Pyrolysis kinetics and reaction mechanism of the electrode materials during the spent LiCoO2 batteries recovery process

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.

Revealing the delithiation process of spent LiMn2O4 and LiNi0.6Co0.2Mn0.2O2 batteries during the biomass-assisted gasthermal and carbothermal reduction

The utilization of biomass-assisted pyrolysis in the recycling of spent lithium-ion batteries has emerged as a promising and reliable process. This article furnishes theoretical underpinnings and analytical insights into this method, showcasing sawdust pyrolysis reduction as an efficient means to recycle spent LiMn2O4 and LiNi0.6Co0.2Mn0.2O2 batteries. Through advanced thermogravimetry-gas chromatography-mass spectrometry analysis complemented by traditional thermodynamic demonstration, the synergistic effects of biomass pyrolysis reduction are elucidated, with minor autodecomposition and major carbothermal and gasthermal reduction pathways identified. The controlled manipulation of transition metals has demonstrated the capability to modulate surface pyrolysis gas catalytic reactions and facilitate the preparation of composite materials with diverse morphologies. Optimization of process conditions has culminated in recovery efficiency exceeding 99.0 % for LiMn2O4 and 99.5 % for LiNi0.6Co0.2Mn0.2O2. Economic and environmental analyses underscore the advantages of biomass reduction and recycling for these two types of spent LIBs: low energy consumption, environmental compatibility, and high economic viability.

A mild and efficient closed-loop recycling strategy for spent lithium-ion battery

As lithium metal resource supply and demand stabilize and prices decrease, the efficient recovery of valuable metals other than lithium from spent lithium-ion batteries is receiving increasing attention. Currently, challenges remain in the selective lithium recovery efficiency and the high cost of regenerating valuable metal slag after lithium extraction, particularly for spent ternary cathode materials. To address these challenges, this study introduces a closed-loop recovery process for spent ternary cathode materials, employing sulfur-assisted roasting to achieve efficient lithium extraction and high-value direct regeneration of ternary leaching residues. At moderate temperatures (500 ℃), LiNixCoyMn1-x-yO2 (NCM) materials undergo a directional transformation of lithium to Li2SO4 in synergy with sulfur and oxygen, achieving a lithium leaching extraction rate of 98.91 %. Additionally, the relatively mild reaction conditions preserve the secondary spherical morphology and uniform distribution of NiCoMn-based oxide residue without introducing adverse impurities, ensuring the successful regeneration of high-value NCM cathode materials (R-NCM). The R-NCM material exhibits good discharge capacity (144.3 mA·h/g at 1 C) and relatively stable cycling performance, with a capacity retention rate of 80 % after 150 cycles. This work provides a viable pathway for the efficient and environmental-friendly pyrometallurgical closed-loop recovery of spent lithium-ion batteries.

Recycling of spent lithium-ion batteries for a sustainable future: recent advancements

Lithium-ion batteries (LIBs) are widely used as power storage systems in electronic devices and electric vehicles (EVs). Recycling of spent LIBs is of utmost importance from various perspectives including recovery of valuable metals (mostly Co and Li) and mitigation of environmental pollution. Recycling methods such as direct recycling, pyrometallurgy, hydrometallurgy, bio-hydrometallurgy (bioleaching) and electrometallurgy are generally used to resynthesise LIBs. These methods have their own benefits and drawbacks. This manuscript provides a critical review of recent advances in the recycling of spent LIBs, including the development of recycling processes, identification of the products obtained from recycling, and the effects of recycling methods on environmental burdens. Insights into chemical reactions, thermodynamics, kinetics, and the influence of operating parameters of each recycling technology are provided. The sustainability of recycling technologies (e.g., life cycle assessment and life cycle cost analysis) is critically evaluated. Finally, the existing challenges and future prospects are presented for further development of sustainable, highly efficient, and environmentally benign recycling of spent LIBs to contribute to the circular economy.

