Multifunctional V3S4-nanowire/graphene composites for high performance Li-S batteries

Abstract

Lithium sulfur (Li-S) batteries have been regarded as a promising next-generation energy storage system with high theoretical specific capacity and energy density, but still facing challenges. In order to make Li-S batteries more competitive, combination of trapping sites and electrocatalytic properties for polysulfides is an effective way to improve the battery performance. In this study, we prepare a type of multifunctional V3S4-nanowire/graphene composites (V3S4-G) by uniformly dispersing V3S4 nanowires on the graphene substrate. This structure contributes to the sufficient exposure of multifunctional V3S4 active sites which can anchor polysulfides and accelerate reaction kinetics. Thus, the Li-S batteries based on the multifunctional V3S4-G sulfur cathode deliver a stable cycling performance and good rate capability. Even at sulfur loading of 3 mg cm−2, the V3S4-G sulfur cathode possesses a low capacity decay rate of 0.186% per cycle at 0.5 C.