Boosting Charge Transport and Catalytic Performance in MoS2 by Zn2+ 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 Zn2+ intercalation strategy was proposed to promote the phase transition from semiconducting 2H-phase to metallic 1T-phase of MoS2. Furthermore, the Zn2+ between layers can expand the interlayer spacing of MoS2 and serve as a charge transfer bridge to promote longitudinal transport along the c-axis of electrons. DFT calculations further prove that Zn-MoS2 possesses better charge transfer ability and stronger adsorption capacity. At the same time, Zn-MoS2 exhibits excellent redox electrocatalytic performance for the conversion and decomposition of polysulfides. As expected, the lithium–sulfur battery using Zn0.12MoS2-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.