Oxygenated Nitrogen-Doped Microporous Nanocarbon as a Permselective Interlayer for Ultrastable Lithium-Sulfur Batteries

The commercial success of lithium-sulfur (Li−S) batteries is still impeded by the severe capacity decay caused by polysulfide shuttling between the cathode and anode. Herein, we present an oxygenated metal-organic framework (MOF)-derived nitrogen-doped microporous carbon (OMNC) interlayer to mitigate the shuttling of polysulfides. The OMNC interlayer with abundant carboxyl and hydroxyl groups is highly permselective to Li ⁺ ions but efficiently suppress the penetration of undesired S _n ²⁻ ions to the anode side owing to electrostatic interactions. The doped nitrogen in OMNC can enhance the binding with polysulfides, thus alleviating the shuttle effect. The strong affinity of oxygenated groups and doped nitrogen with polysulfides is demonstrated by density functional theory (DFT) calculations. Furthermore, the highly conductive OMNC interlayer can also act as a second current collector to promote electron transportation, thus strengthening the utilization of the active material and improving the cycling performance of the cells. At a high sulfur loading up to 3 mg cm ⁻² , the multi-walled carbon nanotubes/sulfur (CNTs/S) cathode matched with the OMNC interlayer exhibits a reversible capacity of 580.5 mAh g ⁻¹ after 610 cycles at 1 C, corresponding to an average capacity loss per cycle of 0.038 %. These results suggest a new way to advanced Li−S batteries using a MOF-derived multifunctional interlayer.