TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Battery: The electrolyte salt is included at concentration 0.8-2 M with respect to the electrolyte solvent.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The cyclic anhydride is compound that is reduced prior to carbonate and propionate-based ester when the secondary battery is initially charged, thus forming solid electrolyte interface film on surface of the anode. The cyclic anhydride (0.1-5 parts by weight (pbw)) is selected from succinic anhydride, citraconic anhydride, itaconic anhydride and phthalic anhydride. The propionate-based ester (3-80 pbw) is selected from methyl propionate, ethyl propionate, propyl propionate and butyl propionate. The carbonate is selected from cyclic carbonate and linear carbonate.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The binder includes water-based binder for the anode having the specific surface area 1.5-4.5 m2/g. The water-based binder is styrene-butadiene rubber. EXAMPLE - Succinic anhydride (0.5 parts by weight) of an electrolyte was added to LiPF6 (1 M) solution in which ethylene carbonate and ethyl propionate are mixed in volume ratio of 3:7 giving an electrolyte (e1). A battery in a coin shape was manufactured in common procedures known in the battery field except that the electrolyte prepared as above, LiCoO2 for a cathode, artificial graphite for an anode and styrene-butadiene rubber for binder were used. Comparative electrolyte (c2) was prepared and a battery having the electrolyte was manufactured in the same way as (e1) except that ethylmethyl carbonate was used instead of ethyl propionate and succinic anhydride was not added. The batteries manufactured were respectively charged/discharged at 60 degrees C. The charging process was carried out at 0.8C current rate (4 mA) and the discharging process was at 0.5C current rate (2.5 mA). The battery of (e1) showed an improved high-temperature performance in contrast to the battery of the comparative (c2). The complementary properties of these two components (ethyl propionate and succinic anhydride) greatly improved general battery performance such as high temperature performance and charging/discharging characteristics.