(516g) Pyrolysis Oil: A Promising Anode Precursor for Lithium-Ion Batteries

Graphite demand is increasing rapidly due to the popularity of electric vehicles (EVs). Lithium-ion batteries (LIBs) are the power source of EVs and the anode of LIBs is made of graphite. This study aims to develop and optimize a novel process for the production of battery-grade graphite from a renewable precursor, pyrolysis oil, using iron as the graphitization catalyst. Catalytic graphitization was carried out under relatively moderate conditions (1500 °C, 20 hours) to reduce costs and environmental impacts as compared to incumbent graphitization technologies. After graphitization, the residual catalyst was separated by washing the graphite-iron mixture with hydrochloric acid under reflux. The efficiency of iron removal was studied using both X-ray fluorescenc (XRF) and inductively coupled plasma (ICP) techniques. To evaluate the quality of graphite, X-ray diffraction (XRD), Raman spectroscopy, and high-resolution transmission electron microscopy (HR-TEM) were applied as the preliminary screeing tools. The optimized graphite sample demonstrated excellent reversible capacity (>350 mAh/g) with minimal capacity loss over 100 cycles and a high initial Coulombic efficiency (90%) when applied as a lithium-ion battery anode, thereby making this technology potentially competitive with commercially available battery-grade graphite.