A comprehensive investigation on electrophoretic self-assembled nano-Co₃O₄ films in aqueous solution as electrode materials for supercapacitors

In this study, the nano-Co₃O₄ films (NCOFs) have been prepared by a one-step cathodic electrophoretic deposition (C-EPD) in aqueous solutions with micro-additive polyethylenimine at ambient temperature and pressure for oxide film-based supercapacitors. The phase composition and morphology of the NCOFs were studied by X-ray diffraction (XRD) and focused ion beam scanning electron microscope (FIB-SEM), respectively. In addition, the deposition kinetics of nano-Co₃O₄ particles using C-EPD process were investigated in detail. The electrochemical capacitance behaviors of the NCOFs electrode were analyzed by cyclic voltammetry, galvanostatic charge–discharge studies, and electrochemical impedance spectroscopy in 2 M KOH solution. The electrochemical experiments revealed that the highest capacitance of 233.6 F g⁻¹ at 0.5 A g⁻¹, 93.5 % of which still be maintained after 2000 charge–discharge cycles. These findings suggested the potential application of the NCOFs prepared by C-EPD in the electrochemical supercapacitors.