Progresses and Prospects of Asymmetrically Coordinated Single Atom Catalysts for Lithium−Sulfur Batteries

Abstract

Lithium–sulfur batteries (LSBs) are widely regarded as promising next‐generation batteries due to their high theoretical specific capacity and low material cost. However, the practical applications of LSBs are limited by the shuttle effect of lithium polysulfides (LiPSs), electronic insulation of charge and discharge products, and slow LiPSs conversion reaction kinetics. Accordingly, the introduction of catalysts into LSBs is one of the effective strategy to solve the issues of the sluggished LiPS conversion. Because of their nearly 100% atom utilization and high electrocatalytic activity, single‐atom catalysts (SACs) have been widely used as reaction mediators for LSBs' reactions. Excitingly, the SACs with asymmetric coordination structures have exhibited intriguing electronic structures and superior catalytic activities when compared to the traditional M–N4 active sites. In this review, we systematically describe the recent advancements in the installation of asymmetrically coordinated single‐atom structure as reactions catalysts in LSBs, including asymmetrically nitrogen coordinated SACs, heteroatom coordinated SACs, support effective asymmetrically coordinated SACs, and bimetallic coordinated SACs. Particularly noteworthy is the discussion of the catalytic conversion mechanism of LiPSs spanning asymmetrically coordinated SACs. Finally, a perspective on the future developments of asymmetrically coordinated SACs in LSB applications is provided.

Good Cycling Stabilities of Sn/SnO2/C/S Composite Electrodes with Introduced Active Tin Atoms in Li–S Batteries

“…Monatomic modification is a good way to change the surface activity of metal oxides and improve the cycling stability of lithium–sulfur batteries. − Marangon et al discovered that the combination of S 8 and nanometric Sn can achieve a high reversible electrochemical process, which was beneficial for achieving high-capacity storage in Li–S batteries at a high current density (2C). Wang et al introduced Sn atoms onto a carbon surface to obtain C/Sn composites.…”