Preparation and electrochemical properties of sulfur-carbon composite as cathode materials for the lithium-sulfur batteries

Sulfur-carbon composites as cathode for lithium-sulfur battery have been synthesized by heating a mixture of elemental sulfur and activated carbon with high specific surface area and microporous structure. The physical structure performance is characterized by X-ray diffraction, scanning electron microscopy and specific surface area measurements. It show two reduction peaks at 2.05 V and 2.35 V, one oxidation peak at 2.4 V during cyclic voltammogram test. The charge-discharge experiment indicates that its initial discharge specific capacity is 1352.5 mA·h·g^-1 at a current density of 100 mA·g^-1. The utilization of electrochemically active sulfur is about 80.9%. The specific capacity still keep as high as 800.7 mA·h·g^-1 after 40 cycles which show good cycle stability.