Unlocking Superior Mechanical Performance in Electrolytic Copper Foils Through Synergistic Competitive Additives

The rapid advancement of high-frequency, high-speed, and multifunctional electronic devices has intensified the need for electrolytic copper foils with exceptional mechanical integrity and enhanced dimensional stability. Addressing these stringent demands, this study introduces a dual-additive system comprising alcohol sulfur propanesulfonate (HP) with depolarizing properties and collagen exhibiting polarizing effects. The effects of these additives on Cu²⁺ ion electrodeposition behavior, copper microstructure, and mechanical characteristics were systematically investigated by varying additive types and concentrations. Results indicate a breakthrough improvement in mechanical properties wherein the copper foil exhibited a tensile strength of 566 MPa and elongation of 9.11%, representing 1.96 and 2.48-fold enhancements, respectively, over additive-free foils. The combined additives induce a significant increase in Σ3 twin boundaries, soaring from 32.3% to 73.5%, through improved polarization behavior, crystalline structural transformations, and refined grain morphology. This synergistic effect arises from the competitive interaction between depolarizing and polarizing mechanisms, which instigate atomic misalignments during lattice growth, fostering the formation of abundant twin crystals. This study provides vital theoretical insights and practical guidelines for tailoring copper foil microstructures, meeting stringent application demands, and advancing the field of electrolytic copper material fabrication for next-generation electronics.