Key Challenges of Lithium-Ion Battery Recycling and Future Direction

The rapid expansion of lithium-ion battery (LIB) applications in electric vehicles, renewable energy storage, and portable electronics has led to a rapidly increasing volume of end-of-life batteries, raising urgent environmental, economic, and resource security concerns. In this context, LIB recycling has become a critical component of a sustainable energy transition; however, its industrial implementation remains limited by fundamental technological and system-level constraints. This review offers a critical and structured assessment of established and emerging LIB recycling technologies, including pyrometallurgical, hydrometallurgical, direct recycling, electrochemical recovery, and deep eutectic solvent-based processes. Rather than identifying a single optimal route, the analysis demonstrates that process performance is highly context dependent, governed by battery chemistry, material degradation state, and system configuration. Key limitations across all routes include inefficient process integration, insufficient scalability of emerging technologies, high energy and chemical intensity, and a lack of standardized evaluation metrics. Beyond process-level considerations, the review highlights the dominant role of system bottlenecks, particularly fragmented collection infrastructure, regulatory inconsistencies, and limited eco-design for recyclability. The findings indicate that advancing LIB recycling requires a shift from isolated process optimization toward integrated, hybrid, and system-oriented frameworks. Future progress will depend on harmonized policy structures, scalable low-impact technologies, and design strategies that incorporate recyclability at the material and product levels to enable true circularity.