▎ 摘　　要

NOVELTY - A graphene nanoparticle composite comprises primary nanoparticles crystallized in a surface of graphene having chemical bonds, at high density. The primary nanoparticles are particles of nickel, silicon, titanium, chromium, manganese, iron, cobalt, copper, tin, indium, platinum, gold and/or magnesium. The content of primary nanoparticles is 30-50 wt.% based on the total weight of the composite. The crystallized primary nanoparticles have average particle diameter of 50-200 nm. USE - Graphene nanoparticle composite is used for stacked structure for electric element, thermoelectric material and electrode for electrochemical device (all claimed) e.g. energy storage device, energy conversion device, fuel cell and sensor, solar cell, high-strength machine component, and catalytic, medicine and biotechnology fields. Can also be used as heat-radiating material for heat-radiating element/component used in display device, LED and electronic equipment e.g. computer component. ADVANTAGE - The graphene nanoparticle composite exhibits excellent mechanical and electric characteristics due to the presence of large amount of the nanoparticles and crystals with large size. The stacked structure containing the graphene nanoparticle composite has excellent mechanical and electric characteristics, interlayer contact characteristics and electric conductivity. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) stacked structure; (2) electrochemical device; and (3) preparation of graphene nanoparticle composite.