▎ 摘　　要

NOVELTY - An active material comprises a core, and a coating layer arranged on the core. The core comprises lithium-metal-oxide (I). The coating layer comprises carbon-based particles including structure in which several graphene sheets are connected to each other, and 1 wt.% or more oxygen. The carbon-based particles have D/G peak ratio of 1.55 or less measured by Raman spectroscopy. USE - Active material used for positive electrode for secondary battery (claimed) such as lithium secondary battery. Uses include but are not limited to hybrid vehicle, electric vehicle, plug-in hybrid electric vehicle, and power storage system. ADVANTAGE - The active material provides battery with excellent charging capacity, durability, cycle characteristics, and charge/discharge efficiency, using graphene sheet having improved surface contact, and carbon-based particles having excellent electroconductivity and thermal conductivity. DETAILED DESCRIPTION - An active material comprises a core, and a coating layer arranged on the core. The core comprises a lithium-metal-oxide of formula: Li1+xMO2+y (I). The coating layer comprises carbonaceous particles including structure in which several graphene sheets are connected to each other, and 1 wt.% or more oxygen. The carbon-based particles have D/G peak ratio of 1.55 or less measured by Raman spectroscopy. M = Ni, Co, or Cu; x = 1-5;and y = 0-2. INDEPENDENT CLAIMS are included for the following: (1) manufacture of cathode active material, which involves preparing carbon-based particles, arranging carbon-based particles on core, preparing preliminary carbon-based particles, oxidizing preliminary carbon-based particles to oxidize the preliminary carbon-based particles, heat-treating (A) of the preliminary carbon-based particles at 200-800 degrees C, in at least one of oxygen atmosphere and air atmosphere, and reacting preliminary carbon-based particles with acidic vapor at 120-300 degrees C; (2) positive electrode, which comprises positive electrode active material; and (3) secondary battery, which comprises positive electrode, negative electrode, electrolyte, and separator arranged between the positive electrode and the negative electrode.