A review on anodes for sodium-ion batteries: carbon-coated SnS and beyond

Sodium-ion batteries (SIBs) featuring the merits of low cost and abundant resources have attracted extensive interest and are considered one of the best alternatives to lithium-ion batteries (LIBs). However, the large radius of Na+ limits the conductivity and energy density of SIBs, and the search for electrode materials with excellent sodium storage properties is imminent. Among various anodes, SnS-based anodes have been considered an excellent candidate for SIBs due to their unique layered structure and superior theoretical capacity. However, the slow ion migration of SnS and the huge volume expansion during the sodiation/desodiation process can lead to material crushing, which results in an impractical capacity. Here, we present a comprehensive review of the recent research progress of SnS and SnS-based composites in SIBs in terms of structural properties, synthesis methods, electrochemical reaction mechanisms, and modification strategies. Among all the modification strategies, carbon coating and heterostructure design of SnS are the effective approaches to these challenges. Finally, this review provides an outlook on the future research and development of SnS-based anodes for high-performance SIB applications, which provides ideas for future research on SnS-based anode materials and promotes their rapid development and practical applications.