TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Process: The catalyst template is placed in a vacuum deposition chamber, and heated to 400-1200 degrees C after supplying hydrogen and protective gas. Carbon source is supplied into the chamber and the template is cooled to room temperature to obtain three-dimensional graphene/metal line or wire composite structure. A layer of a framework material is further formed on the surface of the composite structure to form a framework material, and the framework material is removed after the etching process. The metal line is iron nano line, copper nano line, nickel nano line, ruthenium nano line, molybdenum nano line, niobium nano line, platinum nano line, iridium nano line, palladium nano line, titanium nano line, cadmium nano line, thallium nano line, tungsten nano line, vanadium nano line or their alloy nano lines. The metal wire is commercial iron wire, copper wire, cobalt wire, nickel wire, ruthenium wire, molybdenum wire, niobium wire, platinum wire, iridium wire, palladium wire, titanium wire, cadmium wire, thallium wire, tungsten wire, vanadium wire or their alloy wires. The metal line is prepared from metal salt and reducing agent by hydrothermal method, or from metal salt solution by electrochemical deposition method. The etching is performed using etching solution chosen from hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid and/or ferric trichloride, at 30-80 degrees C for 20-800 minutes. The protective gas is nitrogen, argon and/or helium. The flow rate of the protective gas is 1-1000 sccm, the flow rate of hydrogen is 1-500 sccm, and the flow rate of gaseous carbon source is 1-200 sccm. The cooling rate during the cooling process is 10-300 degrees C/minute.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The carbon source is methane, ethylene, ethyne, ethane, propane and/or propylene, liquid carbon source of methanol, ethanol, propanol, butanol, butanone, toluene, N-methylpyrrolidone and/or dimethylformamide, or solid carbon source of polyvinylidene fluoride, polyvinylpyrrolidone, polyethylene glycol, polyvinyl alcohol, polymethylmethacrylate and/or polydimethylsiloxane. The framework material is removed using ethanol, isopropanol, and/or acetone.    TECHNOLOGY FOCUS - POLYMERS - Preferred Material: The framework material is obtained by dissolving polyvinylidene fluoride, polyvinylpyrrolidone, polyethylene glycol, polyvinyl alcohol, polymethylmethacrylate or polydimethylsiloxane in water, ethanol, acetone, N,N-dimethylformamide, methylpyrrolidone or anisole solvent to obtain a solution, and drying the solution on the surface of the three-dimensional graphene/metal line or metal wire composite structure.