Unveiling the lithium deintercalation mechanisms in spent lithium-ion batteries via sulfation roasting

Recovery of valuable metals from spent lithium-ion batteries (LIBs) is of great importance for resource sustainability and environmental protection. This study introduced pyrite ore (FeS2) as an alternative additive to achieve the selective recovery of Li2CO3 from spent LiCoO2 (LCO) batteries. The mechanism study revealed that the sulfation reaction followed two pathways. During the initial stage (550 °C-800 °C), the decomposition and oxidation of FeS2 and the subsequent gas-solid reaction between the resulting SO2 and layered LCO play crucial roles. The sulfation of lithium occurred prior to cobalt, resulting in the disruption of layered structure of LCO and the transformation into tetragonal spinel. In the second stage (over 800 °C), the dominated reactions were the decomposition of orthorhombic cobalt sulfate and its combination with rhombohedral Fe2O3 to form CoFe2O4. The deintercalation of Li from LCO by the substitution of Fe and conversion of Co(III)/Fe(II) into Co3O4/CoFe2O4 were further confirmed by density functional theory (DFT) calculation results. This fundamental understanding of the sulfation reaction facilitated the future development of lithium extraction methods that utilized additives to substantially reduce energy consumption.

Recovery of LiCoO2 and graphite from spent lithium-ion batteries by molten-salt electrolysis

The recovery of spent lithium-ion batteries has not only economic value but also ecological benefits. In this paper, molten-salt electrolysis was employed to recover spent LiCoO2 batteries, in which NaCl-Na2CO3 melts were used as the electrolyte, the graphite rod and the mixtures of the spent LiCoO2 cathode and anode were used as the anode and cathode, respectively. During the electrolysis, the LiCoO2 was electrochemically reduced to Co, and Li+ and O2- entered into the molten salt. The O2- was discharged at the anode to generate CO2 and formed Li2CO3. After electrolysis, the cathodic products were separated by magnetic separation to obtain Co and graphite, and Li2CO3 was recovered by water leaching. The recovery efficiencies of Li, Co, and graphite reached 99.3%, 98.1%, and 83.6%, respectively. Overall, this paper provides a simple and efficient electrochemical method for the simultaneous recovery of the cathode and the anode of spent LiCoO2 batteries.

In-situ pyrolysis based on alkaline medium removes fluorine-containing contaminants from spent lithium-ion batteries

Pyrolysis is an effective method for removing organic contaminants (e.g. electrolytes, solid electrolyte interface (SEI), and polyvinylidene fluoride (PVDF) binders) from spent lithium-ion batteries (LIBs). However, during pyrolysis, the metal oxides in black mass (BM) readily react with fluorine-containing contaminants, resulting in a high content of dissociable fluorine in pyrolyzed BM and fluorine-containing wastewater in subsequent hydrometallurgical processes. Herein, an in-situ pyrolysis process is proposed to control the transition pathway of fluorine species in BM using Ca(OH)₂-based materials. Results show that the designed fluorine removal additives (FRA@Ca(OH)₂) can effectively scavenge SEI components (Li_xPOF_y) and PVDF binders from BM. During the in-situ pyrolysis, potential fluorine species (e.g. HF, PF₅, and POF₃) are adsorbed and converted to CaF₂ on the surface of FRA@Ca(OH)₂ additives, thereby inhibiting the fluorination reaction with electrode materials. Under the optimal experimental conditions (temperature = 400 °C, BM: FRA@Ca(OH)₂ = 1: 4, holding time = 1.0 h), the dissociable fluorine content in BM was reduced from 3.84 wt% to 2.54 wt%. The inherent metal fluorides in BM feedstock hinder the further removal of fluorine with pyrolysis treatment. This study provides a potential strategy for source control of fluorine-containing contaminants in the recycling process of spent LIBs.

