A metal organic foam-derived zinc cobalt sulfide with improved binding energies towards polysulfides for lithium-sulfur batteries

The shuttle effect of polysulfides is a serious issue for lithium-sulfur (Li-S) batteries, because it leads to rapid capacity decay. Herein, we present a metal organic foam-derived ZnCo2S4 that is capable of forming polar bonds with soluble polysulfides and improving the binding force to suppress the shuttle effect. The ZnCo2S4 also has a smaller Li ion diffusion barrier energy than ZnCo2O4. ZnCo2S4 grown on conductive carbon cloth facilitates fast electron transfer, while its hierarchical structure accommodates the volumetric expansion of sulfur in Li-S batteries. The ZnC(o)2S(4)/S cathodes exhibit a stable capacity of 833 mAh g(-1) after 100 cycles at 0.1C and a high Coulombic efficiency of 99.9%, along with a high rate-performance after repeated tests; these features indicate a good potential for energy storage applications.