Close loop separation process for the recovery of Co, Cu, Mn, Fe and Li from spent lithium-ion batteries

Emerging Processes for Sustainable Li-Ion Battery Cathode Recycling

The colossal growth in the use of Li-ion batteries (LiBs) has raised serious concerns over the supply chain of strategic minerals, e.g., Co, Ni, and Li, that make up the cathode active materials (CAM). Recycling spent LiBs is an important step toward sustainability that can establish a circular economy by effectively tackling large amounts of e-waste while ensuring an unhindered supply of critical minerals. Among the various methods of LiB recycling available, pyro- and hydrometallurgy have been utilized in the industry owing to their ease of operation and high efficiency, although they are associated with significant environmental concerns. Direct recycling, a more recent concept that aims to relithiate spent LiBs without disrupting the lattice structure of the CAMs, has been realized only in the laboratory scale so far and further optimization is required before it can be extended to the bulk scale. Additionally, significant progress has been made in the areas of hydrometallurgy in terms of using ecofriendly green lixiviants and alternate sources of energy, e.g., microwave and electrochemical, that makes the recycling processes more efficient and sustainable. In this review, the latest developments in LiB recycling are discussed that have focused on environmental and economic viability, as well as process intensification. These include deep eutectic solvent based recycling, electrochemical and microwave-assisted recycling, and various types of direct recycling.

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.

Review of lithium-ion batteries' supply-chain in Europe: Material flow analysis and environmental assessment

European legislation stated that electric vehicles' sale must increase to 35% of circulating vehicles by 2030, and concern is associated to the batteries' supply chain. This review aims at analysing the impacts (about material flows and CO2 eq emissions) of Lithium-Ion Batteries' (LIBs) recycling at full-scale in Europe in 2030 on the European LIBs' supply-chain. Literature review provided the recycling technologies' (e.g., pyro- and hydrometallurgy) efficiencies, and an inventory of existing LIBs' production and recycling plants in Europe. European production plants exhibit production capacity adequate for the expected 2030 needs. The key critical issues associated to recycling regard pre-treatments and the high costs and environmental impacts of metallurgical processes. Then, according to different LIBs' composition and market shares in 2020, and assuming a 10-year battery lifetime, the Material Flow Analysis (MFA) of the metals embodied in End of Life (EoL) LIBs forecasted in Europe in 2030 was modelled, and the related CO2 eq emissions calculated. In 2030 the European LIBs' recycling structure is expected to receive 664 t of Al, 530 t of Co, 1308 t of Cu, 219 t of Fe, 175 t of Li, 287 t of Mn and 486 t of Ni. Of these, 99% Al, 86% Co, 96% Cu, 88% Mn and 98% Ni will be potentially recovered by pyrometallurgy, and 71% Al, 92% Co, 92% Fe, 96% Li, 88 % Mn and 90% Ni by hydrometallurgy. However, even if the recycling efficiencies of the technologies applied at full-scale are high, the treatment capacity of European recycling plants could supply as recycled metals only 2%-wt of the materials required for European LIBs' production in 2030 (specifically 278 t of Al, 468 t of Co, 531 t of Cu, 114 t of Fe, 95 t of Li, 250 t of Mn and 428 t of Ni). Nevertheless, including recycled metals in the production of new LIBs could cut up 28% of CO2 eq emissions, compared to the use of virgin raw materials, and support the European batteries' value chain.

Green and efficient recycling method for spent Ni-Co-Mn lithium batteries utilizing multifunctional deep eutectic solvents

Given the growing volume of discarded lithium-ion batteries (LIBs), the extraction and recovery of valuable metals through environmentally-friendly solvent processes have become crucial, but they remain challenging tasks. Deep eutectic solvent (DES), an innovative and green solvents, have demonstrated significant promise in the extraction of valued metal elements from spent LIBs. This work employed a multifunctional DES based on natural molecules dimethyl-beta-propiothetin (DMPT) and ethylene glycol (EG) for the efficient leaching of transition metal ions. Under the reduction effect of EG and the action of carboxyl groups and chloride ions in DMPT, the leaching rate of Li, Ni, Co, and Mn can reach 99.59%, 99.28%, 99.04%, and 99.45%, respectively. Furthermore, DFT calculations were employed to explore the microstructure of DES and its interactions with metal ions. The main active site in the DES molecule is near the chloride ion, and DES binds most strongly to Mn, followed by Co, and weakest to Ni. This work avoids the use of volatile acids and demonstrates great potential in extracting valuable metals, providing a sustainable and environment-friendly alternative for the efficient recycling of waste LIBs.

