Oxygen Dopants in MoS2 Catalysts as Dual Anchors for a Lithium Polysulfide Chain to Accelerate Conversion to Solid Li2S: A Strategy to Mitigate the Shuttle Effect in Li–S Batteries

The development of lithium-sulfur batteries (LSBs) is hindered by the solubility of polysulfide intermediates. Herein, we synthesized oxygen-doped MoS2 on a highly conductive CNT as a cathode material for LSBs. The spaced oxygen dopants on the catalyst surface enable Li polysulfide chains to adsorb parallel to the catalyst surface. This configuration restricts solubility and accelerates the conversion of soluble Li polysulfides to insoluble Li2S. Therefore, the Mo(S-O)2/CNT cathode demonstrates an impressive discharge capacity (1410.4 mAh g-1 at 0.2 C and 880.3 mAh g-1 at 2 C) along with exceptional cycle stability, retaining 62.7% capacity after 100 cycles at 0.2 C and showing a low decay rate of 0.094% per cycle over 400 cycles at 2 C in LSBs. This work will inspire further research on the deanchoring design of Li2S from negatively charged polar dopants in catalysts as well as studies on the synchronization of catalysis with the anchoring-deanchoring process.