Efficient recovery of valuable metals from cathode materials of spent LiCoO2 batteries via co-pyrolysis with cheap carbonaceous materials

The influence of chlorination additives on metal separation during the pyrometallurgical recovery of spent lithium-ion batteries

The difficulty of separating Li during pyrometallurgical smelting of spent lithium-ion batteries (LIBs) has limited the development of pyrometallurgical processes. Chlorination enables the conversion of Li from spent LIBs to the gas phase during the smelting process. In this paper, the effects of four solid chlorinating agents (KCl, NaCl, CaCl2 and MgCl2) on Li volatilization and metal (Co, Cu, Ni and Fe) recovery were investigated. The four solid chlorinating agents were systematically compared in terms of the direct chlorination capacities, indirect chlorination capacities, alloy physical losses and chemical losses in the slag. CaCl2 was better suited for use as a solid chlorinating agent to promote Li volatilization due to its excellent results in these indexes. The temperature required for the release of HCl from MgCl2, facilitated by CO2 and SiO2, was lower than 500 °C. The prematurely released HCl failed to participate in the chlorination reaction. This resulted in approximately 12 % less Li volatilization when MgCl2 was used as a chlorinating agent compared to when CaCl2 was used. In addition, the use of KCl as a chlorinating agent decreased the chemical dissolution loss of alloys in the slag. The performance of NaCl was mediocre. Finally, based on evaluations of the four indexes, recommendations for the selection and optimization of solid chlorinating agents were provided.

Improved recovery of lithium from spent lithium-ion batteries by reduction roasting and NaHCO3 leaching

Lithium supply risk is increasing and driving rapid progress in lithium recovery schemes from spent lithium-ion batteries (LIBs). In this study, a facile recycling process consisting mainly of reduction roasting and NaHCO3 leaching was adopted to improve lithium recovery. The Li of spent LiNixCoyMn1-x-yO2 powder were converted to Li2CO3 and LiAlO2 with the reduction effect of C and residual Al in the roasting process. NaHCO3 leaching was utilized to selectively dissolve lithium from Li2CO3 and water-insoluble LiAlO2. The activation energy of NaHCO3 leaching was 9.31 kJ∙mol-1 and the leaching of lithium was a diffusion control reaction. More than 95.19 % lithium was leached and recovered as a Li2CO3 product with a purity of 99.80 %. Thus, this approach provides a green path to selective recovery of lithium with good economics.

Crystal phase and nanoscale size regulation utilizing the in-situ catalytic pyrolysis of bamboo sawdust in the recycling of spent lithium batteries

Current Li-ion battery (LIB) recycling methods exhibit the disadvantages of low metal recovery efficiencies and high levels of pollution and energy consumption. Here, products generated via the in-situ catalytic pyrolysis of bamboo sawdust (BS) were utilized to regulate the crystal phase and nanoscale size of the NCM cathode to enhance the selective Li extraction and leaching efficiencies of other valuable metals from spent LIBs. The catalytic effect of the NCM cathode significantly promoted the release of gases from BS pyrolysis. These gases (H2, CO, and CH4) finally transformed the crystal phase of the NCM cathode from LiNixCoyMnzO2 into (Ni-Co/MnO/Li2CO3)/C. The size of the spent NCM cathode material was reduced approximately 31.7-fold (from 4.1 μm to 129.2 nm) after roasting. This could be ascribed to the in-situ catalytic decomposition of aromatic compounds generated via the primary pyrolysis of BS into C and H2 on the surface of the cathode material, resulting in the formation of the nanoscale composite (Ni-Co/MnO/Li2CO3)/C. This process enabled the targeted control of the crystal phase and nanoscale size of the material. Water leaching studies revealed a remarkable selective Li extraction efficiency of 99.27 %, and sulfuric acid leaching experiments with a concentration of 2 M revealed high extraction efficiencies of 99.15 % (Ni), 93.87 % (Co), and 99.46 % (Mn). Finally, a novel mechanism involving synergistic thermo-reduction and carbon modification for crystal phase regulation and nanoscale control was proposed. This study provides a novel concept for use in enhancing the recycling of valuable metals from spent LIBs utilizing biomass waste and practices the concept of "treating waste with waste".

