TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The electrolyte salt is formed by a combination of a cation of lithium (Li+), sodium (Na+) or potassium (K+); with an anion of potassium hexafluoride (PF6-), boron tetrafluoride (BF4-), chlorine (Cl-), bromine (Br-), iodine (I-), chlorine oxide (ClO4-), arsenic hexafluoride (AsF6-), methyl-containing compound (CH3CO2-), or sulfonate-containing compound (CF3SO3-, N(CF3SO2)2- or C(CF2SO-2)3-).    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Component: The cyclic compound as the first crosslinking agent is a compound of formula (1), and/or a compound of formula (2). It is compound(s) of 2,4,6,8-tetramethyl-2,4,6,8-tetravinyl-cyclotetrasiloxane, 2,4,6,8-tetramethyl-2,4,6,8-tetraacrylate-cyclotetrasiloxane, 1,3,5-trimethyl-1,3,5-trivinyl-cyclohexane, or 1,3,5-trimethyl-l,3,5-triacrylate-cyclohexane. The linear or branched compound is a compound of formula (CH2-C(B)-C(O)-(O-A)a-O-CH2)b-X. It is compound(s) of tetraethylene glycol diacrylate, polyethylene glycol diacrylate (molecular weight 50-20000), 1,4-butanediol diacrylate, 1,6-hexandiol diacrylate, trimethylolpropane triacrylate, trimethylolpropane ethoxylate triacrylate, trimethylolpropane propoxylate triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol tetraacrylate, pentaerythritol ethoxylate tetraacrylate, dipentaerythritol pentaacrylate, or dipentaerythritol hexaacrylate. The electrolyte solvent is solvent(s) of cyclic carbonates, linear carbonates, lactones, ethers, esters, sulfoxides, acetonitriles, lactams, ketones, halogen, or their derivatives.R1=H or Me;R2=1-12C alkylene;n=0 or 1;W=vinyl or (meth)acrylate;R3=R1;R4=R2;A=1-12C alkylene or 1-12C haloalkylene;a=0-30;B=H or methyl;b=2-6;X=-CH2-O-(CH2-CH2-O-)m-CH2-, -(CH2)m-, -C-, -C(E1)-, -C(E1)(E2)-, -C(E1)(E2)-E3, -C-CH2-O-CH2-C-, -C(E1)-CH2-O-CH2-C-, -C(E1)(E2)-CH2-O-CH2-C-, -C(E1)-CH2-O-CH2-C(E2)-, -C(E1)(E2)-CH2-O-CH2-C(E3)-, or -C(E1)(E2)-CH2-O-CH2-C(E3)(E4)-;E1-E4=H, 1-12C alkyl, 1-12C haloalkyl, or 1-12C hydroxyalkyl;andm=0-30Preferred Composition: The composition contains 0.01-0.5 wt.% of the cyclic compound as the first crosslinking agent and 1.5-10 wt.% of the linear or branched compound as the second crosslinking agent.    TECHNOLOGY FOCUS - POLYMERS - Preferred Component: The electrolyte is formed via in-situ polymerization inside an electrochemical device. EXAMPLE - Lithium hexafluorophosphate (LiPF6) (1M) was dissolved into an electrolyte solvent containing ethylene carbonate (EC), propylene carbonate (PC) and dimethyl carbonate (DMC) in a weight ratio of 2:1:7 (EC:PC:DMC) to provide an electrolyte. The electrolyte (97 wt.%) was mixed with 2,4,6,8-tetramethyl-2,4,6,8-tetravinyl-cyclotetra siloxane (0.5 wt.%) as a first crosslinking agent, dipentaerythritol pentaacrylate (1.5 wt.%) as a second crosslinking agent, and azobisisobutyronitrile (AIBN) (1 wt.%) as a polymerization initiator to provide a composition for a gel polymer electrolyte. Lithium cobalt oxide (LiCoO2) (94 wt.%) as a cathode active material, carbon black (3 wt.%) as a conductive agent and polyvinylidene fluoride (PVdF) (3 wt.%) as a binder were added to N-methyl-2-pyrrolidone (NMP) as a solvent, to form slurry for a cathode. The slurry was coated on A1 foil as a cathode collector, and then dried to form a cathode, which was subjected to roll press. Carbon powder (96 wt.%) as an anode active material, PVdF (3 wt.%) as a binder and carbon black (1 wt.%) as a conductive agent were added to NMP as a solvent to form mixed slurry for an anode. The slurry was coated on copper foil as an anode collector, and dried to form an anode, which was subjected to roll press. The cathode, anode and polypropylene/poly ethylene/polypropylene (PP/PE/PP) tri-layer separator were used to provide a battery. The composition for a gel polymer electrolyte was injected into the assembled battery and the resultant battery was stored for 3 hours. After 3 hours, the composition was subjected to polymerization under a nitrogen atmosphere at 80 degrees C for 4 hours to provide a finished battery.