High-efficiency selective leaching of valuable metals from spent lithium-ion batteries: Effects of Na2S2O8 on the leaching of metals

A new method was presented for the high-efficiency selective leaching of Li and the efficient recovery of transition metals (TMs) from the cathode materials of spent lithium-ion batteries (spent LIBs). Selective leaching of Li was achieved by carbothermic reduction roasting and leaching with Na₂S₂O₈. After reduction roasting, high-valence TMs were reduced to low-valence metals or metal oxides, and Li was converted to Li₂CO₃. Then Na₂S₂O₈ solution selectively extracted 94.15% of Li from roasted product with leaching selectivity of more than 99%. At last, TMs were leached with H₂SO₄ without adding reductant with the leaching efficiency of metals all exceeding 99%. Na₂S₂O₈ added during the leaching process destroyed the agglomerated structure of the roasted product to open the way Li entered the solution. Under the oxidative environment of Na₂S₂O₈ solution, TMs would not be extracted. At the same time, it helped to regulate the phase of TMs and improved the extraction of TMs. Furthermore, the phase transformation mechanism of roasting and leaching was discussed through thermodynamic analysis, XRD, XPS, and SEM-EDS. This process not only realized the selectively comprehensive recycling of valuable metals in spent LIBs cathode materials; but also followed the principle of green chemistry.

Recycling Spent Lithium-Ion Batteries Using Waste Benzene-Containing Plastics: Synergetic Thermal Reduction and Benzene Decomposition

Spent lithium-ion batteries (LIBs) and benzene-containing polymers (BCPs) are two major pollutants that cause serious environmental burdens. Herein, spent LIBs and BCPs are copyrolyzed in a sealed reactor to generate Li₂CO₃, metals, and/or metal oxides without emitting toxic benzene-based gases. The use of a closed reactor allows the sufficient reduction reaction between the BCP-derived polycyclic aromatic hydrocarbon (PAH) gases and lithium transition metal oxides, achieving the Li recovery efficiencies of 98.3, 99.9, and 97.5% for LiCoO₂, LiMn₂O₄, and LiNi_0.6Co_0.2Mn_0.2O₂, respectively. More importantly, the thermal decomposition of PAHs (e.g., phenol and benzene) is further catalyzed by the in situ generated Co, Ni, and MnO₂ particles, which forms metal/carbon composites and thus prevent the emissions of toxic gases. Overall, the copyrolysis in a closed system paves a green way to synergistically recycle spent LIBs and handle waste BCPs.

Two-step leaching of spent lithium-ion batteries and effective regeneration of critical metals and graphitic carbon employing hexuronic acid

Recovering precious metal ions like Co, Li, Mn, and Ni from discarded lithium-ion batteries (LIBs) has significant environmental and economic benefits. Also, graphite will be in high demand in the coming years due to the development of LIBs for use in electric vehicles (EVs) and the need for it for electrodes in a variety of energy storage devices. However, it has been overlooked during the recycling of used LIBs, which resulted in resource waste and environmental pollution. In this work, a comprehensive and environmentally friendly approach for recycling critical metals as well as graphitic carbon from discarded LIBs was proposed. To optimize the leaching process, various leaching parameters were investigated by employing hexuronic acid or ascorbic acid. The feed sample was analyzed using XRD, SEM-EDS, and a Laser Scattering Particle Size Distribution Analyzer to determine the phases, morphology, and particle size. 100% of Li and 99.5% of Co were leached at the optimum conditions of 0.8 mol L^-1 ascorbic acid, a particle size of -25 μm, 70 °C, 60 min of leaching time, and 50 g L^-1 of S/L ratio. A detailed study of the leaching kinetics was carried out. The leaching process was found to be well-fitted with the surface chemical reaction model based on the findings of temperature, acid concentration, and particle size variations. To obtain pure graphitic carbon after the initial leaching, the leached residue was subjected to further leaching with various acids (HCl, H₂SO₄, and HNO₃). The Raman spectra, XRD, TGA, and SEM-EDS analysis of the leached residues following the two-step leaching process were examined to exemplify the quality of the graphitic carbon.

