TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The cyclic carbonate ester is contained in a ratio of 0.1-5 mass part with respect to 100 mass parts of electrolyte liquid. The electrolyte liquid contains a vinylene carbonate or vinyl ethylene carbonate as cyclic carbonate ester.    TECHNOLOGY FOCUS - POLYMERS - Preferred Compound: The polymerizable compound contains compound having structure of formula (1), compound having structure of formula (2) and compound having structure of formula (3), compound having structure of formula (4), compound having structure of formula (5) and compound having structure of formula (6), or compound having structure of formula (4), compound having structure of formula (10) and compound having structure of formula (11).X11, X12, X2 and X3 = hydrogen atom or methyl group;R1 = structure portion which contains a carbon and does not contain an ether group;R2 and R3 = structure portion which contains hydrogen atom or carbon and does not contain an ether group;R21 = hydrogen atom, 10C or less alkyl group or group having 12C or less aromatic ring ;andR31 = hydrogen atom, 10C or less alkyl group, group having 12C or less aromatic ring, compound of formula (7): -(-CH2-)a-(-CF2-)b-C(F-)c-(-R32)d or compound of formula (8): -R33-R34 (R32=hydrogen atom, fluorine or methyl fluoride;a = 0-6;b = 0-16;c = 1 or 2;d = 1 or 2;R33 = bivalent connection group;andR34 = cyclic-carbonate group);andR25 and R35 = 6C or less alkyl group.Preferred Arrangement: The anode, cathode and polyelectrolyte are accommodated inside a packing component. The polymer compound is polymerized in the inner side of the packing component. EXAMPLE - Lithium hexafluoro phosphate and vinylene carbonate were added to solvent mixture of ethylene carbonate and diethyl carbonate in a mass ratio of 3:7 and resulting liquid was used as electrolyte liquid. The concentration of lithium hexafluoro phosphate in the electrolyte liquid was 1 mol/l. The ratio of vinylene carbonate with respect to 100 mass parts of electrolyte was 3 mass parts. Trimethylol propane triacrylate of formula (55) having 3-structure portion (a:b:c=2:3:5) was used as polymerizable compound. The polymerizable compound (in mass parts) (5) and t-butyl peroxy neodecanoate (0.1) were mixed to the electrolyte liquid (100) and composition for electrolyte was produced. Anode and cathode were accommodated inside packing component, and electrolyte was poured into the packing component and sealed. The polymer compound was polymerized in the inner side of the packing component, so that the composition was gelatinized and set as polyelectrolyte. The secondary battery was obtained. The obtained battery had discharge capacitance 520 mAh and capacitance maintenance factor of 86%.