Simple Route for Graphite Recycling from Waste Lithium-Ion Batteries to Environmental Functional Materials

The acid leaching residue from the recovery of spent lithium-ion batteries (LIBs) is difficult to handle properly due to its high risk and cost. In this study, a simple recovery method was developed to prepare modified graphite into catalysts for wastewater treatment, and the influence of the impurities and the modification parameters was intensively investigated. It was observed that the modified graphite demonstrated a fairly high performance in catalytic ozonation of the simulated refractory contaminant oxalic acid. Inorganic impurities were probably beneficial to the catalytic activity of the modified graphite, and annealing at 550 °C enhanced the catalytic efficiency the most. The relationship of the structure and surface properties and the catalytic activity was also established, and it confirmed that pyridinic N and surface defects are the main active sites, and the catalysts with defects as the dominant active sites had a better catalytic stability. Quenching experiments and mass spectrometry proved that •OH was the main reactive oxygen species. This study proposed a practicable recycling method of the acid leaching residue from waste LIBs, and the modified graphite showed great potential in catalytic ozonation of aqueous organic pollutants.