Using Tangerine Peel as a Reducing Agent in the Process of Recovering the Cathode Elements from Spent Lithium-Ion Batteries

This study assessed the potential for recycling the Ni-Co-Mn (NCM) cathode from spent Lithium-Ion Batteries (LIBs) using Tangerine Peel (TP) as a reducing agent in CH3COOH media. The impact of various parameters, including CH3COOH concentration (ranging from 1-6 M), temperature (ranging from 30-100 ºC), leaching time (ranging from 0.33 to 7 h), TP/NCM (0.1-2 g/g), was investigated. The results indicated that adding TP improved the recovery of Ni, Co, Mn, and Li. The temperature was the most critical parameter in the reductive leaching process as it facilitated the hydrolysis of TP compounds into glucose. Generally, increasing leaching time, CH3COOH, and TP concentration improved the recovery. Dissolution of Li was less dependent on reducing agent concentration, while strong dependence was observed for Ni, Co, and Mn elements. Based on parameter optimization results, optimal levels were obtained for time (6 h), temperature (100 °C), CH3COOH concentration (3 M), and TP/NCM (2 g/g). The FT-IR analysis of TP suggests the presence of cellulose, lignin, and hemicellulose bonds in the spectrum. The FT-IR profile of TP hydrolysis in acetic acid reveals the peaks for CH3COOH and glucose structure. Interestingly, the IR profile of leaching samples in the presence and absence of TP did not display any discernible differences, indicating that glucose molecules produced during leaching were immediately consumed by spent LIBs compounds and did not persist.