Recent advances in alloying anode materials for sodium-ion batteries: material design and prospects

Sodium-ion batteries (SIBs) are close to commercialization. Although alloying anodes have potential use in next-generation SIB anodes, their limitations of low capacities and colossal volume expansions must be resolved. Traditional approaches involving structural and compositional tunings have not been able to break these lofty barriers. This review is devoted to recent progress in research on alloy-based SIB anodes comprising Sn, Sb, P, Ge, and Si. Current level of understanding, challenges, modifications, optimizations employed up to date, and shortfalls faced by alloying anodes are also described. A detailed future outlook is proposed, focusing on advanced nanomaterial tailoring methods and component modifications in SIB fabrication. Utilizing the latest state-of-the-art characterization techniques including ex-situ and operando characterization tools can help us better understand the (de)sodiation mechanism and accompanying capacity fading pathways to pave the way for next-generation SIBs with alloying anode materials.