Worldwide research on extraction and recovery of cobalt through bibliometric analysis: a review

Cobalt is a strategic and critical mineral whose demand is expected to grow rapidly. This study aims to provide a comprehensive summary of cobalt extraction and recovery research from 2012 to 2021 in the form of bibliometric analysis. The work was based on the Science Citation Index Expanded (Web of Science) and carried out using the InCites of Clarivate for bibliometric data analysis and the software VOSviewer for science mapping. By analyzing a dataset of 4967 publications, the most influential journals, countries, authors, institutions, and publications were identified, and the keyword co-occurrence networks were mapped. The China mainland produced the most publications, while the USA had the highest average number of citations per publication and the UK was the most collaborative with other countries. The keyword analysis shows that the research hotspots gradually shifted over time from early means and methods for determination of cobalt in solution to recovery of cobalt from spent lithium batteries, smelting slag, copper-cobalt ore, etc. The research will be focused on further improvement and optimization of the separation, extraction, and recovery processes of cobalt from spent batteries in recent and future years, and three approaches were promoted to facilitate economization and industrialization of the processes in this field.

Kinetics study and recycling strategies in different stages of full-component pyrolysis of spent LiNixCoyMnzO2 lithium-ion batteries

Full-component pyrolysis has been proven to be a prospective method for the disposal of organic matters and the cathode material reduction of spent LiNi_xCo_yMn_zO₂ (NCM) lithium-ion batteries (LIBs). However, the kinetics of the full-component pyrolysis of spent NCM LIBs is still unclear. This work represents the first attempt to study the kinetics of different stages of full-component pyrolysis of NCM LIBs based on isoconversional method to guide the recycling of spent LIBs. Pyrolysis process was divided into four stages in accordance to the main weight loss temperature ranges and the classical Kissinger-Akahira-Sunose and Flynn-Wall-Ozawa kinetics models were employed to calculate the activation energy (E) in each stage. The main physicochemical reactions were clarified though in situ analysis, and the average E in the four stages was determined: (I) The volatilization of electrolytes occurred in the temperature range of 100-200 °C with the E of 98.6 kJ/mol. (II) The decomposition of organic matters and the preliminary reduction of cathode material transpired in the temperature range of 400-500 °C with the E of 227.2 kJ/mol. (III) The further reduction of NiO and CoO occurred from 650 to 800 °C with the E of 258.8 kJ/mol. (Ⅳ) The reduction of MnO took place from 850 to 1000 °C with the E of 334.9 kJ/mol. The recycling strategies based on full-component pyrolysis of spent NCM LIBs was accordingly proposed. During pyrolysis, the cathode material was gradually reduced and the pyrolytic products can be controlled through temperature regulation.

Repurposing of spent lithium-ion battery separator as a green reductant for efficiently refining the cathode metals

Developing green and high-efficient pyrometallurgy processes to recycle precious metals from spent lithium-ion batteries (LIBs) is of great importance for resource sustainability and environmental protection. Herein, a novel reduction roasting approach relying on spent LIB separator to refine the spent cathode is proposed. The efficiency of repurposing separator as a reductant for roasting the spent LiCoO₂ cathode and the underlying mechanisms were investigated. After the separator-mediated roasting at 500 °C for 2 h, Li⁺ leaching efficiency of the cathode reached 93.2 %, >2.6 times higher than those after roasting without reductant (25.2 %) or with benchmark reductant graphite (26.1 %). Under the separator-added roasting condition, the cathode was converted to the desired products, CoO and Li₂CO₃. Based on the analysis of in-situ reaction using thermogravimetric/differential scanning calorimetry and pyrolysis gas species identification, the separator-mediated reduction roasting of cathode was composed of two stages, i.e., reducing gas generation due to separator pyrolysis, followed by the reducing gas mediated LiCoO₂ reduction. During the process, the generated C₂H₄ and CO dominated the reduction. The use of co-existing separator to recover precious metals from spent LIBs is an effective and sustainable strategy to maximize the utilization of spent LIBs.

