▎ 摘　　要

Because of the severe "shuttle effect" and poor conductivity of polysulfides for lithium-sulfur batteries, some sulfur hosts as cathodes exhibit unsatisfying electrochemical performances. In this work, ZIF-8 nanocrystals attached on reduced graphene oxide (ZIF-8@rGO) was prepared through a hydrothermal process and subsequent in-situ conversion reaction. When served as sulfur host for lithium-sulfur batteries, the ZIF-8@rGO/S nanocomposite delivered a discharge capacity of 523 mAh g(-1) for 0.2 A g(-1) over 200 cycles along with a high Coulombic efficiency, exhibiting an improved long-term cycle stability. Such an improved cycle stability is related to the unique merits of ZIF-8@rGO/S nanocomposite, including tight combination, excellent conductivity, abundant reactive sites and adequate specific surface area. Consequently, the in-situ conversion reaction strategy could be also used to construct many other graphene-based nanocomposites as sulfur hosts to enhance their electrochemical performances in lithium-sulfur batteries.