Hollow carbon fiber supported MoS2 nanosheets composite for reliable sulfur electrochemistry

Abstract

The structural modification of sulfur hosts plays a pivotal role in addressing the current challenges encountered by lithium-sulfur batteries (LSBs), including severe shuttle effects, slow redox reactions, and volume expansion. In this research, we synthesize a novel hollow "tube-in-tube" carbon fiber support (CNT@HCNF) through electrospinning followed by a carbonization process. On this basis, molybdenum disulfide (MoS₂) nanosheets are uniformly deposited on the internal and external surfaces of the CNT@HCNF via a hydrothermal synthesis strategy to form a novel composite cathode material designated as CNT@HCNF@MoS₂. The interwoven CNT@HCNF enhances the conductivity and offers sufficient sulfur storage space, while the in-situ generated MoS₂ further improves the specific surface area with a large number of catalytic active sites. This particular structural design promotes the adsorption of soluble long-chain polysulfides, and accelerates the migration rate of lithium ions, effectively alleviating the aforementioned issues. Owing to its unique structure and the intrinsic properties of robust adsorptive and catalytic capabilities towards soluble polythionates, CNT@HCNF@MoS₂/S electrode exhibits a high large discharge capacity of 1176 mAh·g^-1 at 0.2 C, with a retention capacity of 733 mAh·g^-1 (2.0 C) after 250 cycles.