Density-Based Recovery Followed by Regeneration of Anode Graphite From Spent Lithium-Ion Batteries Containing Mixed Battery Types

Abstract

Lithium (Li)-ion batteries (LIBs) are extensively used in modern electronics and electric vehicles, leading to a growing accumulation of spent batteries. Improper disposal poses serious environmental and economic challenges. While most recycling efforts focus on recovering valuable metals such as Li, cobalt (Co), and nickel (Ni) from cathodes, the anode material—primarily graphite—is often overlooked and discarded, contributing to resource inefficiency. In this study, a practical and sustainable method was developed to recover and regenerate anode graphite from mixed spent LIBs containing diverse chemistries, including Li Co oxide (LCO), Li iron phosphate (LFP), LMO, Ni manganese Co oxide (NMC), and NCA. A density-based separation technique, based on Stokes’ law, was employed to isolate graphite from cathode residues. The separation efficiency was confirmed through scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX), both of which revealed a clean and complete separation of graphite. Structural analysis using X-ray diffraction (XRD) showed sharp diffraction peaks at (002), (100), and (004) planes, indicating high crystallinity and minimal lattice degradation during processing. The recovered graphite was subjected to thermal treatment and evaluated through galvanostatic cycling. The regenerated anode material exhibited a specific capacity of 340 mAh/g, closely matching that of commercial graphite (342 mAh/g), confirming excellent electrochemical performance. These findings demonstrate the viability of regenerating anode materials from mixed battery waste and underscore its role in reducing environmental impact, conserving critical raw materials, and enhancing the sustainability of LIB recycling systems.