Regulating Electronic Structure of Fe-N4 Single Atomic Catalyst via Neighboring Sulfur Doping for High Performance Lithium-Sulfur Batteries

Constructing high performance electrocatalysts for lithium polysulfides (LiPSs) adsorption and fast conversion is the effective way to boost practical energy density and cycle life of rechargeable lithium-sulfur (Li-S) batteries, which have been regarded as the most promising next generation high energy density battery but still suffering from LiPSs shuttle effect and slow sulfur redox kinetics. Herein, a single atomic catalyst of Fe-N-4 moiety doping periphery with S (Fe-NSC) is theoretically and experimentally demonstrated to enhance LiPSs adsorption and facilitated sulfur conversion, due to more charge density accumulated around Fe-NSC configuration relative to bare Fe-N-4 moiety. Thereafter, the graphene oxide supported Fe-NSC catalyst (Fe-NSC@GO) is modified to the commercial separator through a simple slurry casting method. Thus, Li-S cells with Fe-NSC@GO modified separators display high discharge capacity and excellent cyclability, showing 1156 mAh g(-1) at 1 C rate and a low capacity decay of only 0.022% per cycle over 1000 cycles. Even with a high sulfur loading of 5.1 mg cm(-2), the cell still delivers excellent cycling stability. This work provides a fresh insight into electrocatalyst structural tuning to improve the electrochemical performance of Li-S batteries.

Automated summary

Constructing high performance electrocatalysts, such as the single atomic catalyst of Fe-N-4 moiety doping periphery with S (Fe-NSC), can effectively enhance lithium polysulfides (LiPSs) adsorption and facilitate sulfur conversion, improving the energy density and cycle life of rechargeable lithium-sulfur (Li-S) batteries. By modifying the graphene oxide supported Fe-NSC catalyst (Fe-NSC@GO) to the commercial separator, Li-S cells exhibit high discharge capacity and excellent cyclability, with 1156 mAh g(-1) at 1 C rate and a low capacity decay of only 0.022% per cycle over 1000 cycles. This work provides new insights into structural tuning of electrocatalysts to improve the electrochemical performance of Li-S batteries.