Metal Scrap to Hydrogen: Manufacture of Hydroreactive Solid Shapes via Combination of Ball Milling, Cold Pressing, and Spark Plasma Sintering

Two sorts of tablets were manufactured from ball-milled powder (aluminum scrap and copper) by cold pressing and spark plasma sintering. Their microstructure, phase, and elemental compositions were investigated via scanning electron microscopy, X-ray diffraction analysis, and energy-dispersive X-ray spectroscopy. New phases, Al2Cu and MgCuAl2, were detected in the samples. Their microstructure was formed by welded scrap particles, the intermetallides, and Cu-rich regions located majorly along 'interparticle boundaries' and, to a lesser extent, within small, micro- and nanosized 'intraparticle spots'. The tablets were sealed with adhesive, so only the top surface was exposed to the environment, and tested in a chlorine aqueous solution for hydrogen generation performance. For both sample sorts, hydrogen yields of nearly 100% were achieved. The sintered tablets reacted faster than the cold-pressed ones: at 60, 70, and 80 °C, their entire 'conversion into hydrogen' took ~80, 40, and 30 min. vs. ~220, 100, and 70 min. The experimental kinetic curves were fitted with a contracting geometry equation, and those for the sintered samples were approximated with higher precision. The key effect of the additive was to enhance hydrogen evolution through the galvanic corrosion of Al in the regions adjacent to the intermetallic inclusions and Cu-rich spots.

Effective leaching of spent lithium-ion batteries using DL-lactic acid as lixiviant and selective separation of metals through precipitation and solvent extraction

Recycling cathodic materials from spent lithium-ion batteries (LIBs) is crucial not just for the environmental aspects but also for the supply of precious raw materials such as cobalt and lithium. As a result, developing a leaching process with low acid consumption, cost-effectiveness, low environmental impact, and high metal recovery is essential. In this article, the sustainable hydrometallurgical route for recovery of Li and Co from spent LIBs using DL-lactic acid as lixiviant is proposed. The different leaching parameters were studied to optimize the leaching conditions. With increasing lactic acid concentration from 0.1 mol/L to 1.0 mol/L, the leaching efficiency of Li and Co increased from 23% to 41% and 2% to 14%, respectively. The reductant H2O2 has a major role which reduced Co3+ to Co2+ and increasing the leaching efficiency of Co from 15.2% (1% H2O2) to 73.4% (6% H2O2). The maximum leaching efficiency of Li (99.8%) and Co (99%) was attained with 1.0 mol/L lactic acid, 6% H2O2, 60 °C, S/L ratio of 10 g/L, and 60 min leaching duration. The R2 values for the surface chemical reaction model were greater than 0.98, indicating that the lactic acid leaching process was controlled by the surface chemical reaction model. With 1.0 mol/L 70% saponified Cyanex 272, a solvent extraction study showed a higher separation factor (βCo/Li) of 35.7 compared to other saponified and nonsaponified organophosphorus extractants. Using the precipitation method, 99.9% of Co and 99% of Li were precipitated as [Formula: see text] and [Formula: see text] with a purity of 99.4% and 98.3%, respectively.

The closed-loop recycling strategy of Li and Co metal ions based on aqueous Zn-air desalination battery

Nowadays, it is a global problem to recycle LiCoO₂ from waste lithium-ion batteries (LIBs) due to the deficiency of high business cost and environmental pollution. Here, a novel three-channel ion recovery device based on a Zn-air desalination battery (ZADB) is proposed which can supply energy while separating Li⁺ and Co²⁺ from the recovered solution. The three-channel ZADB device consists of a Zn foil anode chamber with ZnSO₄ anolyte stream, an intermediate chamber with Li⁺ and Co²⁺ recovered stream and an air cathode chamber with LiOH and Co(OH)₂ catholyte stream, chambers are separated by anion exchange membrane (AEM) and cation exchange membrane (CEM) respectively. It can be described by the finite element simulation (FES) of physics field that, the Li⁺ and Co²⁺ in the recovered solution move to the cathode chamber, where the OH^- are produced by absorbing O₂ from the air combined with electronic in the discharge process. At the same time, the SO₄^2- moves to the other end of the Zn foil anode chamber according to the law of charge conservation, which combined with the Zn²⁺ removed from the Zn foil. The results show that the recovery efficiency of the ZADB device is closely related to the discharge current density and the concentration of the recovered stream. The best recovery effect has achieved when 0.2 mol L^-1 recovered solution is run for 24 h at the discharge current density of 0.2 mA cm^-2. The average recovery rate is 0.275 mg min^-1 with the highest recovery rate is 40.73 mg h^-1, and the output energy density is 102.5 Wh Kg^-1 during the experiment process. In addition, the ZADB device has the excellent long-term cycling performance and recycling stability. By comparing this device with other ion recovery methods, which provides that it is a splendid way to recycle Li⁺ and Co²⁺ from waste LIBs.

