Sputtered MoN nanolayer as a multifunctional polysulfide catalyst for high-performance lithium-sulfur batteries

Two major obstacles for the practical application of lithium-sulfur batteries are sluggish redox kinetics and the shuttle effect of lithium polysulfides (LiPSs). Herein, MoN nanolayer-decorated multilayer graphene is fabricated via magnetron sputtering then serves as a multifunctional interlayer in Li-S batteries to suppress the shuttle effect and enhance redox kinetics. It is revealed that after the initial discharge process, the MoN layers break up into independent microreaction units consisting of MoN bodies and MoS2 edges, forming a heterogeneous composite catalyst in situ. The MoN bodies not only have high sulfur affinity to trap LiPSs but also enhance their redox kinetics. At the same time, the MoS2 edge weakens the mobility of LiPSs via the anchoring effect. As a result, Li-S cells using the interlayer present superior cycling stability under a high sulfur loading of 4.8 mg cm-2. This work may open a new avenue for developing high-performance Li-S batteries.

Automated summary

In this study, MoN nanolayer-decorated multilayer graphene was used as a layer material to suppress the shuttle effect of lithium polysulfides and enhance the redox kinetics in Li-S batteries. After the initial discharge process, the MoN layers break up into independent microreaction units consisting of MoN bodies and MoS2 edges, forming an in situ heterogeneous composite catalyst. The MoN bodies can trap LiPSs and enhance their redox kinetics, while the MoS2 edges weaken the mobility of LiPSs through the anchoring effect. Li-S cells using this interlayer exhibit excellent cycling stability under a high sulfur loading.