In-situ CO sustained-release enhancing carbothermal reduction process for selective extraction of lithium from spent LiNi_xCo_yMn_zO₂ powder

The scarcity of lithium resources makes it necessary to extract lithium from spent lithium-ion batteries (LIBs). However, there are some persistent problems with the existing lithium extraction methods, including long process, high cost and low efficiency. Comparatively, carbothermal reduction (CTR) method simplifies the process and reduces the cost while still obstructed by the insufficient restoration. This work proposes an enhanced CTR method (E-CTR) to strengthen the selective extraction of lithium via in-situ CO sustained-release and to enrich the remaining transition metals (TMs) into Ni/Co/MnO in the residue. By optimizing the roasting conditions, combined with water leaching, it can achieve as high as 96.9% preferential extraction of lithium along with the fabrication of carbon-based anode of resin material. TG/DTG-MS as well as thermodynamic analyses demonstrate that FeCO₃ and resin play a critical synergistic role in the E-CTR process, with higher efficiency compared to conventional lithium extraction approaches. Molecular dynamics simulations further prove the indispensable role of the CO donor FeCO₃, powerfully supporting the results of the present work. The economic-environmental assessment proves that the present work is economically competitive and environmentally friendly and further enriches the selective lithium extraction techniques.