Hierarchically Porous C/Fe<sub>3</sub>C Membranes with Fast Ion-Transporting Channels and Polysulfide-Trapping Networks for High-Areal-Capacity Li-S Batteries.

Li, Xiangcun; Zhang, Yue; Wang, Shuting; Liu, Yang; Ding, Yu; He, Gaohong; Zhang, Ning; Yu, Guihua · Nano Lett · 2020

basic_science · Level V

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Abstract

We report here highly scalable yet stackable C/Fe<sub>3</sub>C 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<sup>+</sup> and electron transportation and meanwhile trap soluble polysulfide intermediates (LiPSs) effectively via strong chemical adsorption of the doped Fe<sub>3</sub>C nanoparticles in the membrane toward LiPSs. We further demonstrated that five-layer membrane electrodes with high S loading of 7.1 mg cm<sup>-2</sup> were readily prepared via layer-by-layer stacking of the C/Fe<sub>3</sub>C membrane, which can deliver a high capacity of 726 mA h g<sup>-1</sup> after 100 cycles, corresponding to an ultra-high-areal-capacity of 5.15 mA h cm<sup>-2</sup> at a low electrolyte/sulfur (<i>E</i>/<i>S</i>) ratio of 6.4 μL mg<sup>-1</sup>. 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.