Polyacrylic Surfactant-Enabled Engineering of Co3O4 Electrodes for Enhanced Asymmetric Supercapacitor Performance

Abstract

In this work, we report a facile and tunable electrodeposition approach for engineering polyacrylic acid (PAA)-modified Co3O4 electrodes on nickel foam for high-performance asymmetric pouch-type supercapacitors. By systematically varying the PAA concentration (0.5 wt %, 1 wt %, and 1.5 wt %), we demonstrate that the CO-1 sample (1 wt % PAA) exhibited the most optimized structure and electrochemical behavior. The CO-1 electrode delivered a remarkable areal capacitance of 3467 mF/cm2 at 30 mA/cm2, attributed to its interconnected nanosheet morphology, enhanced ion diffusion, and reversible Co2+/Co3+/Co4+ redox transitions. Electrochemical impedance spectroscopy confirmed low internal resistance (0.4267 Omega), while kinetic analysis revealed a dominant diffusion-controlled charge storage contribution of 91.7%. To evaluate practical applicability, an asymmetric pouch-type supercapacitor device was assembled using CO-1 as the positive electrode and activated carbon as the negative electrode. The device operated efficiently within a 1.6 V window, achieving an impressive areal capacitance of 157 mF/cm2, an energy density of 0.056 mWh/cm2, a power density of 1.9 mW/cm2, and excellent cycling stability. This study underscores the critical role of polymer-assisted growth in tailoring electrode architecture and provides a promising route for integrating cost-effective and scalable supercapacitor devices into next-generation energy storage technologies.