High-efficiency recycling of spent lithium-ion batteries: A double closed-loop process

Due to the scarcity of raw materials and negative environmental effects, it is essential to selectively recover lithium and other transition metals from end-of-life lithium-ion batteries (LIBs). Here, we propose a dual closed-loop process for resource utilization of spent LIBs. As an alternative to strong inorganic acids, deep eutectic solvents (DESs) as green solvents are employed for the recycling of spent LIBs. The DES based on oxalic acid (OA) and choline chloride (ChCl) achieves efficient leaching of valued metals within a short time. Through the coordination adjustment of water, it can form high-value battery precursors directly in DES, changing wastes into valuables. Meanwhile, water as a diluent can achieve the selective separation of lithium ions via filtration. More importantly, DES can be perfectly re-generated and recycled many times, indicating that the process is cost-effective and eco-friendly. As experimental proof, the re-generated precursors were used to produce new Li(Ni_0.5Co_0.2Mn_0.3)O₂ (NCM523) button batteries. The constant current charge-discharge test revealed that the initial charge and discharge values of the re-generated cells were 177.1 and 149.5 mAh/g, respectively, corresponding to the performance of commercial NCM523 cells. The whole recycling process is clean, efficient, and environment-friendly, realizing the double closed loop of spent battery regeneration and deep eutectic solvent re-use. This fruitful research demonstrates DES has excellent potential for recycling spent LIBs and provides an efficient and eco-friendly double closed-loop solution for the sustainable re-generation of spent LIBs.

An approach of cobalt recovery from waste copper converter slags using pig iron as capturing agent and simultaneous recovery of copper and tin

Massive amounts of waste copper converter slags have been produced from pyrometallurgical extraction of copper from copper concentrates, and the disposal of them in landfills creates serious environmental problems. However, this converter slag contains numerous valuable heavy metals, including copper, cobalt and tin etc. In this research, due to similar properties of iron and cobalt, pig iron with a low melting point was creatively used as capturing agent for cobalt recycling in a smelting reduction. The recovery of copper and tin was also studied. The phase transformation during reduction process was clarified by X-ray diffraction and Scanning electron microscope-energy dispersive spectrometer analyses. After the reduction performed at 1250 °C, the copper, cobalt and tin were recovered in a copper-cobalt-tin-iron alloy. The addition of pig iron improved cobalt yield, which was ascribed to the enrichment of cobalt in an iron-cobalt alloy phase. This decreased activity of the reduced cobalt and promoted reduction of cobalt oxide. As a result, the cobalt yield had a significant increase from 66.2% to 90.1% by adding 2% pig iron. Similarly, the copper also accelerated tin recovery through the formation of a copper-tin alloy. The copper and tin yields reached 94.4% and 95.0%, respectively. This work provided a high efficiency method to recover copper, cobalt and tin from waste copper converter slags.

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.

A review on recovery processes of metals from E-waste: A green perspective

E-waste management has become a global concern because of the enormous rise in the rate of end-of-life electrical and electronic equipment's (EEEs). Disposal of waste EEE directly into the environment leads to adverse effects on the environment as well as on human health. For the management of E-waste, numerous studies have been carried out for extracting metals (base, precious, and rare earth) following pyrometallurgy, hydrometallurgy, and biometallurgy. Irrespective of the advantages of these processes, certain limitations still exist with each of these options in terms of their adoption as treatment techniques. Several journal publications regarding the different processes have been made which aids in future research in the field of E-waste management. This review provides a comprehensive summary of the various metal recovery processes (pyrometallurgy, hydrometallurgy, and biometallurgy) from E-waste, along with their advantages and limitations. A bibliometric study based on the published articles using different keywords in Scopus has been provided for a complete idea about E-waste with green technology perspective like bioleaching, biosorption, etc. The present study also focussed on the circular economic approach towards sustainable E-waste management along with its socio-economic aspects and the economic growth of the country. The present study would provide valuable knowledge in understanding E-waste and its different treatment processes to the students, researchers, industrialists, and policymakers of the country.

