Investigation of Vanadium Pentoxide–Sulfur Cathodes for Enhanced Lithium–Sulfur Battery Performance

Lithium–sulfur batteries (LSBs), widely regarded as a promising next-generation energy storage system due to their high theoretical specific capacity and environmental compatibility, remain constrained by the insulating nature of sulfur and the shuttle effect of soluble long-chain polysulfides. Here, we report the multiwalled carbon nanotube sulfur (S)/(MWCNT)/vanadium pentoxide (V2O5) composite prepared via a tube-furnace encapsulation process in an argon atmosphere that effectively addresses these shortcomings. In this design, MWCNTs establish a robust electron conduction framework, while polar V2O5 sequesters polysulfides, thereby mitigating their dissolution into the electrolyte. Electrochemical tests demonstrate that the encapsulated S/MWCNT/ V2O5/CMC electrode achieves a specific capacity of 1605 mAh g-1 at 0.1C, a substantial improvement over pristine S/MWCNT/CMC electrodes, which delivered ~550 mAh g-1 at 0.5C and are prone to short circuits at higher current densities. The V2O5-encapsulated electrodes also retain significant performance, exhibiting capacities of 750 mAh g-1 at 1C after 80 cycles and 600 mAh g-1 at 0.5C after 120 cycles, surpassing unencapsulated MWCNT/ V2O5 (initial capacity ~1203 mAh g-1 at C/20). Cyclic voltammetry and electrochemical impedance spectroscopy further demonstrate enhanced redox kinetics and reduced interfacial resistance. Overall, our work highlights a robust strategy to overcome critical barriers in LSBs technology, paving the way for high-capacity, long-life energy storage systems. We will present these findings in detail, including XPS, XRD, Raman, TGS, and DSC analyses, at the conference.