Preparation of CoO/SnO2@NC/S composite as high-stability cathode material for lithium-sulfur batteries

To improve the sulfur loading capacity of lithium-sulfur batteries (Li-S batteries) cathode and avoid the inevitable "shuttle effect", hollow N doped carbon coated CoO/SnO2 (CoO/SnO2@NC) composite has been designed and prepared by a hydrothermal-calcination method. The specific surface area of CoO/SnO2@NC composite is 85.464 m(2)center dot g(-1), and the pore volume is 0.1189 cm(3)center dot g(-1). The hollow core-shell structure as a carrier has a sulfur loading amount of 66.10%. The initial specific capacity of the assembled Li-S batteries is 395.7 mAh center dot g(-1) at 0.2 C, which maintains 302.7 mAh center dot g(-1) after 400 cycles. When the rate increases to 2.5 C, the specific capacity still has 221.2 mAh center dot g(-1). The excellent lithium storage performance is attributed to the core-shell structure with high specific surface area and porosity. This structure effectively increases the sulfur loading, enhances the chemical adsorption of lithium polysulfides, and reduces direct contact between CoO/SnO2 and the electrolyte.