability of Li-S batteries, the poor catalytic conversion ability of the polysulfide host results in an imbalance between chemical adsorption and catalytic conversion. Recent studies have revealed that metal oxides with adjustable electronic structures exhibit good catalytic ability as polysulfide hosts. However, there is currently no systematic review of the catalytic mechanism of metal oxides in Li-S batteries. Herein, the working principle and primary challenge of Li-S batteries are first introduced, followed by a categorization of catalyst design strategies. Furthermore, a comprehensive review of recent advancements in understanding the reaction mechanism of metal oxide catalysts in Li-S batteries is also provided. Finally, personal perspectives on the future development of Li-S batteries enhanced by metal oxide catalysis are offered. It is hoped that this review can provide valuable insights into the catalytic role of metal oxides in accelerating polysulfide conversion for Li-S batteries.