A New Finding on the Enhancement of the Ability of Polysulfide Adsorption of V2O5 by Doping Tungsten in Lithium-Sulfur Batteries

Lithium-sulfur batteries are considered to be the most commercially promising lithium metal secondary batteries due to their high specific capacity. However, the shuttle effect of lithium polysulfide (LiPS) in the electrolyte seriously hinders the development of lithium-sulfur batteries. W-doped V2O5 (W-V2O5) is prepared by a hydrothermal method, which greatly improves the LiPS adsorption ability of V2O5. The W-V2O5 powder can discolor the LiPS solution in 1 min. Then, W-V2O5 is combined with a graphene/carbon nanotube composite (G/CNT) with good conductivity to modify the separator. As a result, the W-V2O5-G/CNT-coated separator allows the sulfur cathode to reach a high initial discharge capacity of 1200 mAh g(-1) at 0.2 C and a reversible capacity of 815 mAh g(-1) after 200 cycles at 0.5 C, and leads to an excellent rate ability (up to 2 C rate) and a high coulombic efficiency of 99.5%. This provides a new direction for designing efficient LiPS catalysts.