Influences of composite additives and technological parameters on the microstructure and properties of electrolytic copper foil

Abstract In this paper, the additives consisting of bis-(3-sulfopropyl)-disulfide (SPS), hydroxyethylcellulose (HEC) and collagen additive compounding, are proposed to fabricate ultra-thin copper foils with low roughness on titanium substrates. The effect of the deposition time, temperature and voltage on the morphology and roughness of electrolytic copper foil is explored. The results show that the deposited layers obtained at the electrodeposition time of 3 min, the electrolyte temperature of 50°C and the output voltage of 2.5 V exhibit small grain size and good adhesion to the substrate. Meanwhile, the effects of the two-component additive and the three-component additive on the microstructures, surface roughness and electrochemical behavior of copper foils are studied. Scanning electron microscopy images reveal that copper foils prepared by simultaneous introduction of 0.06 g/L SPS and 0.08 g/L collagen possess a dense and homogeneous structure with the smallest grain size (6.21 µm) and the lowest roughness (Rz = 2.30 µm), which is diminished by 26.17%. The electrodeposition principle and the action mechanism of additives suggest that the antagonistic interaction between SPS and HEC hinders the preferential adsorption of the additive at the surface protrusions and reduces the refinement ability of SPS additive. Benefiting from the synergistic effect of the SPS and collagen additive, the electrochemical properties of the copper foil are improved. Besides, the levels of three-component additives are determined by orthogonal experiments as 0.06 g/L SPS, 0.12 g/L HEC and 0.10 g/L collagen.