Hydrogen reduction of spent lithium-ion battery cathode material for metal recovery: Mechanism and kinetics

Hydrogen reduction is becoming a promising method for recycling lithium-ion battery cathode materials. However, the reaction mechanism and kinetics during hydrogen reduction are unclear, requiring further investigation. Therefore, non-isothermal and isothermal reduction experiments were conducted to evaluate the temperature dependence of the hydrogen reduction kinetics using simultaneous thermogravimetric and differential thermal analysis equipped with mass spectrometry. XRD and SEM were used to characterize the reduction products to understand the underlying reduction mechanisms. The hydrogen reduction profile could be divided into three main stages: decomposition of cathode materials, reduction of the resultant nickel and cobalt oxides, and reduction of LiMnO2 and residual nickel and cobalt oxides. The hydrogen reduction rate increased with increasing temperature, and 800°C was the optimum temperature for separating the magnetic Ni-Co alloy from the non-magnetic manganese oxide particles. The apparent activation energy for the isothermal tests in the range of 500–700°C was 84.86 kJ/mol, and the rate-controlling step was the inward diffusion of H2(g) within each particle. There was an downward progression of the reduction through the material bed for the isothermal tests in the range of 700–900°C, with an apparent activation energy of 51.82 kJ/mol.

Transformation and migration mechanism of fluorine-containing pollutants in the pyrolysis process of spent lithium-ion battery

Pyrolysis is an effective method to remove organics (e.g. electrolytes and binders) from spent lithium-ion battery (LIB). In this study, the co-pyrolysis characteristics of fluorine-containing substances and active materials from LIB were investigated using thermogravimetric-differential scanning calorimetry (TG-DSC), infrared spectroscopy (IR), and mass spectrometry (MS) analysis. Associated with the pyrolysis, active materials adsorb the residues of electrolyte on the surface and into the pores (20-200 °C), while polyvinylidene fluoride (PVDF) forms a liquid film to cover the local surface of active materials (400-500 °C). These interactions prevent deep removal of organics, leaving fluorine-containing contaminants in active materials. The barrier effect of PVDF liquid mesophase on the removal of organics with secondary liquidous phase formation during pyrolysis was confirmed by in situ optical observation. The migration behavior of fluorine element during the pyrolysis of black mass (BM) from spent LIB was also investigated. With pyrolysis temperature increasing from 100 °C to 600 °C, the dissociable fluorine content in pyrolyzed BM increased from 1.4 wt% to 3.7 wt%. The fluorine-containing contaminants in BM cannot be removed completely by simply increasing pyrolysis temperature. This study provides a better understanding on the transformation of fluorine-containing pollutants during the pyrolysis of BM.

Unveiling the recycling characteristics and trends of spent lithium-ion battery: a scientometric study

The recycling of spent lithium-ion batteries (LIBs) is both essential to sustainable resource utilization and environmental conservation. While spent batteries possess a resource value, they pose an environmental hazard at the same time. Since the start of development to recycle spent LIBs in 1990s, important contributions have been made and a number of achievements have been accomplished by scholars globally. Therefore, it is valuable to summarize the developments on spent LIB recycling and to analyze the characteristics and trends comprehensively. A review of the progress in this field will provide guidance for future development. In this study, recycling characteristics and developing trends including the research foundation, milestone, research hotspot, key technologies, and emerging trends were identified based on visual scientometric analysis followed by a discussion on future research directions in this area. For the analysis, 1041 publications in English were collected, summarized, and categorized. The distribution of scientific publications on spent LIB recycling from 1995 to 2020 displayed an increasing trend in numbers. China made the biggest contribution with 528 publications and basically cooperated with all other countries. The research fields with the highest contributions were "engineering", "chemistry", and "environmental science and technology". The keywords recovery, lithium ion battery, and cobalt appeared in high frequency. "Metal value" was identified as the most frequently used keyword which began to burst in 2005 and ended in 2013.

