Two-dimensional multimetallic sulfide nanosheets with multi-active sites to enhance polysulfide redox reactions in liquid Li2S6-based lithium-polysulfide batteries

Abstract

Two-dimensional Cu, Zn and Sn-based multimetallic sulfide nanosheets were prepared to construct multi-active sites for the immobilization and entrapment of polysulfides with offering better performance in liquid Li 2 S 6 -based lithium-polysulfide batteries. The lithium-sulfur battery has attracted enormous attention as being one of the most significant energy storage technologies due to its high energy density and cost-effectiveness. However, the “shuttle effect” of polysulfide intermediates represents a formidable challenge towards its wide applications. Herein, we have designed and synthesized two-dimensional Cu, Zn and Sn-based multimetallic sulfide nanosheets to construct multi-active sites for the immobilization and entrapment of polysulfides with offering better performance in liquid Li 2 S 6 -based lithium-polysulfide batteries. Both experimental measurements and theoretical computations demonstrate that the interfacial multi-active sites of multimetallic sulfides not only accelerate the multi-chained redox reactions of highly diffusible polysulfides, but also strengthen affinities toward polysulfides. By adopting multimetallic sulfide nanosheets as the sulfur host, the liquid Li 2 S 6 -based cell exhibits an impressive rate capability with 1200 mAh/g and retains 580 mAh/g at 0.5 mA/cm 2 after 1000 cycles. With high sulfur mass loading conditions, the cell with 2.0 mg/cm 2 sulfur loading delivers a cell capacity of 1068 mAh/g and maintains 480 mAh/g with 0.8 mA/cm 2 and 500 cycles. This study provides new insights into the multifunctional material design with multi-active sites for elevated lithium-polysulfide batteries.