Efficient and selective recovery of lithium from spent lithium-ion batteries by biomass single-component regulated pyrolysis with synergistic water leaching approach

In this study, we developed a synergistic recycling technology based on biomass pyrolysis, roasting, and water leaching of biomass single components (cellulose, hemicellulose, and lignin), aiming to address the environmental risks posed by spent lithium-ion batteries due to the rapid growth of the new energy battery industry. By innovatively utilizing the reducing gases (H 2 , CO) produced during the biomass pyrolysis process, we have not only achieved the structural cracking of ternary cathode materials but also reduced high-valent metal oxides (such as nickel, cobalt, and manganese oxides) to metallic states, thereby realizing selective lithium leaching. This study systematically explored how biomass type , dosage ratio, roasting temperature, and roasting time affect lithium reduction efficiency and leaching behaviour. Experimental results demonstrated that lignin exhibited the most potent synergistic effect under pyrolysis at 600 ℃. At a dosage ratio of 1:0.25, the lithium leaching rate exceeded 90 %, outperforming cellulose and hemicellulose under equivalent low-temperature and low-dosage conditions. A component-property database of biomass could be established to optimize dosing strategies for diverse cathode materials. Economic and environmental impact analyses using the Everbatt model indicate that biomass reduction leads to reduced energy consumption and greenhouse gas emissions, resulting in significant energy and environmental benefits. This study proposes a green and low-carbon lithium recycling method that integrates with metal recovery, providing technological innovation and practical significance for promoting sustainable development in the new energy sector.