Hierarchically Porous C/Fe3C Membranes with Fast Ion-Transporting Channels and Polysulfide-Trapping Networks for High-Areal-Capacity Li-S Batteries.

Abstract

We report here highly scalable yet stackable C/Fe3C membranes with fast ion-transport micro-/nanochannels and polysulfide-trapping networks via a facile phase-inversion process for high-areal-capacity Li-S batteries. The membrane cathodes with aligned channels and hierarchically porous networks significantly promote Li+ and electron transportation and meanwhile trap soluble polysulfide intermediates (LiPSs) effectively via strong chemical adsorption of the doped Fe3C nanoparticles in the membrane toward LiPSs. We further demonstrated that five-layer membrane electrodes with high S loading of 7.1 mg cm-2 were readily prepared via layer-by-layer stacking of the C/Fe3C membrane, which can deliver a high capacity of 726 mA h g-1 after 100 cycles, corresponding to an ultra-high-areal-capacity of 5.15 mA h cm-2 at a low electrolyte/sulfur (E/S) ratio of 6.4 μL mg-1. The scalable multifunctional membrane electrodes with excellent electrochemical performance under high-sulfur-loading and lean electrolyte conditions reveal its promising applications in practical Li-S batteries.