Inorganic Mediator toward Organosulfide Active Material: Anchoring and Electrocatalysis

Organosulfides are promising high-capacity cathode materials for rechargeable lithium batteries. However, they are hindered by several key challenges including the electronic/ionic insulation and solubility issues of the discharged products. Herein, TiS 2 nanosheets@carbon nanotubes (TiS 2 NSs@MWCNT) are proposed as a promoter and booster toward phenyl tetrasulfide (PTS). It serves as a bifunctional mediator, not only anchoring active materials in the cathode through chemical adsorption but also facilitating the reaction kinetics. The Li-organosulfide cell yields a reversible discharge capacity of 467.6 mAh g −1 and a high capacity retention of 81.9% after 200 cycles at 0.5 C rate. When the PTS areal mass loading is 5.8 mg cm −2 and the electrolyte/PTS ratio is 3.8 µL mg −1 , a high specific capacity of 444 mAh g −1 at 0.5 C rate can still be achieved. The strong anchoring and electrocatalysis effects of TiS 2 toward PhSLi and polysulfide are revealed using experimental and computational approaches. The study sheds light on metal sulfides as mediators to improve the cycling life of Li-organosulfide batteries and provides deep comprehension of the instinct interaction evolution at molecular level, which is invaluable for fabrication of electrode materials.