Nanoscale structures have attracted considerable interest owing to their high surface-to-volume ratios and unique chemical and physical properties. Various methods have been developed to synthesize two-dimensional and nanoscale structures, with surfactant-assisted approaches being particularly effective for forming nanoscale structures at water interfaces. In this study, a surfactant-assisted method is developed for synthesizing Cu x O/Cu(OH) 2 nanostructures with belt and urchin morphologies. The two distinct nanostructures are characterized using atomic force microscopy, and the mechanisms governing their formation are elucidated. From an electrochemical perspective, these structures exhibit enhanced supercapacitor performance because of the improved contact with electrolytes. Further, supercapacitor performance tests highlighted the potential of specimens for various electronic applications. The findings of this study demonstrate the potential applicability of these nanostructures in electrochemical catalyst, batteries, and supercapacitors. • Surfactant-assisted method developed for synthesizing Cu x O/Cu(OH) 2 nanostructures. • Two morphologies—belt and urchin—were achieved by varying temperature. • Mechanisms underlying formation of Cu oxide structures revealed. • Potential application areas of 3D copper oxide nanostructures highlighted.