▎ 摘　　要

NOVELTY - The method involves preparing the graphene oxide. The graphene oxide and silicon-based material are added to the solvent, and mixed to produce the first composites. A portion of the graphene oxide is reduced to graphene so as to produce the second composites. USE - Method for manufacturing cathode material of lithium secondary battery (claimed) used for electric vehicle, medium-large-sized energy storage device, and cellular phone. ADVANTAGE - The first composite is subjected to heat treatment to reduce a portion of the graphene oxide to graphene, so that the graphene-coated second composite is produced on the surface of the silicon-based material. Since the graphene oxide has a higher dispersibility in the solvent than graphene, the graphene is uniformly coated on the surface of the silicon-based material. The thickness of the graphene coated on the surface of the silicon-based material is easily controlled by adjusting the time at which the mechanical mixing is performed and the content of the graphene oxide is used in the production. Since the graphene coated on the surface of the silicon-based material controls the volume expansion of the silicon-based material as the battery cycle increases, the lifetime and reliability of the battery including the cathode material manufactured using the second composite is improved. The electrical conductivity of the cathode material to the graphene coated on the surface of the silicon-based material is improved. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) a method for manufacturing lithium secondary battery; and (2) a lithium secondary battery. DESCRIPTION OF DRAWING(S) - The drawing shows a flow chart illustrating the process for manufacturing cathode material. (Drawing includes non-English language text)