Technological pathways and sustainability insights into spent lithium-ion batteries

Recycling spent lithium-ion batteries (LIBs) provides a strategic pathway toward resource circularity, carbon emission reduction, and supply chain resilience amid the growing accumulation of end-of-life LIBs. This review synthesizes state-of-the-art developments in LIB recycling technologies and provides a critical comparison of their technical mechanisms, process efficiencies, and scalability at both laboratory and industrial levels. Existing life cycle assessment and techno-economic analysis studies are critically compared for evaluating the environmental impacts and economic feasibility of different recycling technologies. This work supports informed decision-making by researchers, policymakers, and industry by identifying key challenges and providing future directions to ensure the long-term sustainability of the battery industry. Although conventional metallurgical approaches demonstrate strong industrial applicability, they are limited by high operating temperatures and the associated greenhouse gas emissions. In contrast, direct recycling and upcycling methods offer simpler and more efficient routes to retain the residual value of spent LIBs. However, the need for advanced pretreatment steps and reliance on accurate assessment of failure states limit practical implementation. Apart from technological advancements, supportive policy frameworks and regulatory standards are essential for the sustainable life-cycle management of LIBs. This review aims to inspire innovative solutions that combine technological advancement with sustainable industrial practices to enhance circular management of LIBs.