TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The temperature (T) is less than or equal to 80 degrees C. The gelling of the electrolyte corresponds to a viscosity of at least greater than 10 Pa.s at 25 degrees C, preferably greater than 100 Pa.s at 25 degrees C. The electrolyte has a conductivity (C1) of 10-4 S.cm-1 at 0.1 S.cm-1 at a temperature below (T) and conductivity (C2) of less than 10-5 S.cm-1 at a temperature equal or higher (T). The polymer segment A and B, each has: molecular weight of 2000-300000 g.mol-1, preferably 8000-80000 g.mol-1; and degree of polymerization of greater than 10, preferably 50 to 800. The polymer segment A comprises polyacrylates, polymethacrylates, polycarbonates, polyester carbonates, polylactones, polylactams, polyesters, polyethers, homopolymers and copolymers of soluble polyethers, preferably polyoxyethylene, polyoxypropylene, polyoxybutylene, or their copolymers. The polymer segment B is: obtained from at least one monomer comprising acrylic and methacrylic acids, N-alkyl-acrylamides or N-alkyl-methacrylamides, preferably N-isopropylacrylamide, N-isopropylmethacrylamide, N,N'-diethylacrylamide, saccharides, vinylidene fluoride or hexafluoropropylene; or a polymer comprising poly (N-alkyl-acrylamides), poly (N-alkyl-methacrylamides), polysaccharides, vinylidene fluoride or copolymers of vinylidene hexafluoropropylene fluorides. The molar ratio of polymer segment B and polymeric segment A is greater than 0.5, preferably 2 to 5. The block copolymer comprises at least one insoluble polymer segment (C). The polymeric segment (C) comprises saturated or unsaturated polyolefins, branched or non-branched, preferably 2-12C polystyrene or their mixtures and copolymers. The molar ratio of polymer segment A and polymer segment C is 0.5-10 preferably 1-5. The molar ratio of polymer segment B and polymer segment C is 1-10, preferably 1-3. The electrolyte comprises 1-15 wt.% block copolymer. At temperature (T), the conductivity of the electrolyte passes to a (C1) value of 10-4 Scm- at 0.1 S.cm-1 and (C2) value of 10-6 S.cm-1 at 10-5 S.cm-1. EXAMPLE - Copolymer (comprising 10000 g.mo-1 polyacrylate, 50000 g.mol-1 poly(methacrylamide) n-butyl and 15000 g.mol-1 polyethylene) was added to a mixture of ethylene carbonate/propylene carbonate/dimethyl carbonate (1/1/3) and 1M (lithium bis-trifluoromethane sulfonimide to obtain electrolyte.