A Future Perspective on Waste Management of Lithium-Ion Batteries for Electric Vehicles in Lao PDR: Current Status and Challenges

Lithium-ion batteries (LIBs) have become a hot topic worldwide because they are not only the best alternative for energy storage systems but also have the potential for developing electric vehicles (EVs) that support greenhouse gas (GHG) emissions reduction and pollution prevention in the transport sector. However, the recent increase in EVs has brought about a rise in demand for LIBs, resulting in a substantial number of used LIBs. The end-of-life (EoL) of batteries is related to issues including, for example, direct disposal of toxic pollutants into the air, water, and soil, which threatens organisms in nature and human health. Currently, there is various research on spent LIB recycling and disposal, but there are no international or united standards for LIB waste management. Most countries have used a single or combination methodology of practices; for instance, pyrometallurgy, hydrometallurgy, direct recycling, full or partial combined recycling, and lastly, landfilling for unnecessary waste. However, EoL LIB recycling is not always easy for developing countries due to multiple limitations, which have been problems and challenges from the beginning and may reach into the future. Laos is one such country that might face those challenges and issues in the future due to the increasing trend of EVs. Therefore, this paper intends to provide a future perspective on EoL LIB management from EVs in Laos PDR, and to point out the best approaches for management mechanisms and sustainability without affecting the environment and human health. Significantly, this review compares the current EV LIB management between Laos, neighboring countries, and some developed countries, thereby suggesting appropriate solutions for the future sustainability of spent LIB management in the nation. The Laos government and domestic stakeholders should focus urgently on specific policies and regulations by including the extended producer responsibility (EPR) scheme in enforcement.

Safety Concerns for the Management of End-of-Life Lithium-Ion Batteries

Lithium-ion battery (LIB) usage is growing dramatically worldwide. Relatedly, there is a need for the management of end-of-life (EOL) LIBs. EOL requires closed-loop systems and supply chains. Although many studies related to managing EOL in closed-loop supply chains exist, one especially pernicious issue is overlooked-safety. This study seeks to address this major safety oversight for EOL LIBs using closed-loop supply chains that are critical to a larger circular economy environment. The evaluation is completed along a technology-organization-environment (TOE) framework; potential research directions for mitigating safety issues are part of the analysis of this study. Specific and general research questions pertaining to secure management of EOL LIBs are put forward to help advance academic research. Practical concerns are also described for policymakers and organizations. This study reveals implications of these questions for the intersection of materials science, supply chain management, and fire-protection engineering.

Regeneration and utilization of graphite from the spent lithium-ion batteries by modified low-temperature sulfuric acid roasting

Recycling spent graphite in spent lithium-ion batteries (LIBs) is crucial for lacking high-quality graphite and environmental protection. Here, an environmentally friendly and economical modified method based on sulfate roasting was proposed to recycle spent graphite via low temperature roasting at 250 °C with sodium fluoride as an assistant additive. Recycling leads to graphite with a high purity of 99.55 % and chemical structures for energy storage. Batteries manufactured in regenerated graphite deliver a high initial charge capacity of 333.9 mAh/g with an initial columbic efficiency of 85.71% and excellent capacity retention of 91.2% after 400 cycles. In addition, the waste produced in the method could be well treated, and by-products 177 g of sodium sulfate would be collected per 1 kg spent graphite and NaF, equivalent to 78.95% of the added amount obtained through wastewater and exhaust gas, respectively. The regenerated sodium fluoride will be re-applied to the recovery spent graphite. The loop-closed method shows great promise for the industrial-scale recycling of spent graphite for energy storage applications.

Green Recycling Methods to Treat Lithium-Ion Batteries E-Waste: A Circular Approach to Sustainability

E-waste generated from end-of-life spent lithium-ion batteries (LIBs) is increasing at a rapid rate owing to the increasing consumption of these batteries in portable electronics, electric vehicles, and renewable energy storage worldwide. On the one hand, landfilling and incinerating LIBs e-waste poses environmental and safety concerns owing to their constituent materials. On the other hand, scarcity of metal resources used in manufacturing LIBs and potential value creation through the recovery of these metal resources from spent LIBs has triggered increased interest in recycling spent LIBs from e-waste. State of the art recycling of spent LIBs involving pyrometallurgy and hydrometallurgy processes generates considerable unwanted environmental concerns. Hence, alternative innovative approaches toward the green recycling process of spent LIBs are essential to tackle large volumes of spent LIBs in an environmentally friendly way. Such evolving techniques for spent LIBs recycling based on green approaches, including bioleaching, waste for waste approach, and electrodeposition, are discussed here. Furthermore, the ways to regenerate strategic metals post leaching, efficiently reprocess extracted high-value materials, and reuse them in applications including electrode materials for new LIBs. The concept of "circular economy" is highlighted through closed-loop recycling of spent LIBs achieved through green-sustainable approaches.

Solvent extraction for recycling of spent lithium-ion batteries

Up to now, solvent extraction not only recycle valuable metals (i.e., Ni, Co, Mn and Li) from the leach liquor of spent cathode materials, but also apply to treat spent electrolyte. This paper summarizes the development of solvent extraction in the field of recycling spent lithium-ion batteries (LIBs) from the aspects of principle, technology and industrialization. Meanwhile, the paper also comments on the challenges and opportunities for the solvent extraction facing in the recycling of spent LIBs.

