Boosting Charge Transport and Catalytic Performance in MoS 2 by Zn 2+ Intercalation Engineering for Lithium-Sulfur Batteries.

Transition metal dichalcogenides (TMDs) have been widely studied as catalysts for lithium-sulfur batteries due to their good catalytic properties. However, their poor electronic conductivity leads to slow sulfur reduction reactions. Herein, a simple Zn 2+ intercalation strategy was proposed to promote the phase transition from semiconducting 2H-phase to metallic 1T-phase of MoS 2 . Furthermore, the Zn 2+ between layers can expand the interlayer spacing of MoS 2 and serve as a charge transfer bridge to promote longitudinal transport along the c -axis of electrons. DFT calculations further prove that Zn-MoS 2 possesses better charge transfer ability and stronger adsorption capacity. At the same time, Zn-MoS 2 exhibits excellent redox electrocatalytic performance for the conversion and decomposition of polysulfides. As expected, the lithium-sulfur battery using Zn 0.12 MoS 2 -carbon nanofibers (CNFs) as the cathode has high specific capacity (1325 mAh g -1 at 0.1 C), excellent rate performance (698 mAh g -1 at 3 C), and outstanding cycle performance (it remains 604 mAh g -1 after 700 cycles with a decay rate of 0.045% per cycle). This study provides valuable insights for improving electrocatalytic performance of lithium-sulfur batteries.