Selective lithium recycling and regeneration from spent lithium-ion batteries via a sulfur roasting method

Recycling spent lithium-ion batteries (LIBs) is crucial for sustainable resource utilization and environmental conservation, especially considering the low recovery rate of lithium from industrial-grade spent batteries powder (black powder). This study presents a cost-effective method using sulfur roasting technique to extract lithium from commercial black powder. Thermal analysis indicates that, under optimized reaction conditions, the spent LiNi_xCo_yMn_zO₂ material undergoes thermal decomposition followed by reduction, resulting in the formation of Li₂SO₄, MnS, MnO, Co₉S₈, Co₃S₄, NiS and Ni₃S₂. Following a water leaching process, lithium is dissolved in the water while other metals remain in the residue, effectively separating lithium from the other metals. Consequently, a sulfur roasting process at 600 °C for 30 min achieves a lithium leaching rate of about 97.0 %, with minimal leaching of Mn, Ni and Co. The high selectivity for lithium recovery, along with its cost-effectiveness and energy efficiency, makes the sulfur roasting method highly suitable for practical use.