A graphene-nanoparticle composite in which primary nanoparticles crystallized in a surface of graphene have chemical bonds formed therein at a high density, wherein the primary nanoparticles are particles of at least one selected from the group consisting of Ni, Si, Ag, Ti, Cr, M n, Fe, Co, Cu, Sn, In, Pt, Au, Mg, and a combination thereof, and are included at a content of 30 to 50% by weight, based on the total weight of the composite, and the primary nanoparticles have a homogeneous crystal shape including one of spherical and hemispherical shapes on the surface of graphene, wherein the crystallized primary nanoparticles have an average particle diameter of 50 to 200 nm, and the chemical bonds are formed directly between at least one of metals of the group the primary nanoparticles and a carbon of the surface of graphene.

A stacked structure obtained by stacking a graphene- nanoparticle composite in which primary nanoparticles crystallized in a surface of graphene have chemical bonds formed therein at a high density, wherein the primary nanoparticles are particles of at least one selected from the group consisting of Ni, Si, Ag, Ti, Cr, M n, Fe, Co, Cu, Sn, In, Pt, Au, Mg, and a combination thereof, and are included at a content of 30 to 50% by weight, based on the total weight of the composite, and the crystallized primary nanoparticles have an average particle diameter of 50 to 200 nm, the chemical bonds are formed directly between at least one of metals of the group the primary nanoparticles and a carbon of the surface of graphene, and the primary nanoparticles have a homogeneous crystal shape including one of spherical and hemispherical shapes on the surface of graphene.

A graphene-nanoparticle composite in which primary nanoparticles crystallized in a surface of graphene have chemical bonds formed therein at a high density, wherein the primary nanoparticles are particles of at least one selected from the group consisting of Ni, Si, Ag, Ti, Cr, M n, Fe, Co, Cu, Sn, In, Pt, Au, Mg, and a combination thereof, and are included at a content of 30 to 50% by weight, based on the total weight of the composite, and the primary nanoparticles have a homogeneous crystal shape including one of spherical and hemispherical shapes on the surface of graphene, wherein the crystallized primary nanoparticles have an average particle diameter of 50 to 200 nm, and the chemical bonds are formed directly between at least one of metals of the group the primary nanoparticles and a carbon of the surface of graphene.

A stacked structure obtained by stacking a graphene- nanoparticle composite in which primary nanoparticles crystallized in a surface of graphene have chemical bonds formed therein at a high density, wherein the primary nanoparticles are particles of at least one selected from the group consisting of Ni, Si, Ag, Ti, Cr, M n, Fe, Co, Cu, Sn, In, Pt, Au, Mg, and a combination thereof, and are included at a content of 30 to 50% by weight, based on the total weight of the composite, and the crystallized primary nanoparticles have an average particle diameter of 50 to 200 nm, the chemical bonds are formed directly between at least one of metals of the group the primary nanoparticles and a carbon of the surface of graphene, and the primary nanoparticles have a homogeneous crystal shape including one of spherical and hemispherical shapes on the surface of graphene.

A graphene-nanoparticle composite in which primary nanoparticles crystallized in a surface of graphene have chemical bonds formed therein at a high density, wherein the primary nanoparticles are particles of at least one selected from the group consisting of Ni, Si, Ag, Ti, Cr, M n, Fe, Co, Cu, Sn, In, Pt, Au, Mg, and a combination thereof, and are included at a content of 30 to 50% by weight, based on the total weight of the composite, and the primary nanoparticles have a homogeneous crystal shape including one of spherical and hemispherical shapes on the surface of graphene, wherein the crystallized primary nanoparticles have an average particle diameter of 50 to 200 nm, and the chemical bonds are formed directly between at least one of metals of the group the primary nanoparticles and a carbon of the surface of graphene.

A stacked structure obtained by stacking a graphene- nanoparticle composite in which primary nanoparticles crystallized in a surface of graphene have chemical bonds formed therein at a high density, wherein the primary nanoparticles are particles of at least one selected from the group consisting of Ni, Si, Ag, Ti, Cr, M n, Fe, Co, Cu, Sn, In, Pt, Au, Mg, and a combination thereof, and are included at a content of 30 to 50% by weight, based on the total weight of the composite, and the crystallized primary nanoparticles have an average particle diameter of 50 to 200 nm, the chemical bonds are formed directly between at least one of metals of the group the primary nanoparticles and a carbon of the surface of graphene, and the primary nanoparticles have a homogeneous crystal shape including one of spherical and hemispherical shapes on the surface of graphene.

A graphene-nanoparticle composite in which primary nanoparticles crystallized in a surface of graphene have chemical bonds formed therein at a high density, wherein the primary nanoparticles are particles of at least one selected from the group consisting of Ni, Si, Ag, Ti, Cr, M n, Fe, Co, Cu, Sn, In, Pt, Au, Mg, and a combination thereof, and are included at a content of 30 to 50% by weight, based on the total weight of the composite, and the primary nanoparticles have a homogeneous crystal shape including one of spherical and hemispherical shapes on the surface of graphene, wherein the crystallized primary nanoparticles have an average particle diameter of 50 to 200 nm, and the chemical bonds are formed directly between at least one of metals of the group the primary nanoparticles and a carbon of the surface of graphene.

A stacked structure obtained by stacking a graphene- nanoparticle composite in which primary nanoparticles crystallized in a surface of graphene have chemical bonds formed therein at a high density, wherein the primary nanoparticles are particles of at least one selected from the group consisting of Ni, Si, Ag, Ti, Cr, M n, Fe, Co, Cu, Sn, In, Pt, Au, Mg, and a combination thereof, and are included at a content of 30 to 50% by weight, based on the total weight of the composite, and the crystallized primary nanoparticles have an average particle diameter of 50 to 200 nm, the chemical bonds are formed directly between at least one of metals of the group the primary nanoparticles and a carbon of the surface of graphene, and the primary nanoparticles have a homogeneous crystal shape including one of spherical and hemispherical shapes on the surface of graphene.