A multi-purpose pilot-scale molten metal & molten salt pyrolysis reactor

This paper describes the design features and operational details of a molten metal pyrolysis reactor. Such a reactor allows pyrolysis experimentation on biomass, aluminium-laminated plastics, mixed plastics, carbon fibre materials, etc. Experimental results on biodegradable plastic, carbon fibre composites, biomass and printed circuit boards (PCBs) are presented.•The inner container can have a sloped or flat-bottom depending on the material.•The method can be used to pyrolyse composite and pure materials.

Efficient separation of aluminum foil from mixed-type spent lithium-ion power batteries

The disposal of spent lithium-ion power batteries (LIBs) has become an important research topic owing to the booming market for electric vehicles. However, the recovery efficiency of the alkaline solution and organic solvent methods currently used to separate Al foil from cathode materials still has room for improvement. The insufficient separation of Al foil and complexity of the battery types present obstacles to the extraction of valuable metals using simple processes. In this study, an efficient approach is developed to separate the Al foil in mixed-type spent LIBs (M-LIBs), namely, LiNi_xCo_yMn_zO₂ (NCM), LiFePO₄ (LFP), and LiMn₂O₄ (LMO) LIBs, by controlled pyrolysis. Hundred percent of the Al foil was recovered at the temperature of 450 °C, holding time of 60 min, and heating rate of 10 °C/min. The purity of Al in the recovered foil was 99.41 %, 99.83 % and 99.92 %, and the recovery efficiency of the active cathode materials was 96.01 %, 99.80 % and 99.15 % for NCM, LFP and LMO, respectively, without the loss of active cathode materials. The obtained active cathode materials exhibited a favorable crystalline structure, and the average particle diameter was reduced from 300.497 to 24.316 μm with a smaller and looser morphology. The process could be well fitted with the Friedman differential equation, and the correlation coefficients were higher than 0.99. The efficient separation could be attributed to the complete rupture of long chain -(CH₂CF₂)-_n bonds in the poly (vinylidene difluoride) (PVDF) binder, which resulted in the formation of HF, trifluorobenzene, alkanes, and gaseous single molecule CH₂CF₂. Therefore, this work potentially provides an alternative approach for the efficient separation of Al foil in M-LIBs, thereby simplifying the process and achieving lower cost, reduced loss of valuable metals, and higher recovery efficiency.

A novel method for carbon removal and valuable metal recovery by incorporating steam into the reduction-roasting process of spent lithium-ion batteries

Oxygen-free roasting could efficiently achieve the recovery of valuable metals from spent lithium-ion batteries (LIBs), but the roasted products have the drawbacks of a high carbon (C) content and a complex separation process. Hence, in this study, a new method incorporating steam (H₂O) into the reduction-roasting recovery process of spent LIBs (steam roasting) was proposed to realize carbon removal and valuable metal recovery simultaneously. The influence of steam on the reduction-roasting process of spent LiNi_0.6Co_0.2Mn_0.2O₂ batteries (NCM) was investigated through experimental methods and thermodynamic analysis. The results indicated that the addition of steam could dramatically facilitate the decomposition and reduction process of spent NCM, and the carbon removal efficiency could reach 84%. H₂O only acted on the reaction process of the anode material, and the main component C could be efficiently gasified by steam to produce hydrogen (H₂) and carbon monoxide (CO), which could significantly accelerate the reduction process of CoO and NiO. The optimal conditions for valuable metal recovery and carbon removal were a H₂O/C mole ratio of 5:1 and a reduction-roasting temperature of 1123 K. After steam roasting, the magnetic recovery efficiencies of Co and Ni were as high as 90% and 93%, respectively. The final recovery products were Co, Ni, and Li₂CO₃ with high purities. Therefore, this study is expected to provide a novel approach to achieve efficient disposal and recovery of metals from spent LIBs.

