2D (Boron Nitride/Graphene/Molybdenum Disulfide) Composite-Modified Separator for High-Performance Li–S Batteries

Lithium–sulfur (Li–S) batteries’ high specific capacity and energy density make them among the most attractive electrochemical energy storage devices. Nevertheless, their practical applicability is greatly impeded by slow redox kinetics and the shuttle effect of polysulfides. It is expected that this study’s separator modification technique will solve these problems. Here, a composite with two-dimensional (2D) materials (BN/MoS2/G) is used to reduce shuttle effects and increase the cyclability of the Li–S battery. The unique interlayer of the BN/MoS2/G (5:5) (B-G:M-5:5) composite on the separator shows remarkable electrolyte wetting capabilities with a large specific surface area, making it suitable for the complete adsorption of lithium polysulfides (LiPSs). Furthermore, the active sites of boron nitride and molybdenum sulfide can bind to LiPSs and catalyze their conversion, thus blocking their penetration. The cell assembled with the modified B-G:M-5:5 separator exhibits a high-rate capability and outstanding cycle stability with a capacity of 562 mAh g–1 at 5C over 500 cycles. B-G:M-5:5 separator also successfully suppresses the dissolution and shuttling of soluble LiPSs in Li–S batteries compared to the other two composites (B-G:M-1:9 and B-G:M-9:1)-modified separators. This research offers fresh perspectives on how Li–S batteries regulate electrochemical processes.