High-strength copper foil prepared with 2-mercaptothiazoline by direct current electrodeposition

A kind of new additive for ultra-thin copper foils with high tensile strength is reported in this work. The highest strength is about 700 MPa with 12 mg/L 2-mercaptothiazoline, and the strengthening effects and mechanisms in different concentrations are studied in detail. 2-Mercaptothiazoline significantly improves the tensile strength of electrolytic copper foils by refining the grains and effectively impeding the slips of dislocations. Fine grains also provide a smooth and flat surface for foils, and weaken the preferred orientation of grains in the cross-section, contributing to the high strength of copper foils at different aspects. The addition of the 2-mercaptothiazoline obviously inhibits the electron transfer process of metal electrodeposition and enhances the electrochemical polarization, resulting in high nucleation density and small nuclei to form fine grains. The high-strength copper foils with a very thin thickness are placed great expectations on the industrial application of lithium-ion batteries.