The present invention pertains to non-aqueous electrolytes which comprise (a) one or more solvents; (b) one or more ionic salts; and, (c) a multifunctional monomer comprising two or more unsaturated aliphatic reactive moieties per molecule, which multifuntional monomer is soluble in said one or more solvents, which multifuctional monomer rapidly polymerizes when said electrolyte is heated to an initiation temperature greater than 100° C., thereby increasing said viscosity and internal resistivity of said electrolyte. When incorporated into a nonaqueous electrolyte, the multifunctional reactive monomer improves the safety of electric current producing cells by rapidly polymerizing at elevated temperatures to increase the viscosity and internal resistivity of the electrolyte. The present invention also pertains to electric current producing cells comprising such non-aqueous electrolytes, methods of making such non-aqueous electrolytes and electric current producing cells, and methods for increasing the safety of an electric current producing cell.