Sulfur@nitrogen-doped carbon yolk@shell nanospheres synthesized via in situ oxidation for Lithium–Sulfur batteries

How to construct the advanced sulfur cathode material with both high conductivity and well-defined structure is an important direction for Li–S batteries. In present study, we report a facile in situ method to prepare sulfur@nitrogen-doped carbon (S@N–C) yolk@shell nanospheres (NSs) as cathodes for Lithium–Sulfur (Li–S) batteries. The In-situ synthesis strategy eliminates the problem of diffusion of LiPSs caused by sulfur accumulated on the outer surface of N–C. Moreover, the yolk@shell structure reduces volume expansion upon lithiation through internal hollow structure and provides physical confinement and chemical adsorption of LiPSs by enclosed N–C outer shell. In addition, the electronic conductivity and reaction kinetic rate increased due to the doped nitrogen. As expected, the S@N–C NSs cathodes exhibited superior electrochemical performance for Li–S batteries (616 mAh g−1 at 1.0 C after 500 cycles).