摘要
The high specific capacity and energy density of lithium-sulfur batteries have attracted strong considerations on their fundamental mechanism and energy applications.However,polysulfide shuttle is still the key issue that impedes the development of Li-S batteries.Exploring nanocrystal hosts for polysulfide immobilization and conversion is a promising way.In this contribution,we have investigated well-dispersed Co9S8 nanocrystals grown on graphene oxide(GO)nanosheets with different degrees of dispersion as cathode host materials for Li-S batteries.The Co9S8-GO composite with 1 wt%GO(GCS1)has an average crystal size of 76 nm and shows the strongest adsorption capability toward lithium polysulfides.When used as the host material for the cathode of Li-S batteries,the GCS1-sulfur composite exhibits an initial specific capacity of^-1000 mAh g^-1 at 0.5 C and shows an average decay rate of 0.11%for 500 cycles.This work on the dispersion control of Co9S8 nanocrystals may inspire more investigations on well-dispersed nanocrystal based hosts for Li-S batteries.
基金
supported by the National Science Fund for Distinguished Young Scholars(51425204,21825501)
the National Natural Science Foundation of China(21776019,51832004 and U1801257)
the National Key R&D Program of China(2016YFA0202603,2016YFA0202500)
the Yellow Crane Talent(Science&Technology)Program of Wuhan City
the Tsinghua University Initiative Scientific Research Program
the National Basic Research Program of China(2013CB934103)。
