NOVELTY - A mixture of polyvinylidene fluoride and polyacrylonitrile and/or polymethylmethacrylate, is mixed with solvent containing lithium salt. The mixture is heat-stirred to form polymer electrolyte composition (4) which is coated on film, dried and separated to form polymer film. A cathode (6)/anode (1) is attached between two films, and the structure is impregnated with liquid electrolyte, to form a battery.    USE - For manufacturing lithium secondary battery used for cellular communication, satellites, portable computers, and electrical vehicles.    ADVANTAGE - The manufacturing method employs polymer electrolyte which has good mechanical strength and adhesiveness, and provides lithium secondary batteries having stable charge/discharge characteristics and high capacity. The mechanical strength is improved and an affinity of the electrolyte with the solvent can be improved to minimize the leakage and evaporation of the solvent in the polymer electrolyte. Since the electrolyte has good adhesiveness to the electrodes, contacting resistance of the obtained battery is small and a local concentration of a current can be prevented to improve the performance of the battery during charge/discharge. The polymer electrolyte is also applicable as an electrolyte of capacitors and sensors.    DETAILED DESCRIPTION - A polymer mixture containing polyvinylidene fluoride-based polymer and at least one polymer chosen from polyacrylonitrile and polymethylmethacrylate, is mixed with a solvent in which a lithium salt is dissolved. The polymer mixture and the solvent are mixed at a ratio of 1:3-10. The obtained mixture is stirred at room temperature for 1-48 hours and heated at 60-250degreesC for 5 minutes to 6 hours while stirring to prepare a polymer electrolyte composition. The obtained polymer electrolyte composition is coated on a molded film and then dried. The dried composition is separated from the molded film to form a polymer film. A cathode or an anode is attached between two polymer films, to form a structure. The resulting structure is then impregnated with a liquid electrolyte for 1 minute to 2 hours under atmospheric pressure, to form a lithium secondary battery.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic diagram of the structure of the unit cell of a lithium secondary battery.    anode (1)    polymer electrolyte composition (4)    cathode (6)