Coral-like reduced graphene oxide/tungsten sulfide hybrid as a cathode host of high performance lithium-sulfur battery

Lithium-sulfur battery is one of the most promising next-generation energy storage devices owing to its high energy density and environment friendliness. However, the low electronic conductivity of sulfur and the high solubility of intermediates in electrolyte are the challenges for its wide applications. To address these issues, we report a novel architecture, a coral-like reduced graphene oxide/tungsten sulfide hybrid, as host for sulfur cathode. This hybrid is fabricated by in-situ growing tungsten sulfide nanoflakes on a reduced graphene oxide aerogel, providing not only a 3D network for electronic conductivity, but also a large surface area to entrap chemically the intermediates. As expected, the sulfur cathode based on this hybrid support exhibits a high discharge capacity of 1531 mAh g(-1) at 0.05 C and a high sulfur utilization of 91.6%. Even at a high rate of 1 C, an initial specific capacity of 883 mAh g(-1) and an extremely low capacity-decay rate of 0.086% per cycle are still achieved. The ability of the resulting hybrid to entrap the intermediates is confirmed by combining physical characterization and theoretical calculations.