PVC-Mediated Chlorination Roasting Enables Green and Selective Lithium Recovery From Mixed Spent LiMn₂O_4-LiCoO₂...

The increasing generation of spent lithium-ion batteries requires green and economic recycling solutions. This study develops a novel PVC-mediated chlorination roasting process for selective lithium recovery from the mixture of spent LiMn₂O₄-LiCoO₂ batteries. Thermodynamic analysis confirmed the preferential chlorination of lithium over cobalt and manganese while LiCl formation was thermodynamically favorable even at low chlorine partial pressure. Thermal behavior analysis indicated PVC dehydrochlorination began at 292°C followed by LiCl formation between 400°C and 600°C. The optimized conditions (600°C, 1:1.2, 120 min) achieved 97.28% lithium recovery efficiency and 98.86% lithium selectivity. Phase evolution analysis revealed the transformation pathways from LiMn₂O₄-LiCoO₂ to LiCl, in which manganese remained in manganese oxides and cobalt-manganese oxide, while cobalt was partially reduced to metallic cobalt. Density functional theory calculations indicated stronger chlorine adsorption on lithium sites compared to manganese/cobalt particularly on the preferentially exposed crystal facets. This process produced battery-grade Li₂CO₃ with high purity (99.65%) while effectively capturing over 80% of chlorine released during PVC pyrolysis. Economic assessment revealed this process generated a net profit of $3,418.5 per metric ton of spent lithium-ion batteries. This work proposes a sustainable strategy for selective lithium extraction, synergistically integrating battery recycling with plastic waste disposal through the circular economy.