Sustainable recycling of spent Li‐ion batteries through waste pine needle‐assisted carbothermal reduction for lithium recovery

Abstract As the global dependence on lithium‐ion batteries continues to grow, the challenge of recovering valuable metals from spent batteries has become increasingly crucial. Furthermore, the inappropriate disposal of spent batteries not only affects the loss of critical metals but also poses significant environmental hazards. To address these issues and develop sustainable recycling methods, the use of renewable and environmentally friendly materials is essential. Therefore, a biomass‐based energy‐intensive reduction method is proposed to recover lithium from spent lithium‐ion batteries. Here, waste pine needle was used as a biomass for carbothermal reduction process to convert lithium in the spent cathode powder into Li 2 CO 3 , while the transition metals were reduced to Ni, Co/CoO, and MnO. The effect of carbothermal reduction process parameters like temperature, mass ratio of pine needle and spent cathode powder, and residence time on leaching efficiency and reduction efficiency along with process modelling and optimization, was done using response surface methodology. Overall, this study provides an energy efficient approach to recycle spent LIBs using waste pine needles, enabling selective lithium recovery from spent lithium‐ion batteries.