ELECTROLYTIC COPPER ALLOY FOIL, METHOD FOR PRODUCING SAME, ELECTROLYTIC SOLUTION USED FOR PRODUCTION OF SAME, NEGATIVE ELECTRODE COLLECTOR FOR SECONDARY BATTERIES USING SAME, SECONDARY BATTERY, AND ELECTRODE OF SECONDARY BATTERY

Provision of an electrolytic copper alloy foil having large mechanical strength in an ordinary state and showing resistant to heat deterioration even when it is heated to 300°C or more. That electrolytic copper foil is an electrolytic copper alloy foil which contains tungsten and has a remainder (balance) comprised of copper. Preferably, that electrolytic copper foil incorporates tungsten into copper foil as a copper alloy, has a tensile strength at ordinary temperature of 650 MPa, has a tensile strength after heat treatment at 300°C for 1 hour of 450 MPa or more, and has a conductivity of 80% or more. Further preferably, the electrolytic copper foil has an elongation at ordinary temperature of 2.5% or more and an elongation after treatment at 300°C for 1 hour of 3.5% or more. The electrolytic copper foil is produced by adding a thiourea compound, tungsten salt, and chloride ions to a sulfuric acid-copper sulfate electrolyte and performing electrolytic deposition.