Vanadium oxide nanorods embed in porous graphene aerogel as high-efficiency polysulfide-trapping-conversion mediator for high performance lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries are highly desirable for next-generation energy storage and conversion systems because of their low cost, high energy density and unparalleled specific capacity. However, the sluggish redox kinetics and shuttling effect severely restrict the practical application of Li-S batteries. Herein, vanadium oxide nanorods were embedded in porous graphene aerogel (GA-VOx) as a dual-functional separator for the inhibition of shuttle effect and enhancement of conversion kinetic. The embedded VOx nanorods not only can chemisorb the lithium polysulfides (LiPSs) but also catalyze the LiPSs into short chain Li2S. Based on these merits, the cell with GA-VOx/CB functional separator exhibits good cycling performance (708 mAh g(-1) after 200 cycles at 0.2 C) and high rate performance (442 mAh g(-1) at 2 C) than that of CB functional separator. Additionally, even with a high sulfur loading of 2.6 mg cm(-2), the cell still delivers a stable specific capacity of 630 mAh g(-1) after 140 cycles at 0.2 C. This work provides a new route for practical application of Li-S batteries.