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.