TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Material: The electrode active material is nickel containing oxide.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The monomer which can be copolymerized is chosen from hexafluoropropylene, perfluoromethyl vinyl ether, perfluoro ethyl vinyl ether, perfluoro propyl vinyl ether, propylene, 1-butene and 2-butene. The fluorine-containing monomer is of formula: CR1R2=CR3-(O)k-(CR4R5)j-R6.R1-R6=fluoroalkyl group, H, fluoro, chloro, bromo or iodo;j=0-6;andk=0 or 1.The fluorine-containing compound is of formula: Y'-Rf-Z1.Y'=H, chloro or fluoro;Rf=2-16C optionally branched saturated fluoroalkylene group which does not contain 7 or more linkages of carbon atom to which fluorine is directly bonded, and contains ether acid;Z1=-COOM1, -SO3M2, -SO2NM3M4 or -PO3M5M6;andM1-M6=H or univalent cation.A fluorine-containing vinyl-containing compound having radical polymerizable unsaturated bond and hydrophilic group is further used for the radical polymerization. The fluorine-containing vinyl-containing compound is of formula: CR1R2=CR3(CR4R5)j-(O)k-R6-Z2 (II), preferably CF2=CFO(CF2CF(CF3)O)l-(CF2)m-Z3 (III).R6=optionally branched fluoroalkylene having oxygen atom in the principal chain;j=0-6;k=0 or 1;Z2=hydrophilic group;l=0-3;m=2-8;Z3=-COOM7, -SO3M8, -SO2NR7R8 or -PO3M9M10;M7-M10=M1;andR7,R8=H, alkali metal, alkyl or sulfonyl containing group.The fluorine-containing vinyl-containing compound is added in an amount equivalent to 2-1000 ppm of the aqueous medium and the fluorine-containing compound is added in an amount equivalent to 100-50000 ppm of the aqueous medium. The organic solvent in the solution contains 50 mass% or more of N-methylpyrrolidone with respect to the whole quantity of the organic solvent.    TECHNOLOGY FOCUS - POLYMERS - Preferred Polymer: The melt-processable fluorine-containing polymer has melting point of 60 degrees C or more. The melt-processable fluorine-containing polymer is vinylidene fluoride homopolymer or vinylidene fluoride copolymer and contains 40-100 mol% of vinylidene fluoride, 0-50 mol% of tetrafluoroethylene and 0-20 mol% of monomers which can be copolymerized. The polymer is concentrated to 15 mass% or more after the radical polymerization to obtain an emulsion. The polymer latex, electrode active material, electroconductive agent, water-soluble polymer and water are mixed to obtain an electrode compound material paste. Polytetrafluoroethylene latex is further added to the paste, in an amount of 75 mass% of less with respect to the total solid in the mixture. EXAMPLE - Hexafluoropropylene and tetrafluoroethylene were polymerized in presence of aqueous solution containing ammonium persulfate and emulsifier of formula: F(CF2)5COONH4 to obtain tetrafluoroethylene/hexafluoropropylene copolymer having melting point of 252.1 degrees C. The obtained copolymer, lithium cobalt oxide, acetylene black and carboxymethyl cellulose were used to prepare electrode material for lithium ion battery. The battery using the electrode material had favorable charging and discharging characteristics.