Alkaline Roasting Approach to Reclaiming Lithium and Graphite from Spent Lithium-Ion Batteries

Abstract

Recycling anode materials from spent lithium-ion batteries (LIBs) plays a significant role in relieving the environmental pollution and shortage of graphite and lithium resources. Most of the current routes employed mineral acids to leach out Li from the graphite anode, inevitably producing hazardous hydrofluoric acid (HF) because some Li exists in the form of lithium fluoride (LiF). In this study, we employ a NaOH roasting approach, by which LiF is converted to NaF and LiOH at 350 °C and thereby avoids the generation of HF. After roasting, the Li and graphite can be separated by a water leaching process without using mineral acids. The leaching efficiency of Li is close to 100%. The regeneration process of NaOH was also discussed considering the large-scale application. Additionally, the recovered graphite delivered an initial charge capacity of 370.8 mA h g–1 and a Coulombic efficiency of 90.05%, showing the comparable performances to the commercial graphite. Overall, the alkaline roasting approach does not use mineral acids and thus avoids generating toxic HF and waste acids, promising a green way to recycle anode materials from various spent LIBs.