Infiltrating sulfur into a highly porous carbon sphere as cathode material for lithium-sulfur batteries

Sulfur composite material with a highly porous carbon sphere as the conducting container was prepared. The highly porous carbon sphere was easily synthesized with resorcinol-formaldehyde precursor as the carbon source. The morphology of the carbon was observed with field emission scanning electron microscope and transmission electron microscope, which showed a well-defined spherical shape. Brunauer-Emmett-Teller analysis indicated that it possesses a high specific surface area of 1563 m(2) g(-1), and a total pore volume of 2.66 cm(3) g(-1) with a bimodal pore size distribution, which allow high sulfur loading and easy transportation of lithium ions. Sulfur carbon composites with varied sulfur contents were prepared by melt-diffusion method and lithium sulfur cells with the sulfur composites showed improved cyclablity and long-term cycle life. (C) 2014 Elsevier Ltd. All rights reserved.