NOVELTY - The mixture has a spinel structure comprises 85-95 wt. % of lithium manganese-based oxide. 1-7 wt. % of conductive material coated on a surface of a shell section of a tetragonal structure for performing an electric discharge process due to phase transition. The conductive material comprises 1-7 wt. % of macromolecular binder, 0.5-1.5 wt. % of conductive polymer, graphite, carbon fiber, carbon, acetylene and ketjen black, carbon nanotube or element, where the conductive polymer comprises polyaniline, polypyrrole, polythiophene i.e. poly 3,4-ethylenedioxy thiophene, or polysulfur nitride.    USE - Positive electrode mixture for an electrochemical device e.g. Nickel-hydrogen metal secondary battery and lithium secondary battery (all claimed), that is utilized for a mobile apparatus e.g. mobile phone, camcorder and notebook computer, and a vehicle e.g. electric vehicle and hybrid electric vehicle.    ADVANTAGE - The mixture coats the conductive polymer on the surface of the shell section of the tetragonal structure so as to improve reaction in a 3V region and conductivity, so that capacity of an electrochemical device and service life property and rate property can be improved.    DETAILED DESCRIPTION - The element is made of aluminum, magnesium, nickel, cobalt, iron, chromium, vanadium, titanium, copper, boron, calcium, zinc, zirconium, niobium, molybdenum, strontium, antimony, tungsten, titanium, bismuth, nitrogen, fluorine, sulfur or chloride. The macromolecular binder is made of polyvinylidene fluoride, hexafluoro propylene, polyvinylidene fluoride-co-hexafluoro propylene, polyvinylidene fluoride-co-trichloroethylene, polymethyl methacrylate, polybutylacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, polyethylene-co-vinyl acetate, polyethylene oxide, polyarylate, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethylpullulan, cyanoethylpolyvinylalcohol, cyanoethylcellulose, cyanoethylsucrose, pullulan, carboxyl methyl cellulose, acrylonitrile-styrene-butadiene copolymer or polyimide. An INDEPENDENT CLAIM is also included for an electrochemical device.    DESCRIPTION OF DRAWING(S) - The drawing shows a graphical view illustrating relationship between capacity retention and cycling of a positive electrode mixture.'(Drawing includes non-English language text)'