▎ 摘　　要

NOVELTY - A cathode active material comprises a core-shell structure including a core comprising a sulfur-carbon complex comprising thermally expanded reduced graphene oxide, and sulfur on at least a portion of the surface and the inside of the thermally expanded reduced graphene oxide, and a shell located on the surface of the core and including carbon nanotubes. USE - Active material used for forming cathode for lithium secondary battery such as lithium-sulfur battery (all claimed). Uses include but are not limited to mobile phones, camcorders, notebook personal computer, and electric vehicles. ADVANTAGE - The cathode active material has excellent electrical conductivity, and improved transport of lithium ions and electrons, and discharge capacity in high rate section. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) manufacture of the cathode active material, which involves thermally expanding the graphene oxide by heat treatment at 300-500 degrees C, reducing the thermally expanded graphene oxide by heat treatment at 700-1200 degrees C, mixing the thermally expanded reduced graphene oxide and sulfur to prepare a sulfur-carbon composite, and mixing the sulfur-carbon composite and carbon nanotubes to place the carbon nanotubes on the surface of the sulfur-carbon composite; and (2) a lithium secondary battery, which comprises an anode, cathode, a separator between the electrodes, and an electrolyte, where the cathode comprises the cathode active material.