▎ 摘　　要

NOVELTY - Composite anode active material formed of different materials comprises graphene lattice and a hollow core-shell structure inside the graphene lattice. The hollow core-shell structure includes a hollow core and two or more layers surrounding the hollow core, and the two or more shells are different from each other. USE - Composite anode active material formed of different materials. ADVANTAGE - The composite anode active material formed of different materials has improved initial coulomb efficiency and life characteristics, have a simple manufacturing process and shorten time. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for following: (1) a method for producing a composite negative electrode active material, which involves preparing a polymer particle having a negative charge on its surface and adding a basic solution to convert the electric charge on the surface of the polymer particle into a positive charge;adding a first metal oxide precursor to polymer particles having a positive charge on the surface to obtain a first core shell structure in which a first layer of a first metal oxide is formed on the surface of the polymer particles;introducing a second metal oxide precursor onto the first core-shell structure to obtain a second core-shell structure in which a second layer of a second metal oxide is formed;obtaining vacuum filtration of the dispersion by dispersing the second core-shell structure and graphene oxide in a solvent to obtain a second core-shell structure containing graphene oxide in a film form;reducing the second core-shell structure containing graphene oxide in the form of a film by heat treatment to prepare the composite anode active material; and (2) an electrochemical device, which comprises anode, and negative electrode that includes composite negative active material, and an electrolyte provided between the positive electrode and the negative electrode.