Multi-shelled hollow carbon nanospheres for lithium–sulfur batteries with superior performances†
Lithium–sulfur batteries are regarded as a promising energy storage system. However, they are plagued by rapid capacity decay, low coulombic efficiency, a severe shuttle effect and low sulfur loading in cathodes. To address these problems, effective carriers are highly demanded to encapsulate sulfur and extend the cycle life. Here, we report an aqueous emulsion approach and in situ sulfur impregnation to synthesize multi-shelled hollow carbon nanosphere-encapsulated sulfur composites with a high percentage of sulfur loading (86 wt%). When applied as cathodes in lithium–sulfur batteries, the composite materials delivered a high specific capacity of 1350 mA h g−1 and excellent capacity retention (92% for 200 cycles). Further measurements at high current densities also demonstrate significantly enhanced cyclability and high rate capability.