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

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.