Abstract: A composite of electrode active material including aggregates formed by self-assembly of electrode active material nanoparticles and carbon nanotubes, and a fabrication method thereof are disclosed. This composite is in the form of a network in which at least some of the carbon nanotubes connect two or more aggregates that are not directly contacting each other, creating an entangled structure in which a plurality of aggregates and a plurality of carbon nanotube strands are intertwined. Due to the highly conductive properties of the carbon nanotubes in this composite, charge carriers can be rapidly transferred between the self-assembled aggregates. This composite may be prepared by preparing a dispersion in which the nanoparticles and/or carbon nanotubes are dispersed without any organic binders, simultaneously spraying the nanoparticles and the carbon nanotubes on a current collector through electrospray, and then subjecting the composite material formed on the current collector to a heat treatment.