Titanium-based nanorods/ketjen black modified separator as polysulfides barrier for lithium sulfur cell

The practical application of lithium sulfur (Li/S) cells is mainly hindered by the shuttle effect. Herein, the titanium-based nanorods/ketjen black (KB) composite prepared by a facile hydrothermal reaction is deposited on polypropylene to fabricate a bi-functional separator (KTO-2/PP) for Li/S cell. Using bare sublimed sulfur cathode, the cell based on KTO-2/PP separator exhibits excellent rate capability, delivering 1122, 856, and 566 mAh g(-1) at 0.2, 1 and 2C, respectively. Moreover, the reversible capacity of the KTO-2/PP based cell can reach 754 mAh g(-1) (1C) in the 200th cycle. Such performance boost is primarily ascribed to the KTO-2/PP separator, that Li+ is allowed to pass through but lithium polysulfides (LiPS) is shielded against shuttle. The conductive KB facilitates electron transport and adsorbs LiPS physically. The titanium-based nanorods adsorbs LiPS chemically by forming Ti-S bond which is confirmed by XPS analysis. Regarding the aged Li/S cell using KTO-2/PP, the smooth surface of PP (facing lithium anode) and the less sediment and negligible corrosion on anode indicate that the KTO-2/PP separator acts as an efficient barrier to inhibit the LiPS migration and enhances the electrochemical performance. (C) 2020 Elsevier B.V. All rights reserved.