Nitrogen–sulfur dual-doped porous carbon spheres/sulfur composites for high-performance lithium–sulfur batteries

A nitrogen–sulfur dual-doped porous carbon spheres/sulfur composite (PCS-NS/S) sample was prepared by a simple hydrothermal method with starch and l-methionine as carbon and nitrogen–sulfur resources, respectively. XRD, XPS, and N(2) adsorption–desorption tests were used to characterize the crystal and pore structure of the PCS-NS/S sample. The morphology and weight ratio of sulfur were investigated by SEM, TEM, and TG analyses. The sample was used as the positive electrode for lithium–sulfur batteries and found to exhibit excellent electrochemical performance.