▎ 摘　　要

NOVELTY - Microball complex comprises microballs having three-dimensional carbon nanotube matrix structure; graphene and silicon nanoparticles dispersed in the carbon nanotube matrix structure; and a carbon coating layer provided on the surface of the microball complex. The microball complex has multiple fine pores. USE - The microball complex is useful in cathode of lithium secondary battery (claimed). ADVANTAGE - The microball complex suppress reaggregation and dispersibility of carbon nanotubes in the solvent, has improved dispersibility, is uniformly dispersed in carbon nanotubes to mitigate change in volume due to adsorption and desorption of lithium ions, induces effective electrochemical reaction by preventing agglomeration of silicon nanoparticles and improving electrical contact by reducing specific resistance of electrode surface of lithium secondary battery, has very large capacity, shows excellent cycle stability and high output characteristics, and maintains discharge capacity at 2000 mAh/g. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) cathode comprising microball complex as cathode active material; and (2) producing microball complex comprising (a) preparing dispersion solution containing graphene oxide, silicon nanoparticles, and carbon nanotubes, (b) spraying the dispersion solution to form a preliminary microball complex and drying, and (c) preparing microball complex by forming a carbon coating layer on the surface of the preliminary microball complex. DESCRIPTION OF DRAWING(S) - The drawing shows a flowchart illustrating the method for producing microball complex.