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

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 SnO2 and SnO2/CNTs and applied them as the separator coating layer. SnO2 can effectively catalyze and adsorb polysulfides based on its unique lamellar structure, and the combination of CNT and SnO2 further enhances the electrical conductance of the material which accelerates the Li ion migration, and thus improves the electrochemical performances. Experiments showed that the SnO2/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 SnO2/CNTs modified separator battery still show stable cycle performance which demonstrate its application potential.