Recycling chains for lithium-ion batteries: A critical examination of current challenges, opportunities and process dependencies

Lithium-ion batteries (LIBs) show high energy densities and are therefore used in a wide range of applications: from portable electronics to stationary energy storage systems and traction batteries used for e-mobility. Considering the projected increase in global demand for this energy storage technology, driven primarily by growth in e-vehicles, and looking at the criticality of some raw materials used in LIBs, the need for an efficient recycling strategy emerges. In this study, current state-of-the-art technologies for LIB recycling are reviewed and future opportunities and challenges, in particular to recover critical raw materials such as lithium or cobalt, are derived. Special attention is paid to the interrelationships between mechanical or thermal pre-treatment and hydro- or pyrometallurgical post-treatment processes. Thus, the unique approach of the article is to link processes beyond individual stages within the recycling chain. It was shown that influencing the physicochemical properties of intermediate products can lead to reduced recycling rates or even the exclusion of certain process options at the end of the recycling chain. More efforts are needed to improve information and data sharing on the exact composition of feedstock for recycling as well as on the processing history of intermediates to enable closed loop LIB recycling. The technical understanding of the interrelationships between different process combinations, such as pyrolytic or mechanical pre-treatment for LIB deactivation and metal separation, respectively, followed by hydrometallurgical treatment, is of crucial importance to increase recovery rates of cathodic metals such as cobalt, nickel, and lithium, but also of other battery components.

Resource Availability and Implications for the Development of Plug-In Electric Vehicles

Plug-in electric vehicles (PEVs) have immense potential for reducing greenhouse gas emissions and dependence on fossil fuels, and for smart grid applications. Although a great deal of research is focused on technological limitations that affect PEV battery performance targets, a major and arguably equal concern is the constraint imposed by the finite availability of elements or resources used in the manufacture of PEV batteries. Availability of resources, such as lithium, for batteries is critical to the future of PEVs and is, therefore, a topic that needs attention. This study addresses the issues related to lithium availability and sustainability, particularly supply and demand related to PEVs and the impact on future PEV growth. In this paper, a detailed review of the research on lithium availability for PEV batteries is presented, key challenges are pinpointed and future impacts on PEV technology are outlined.

The Role of Sulphonic and Phosphoric Pendant Groups on the Diffusion of Monovalent Ions in Polyelectrolyte Membranes: A Molecular Dynamics Study

Lithium-ion consumption has risen significantly in recent years due to its use in portable devices. Alternative sources of lithium, which include the recovery from brine using the sustainable and eco-friendly electrodialysis technology, has been explored. This technology, however, requires effective cation-exchange membranes that allow the selective permeation of lithium ions. In this study, we have investigated, via molecular dynamics simulations, the role of the two common charged groups, the sulfonic and the phosphoric groups, in promoting the adsorption of monovalent ions from brine comprising Li+, Na+, Mg2+, and Ca2+ ions. The analysis of the mean square displacement of the ions revealed that Li+ and Na+ ions exhibit superior diffusion behaviors within the polyelectrolyte system. The O-atoms of the charged groups bind strongly with the divalent ions (Mg2+ and Ca2+), which raises their diffusion energy barrier and consequently lowers their rate of permeation. In contrast, the monovalent ions exhibit weaker interactions, with Na+ being slightly above Li+, enabling the permeation of Li+ ions. The present study demonstrates the role of both charged groups in cation-exchange membranes in promoting the diffusion of Li+ and Na+ ions, and could serve as a guide for the design of effective membranes for the recovery of these ions from brine.

Ethylammonium nitrate enhances the extraction of transition metal nitrates by tri-n-butyl phosphate (TBP)

Several molecular polar solvents have been used as solvents of the more polar phase in the solvent extraction (SX) of metals. However, the use of hydrophilic ionic liquids (ILs) as solvents has seldomly been explored for this application. Here, the hydrophilic IL ethylammonium nitrate (EAN), has been utilized as a polar solvent in SX of transition metal nitrates by tri-n-butyl phosphate (TBP). It was found that the extraction from EAN is considerably stronger than that from a range of molecular polar solvents. The main species of Co(II) and Fe(III) in EAN are likely [Co(NO3)4]2- and [Fe(NO3)4]-, respectively. The extracted species are likely Fe(TBP)3(NO3)3 and a mixture of Co(TBP)2(NO3)2 and Co(TBP)3(NO3)2. The addition of H2O or LiCl to EAN reduces the extraction because the metal cations coordinate to water molecules and chloride ions stronger than to nitrate ions. This study highlights the potential of using hydrophilic ILs to enhance SX of metals.