Direct recovery of degraded LiCoO2 cathode material from spent lithium-ion batteries: Efficient impurity removal toward practical applications

Regenerating cathode material from spent lithium-ion batteries (LIBs) permits an effective approach to resolve resource shortage and environmental pollution in the increasing battery industry. Directly renovating the spent cathode materials is a promising way, but it is still challenging to efficiently remove all of the complex impurities (such as binder, carbon black, graphite and current collectors) without destroying the material structure in the electrode. Herein, a facile strategy to directly remove these impurities and simultaneously repair the degraded LiCoO₂ by a target healing method is reported. Specifically, by using an optimized molten salt system of LiOH-KOH (molar ratio of 3:7) where LiNO₃ and O₂ both serve as oxidants, the impurities can be completely removed, while the structure, composition and morphology of degraded LiCoO₂ can be successfully repaired to commercial level based on a two-stage heating process (300 °C for 8 h and 500 °C for 16 h, respectively), resulting in a high recovery rate of approximately 100% for cathode material. More importantly, the regenerated LiCoO₂ exhibits a high reversible capacity, good cycling stability and excellent rate capability, which are comparable with commercial LiCoO₂. This work demonstrates an efficient approach to recycle and reuse advanced energy materials.

A Combined Pyro- and Hydrometallurgical Approach to Recycle Pyrolyzed Lithium-Ion Battery Black Mass Part 2: Lithium Recovery from Li Enriched Slag—Thermodynamic Study, Kinetic Study, and Dry Digestion

Due to the increasing demand for battery raw materials, such as cobalt, nickel, manganese, and lithium, the extraction of these metals, not only from primary, but also from secondary sources, is becoming increasingly important. Spent lithium-ion batteries (LIBs) represent a potential source of raw materials. One possible approach for an optimized recovery of valuable metals from spent LIBs is a combined pyro- and hydrometallurgical process. The generation of mixed cobalt, nickel, and copper alloy and lithium slag as intermediate products in an electric arc furnace is investigated in part 1. Hydrometallurgical recovery of lithium from the Li slag is investigated in part 2 of this article. Kinetic study has shown that the leaching of slag in H2SO4 takes place according to the 3-dimensional diffusion model and the activation energy is 22–24 kJ/mol. Leaching of the silicon from slag is causing formation of gels, which complicates filtration and further recovery of lithium from solutions. The thermodynamic study presented in the work describes the reasons for the formation of gels and the possibilities of their prevention by SiO2 precipitation. Based on these findings, the Li slag was treated by the dry digestion (DD) method followed by dissolution in water. The silicon leaching efficiency was significantly reduced from 50% in the direct leaching experiment to 5% in the DD experiment followed by dissolution, while the high leaching efficiency of lithium was maintained. The study takes into account the preparation of solutions for the future trouble-free acquisition of marketable products from solutions.

A Combined Pyro- and Hydrometallurgical Approach to Recycle Pyrolyzed Lithium-Ion Battery Black Mass Part 1: Production of Lithium Concentrates in an Electric Arc Furnace

Due to the increasing demand for battery raw materials such as cobalt, nickel, manganese, and lithium, the extraction of these metals not only from primary, but also from secondary sources like spent lithium-ion batteries (LIBs) is becoming increasingly important. One possible approach for an optimized recovery of valuable metals from spent LIBs is a combined pyro- and hydrometallurgical process. According to the pyrometallurgical process route, in this paper, a suitable slag design for the generation of slag enriched by lithium and mixed cobalt, nickel, and copper alloy as intermediate products in a laboratory electric arc furnace was investigated. Smelting experiments were carried out using pyrolyzed pelletized black mass, copper(II) oxide, and different quartz additions as a flux to investigate the influence on lithium-slagging. With the proposed smelting operation, lithium could be enriched with a maximum yield of 82.4% in the slag, whereas the yield for cobalt, nickel, and copper in the metal alloy was 81.6%, 93.3%, and 90.7% respectively. The slag obtained from the melting process is investigated by chemical and mineralogical characterization techniques. Hydrometallurgical treatment to recover lithium is carried out with the slag and presented in part 2.