Recent progress in electronic modulation of electrocatalysts for high-efficient polysulfide conversion of Li-S batteries

With the merits of high energy density, environmental friendliness, and cost effectiveness, lithium-sulfur (Li-S) batteries are considered as one of the most promising next-generation electrochemical storage systems. However, the notorious polysulfide shuttle effect, which results in low active material utilization and serious capacity fading, severely impedes the practical application of Li-S batteries. Utilizing various electrocatalysts to improve the polysulfide redox kinetics has recently emerged as a promising strategy to address the shuttle effect. Specially, the electronic structure of the electrocatalysts plays a decisive role in determining the catalytic activity to facilitate the polysulfide conversion. Therefore, reasonably modulating the electronic structure of electrocatalysts is of paramount significance for improving the electrochemical performance of Li-S batteries. Herein, a comprehensive overview of the fascinating strategies to tailor the electronic structure of electrocatalysts for Li-S batteries is presented, including but not limited to vacancy engineering, heteroatom doping, single atom doping, band regulation, alloying, and heterostructure engineering. The future perspectives and challenges are also proposed for designing high-efficient electrocatalysts to construct high-energy-density and long-lifetime Li-S batteries.