Recycling Anodic Residues of Dead Zn–C Batteries: Microwave-Assisted Synthesis of Co3O4 Incorporated ZnO/MnO2/ZnMn2O4 Electrodes for Asymmetric Supercapacitor Applications

Abstract

With an emphasis on sustainability, this study attempts to turn waste battery components, especially anodic residues, into high-performance supercapacitor electrodes. Cobalt oxides were added in the anodic residues using a microwave route and an annealing process to improve the electrochemical performance. XRD analysis reveals that the prepared composites consisted of ZnO/MnO₂/ZnMn₂O₄/Co₃O₄. The Co₃O₄ morphology was highly influenced by its concentration, determined using SEM. Spherical/cloudy-like nanohybrids were formed for composites consisting of 10 wt % Co₃O₄. Half-cell configurations were utilized to examine electrochemical properties, signifying a redox reaction based electrochemical process, and it yielded a maximum capacity of 687 C g^–1 at 2 mA cm^–2. Moreover, an asymmetric supercapacitor cell was fabricated using the composite consisting of 10 wt % Co₃O₄, and it could yield a specific energy of 33 Wh kg^–1 (for total mass of active materials) and retained 30.3% of energy at a very fast rate of 15 652 W kg^–1. Besides, the charged cell could power red LEDs for 120 seconds. This study highlights the enormous potential in converting waste materials into useful resources, therefore contributing to the achievement of the United Nations’ sustainable development goals through promoting affordable and clean energy, industry, innovations and infrastructure, and responsible consumption and production in the realm of energy storage.