Adsorption-catalysis synergy within pyrrolic-N-rich carbon nanosheets: Propelling electrochemical kinetics and shielding polysulfides for lithium-sulfur batteries.

[Display omitted] • The N pr -CNs is synthesized by pre-pelletizing and subsequent pyrolysis process. • The N pr -CNs have dominate pyrrolic N-doping, unique structure and electronic state. • It can inhibit the shuttle effect and improve redox kinetics by synergistic effect. • The Li-S cell with N pr -CNs/PP deliver high discharge capacity of 932 mAh g−1 at 1C. The practical applications of lithium-sulfur (Li-S) batteries are rather limited by the shuttle effect of lithium polysulfides (LiPSs) and sluggish redox reaction kinetics. Here, a kind of pyrrolic-N-rich carbon nanosheets (N pr -CNs) are prepared by introducing melamine cyanurate (MCA) into the carbonization process of polyacrylonitrile (PAN). As a mediator in Li-S batteries, hierarchical pores, dominant pyrrolic-N-doping, disorder/defective structures and unique electronic states endow N pr -CNs with synergistic adsorption-catalysis function for S species. Specifically, they can effectively inhibit LiPSs shuttle, catalyze the conversion of both liquid-phase LiPSs and solid-phase Li 2 S, reduce the charge transfer resistance and enhance Li-ions migration rate. Hence, it can make the Li-S batteries deliver excellent rate performance and cycling stability. The battery can reach ultrahigh discharge capacity of 932.0 mAh g−1 at the beginning under current density of 1C and even liberate a capacity as high as 1109.4 mAh g−1 at 0.2C with high sulfur loading of 3.8 mg cm−2. [ABSTRACT FROM AUTHOR]