3D CoS2/rGO aerogel as trapping-catalyst sulfur host to promote polysulfide conversion for stable Li-S batteries

Abstract

Lithium-sulfur (Li-S) batteries have been regarded as one of the most promising candidates for next-generation energy storage devices owing to their low cost and high energy density. However, the shuttle effect and sluggish conversion of lithium polysulfides (LiPSs) are still thorny issues for its practical application. Here, an efficient three-dimensional conductive CoS2/rGO aerogel is constructed and used as a trapping-catalyst sulfur host to improve the overall performance of Li-S batteries. CoS2 nanoparticles, uniformly in-situ anchored on rGO sheets, provide strong trapping ability to LiPSs and then catalyze its conversion, thus inhibiting the shuttle effect and accelerating the reaction kinetics. Highly conductive porous rGO aerogel ensures fast ion and electron transfer for electrochemical reaction and electrocatalysis process. As a result, the electrode exhibits a high initial capacity of 1457 mAh g−1 at 0.2 C, superior high-rate capability of 1156 mAh g−1 at 2 C, ultra-low capacity decay rate per cycle of 0.04% at 1 C for 400 cycles, and a high areal capacity of 5.7 mA h cm−2 (high sulfur loading of 6.37 mg cm−2).