Performance Analysis of Regenerated rGO Electrodes from Spent Li-ion Battery Anodes for Secondary Energy Device Applications

At the end of their life, disposal of Li-ion batteries is a severe issue. Therefore, this study aims to recycle graphite from the spent anode material and synthesize reduced graphene oxide (rGO) in an eco-friendly approach. rGO was prepared from graphene oxide (GO), which is obtained from the spent graphite (G) by the modified Hummer’s method. The graphene powder was reduced by ascorbic acid at 60 °C through a chemical reduction process using GO. The structural morphology of G, GO, and rGO was characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, ultraviolet–visible (UV–vis) spectroscopy, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, field-emission scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscopy (HR-TEM). The Brunauer–Emmett–Teller (BET) surface area and porous behavior of rGO are studied and checked for their capacity in supercapacitor applications. The cyclic voltammogram of rGO (between 0.0–1.0 V) showed a pair of redox peaks corresponding to the electrical double-layer capacitance. The galvanostatic charge/discharge studies for rGO showed a discharge capacity of 278.5 F/g after 200 cycles (coated on a glassy carbon electrode) and 207.9 F/g after 2000 cycles (coated on a Toray carbon electrode) at a 1 A/g current density.