Effect of additives on the microstructure and properties of electrolytic copper foils

A low-roughness ultra-thin copper foil was prepared by pulsed electrodeposition on titanium substrate. The influence of sodium 3,3'-dithiodipropane sulfonate (SPS), hydroxyethyl cellulose (HEC), gelatin and collagen additives on the microstructure, mechanical properties and electrochemical behavior of electrolytic copper foil was explored. Furthermore, the reaction mechanism of SPS and collagen additives on electrodeposited copper was discussed. The results showed that at 0.08 g/L collagen concentration, the lowest thickness, the highest microhardness and the optimal surface roughness were achieved to be 5.12 µm, 279.63 HV 0.05 and 1.885 µm, respectively. X-ray diffraction results confirmed that electrolytic copper foils prepared by SPS was introduced into the blank solution had a preferred orientation of (220) texture, which benefitted from the synergistic effect of copper ions and additives. The intermediates formed by the additive and Cu + occupied the active sites on the cathode surface that increased nucleation sites for deposition. Besides, the formed complexes can act as a barrier to narrow ion deposition channels and inhibit the growth of Cu ions.