Abstract: A polymer gel electrolyte comprising a metal salt, a polymer, optionally a plasticizer, characterized in that the polymer comprises a carbon-hydrogen base chain having at least two reactive groups incorporated wherein the reactive groups have different reactivities. The polymer gel electrolyte neutralises a passivating layer in the form of waste products produced in the electrolyte phase by the metal salt and solvents. The decrease in the growth of the passivating layer provides a battery cell with a better effect and a longer life.