Insight into the Anchoring and Catalytic Effects of VO2 and VS2 Nanosheets as Sulfur Cathode Hosts for Li–S Batteries

Abstract Transition metal oxides and sulfides have been intensively investigated as host materials for the S cathode in lithium–sulfur (Li–S) batteries; however, the distinctions between them in battery operation have remained unclear. In this study, VO 2 and VS 2 nanosheets were systematically studied as host materials for Li–S batteries through theoretical calculations and experimental testing. First‐principles calculations demonstrated that VS 2 showed more favorable properties, including the inherent semi‐metallic conductivity of VS 2 , moderate adsorption strength for Li 2 S n , fast Li + transport with a low diffusion barrier, and accelerated surface redox reactions with a low Li 2 S decomposition barrier. In comparison, the low electronic conductivity and strong adsorption strength of VO 2 increased Li + diffusion as well as Li 2 S decomposition barriers of the electrode, resulting in relatively poor rate capability and cycle stability. In experiments, the VS 2 @S electrode exhibited superior electrochemical performance compared with VO 2 @S, giving a large capacity of 713 mAh g −1 at 5 C and a low capacity fading rate of 0.13 % per cycle over 200 cycles at 1 C. The constructed relationships between S cathode and host materials could guide the future design of high‐performance S cathodes for Li–S batteries.