Synthesis of 3D Porous and Interconnected Hollow Carbon Nanospheres Array and Its Applications in Lithium-sulfur Batteries

摘要

Lithium-sulfur (Li-S) batteries are receiving much attention due to their high theoretical lithium storage capacity and energy density.However,the commercialization of Li-S batteries is mainly impeded by the inherent poor electrical conductivity of sulfur,the side shuttle behavior of polysulfides,and the volumetric change of sulfur during cycles.To solve these problems,here we report a unique 3D porous and interconnected hollow carbon nanospheres array (3D-HCNA) as sulfur host for lithium-sulfur batteries.This 3D-HCNA was synthesized through a nanocasting approach with sucrose as carbon precursors and mesoporous silica nanospheres as hard-templates.The silica nanospheres with special nanostructure were obtained by a biphase stratification approach.Owing to its unique architecture,as-prepared 3D-HCNA/S cathode with a high sulfur loading of 76 wt％ exhibited excellent electrochemical performance.It showed high initial capacity of 1318 mAh/g at 0.05 C and good rate capability of 760 mAh/g at 1 C.Moreover,excellent cycling performance was also observed with a capacity of 757 mAh/g maintained after 200 cycles at 0.5 C.