Slow-Scan anodization of copper in alkaline Solution: Synthesis, performance Evolution, and theoretical analysis of Cu(OH)2 nanowires for High-Performance supercapacitors

Abstract

In this work, a binder-free Cu/Cu(OH)₂ NwBs electrode was fabricated using a simple potentiodynamic anodization method. The effect of anodization scan rates of 3, 0.5, and 0.1 mV/s on the structural, morphological, and supercapacitive properties was thoroughly investigated. An areal capacitance of 22.5 mF/cm² at 1 mA/cm² was achieved at scan rate of anodization 0.1 mV/s. The Cu/Cu(OH)₂ electrode demonstrates excellent retention cyclic stability of 120 % after 10,000 cycles. Post-cycling analysis revealed a phase transformation from Cu(OH)₂ to CuO, accompanied by significant morphological changes. A theoretical model based on Fick’s law was employed, which aligned well with the experimental data. The diffusion coefficient values were calculated from charge/discharge data, and the results indicated that higher diffusion coefficients corresponded to higher specific capacitance, demonstrating improved supercapacitor performance.