A Sustainable Recycling Approach to Regenerate Graphite from Industrially Sourced Failed Anodes

Recycling graphite from Li-ion battery (LIB) waste plays an important role in increasing the accessibility of graphite resources and sustainable recovery. This presentation describes our work to purify graphite from failed (i.e., out-of-specification) anodes in LIB manufacturing by focusing on the most common contaminant: copper, used as the current collector in LIB anodes. A new, three-step scalable and environmentally friendly approach was used to provide a cost-effective and sustainable method in industrial settings to recycle failed anodes during the early stages of battery manufacturing. The study aimed to understand the differences between new, battery-grade graphite and recycled graphite from anode production waste. In particular, focus was placed on the effect of metallic Cu residues on electrochemical performance. The efficiency of Cu removal from graphite was quantified by Microwave Plasma – Atomic Emission Spectroscopy (MP-AES) analysis of leachates. The following experimental parameters were studied to maximize Cu leaching efficiency: solid-to-liquid ratio, temperature, acid concentration, time and stirring speed. The surface morphology and elemental composition of leached and thermally treated purified graphite were analysed by Scanning Electron Microscopy – Energy Dispersive Spectroscopy (SEM-EDS) and Laser Induced Breakdown Spectroscopy (LIBS). The specific surface area and crystallographic parameters were measured by Braunauer–Emmett–Teller Analysis (BET) and X-Ray Diffraction (XRD), respectively. The electrochemical performance was evaluated by galvanostatic cycling with potential limitation versus Li + /Li. These five techniques were carried out on the solid residues after each stage of the regeneration procedure. The results were compared with battery-grade graphite to assess the effectiveness of our sustainable recycling approach to reuse graphite from failed anodes in LIBs.