Application of Sn-MOF-derived SnO2 and SnO2/CNTs composites in separator modification for lithium-sulfur batteries.

• Sn-MOF derived a novel layer structure SnO 2. • Sn-MOF/CNTs derived a novel wool ball-like structure SnO 2 /CNTs composite. • SnO 2 and SnO 2 /CNTs are used as separator coatings for lithium-sulfur batteries. • SnO 2 and SnO 2 /CNTs show good adsorption and catalytic effect on polysulfides. Lithium-sulfur batteries (LSBs) are novel energy storage devices based on their high energy density. However, the application of LSBs faces many difficulties because of several obstacles, especially the shuttle effect of lithium polysulfides (LPs). In order to reduce the influence of the shuttle effect, we conducted the preparation of Sn-MOF which was successfully derived to SnO 2 and SnO 2 /CNTs and applied them as the separator coating layer. SnO 2 can effectively catalyze and adsorb polysulfides based on its unique lamellar structure, and the combination of CNT and SnO 2 further enhances the electrical conductance of the material which accelerates the Li ion migration, and thus improves the electrochemical performances. Experiments showed that the SnO 2 /CNTs coated separator LSB has a discharge capacity of 886.4 mAhg−1 in the first cycle under the sulfur areal density of 2.8 mgcm−2, and after 500 cycles, it still remains 509.6 mAhg−1. Furthermore, under the high sulfur areal density of 5 mgcm−2, the SnO 2 /CNTs modified separator battery still show stable cycle performance which demonstrate its application potential. [ABSTRACT FROM AUTHOR]