TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The metal comprises cobalt, nickel, iron, gold, silver, platinum, ruthenium, rhodium, osmium, iridium, palladium, copper, manganese, titanium, vanadium, tungsten, molybdenum or niobium, and their alloy. The metal oxide comprises manganese oxide, cobalt oxide, iron oxide, zinc oxide, nickel oxide, vanadium oxide, molybdenum oxide, niobium oxide, titanium oxide, tungsten oxide and/or chrome oxide.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The coating layer is disposed on at least a portion of the core. The carbonaceous material is a sintered product of the carbon precursor. The porous carbonaceous composite material has an average pore size of 7-30 nm, and a specific surface area of 45-900 m2/g, when measured by the Brunauer-Emmett-Teller method. The carbon nanoparticle has an average diameter of 2-900 nm. The positive electrode has an average pore size of 10-30 nm, and a specific surface area of 50-400 m2/g, when measured by the Brunauer-Emmett-Teller method. The step of contacting comprises mixing the carbon nanotube and carbon precursor in a solution, and drying the solution. The step of sintering is performed for 1-72 hours under an inert atmosphere at a temperature of 400-1000 degrees C. The method further comprises after the step of sintering, refining the porous carbonaceous composite material, which is a product of the sintering. The step of refining comprises immersing the porous carbonaceous composite material in aqueous hydrofluoric acid, aqueous hydrochloric acid, aqueous nitric acid, aqueous hydrogen peroxide and/or aqueous sulfuric acid. Preferred Components: The core comprises a carbon nanotube, which define a pore between the carbon nanotubes. The carbonaceous material comprises a carbon nanoparticle, mesoporous carbon, carbon nanotube, carbon nanofiber, carbon nanosheet, carbon nanorod and/or carbon nanobelt. The hetero element comprises at least one element comprising groups 13-16 of the periodic table of the elements, preferably nitrogen, sulfur, phosphorus, selenium, tellurium and boron. In the porous carbonaceous composite material, an amount of the hetero element in the coating layer is 30 wt.% or less. The carbon nanotube comprises: a single walled carbon nanotube, dual walled carbon nanotube or multi walled carbon nanotube; and a semiconducting carbon nanotube or metallic carbon nanotube. The positive electrode further comprises an oxygen oxidation/reduction catalyst. The oxygen oxidation/reduction catalyst comprises at least one comprising a metal, a metal oxide, and an organo metallic compound. The carbon precursor comprises: a substituted or unsubstituted aromatic cyclic compound or aromatic heterocyclic compound; and quinoxaline, hemin, p-toluene sulfonic acid, porphyrin, cobalt-tetramethoxy-phenylporphyrin, iron-tetramethoxyphenylporphyrin, phthalocyanine, cobalt-phthalocyanine, iron-phthalocyanine, pyrazine and/or bipyridine.