Toward a practical Li-S battery enabled by synergistic confinement of a nitrogen-enriched porous carbon as a multifunctional interlayer and sulfur-host material

Abstract

Lithium-sulfur (Li-S) battery has become the most promising advanced energy storage devices due to their ultrahigh theoretical energy density. However, the notorious shuttle effect of polysulfides and low areal sulfur loading still hinder its practical application. Herein, a nitrogen-enriched hierarchical porous carbon (NEPC) was prepared via a one-step activation process, which is simultaneously served as a coating layer on the polypropylene (PP) separator and sulfur-host material in cathode, acting as a physical barrier for blocking the migration of polysulfides, playing an important role in chemical and/or physical adsorption of polysulfides, and thus significantly improving the electrochemical performance in a Li-S battery with good prospects for the practical application. Specifically, a Li-S battery assembled by a modified separator with an optimum coating thickness and S/NEPC cathode with high areal sulfur loading of 7.1 mg cm−2 shows superior electrochemical performance, with high specific and areal capacities of respective ~950 mAh·g−1 and ~6.8 mAh·cm−2 as well as stable cycle capability at 0.2C (1C = 1675 mA·g−1) rate. This dual polysulfides confinement strategy provides new guidance to rational design of multifunctional carbon-based materials for boosting the performance of a practical Li-S battery.