Electrolytic copper foil having high tensile strength, electrode including the same, secondary battery including the same, and method of manufacturing the same
A high strength electrolytic copper foil preventing generation of folds, wrinkles, pleats, and breaks during a roll-to-roll (RTR) process, a method of manufacturing the same, and an electrode and a secondary battery which allow high productivity to be secured by being manufactured with such an electrolytic copper foil. The electrolytic copper foil includes a copper film including 99 weight % or more of copper and a protective layer on the copper film, wherein the electrolytic copper foil has a tensile strength of 45 to 65 kgf/mm 2 .
1. A method of manufacturing an electrolytic copper foil, comprising:
applying electricity between a positive electrode plate and a rotating negative electrode drum which are disposed in an electrolyte to be spaced apart from each other in an electrolytic bath to form a copper film on the rotating negative electrode drum,
wherein the electrolyte includes in a range of 50 to 100 g/L of copper ions, 50 to 150 g/L of sulfuric acid, 0.5 to 6.5 ppm of imidazolidine-2-thione, and 0.2 to 5.5 ppm of silver (Ag).
2. The method of claim 1 , wherein the electrolyte further includes in a range of 3 to 7 ppm of sulfonate and 3 to 7 ppm of polymeric nitride.
3. The method of claim 1 , wherein:
the electrolyte is maintained at 40 to 60° C.; and
a current density provided by the positive electrode plate is in a range of 40 to 80 A/dm 2 .
4. The method of claim 1 , wherein, in the forming of the copper film, a flow rate of the electrolyte supplied into the electrolytic bath is in a range of 30 to 50 m 3 /hour, and a content of total organic carbon (TOC) in the electrolyte is maintained to be 0.3 g/L or less.