Disclosed are copper foil or net comprising a Cu-nitrile compound complex formed on the surface thereof, a method for preparing the same, and a lithium secondary battery that comprises an electrode using the same copper foil or net as a collector. The lithium secondary battery, which uses a copper collector comprising a Cu-nitrile compound complex formed on the surface thereof through the application of a certain voltage level, can prevent the corrosion of Cu occurring at a voltage of 3.6V or higher under overdischarge conditions away from the normal drive condition, and thus can significantly improve the capacity restorability after overdischarge.