Toward Sustainable Lithium-Ion Batteries: Recycling and Reuse Strategies for Spent Graphite Anodes.

The growing demand for lithium-ion batteries (LIBs) has intensified the need for sustainable graphite recycling and reuse. Spent graphite anodes, accounting for a significant portion of battery waste, suffer from structural degradation, surface contamination, and the formation of complex impurities, posing challenges for direct reuse. This review introduces the general degradation origins of spent graphite anodes and focuses on recycling, regeneration, and modification strategies, including hydrometallurgical and pyrometallurgical approaches. The emerging technique of Flash Joule heating (FJH) is also discussed. Regenerated graphite generally fails to meet the desired electrochemical performance and therefore needs further modification. Strategies including surface engineering, structural regulation, and hybridization with other materials have been widely explored, leading to improved structural stability, fast-charging capability, and even higher energy density. Finally, the key challenges hindering large-scale application are identified. This review aims to provide comprehensive insights into sustainable graphite recycling and reuse, promoting the development of high-performance and environmentally responsible LIBs.