Single-atom electrocatalysts for lithium–sulfur chemistry: Design principle, mechanism, and outlook

Abstract

Lithium–sulfur batteries (LSBs) have been regarded as one of the promising candidates for the next-generation “lithium-ion battery beyond” owing to their high energy density and due to the low cost of sulfur. However, the main obstacles encountered in the commercial implementation of LSBs are the notorious shuttle effect, retarded sulfur redox kinetics, and uncontrolled dendrite growth. Accordingly, single-atom catalysts (SACs), which have ultrahigh catalytic efficiency, tunable coordination configuration, and light weight, have shown huge potential in the field of LSBs to date. This review summarizes the recent research progress of SACs applied as multifunctional components in LSBs. The design principles and typical synthetic strategies of SACs toward effective Li–S chemistry as well as the working mechanism promoting sulfur conversion reactions, inhibiting the lithium polysulfide shuttle effect, and regulating Li+ nucleation are comprehensively illustrated. Potential future directions in terms of research on SACs for the realization of commercially viable LSBs are also outlined.