A novel separator modified by titanium dioxide nanotubes/carbon nanotubes composite for high performance lithium-sulfur batteries

The rechargeable lithium-sulfur batteries were investigated as the most promising energy storage system. Although the composites of carbonaceous materials and metal oxides as the hosts of sulfur have been applied to improve the performance, their structures usually collapsed due to huge volumetric expansion of sulfur. Therefore, interlayer reported as a novel cell configuration could efficiently restrict the shuttle effect of polysulfide. Here, we design a unique separator modified by a functional "polysulfide trapping net" which consists of intertwined TiO2 nanotubes and carbon nanotubes to improve the electrochemical performance of lithium sulfur batteries. Benefiting from the network structure, there are abundant ion pathways, meanwhile, TiO2 nanotubes provide strong chemical and physical adsorption, carbon nanotubes serve as a conductive network which accelerates the transport of electrons. With the modified separator, the electrode exhibits an initial capacity of 936 mAh g(-1) at 1 C rate and maintains a stable cycling performance over 200 cycles.