Reuse of LiCoO2 Electrodes Collected from Spent Li-Ion Batteries after Electrochemical Re-Lithiation of the Electrode

The recycling of used Li-ion batteries is important as the consumption of batteries is increasing every year. However, the recycling of electrode materials is tedious and energy intensive with current methods, and part of the material is lost in the process. In this study, an alternative recycling method is presented to minimize the number of steps needed in the positive electrode recovery process. The electrochemical performance of aged and re-lithiated Mg-Ti-doped LiCoO2 and stoichiometric LiCoO2 was investigated and compared. The results showed that after re-lithiation the structure of original LiCoO2 was restored, the capacity of an aged LiCoO2 reverted close to the capacity of a fresh LiCoO2 , and the material could thus be recovered. The re-lithiated Mg-Ti-doped LiCoO2 provided rate capability properties only slightly declined from the rate capability of a fresh material and showed promising cyclability in half-cells.

Biotreatment for the spent lithium-ion battery in a three-module integrated microbial-fuel-cell recycling system

A bio-electrochemically (BE) recycling platform was assembled to recover Li and Co from the cathodic materials of spent LIBs in one integrated system. The BE platform consists of three microbial-fuel-cell (MFC) subsystems, including MFC-A, MFC-B, and MFC-C. Co and Li were smoothly recovered from the cathodic materials in the assembled platform. The initial pH and the loading ratios of LiCoO₂ both significantly influenced the leaching efficiencies of Li and Co in MFC-A. Approximately 45% Li and 93% Co were simultaneously released through the reduction of LiCoO₂ at the initial pH of 1 and the loading ratios of LiCoO₂ of 0.2 g/L. The (NH₄)₂C₂O₄-modified granular activated carbons (GAC) with a thickness of 1.5 cm was favorably stacked adjacent to the cathode of the MFC-B system. About 98% of removal efficiency (RE_Co1) and 96% of recovery efficiency (RE_Co2) of Co were achieved in MFC-B under optimum conditions. The dosing concentration of Li⁺ lower than 2 mg/L and the (NH₄)₂CO₃ of 0.01-0.02 M were conducive to enhancing the recovery of Li from raffinate and guaranteed the higher power output and coulombic efficiencies in MFC-C. The continuous release of CO₂ caused by exoelectrogenic microorganisms on the biofilm facilitated the precipitation of Li₂CO₃.

High-efficiency core-shell magnetic heavy-metal absorbents derived from spent-LiFePO4 Battery

Search for simple and efficient recycling methods to utilize spent lithium-ion batteries is crucial for achieving sustainable resource development and reducing the hazardous materials released from the spent batteries. Herein, we have developed a new strategy to utilize the spent LiFePO₄ batteries by utilizing the cathode plate as raw material to synthesize mesoporous core-shell adsorbent Mm@SiO₂ (Mm denoted as the magnetic material) through a simple alkaline leaching process. The as-converted material exhibits excellent adsorption capacity when it has been used to remove heavy metal ions in heavy metal polluted water. The adsorption capacities for Cu²⁺, Cd²⁺, and Mn²⁺ have been achieved up to 71.23, 80.31 and 68.73 mg g^-1, respectively. The detailed adsorption mechanism has been elucidated with comprehensive characterization techniques, including TEM, XPS, NEXAS, and EXAFS, the edge shared [Cu₂O₈] bipyramids can be fit against the EXAFS data to represent the atomic-scale local structure after Mm@SiO₂ adsorbs Cu²⁺. The present work demonstrates a novel routine to reutilize the spent lithium batteries, which is of great importance to achieve sustainable development based on the "waste-to-treasure" and "waste-to-control-waste" strategy for simultaneously reducing the hazardous release from industrial solid waste and heavy metal polluted water.

Recovery of valuable metals from mixed spent lithium-ion batteries by multi-step directional precipitation

The novel strategy of multi-step directional precipitation is proposed for recovering valuable metals from the leachate of cathode material obtained by mechanical disassembly from mixed spent lithium-ion batteries. Based on thermodynamics and directional precipitation, Mn²⁺ is selectively precipitated under conditions of MRNM (molar ratio of (NH₄)₂S₂O₈ to Mn²⁺) = 3, pH = 5.5 and 80 °C for 90 min. Ni²⁺ was then selectively precipitated using C₄H₈N₂O₂ under conditions of pH = 6, MRCN (molar ratio of C₄H₈N₂O₂ to Ni²⁺) = 2, 30 °C and 20 min. Then, the pH was adjusted to 10 to precipitate Co²⁺ as Co(OH)₂. Finally, Li⁺ was recovered by Na₂CO₃ at 90 °C. The precipitation rates of Mn, Ni, Co, and Li reached 99.5%, 99.6%, 99.2% and 90%, respectively. The precipitation products with high purity can be used as raw materials for industrial production based on characterization. The economical and efficient recovery process can be applied in industrialized large-scale recycling of spent lithium-ion batteries.

