Sustainable Production of Few-Layer Graphene From Spent Zinc–Carbon Batteries via Surfactant-Free Electrochemical Exfoliation

Abstract

The increasing generation of e-waste, particularly spent Zn–C (zinc–carbon) batteries, poses serious environmental and economic challenges. In this study, a surfactant-free, one-step electrochemical exfoliation method was developed to convert battery-derived graphite into few-layer graphene. The recovered graphite rods were subjected to mild electrochemical treatment in sulfuric acid (H₂SO₄, 98%), followed by bath sonication and centrifugation. The process yielded reproducible graphene with an average mass recovery of 59.8% across eight independent batches. Comprehensive characterization using ultraviolet–visible (UV–Vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, x-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive x-ray spectroscopy (EDX) confirmed the formation of few-layer graphene with low defect density, high carbon purity, and preserved sp² conjugation. Compared with previous surfactant-assisted or high-voltage methods, this surfactant-free approach eliminates complex purification steps and reduces environmental impact while maintaining high structural quality. The study demonstrates a scalable, environmentally benign route for sustainable graphene production from e-waste, within a circular economy framework.