TECHNOLOGY FOCUS - ELECTRONICS - Preferred Composition: (C1) comprises (wt.%): (a) (0.1 - 5). The high molecular weight compound is obtained by polymerizing (b). Preferred Battery: The cathode, anode and the high molecular weight electrolyte are housed inside exterior members, and the high molecular weight compound is polymerized inside the exterior members.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: (b) Has an acrylate group or a methacrylate group, and does not include an ether group. (b) Includes a compound of formula -CH2-C(X11)(C(O)O-R1-CH(OH)-CH2-O-C(O)-C(X12)=CH2)- (Ib), -CH2-C( X2)(C(O)O-R2)- (IIb), or -CH2-C( X3)(C(O)O-R3)- (IIIb).X11, X12, X2 and X3=H or methyl;R1=structure part including a carbon but not including an ether group (preferably CH2);R2 and R3=H or a structure part including carbon but not including an ether group (preferably an 1 - 10C alkyl, or an aromatic ring having less than or equal to 12C, group of formula -(CH2)a-(CF2)b-C(F)c-(R32)d or -R33-R34, especially 1 - 6C alkyl);R32=H, F or CF3;a=0 - 6;b=0 - 16;c and d=1 or 2;R33=diavalent linkage;andR34=circular carbonate group. SPECIFIC COMPOUNDS - Tris(trimethylsilyl)phosphate, tris(triethylsilyl)phosphate, tris(trimethylsilyl)borate or tris(triethylsilyl)borate are specifically claimed as (Ia).    EXAMPLE - lithium carbonate (0.5 mol) and cobalt carbonate (1 mol) were fired for 5 hours at 900degreesC in the air to give lithium cobalt complex oxide. Lithium cobalt complex oxide (85 parts by mass), graphite (5 parts by mass), and polyvinylidene fluoride (10 parts by mass) were mixed to give a cathode mixture which was dispersed in N-methyl-2-pyrrolidone to give cathode mixture slurry. Both faces of the cathode current collector made of aluminum foil 20microns thick were uniformly coated with cathode mixture slurry, dried and compression-molded to form cathode. Graphite powders (90 parts by mass) and polyvinylidene fluoride (10 parts by mass) were mixed to give anode mixture which was dispersed in N-methyl-2-pyrrolidone, to give anode mixture slurry. Both faces of the anode current collector made of a copper foil 15microns thick were uniformly coated with anode mixture slurry, dried, and compression-molded to form the anode. The cathode and the anode were contacted with the separator made of a micro-porous polyethylene film 25 microns thick in between, wound in the longitudinal direction, and the protective tape. Electrolytic solution (100 parts by mass) (mixture of lithium phosphate hexafluoride in a solvent having ethylene carbonate and diethyl carbonate mixed at a mole ratio 3:7, a compound having phosphorus-Oxygen-silicon bond and an additive, tris(trimethylsilyl)phosphate (1 wt.%)), a polymerizable compound (a mixture of trimethylol propane triacrylate and neopentyl glycol diacrylate at a mole ratio of 3:7) solution (5 parts by mass), and t-butyl peroxyneodecanoate (0.1 parts by mass) were mixed to prepare a composition for electrolyte. Fabricated winding electrode was loaded between the exterior members and thermally fusion-bonded. For the exterior members, a damp proof aluminum laminated film, in which a nylon film is 25microns thick, aluminum foil 40microns thick, and a polypropylene film 30microns thick were sequentially layered from the outermost layer. The composition for electrolyte was injected inside the exterior members, the remaining one side of the exterior members was thermally fusion-bonded under the reduced pressure, and hermetically sealed. The resultant was sandwiched between glass plates, heated for 15 minutes at 70degreesC to polymerize the polymerizable compound. The composition for electrolyte was gelated to obtain the high molecular weight electrolyte. Another secondary battery (control) was fabricated similarly except that the additive was not used. The secondary batteries were supplied with 500 mA constant current constant voltage charge at 23degreesC for 2 hours up to 4.2 V. Battery resistance was measured, 250 mA constant current discharge at -20degreesC was performed until a final voltage of 3.0 V, and a discharge capacity at low temperatures was measured. Further, 500 mA constant current constant voltage charge at 23degreesC was performed for 2 hours up to 4.2 V, and the secondary batteries were stored in the charge state for 20 days at 23degreesC. The battery resistance after storage was measured. 250 mA constant current discharge was performed at -20degreesC until a final voltage of 3.0 V under the conditions similar to the above conditions, and a discharge capacity at low temperatures after storage was obtained. The resistance increase ratio before and after storage, discharge capacity retention ratio at low temperatures was calculated. The test/control showed resistance increase ratio (%) and discharge capacity retention ratio (%) of 11/29 and 93/80 respectively. The test electrolyte is gelatinous where as control is in liquid form.