A Dual-Function Platform of green Cobalt Oxide nanoparticles for antimicrobial activity and High-Performance Symmetric Supercapacitors

In this study, cobalt oxide (Co ₃ O ₄ ) nanoparticles were synthesized via a green extraction method using Aloe vera as a bio-reducing agent. Fundamental characterizations of the synthesized Co ₃ O ₄ were carried out using Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), and Energy-Dispersive X-ray Analysis (EDAX). The minimum inhibitory concentration (MIC) and antimicrobial activity were evaluated against Bacillus cereus , Escherichia coli , and Pseudomonas aeruginosa , with zones of inhibition measured in millimeters after incubation. The Co ₃ O ₄ nanoparticles were then coated onto Aluminum plate of (1 x 1 x 0.1 cm) and assembled in a symmetric two-electrode supercapacitor configuration using a Na₂SO₄ electrolyte. Galvanostatic charge–discharge (GCD) testing at 50 µA revealed nearly symmetric charge–discharge curves, indicating excellent capacitive behavior. The system exhibited a specific capacitance of 314.8 F/g, with an energy density of 39.88 Wh/kg and a power density of 8,451.4 W/kg. Minimal resistance variation after cycling and a Coulombic efficiency approaching ~ 100% confirmed the system’s outstanding cyclic stability and potential for high-performance energy storage applications.