Theoretical-molar Fe3+ recovering lithium from spent LiFePO4 batteries: an acid-free, efficient, and selective process

In spent lithium iron phosphate batteries, lithium has a considerable recovery value but its content is quite low, thus a low-cost and efficient recycling process has become a challenging research topic. In this paper, two methods about using the non-oxidizing inorganic iron salt - Fe₂(SO₄)₃ to recover lithium from LiFePO₄ are proposed. The method-1 is theoretical-molar Fe₂(SO₄)₃ (Fe₂(SO₄)₃ : LiFePO₄ =1:2) dosage is added and more than 97% of lithium can be leached in just 30 min even under a pretty high solid-liquid ratio of 500 g/L. Spectrophotometry provides the evidence of Fe²⁺/Fe³⁺ substitution in the leaching process. In the method-2, the generated Fe²⁺ originating from LiFePO₄ is fully utilized with the addition of H₂O₂, and the dosage of Fe₂(SO₄)₃ is decreased by two thirds (Fe₂(SO₄)₃ : LiFePO₄ =1:6). Several sulphates (CuSO₄, NiSO₄, MgSO₄) are employed to explore the leaching mechanism. All the results reveal that the reaction of Fe³⁺ substituting Fe²⁺ has a powerful driving force. In addition, these two leaching processes simultaneously present superior selectivity for the impurities. The Fe₂(SO₄)₃ in two methods does not cause pollution and is easily regenerated by adding H₂SO₄. The proposed rapid, efficient and selective leaching thought would be a competitive candidate for recycling spent LiFePO₄ batteries.

Rapid leaching and recovery of valuable metals from spent Lithium Ion batteries (LIBs) via environmentally benign subcritical nickel-containing water over chlorinated polyvinyl chloride

This study presents the development of an effective and environmentally friendly method to leach and to recover valuable metals, such as lithium (Li) and cobalt (Co) from the spent lithium-ion batteries (LIBs) using subcritical water assisted by nickel catalyst and waste chlorinated polyvinyl chloride (CPVC). The effects of reaction parameters, such as Ni²⁺ concentration, temperature, time, and liquid-solid ratio on the leaching efficiencies of Li and Co were carefully investigated. The solid residues obtained thereof were characterized by XRD and SEM-EDS analyses, while the leachates were analyzed by ICP-OES. The ICP-OES results showed that about 99.05% of Li and 98.08% of Co were effectively leached from the spent LiCoO₂ powder under the following optimized reaction conditions: temperature of 240 °C, reaction time of 40 min, Ni²⁺ concentration of 0.04 M, and the liquid-solid ratio of 25:1 mL/g, respectively. Finally, based on the precipitation method, the Li and Co were recovered from the leachate as Li₂CO₃ and Co(OH)₂. The results and the method applied in this research suggest that the leaching and recovery of Li and Co from the spent LIBs using subcritical nickel-containing water is an inexpensive, efficient, sustainable and eco-friendly technology.

Chlorinated polyvinyl chloride (CPVC) assisted leaching of lithium and cobalt from spent lithium-ion battery in subcritical water

The objective of this study was to determine leaching efficiency of Li and Co from spent lithium-ion batteries (LIBs) by using waste chlorinated polyvinyl chloride (CPVC) in hydrothermal subcritical water process. Waste CPVC was used as the source of HCl to speed up leaching efficiency. Effects of temperature, time, LiCoO₂: CPVC mass ratio and liquid-solid ratio on leaching efficiencies of Li and Co were investigated. Solid residues were characterized by XRD and SEM-EDS elemental mapping to predict chemical compounds remained after leaching. Results showed that more than 98.71 % of Li and 97.69 % of Co were effectively leached from LiCoO₂ powder under the following conditions: temperature of 250 °C, reaction time of 60 min, and LiCoO₂: CPVC mass ratio of 1:3. Results of this study suggest that recovery of Li and Co from spent LIBs using hydrothermal subcritical water is an efficient, environmental friendly and sustainable technology.

