▎ 摘　　要

NOVELTY - A positive electrode active material comprises a core-shell structure comprising a core comprising a lithium composite transition metal oxide (I), and a coating layer formed on the surface of the core. The coating layer comprises 0.1-5.0 pts. wt. graphene and Denka black (RTM: ultra-pure acetylene black) (in total), 0.01-0.1 pt. wt. germanium oxide, and 0.01-0.05 pt. wt. sodium naphthalenide. The weight ratio of the graphene with respect to the Denka black is 1-5:1-5. USE - Active material used for forming positive electrode for battery. Uses include but are not limited to lithium secondary battery, sodium secondary battery, magnesium secondary battery, supercapacitor, lithium-sulfur battery, lithium-air battery, field effect transistor, optical sensor, light emitting device, photodetector, and magneto-optical memory for photocatalyst, electrochemical catalyst, flat panel display, flexible device, mobile phone, notebook computer, and electric vehicle. ADVANTAGE - The positive electrode active material provides battery having excellent durability and electroconductivity, improved voltage characteristics, suppressed decomposition reaction, high efficiency even at high temperature and high speed charging and discharging, stability even for long charging and discharging, and electrochemical property e.g. electroconductivity. DETAILED DESCRIPTION - A positive electrode active material comprises a core-shell structure comprising a core comprising a lithium composite transition metal oxide of formula: LiNixCo1-x-yMnyO (I), where x is less than 0 to less than 0.5 and y is less than 0 to less than 0.5, and a coating layer formed on the surface of the core. The coating layer comprises 0.1-5.0 pts. wt. graphene and Denka black (RTM: ultra-pure acetylene black) (in total), 0.01-0.1 pt. wt. germanium oxide, and 0.01-0.05 pts. wt. sodium naphthalenide. The weight ratio of the graphene with respect to the Denka black is 1-5:1-5.