Branch-structured Bi2S3–CNT hybrids with improved lithium storage capability

Abstract

Bismuth sulfide (Bi₂S₃) is a promising Li-storage material due to its high gravimetric and volumetric capacities. However, this intrinsic merit has often been compromised by the poor cycle and rate capability due to the lack of structural integrity upon the Li insertion/extraction process. Here, we engineer a branch-structured bismuth sulfide–carbon nanotube (CNT) hybrid by growing Bi₂S₃ nanorods onto CNTs to mitigate this issue. The hierarchical Bi₂S₃–CNT hybrids possess high surface areas, rich porosity for electrolyte infiltration, and direct electron transport pathways, and can be employed as efficient electrode materials for Li storage. These electrochemical results show that the Bi₂S₃–CNT hybrid exhibits a high reversible capacity (671 mA h g⁻¹ at 120 mA g⁻¹), stable cycling retention (534 mA h g⁻¹ after 90 cycles), and remarkable rate capability (399 mA h g⁻¹ at 3000 mA g⁻¹), notably outperforming other reported Bi₂S₃ materials. Such superb Li storage capabilities suggest that the Bi₂S₃–CNT branches could be potential electrodes for rechargeable batteries.