The effect of additives and current density on mechanical properties of cathode metal for secondary battery

Electrolyte copper foils used as a cathode material in secondary cells require the mechanical characteristic of high elongation ratios. In this study the effects of additives, current densities, and concentrations of sulfuric acid used in electrolyte plating on the mechanical characteristics of copper foils are analyzed. In the case of additive A, no significant changes in tensile strength and crystal structure were observed, but the elongation ratio is reduced by 43% when 100 ppm of additive is added. For additive B, the elongation ratio is rapidly decreased even though the growing orientation of crystals becomes parallel to the faces of (111) and (220) from the face of (200). In the case of decreasing current densities or increasing concentrations of sulfuric acid, the elongation ratio is respectively increased by 74% and 54%, and the growing orientation of crystals is directed from (200) to (111). Also, for additive A at low current densities, the increase in crystal sizes differed from that of high current densities. This approach represents a possible method for additionally improving elongation ratios by properly controlling the amount of the additive A.