Transition metal chalcogenide anodes for sodium storage

Owing to the low cost and indefinite availability of sodium resources, rechargeable sodium-ion batteries (SIBs) are now being considered as the most appealing alternatives to their lithium-ion counterparts for large scale applications. On the other hand, transition metal chalcogenides (TMCs) have emerged as potential candidates of SIB anodes due to their versatile material species, ample abundance, low cost, robust nature and high theoretical capacities. However, TMCs still face several challenges like severe volume changes during sodiation/desodiation, inadequate conductivities and large-scale productions. Hence, many traditional and unconventional techniques have been developed to mitigate these issues and obtain high quality electrode materials for practical applications. In this review, recent progress and the rectification stratagems of the problems of TMCs have been summarized firstly. Then, a detailed comparison of transition metal selenides with sulfide TMCs family members was provided to investigate the factors which govern the relative performance improvements of selenides. Besides this, multiple transition metals containing TMCs (M-TMCs) have exhibited intriguingly better performances compared to mono-metal TMCs. Hence, various inspirational features of M-TMCs were discussed. As an outcome of these discussions, we were able to outline several outlooks and prospective solutions for the rectification of potential challenges of TMC anode materials.