Sulfur-carbon composite (CAS number: 7440-44-0/7704-34-9) is a cathode active material used in lithium-sulfur (Li–S) batteries. Li–S batteries have an exceptionally high theoretical energy density of 2600 Wh/kg and specific capacity of 1672 mAh/g.
Sulfur-carbon composite is synthesized through melt diffusion at 155°C for 12 hours from ground sulfur and carbon powder. Carbon acts as a host material in the sulfur-carbon composite, providing sufficient conductive surface and ion/electron transport channels, particularly at high sulfur loading and great electrode thickness. Sulfur-carbon composite enhances electrolyte permeability, allowing fast reactions between lithium ions and sulfur. Sulfur-carbon composite with vary sulfur content from 40-70% can achieve discharge capacities of 500-900 mAh/g, with 50-70% capacity retention over 50-150 cycles.