Three-dimensional graphene hollow spheres with high sulfur loading for high-performance lithium-sulfur batteries

Zhen Wu, Wei Wang, Yanting Wang, Chen Chen, Kelun Li, Gangjin Zhao, Chunyu Sun,

Wenjian Chen, Lubin Ni*, Guowang Diao*

College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, Jiangsu, People’s Republic of China.

Abstract:Lithium-sulfur batteries have currently attracted wide interest due to their high theoretical capacity, but the practical applications are being hampered by capacity decay, mainly attributed tothe polysulfide shuttle. Here, we havedesigned a novel three-dimensional (3D) nanostructure ofgraphene hollow spheres(HGs) as the sulfur host. The 3D HGs were successfully prepared viaa self-assembly method ofwrapping graphene oxide (GO) on SiO2 spheres, and thenfollowed by carbonization and etching of the SiO2.The impregnation of sulfur into the hollow graphene spheres lead to obtaining the HGs/S cathode, which reaches up a high sulfur loading of 90 wt% in the composite (72 wt % in the whole cathode). The HGs/S cathode material remains a high discharge capacity of 810 mAh g-1 after 200 cycles at 0.5 C rate. Furthermore, it demonstrates a low capacity-decay rate of 0.083 % per cycle after 600 cycles at 1 C rate. Compared withpristine reduced graphene oxide/sulfur composites (RGO/S), the as-prepared 3D self-assembled graphene hollow spheres HGs/S exhibit significantly improved electrochemical performances in terms of high specific capacity, remarkable rate capability and excellent cycling stability. These synergistic effects are achieved by more effective 3D ion/electron transport pathways, and efficient confinement of polysulfide dissolution and shuttling.

Electrochimica Acta2017, 224,527–533.IF：4.803

文章链接:http://www.sciencedirect.com/science/article/pii/S0013468616326196