A review on spent Mn-containing Li-ion batteries: Recovery technologies, challenges, and future perspectives

Mn-containing Li-ion batteries have become primary power sources for electronic devices and electric vehicles because of their high-energy density, extended cycle life, low cost, and heightened safety. In recent years, Li-ion batteries (LIBs) have undergone rapid updates, paralleling the swift advancement of the lithium battery industry, resulting in a growing accumulation of LIB scraps annually, necessitating comprehensive recovery strategies. This article reviews the recent progress in recovering spent Mn-containing LIBs (SM-LIBs), specifically focusing on LiMn2O4 and ternary LiCoxMnyNizO2 (NCM). Initially, the study analyzes the current resource profile of SM-LIBs and elucidates their service mechanisms. Subsequently, the study explores the recovery of SM-LIBs, discussing various methods such as the hydrometallurgical approach, combined pyrolytic treatment-wet leaching process, bioleaching pathway, and electrochemical extraction. These discussions include recovery processes, reaction principles, and technological features. In addition, this study evaluates the potential applications of these recovery technologies, considering aspects such as complexity, economic viability, energy consumption, environmental sustainability, and scalability. Finally, it summarizes the challenges associated with the comprehensive recovery and resource utilization of SM-LIBs and offers insights into future directions.

Recovery of valuable metals from spent lithium-ion batteries through biomass pyrolysis gas-induced reduction

The development of spent lithium-ion batteries (LIBs) recycling technologies can effectively alleviate environmental pressure and conserve metal resources. We propose a win-win strategy for pyrolysis gas reduction by lignocellulosic biomass, ensuring gas-induced reduction by spatial isolation of biomass and lithium transition metal oxides (LiTMOX (TM = Ni, Co, Mn)), and avoiding the separation of solid carbon and TMOX (TM = Ni, Co, Mn). In the spent LiCoO2 batteries, the lithium recovery efficiency reaches 99.99% and purity reaches 98.3% at 500 °C. In addition, biomass pyrolysis gas reduction is also applicable to treat spent LiMn2O4 and LiNi0.6Co0.2Mn0.2O2 batteries. Thermodynamic analysis verifies that CO dominates the gas reduction recovery process. DFT calculation indicates that the gas reduction induces the collapse of the oxygen framework of LiTMOX (TM = Ni, Co, Mn). Everbatt-based economic and environmental analysis illustrates that this is an environment-friendly and energy-saving method.

Applicability of the reduction smelting recycling process to different types of spent lithium-ion batteries cathode materials

The high-temperature smelting process based on pyrometallurgy is influential in the field of recycling spent lithium-ion batteries (LIBs) on an industrial scale. However, there are a variety of cathode materials for spent LIBs. The applicability of the high-temperature smelting process to different kinds of cathode materials has not been reported. In this work, the applicability of the reduction smelting process to four different cathode materials is studied. The phase transition, distribution and existence of target elements and the characteristics of the smelting products when different cathode materials are used as raw materials are systematically discussed. The results show that the reduction smelting process can recover the four different cathode materials (LiCoO₂, LiFePO₄, LiMn₂O₄, LiNi_0.8Co_0.1Mn_0.1O₂) of spent LIBs. The reduction smelting process is also suitable for complex feedstocks containing the four cathode materials. The target elements Co, Cu, Ni, Fe and P are transferred to the alloy. The target elements Li and Mn volatilize into the gas phase. In addition, the future application of the reduction smelting process on an industrial scale is discussed and proposed. This study reveals the excellent applicability of the reduction smelting process to different LIB cathode materials and provides support for the development of a high-temperature smelting process based on pyrometallurgy.