Synthesis and Development of AlCoCrFeNi High-Entropy Alloy from Recycled Battery Scrap and Primary Metals

The electric vehicle market is expanding rapidly and steadily, and with it, global demand for lithium-ion batteries is growing. The management of these devices at the end of their life cycle has become a central issue, both in relation to environmental and climate protection and to ensuring the security of supply of critical materials. The recycling of used batteries is a strategic resource for the recovery of high-value metals, including aluminum, cobalt, chromium, iron, and nickel, which are essential for the production of advanced materials. Among the possible applications for these recovered metals, the synthesis of high-entropy alloys (HEAs) is a particularly promising area. These alloys, characterized by unconventional compositions based on elements in comparable proportions, exhibit an interesting combination of mechanical, thermal, and chemical properties, making them excellent candidates for structural and high-performance applications. The objective of this thesis is to evaluate the effectiveness of pyrometallurgical processes applied to black mass derived from end-of-life batteries for the recovery of strategic metals and subsequently investigate the use of these elements in the synthesis of AlCoCrFeNi and AlCoCrFeNi2 alloys. After contextualizing the state of the art on lithium-ion battery recycling and high-entropy alloys, the thesis describes in detail the experimental protocols adopted and presents the results obtained. The analysis shows the high complexity of black mass treatment processes and the critical issues associated with metal separation and recovery, highlighting the need for further studies to make these processes more efficient, sustainable, and scalable on an industrial scale. The characterization of the AlCoCrFeNi and AlCoCrFeNi2 alloys synthesized in this work confirms the significant potential of this emerging class of materials, underlining their technological interest and their ability to stimulate the development of new innovative formulations. The integration of electric vehicle battery recycling and high-entropy alloy production ultimately represents a highly promising strategy for promoting a truly circular economy and enabling new high-performance applications through a more intelligent and targeted use of strategic metal resources.