Enhanced polysulfide regulation via honeycomb-like carbon with catalytic MoC for lithium–sulfur batteries

Abstract

To step into the exploration of practical lithium–sulfur batteries as a high-energy output solution, several challenges such as the shuttle effect and sluggish reaction kinetics remain to be overcome. In this direction, we design a unique sulfur host derived from a honeycomb-like, porous nitrogen-doped carbon framework consisting of MoC with a three-dimensional architecture (H-MoC-NC) as both the adsorbent and catalyst for high-rate and long-lasting lithium-sulfur batteries. The interconnected carbon skeletons with a nitrogen-doped polar surface induce uniform sulfur distribution and fast charge transfer, which are supplied with strong physical confinement and the high-efficiency reaction of sulfur species. The adsorptive/catalytic MoC planes with maximized exposure endow sulfiphilic and catalytic sites that improve the ion conduction, chemical interaction, and redox kinetics in polysulfide regulation. Owing to the synergistic mode between conductive and catalytic functions, sulfur electrodes based on S/H-MoC-NC are characterized by enhanced battery performance with low polarization, high initial discharge capacity (1316 mA h g⁻¹ at 0.1C), superior rate capacities (646 mA h g⁻¹ at 3C), and decent cycling durability with a minimized capacity fading rate of 0.049% per cycle over 1000 cycles at 3C. The work not only probes the design of conductive and catalytic networks to be a promising architecture, but also demonstrates the enormous potential of MoC as an effective sulfur host for high-performance in the Li–S chemistry.