NOVELTY - The device has a gel type organic/inorganic composite porous film placed between a cathode and an anode. The gel type organic/inorganic composite porous film comprises gel provided with a product of binder polymer and electrolyte. The gel is placed on inorganic particles, and connects inorganic particles to each other. Curved shaped interstitial volumes are defined by the interconnected inorganic particles. The binder polymer is placed between adjacent inorganic particles of the interconnected inorganic particles.    USE - Electrochemical device i.e. lithium secondary battery, for use as an energy source. Uses include but are not limited to a portable phone, camcorder, notebook computer, personal computer (PC) and an electric car.    ADVANTAGE - The inorganic particles are interconnected and fixed by the binder polymer, and interstitial volumes among the inorganic particles form a heat resistant micropore structure, so that space to be filled with the electrolyte is increased, thus improving degree of swelling with electrolyte and lithium ion conductivity, and hence improving thermal safety and quality of the device. The micropore structure is filled with liquid electrolyte, so that interfacial resistance generating among the inorganic particles or between the inorganic particles and the binder polymer can be reduced.    DETAILED DESCRIPTION - The binder polymer is selected from a group consisting of polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polymethylmethacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinyl acetate, polyethylene-co-vinyl acetate, polyethylene oxide, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethylpullulan, cyanoethyl polyvinylalcohol, cyanoethylcellulose, cyanoethylsucrose, pullulan, carboxymethyl cellulose, acrylonitrile-styrene-butadiene copolymer and polyimide. The inorganic particles comprises barium titanate, lead-zirconate-titanate, hafnium oxide powder, strontium titanate, tin oxide, cerium oxide powder, magnesium oxide, Calcium oxide, Zinc oxide, Zirconium oxide, Yttrium Oxide, Alumina, Titanium dioxide and Silicon carbide.    DESCRIPTION OF DRAWING(S) - The drawing shows a perspective view of an organic/inorganic composite porous film.