Co/MoN Invigorated Bilateral Kinetics Modulation for Advanced Lithium–Sulfur Batteries

Abstract

Sluggish sulfur redox kinetics and Li-dendrite growth are the main bottlenecks for lithium-sulfur (Li-S) batteries. Separator modification serves as a dual-purpose approach to address both of these challenges. In this study, the Co/MoN composite is rationally designed and applied as the modifier to modulate the electrochemical kinetics on both sides of the sulfur cathode and lithium anode. Benefiting from its adsorption-catalysis function, the decorated separators (Co/MoN@PP) not only effectively inhibit polysulfides (LiPSs) shuttle and accelerate their electrochemical conversion but also boost Li⁺ flux, realizing uniform Li plating/stripping. The accelerated LiPSs conversion kinetics and excellent sulfur redox reversibility triggered by Co/MoN modified separators are evidenced by performance, in-situ Raman detection and theoretical calculations. The batteries with Co/MoN@PP achieve a high initial discharge capacity of 1570 mAh g^-1 at 0.2 C with a low decay rate of 0.39%, uniform Li⁺ transportation at 1 mA cm^-2 over 800 h. Moreover, the areal capacity of 4.62 mAh cm^-2 is achieved under high mass loadings of 4.92 mg cm^-2. This study provides a feasible strategy for the rational utilization of the synergistic effect of composite with multifunctional microdomains to solve the problems of Li anode and S cathode toward long-cycling Li-S batteries.