Sandwiched Cathodes Assembled from CoS2-Modified Carbon Clothes for High-Performance Lithium-Sulfur Batteries

Structural design of advanced cathodes is a promising strategy to suppress the shuttle effect for lithium-sulfur batteries (LSBs). In this work, the carbon cloth covered with CoS2 nanoparticles (CC-CoS2) is prepared to function as both three-dimensional (3D) current collector and physicochemical barrier to retard migration of soluble lithium polysulfides. On the one hand, the CC-CoS2 film works as a robust 3D current collector and host with high conductivity, high sulfur loading, and high capability of capturing polysulfides. On the other hand, the 3D porous CC-CoS2 film serves as a multifunctional interlayer that exhibits efficient physical blocking, strong chemisorption, and fast catalytic redox reaction kinetics toward soluble polysulfides. Consequently, the Al@S/AB@CC-CoS2 cell with a sulfur loading of 1.2 mg cm(-2) exhibits a high rate capability (approximate to 823 mAh g(-1) at 4 C) and delivers excellent capacity retention (a decay of approximate to 0.021% per cycle for 1000 cycles at 4 C). Moreover, the sandwiched cathode of CC-CoS2@S/AB@CC-CoS2 is designed for high sulfur loading LSBs. The CC-CoS2@S/AB@CC-CoS2 cells with sulfur loadings of 4.2 and 6.1 mg cm(-2) deliver high reversible capacities of 1106 and 885 mAh g(-1), respectively, after 100 cycles at 0.2 C. The outstanding electrochemical performance is attributed to the sandwiched structure with active catalytic component.

Automated summary

The design of advanced cathodes utilizing CC-CoS2 has shown high rate capability and excellent capacity retention in lithium-sulfur batteries. The sandwiched structure with active catalytic component contributes to the outstanding electrochemical performance, enabling high reversible capacities even at high sulfur loadings.