Stepped Porous Carbon-Multilayer Graphene@Fe3C/Fe3N Membrane to Inhibit the Polysulfides Shuttle for High-Performance Lithium–Sulfur Batteries

Lithium–sulfur (Li–S) batteries are regarded as one of the most prominent future-oriented energy battery systems due to their high theoretical energy density (2600 Wh kg −1 ). However, the shuttle effect of polysulfides and short cycle life have critically hindered their commercialization. Herein, a stepped porous heterostructured membrane of carbon-multilayer graphene (MG)@Fe 3 C/Fe 3 N is developed by a facile phase inversion method and applied as a current collector to replace Al foil. The special heterostructured membrane with MG can further boost the charge/Li + ion transfer speed while accommodating the volume expansion in the charge/discharge cycle. The shuttle effect of polysulfides is inhibited by the heterostructure phase of the Fe 3 C/Fe 3 N catalytic effect and chemisorption. This synergistic effect is confirmed by density function theory (DFT) calculations. As a result, the C-MG@Fe 3 C/Fe 3 N membranes delivers distinguished discharge capacity and cycling stability of 508.92 mAh g −1 (693.47 mAh g −1 ) at a large discharge of current of 2 C (at 0.5 C) after 400 cycles (300 cycles) with only 0.36% capacity attenuation per cycle.