Synthesis and characterization of sulfur-carbon-vanadium pentoxide composites for improved electrochemical properties of lithium-sulfur batteries

Sulfur (S)-carbon (C)-vanadium pentoxide (V₂O₅) composites were prepared by wet ball milling, and their physical and electrochemical properties were evaluated. Firstly, the effect of the carbon content of S-C composite electrodes on their physical and electrochemical properties was investigated. The S-C composite electrode with 60 wt.% S delivers a first discharge capacity of 1077 mAh g^-1. However, its capacity markedly decreases to 606 mAh g^-1 after 10 cycles, which corresponds to a capacity fading rate of 47 mAh g^-1 per cycle. To improve the electrochemical performance of the S-C composite electrode, carbon was partially replaced by V₂O₅. The S-C-V₂O₅ composite electrode with a composition of 60 wt.% - S, 30 wt.% - V₂O₅ and 10 wt.% - C exhibits a lower capacity fading rate of 23 mAh g^-1 per cycle in the first 10 cycles and better capacity retention than the S-C composite electrode over 50 cycles.