Enhanced electrochemical performance of sulfur on Y2O3-modified porous carbon aerogels for high performance lithium-sulfur batteries

摘要

Ultrafine Y2O3 modified carbon aerogels (Y-CAs) were successfully fabricated via in situ and sol-gel methods. The Y-CA materials exhibit interconnected porous structures and high adsorption ability. The Y-CA/S composites loaded with sulfur served as cathode materials in lithium-sulfur batteries to suppress the polysulfide diffusion and offer high electrical conductivity during the charge/discharge process. In particular, the designed Y2-CA/S cathode exhibits a high initial discharge capacity of 1369 mA h g(-1) and retained 1108 mA h g(-1) after 100 cycles at 0.2C. The Y2-CA/S cathode presents a good rate capability of 994 mA h g(-1) up to 2C and nice long-term cycling stability with a high reversible capacity of 892 mA h g(-1) after 300 cycles at 0.5C. The excellent electrochemical performance of the batteries is attributed to high adsorption ability and the uniform Y2O3 distribution on the porous and interrelated carbon spheres.