Recycle, Recover and Repurpose Strategy of Spent Li-ion Batteries and Catalysts: Current Status and Future Opportunities

The disposal of hazardous waste of any form has become a great concern for the industrial sector due to increased environmental awareness. The increase in usage of hydroprocessing catalysts by petrochemical industries and lithium-ion batteries (LIBs) in portable electronics and electric vehicles will soon generate a large amount of scrap and create significant environmental problems. Like general electronic wastes, spent catalysts and LIBs are currently discarded in municipal solid waste and disposed of in landfills in the absence of policy and feasible technology to drive alternatives. Such inactive catalyst materials and spent LIBs not only contain not only hazardous heavy metals but also toxic and carcinogenic chemicals. Besides polluting the environment, these systems (spent catalysts and LIBs) contain valuable metals such as Ni, Mo, Co, Li, Mn, Rh, Pt, and Pd. Therefore, the extraction and recovery of these valuable metals has significant importance. In this Review, we have summarized the strategies used to recover valuable (expensive) as well as cheap metals from secondary resources-especially spent catalysts and LIBs. The first section contains the background and sources of LIBs and catalyst scraps with their current recycling status, followed by a brief explanation of metal recovery methods such as pyrometallurgy, hydrometallurgy, and biometallurgy. The recent advances achieved in these methods are critically summarized. Thus, the Review provides a guide for the selection of adequate methods for metal recovery and future opportunities for the repurposing of recovered materials.

Electrochemical recovery of cobalt using nanoparticles film of copper hexacyanoferrates from aqueous solution

Nanoparticles film of copper metal hexacyanoferrates (CuHCF) was fabricated to electrochemically separate Co²⁺ in aqueous solutions under various conditions such as applied potential, solution pHs, initial concentrations, contact time and coexisting ions. Results showed that the removal efficiency conducted in reduction potential was obviously higher than that in oxidation potential. The optimal pH for Co²⁺ adsorption occurred at 8.0. Coexisting ions studies revealed that Co²⁺ could be removed from aqueous solutions containing Li⁺, Cu²⁺ and Al³⁺. Considering that cobalt and lithium are the main metallic elements in LiCoO₂, the effect of different ionic strengths (IS) of LiNO₃ (0.5, 1, 2, 5, 10) on adsorption was further investigated. Results showed that IS of LiNO₃ had little impact on the removal efficiency of Co²⁺, which indicated the potential of selective recovery of cobalt from LiCoO₂ in spent lithium-ion batteries. X-ray energy-dispersion spectroscopy (EDS) confirmed that the Co²⁺ could be adsorbed effectively onto CuHCF film. The adsorption was well described by Langmuir isotherm and the maximum sorption capacity is 218.82 mg/g. The kinetic rate of Co²⁺ adsorption was rapid initially and attained equilibrium within 60 min, and the data well fitted the Redlich-Peterson and the Elovich model, implying a chemisorption dominated process.

Progress and Status of Hydrometallurgical and Direct Recycling of Li-Ion Batteries and Beyond

An exponential market growth of Li-ion batteries (LIBs) has been observed in the past 20 years; approximately 670,000 tons of LIBs have been sold in 2017 alone. This trend will continue owing to the growing interest of consumers for electric vehicles, recent engagement of car manufacturers to produce them, recent developments in energy storage facilities, and commitment of governments for the electrification of transportation. Although some limited recycling processes were developed earlier after the commercialization of LIBs, these are inadequate in the context of sustainable development. Therefore, significant efforts have been made to replace the commonly employed pyrometallurgical recycling method with a less detrimental approach, such as hydrometallurgical, in particular sulfate-based leaching, or direct recycling. Sulfate-based leaching is the only large-scale hydrometallurgical method currently used for recycling LIBs and serves as baseline for several pilot or demonstration projects currently under development. Conversely, most project and processes focus only on the recovery of Ni, Co, Mn, and less Li, and are wasting the iron phosphate originating from lithium iron phosphate (LFP) batteries. Although this battery type does not dominate the LIB market, its presence in the waste stream of LIBs causes some technical concerns that affect the profitability of current recycling processes. This review explores the current processes and alternative solutions to pyrometallurgy, including novel selective leaching processes or direct recycling approaches.

Separation and recovery of carbon powder in anodes from spent lithium-ion batteries to synthesize graphene

Based on the structural characteristics of the anodes of lithium-ion batteries, an improved Hummers’ method is proposed to recycle the anode materials of spent lithium-ion batteries into graphene. In order to effectively separate the active material from the copper foil, water was selected as an ultrasonic solvent in this experiment. In order to further verify whether lithium ions exist in the active material, carbon powder, it was digested by microwave digestion. ICP-AES was then used to analyse the solution. It was found that lithium ions were almost non-existent in the carbon powder. In order to further increase the added value of the active material, graphene oxide was obtained by an improved Hummers’ method using the carbon powder. The graphene material was also reduced by adding vitamin C as a reducing agent through a chemical reduction method using graphene oxide. Meanwhile, the negative graphite, graphite oxide and graphene samples were characterized by XRD, SEM, FTIR and TEM. The conductivity of the negative graphite, graphite oxide and graphene was tested. The results show that graphene prepared by a redox method has a better layered structure, less impurities and oxygen groups in its molecular structure, wider interlayer spacing and smaller resistivity.