Mo(2)C-Loaded Porous Carbon Nanosheets as a Multifunctional Separator Coating for High-Performance Lithium–Sulfur Batteries

Lithium–sulfur batteries have emerged as one of the promising next-generation energy storage devices. However, the dissolution and shuttling of polysulfides in the electrolyte leads to a rapid decrease in capacity, severe self-discharge, and poor high-temperature performance. Here, we demonstrate the design and preparation of a Mo(2)C nanoparticle-embedded carbon nanosheet matrix material (Mo(2)C/C) and its application in lithium–sulfur battery separator modification. As a polar catalyst, Mo(2)C/C can effectively adsorb and promote the reversible conversion of lithium polysulfides, suppress the shuttle effect, and improve the electrochemical performance of the battery. The lithium–sulfur battery with the Mo(2)C/C =-modified separator showed a good rate of performance with high specific capacities of 1470 and 799 mAh g(−1) at 0.1 and 2 C, respectively. In addition, the long-cycle performance of only 0.09% decay per cycle for 400 cycles and the stable cycling under high sulfur loading indicate that the Mo(2)C/C-modified separator holds great promise for the development of high-energy-density lithium–sulfur batteries.