Electrochemically converting Sb2S3/CNTs to Sb/CNTs composite anodes for sodium-ion batteries

Facile synthesis methods and rich-reserve feedstocks are the keys to accelerating the scale commercial use of Sb-based anodes for sodium-ion batteries (SIBs). In this paper, we synthesize Sb/carbon nanotubes (CNTs) composite anodes by a straightforward electrochemical approach using stibnite and CNTs as feedstocks. The concentrated sodium hydrate solution profits the formation of antimony and electrons enables the solid-state electrochemical desulfurization. The low-cost stibnite can be directly obtained from the earth's crust avoiding the intermediate processes and pollution of preparing the common-used raw materials SbCl3 and metallic Sb. CNTs provides a network for both electron and ion transport, thereby resulting in producing Sb particles anchored in the CNTs network as well as restraining the cluster of electrolytic Sb particles. The electrolytic Sb-0.5CNTs anode delivers a decent capacity of 510 mAh g−1 at 0.1 A g−1 after 200 cycles and even 425 mAh g−1 at 1 A g−1 over 100 cycles. The excellent sodium-storage performances are attributed to the unique structure of the electrolytic Sb/CNTs composite. This electrochemical desulfurization method can be expanded to prepare other metal-carbon type anodes from metal sulfides ores and carbon materials composites.