Ultrasound-Assisted Recovery of Cathode Active Materials Using Green Solvents: A Comparative Study

The widespread adoption of lithium-ion batteries (LIBs) in various applications has led to an increasing demand for efficient and environmentally sustainable recycling processes. This necessity stems from the broader goal of establishing a sustainable and circular economy for LIBs while simultaneously addressing the challenges within the supply chain. One of the primary challenges in LIB recycling lies in the retrieval of valuable materials from end-of-life LIBs or electrode scraps in an environmentally benign manner. In particular, reclaiming the high purity of cathode active materials is a critical step to further development of direct recycling. The recovered materials need to be binder- and carbon black-free while retaining their inherent characteristics, including morphology, crystallinity, and electrochemical activity. Traditional methods for solvent-based cathode recovery involve energy-intensive processes and often employ hazardous solvents, leading to environmental concerns and safety issues. In response, recent studies have proposed several green solvents as environmentally friendly and economically viable alternatives for sustainable cathode recovery processes. In this study, we conduct a comprehensive comparative analysis of various green solvents to assess their efficiency in recovering cathode materials from electrode scraps. We employ an ultrasound-assisted recovery process using different green solvents to compare the characteristics of the recovered cathode active materials in terms of morphology, purity, surface characteristics, and electrochemical performance. By evaluating the key challenges and advantages of each green solvent, we aim to provide valuable insights into the development of solvent-based cathode recovery.