A sustainable process for metal recycling from spent lithium-ion batteries using ammonium chloride

High-performance expanded graphite regenerated from spent lithium-ion batteries by integrated oxidation and purification method

Currently, the recycling of spent lithium-ion batteries (LIBs) has mainly been focused on the extraction of precious metals, such as lithium, cobalt and nickel from cathodes, while the waste graphite anode has been overlooked due to its low-cost production and abundant resources reserve. However, there are enormous potential value and pollution risk in the view of graphite recycling. Thus, we propose an original method to prepare expanded graphite (EG) as new anode material generated from waste graphite in LIBs which integrates the oxidation and purification in one-step. By regulating the oxidizability of potassium hypermanganate in the sulfur-phosphorus mixed acid system, the expansion of graphite and removal of impurities are realized simultaneously and thoroughly. As anticipated, the shortening of preparation process and purification procedure can also reduce the generation of polluting substances and production cost. It displays excellent electrochemical performance (reversible capacity of 435.8 mAh·g-1 at 0.1C and long-term cycling property of 370 mAh·g-1 at 1C after 1000 cycles), which is even higher than that of pristine commercial graphite. This delicate strategy of high-performance expanded graphite recycling achieves the integration of purification and value-added processes, providing the instructive guide to regenerate industrial-grade anode materials for the increasing LIBs demand in the future.

A mechanochemical method for one-step leaching of metals from spent LIBs

A one-step system based on mechanochemical activation and the use of grape skins (GS) was proposed to recover metals from lithium-ion batteries (LIBs) cathode waste. The effects of the ball-milling (BM) speed, BM time, and quantity of added GS on the metal leaching rate were explored. The spent lithium cobalt oxide (LCO) and its leaching residue before and after mechanochemistry were characterized by SEM, BET, PSD, XRD, FT-IR, and XPS analysis. Our study shows that mechanochemistry promotes the leaching efficiency of metals from LIBs battery cathode waste by changing the cathode material properties (that is, reducing the LCO particle size (12.126 μm ∼ 0.0928 μm), increasing the specific surface area (0.123 m²/g ∼ 15.957 m²/g), enhancing the hydrophilicity and surface free energy (57.44 mN/m² ∼ 66.18 mN/m²), promoting the generation of mesoporous structures, refining grains, disrupting the crystal structure, and increasing the microscopic strain, while deflecting the binding energy of the metal ions). A green, efficient and environmentally friendly process for the harmless and resource-friendly treatment of spent LIBs has been developed in this study.

Leaching valuable metals from spent lithium-ion batteries using the reducing agent methanol

When considering resource shortages and environmental pressures, salvaging valuable metals from the cathode materials of spent lithium-ion batteries (LIBs) is a very promising strategy to realize the green and sustainable development of batteries. The reductive acid leaching of valuable metals from cathode materials using methanol as a reducing agent was studied. The results show that the leaching efficiencies of Co and Li are 99% under optimal leaching conditions. The leaching kinetics of cathode materials in a H₂SO₄-methanol system indicate that the leaching of Co and Li is controlled by diffusion, with activation energies of 69.98 and 10.78 kJ/mol, respectively. Detailed analysis of the leaching reaction mechanism indicates that methanol is ultimately transformed into formic acid through a two-step process to further enhance leaching. No side reactions occur during leaching. Methanol can be a sustainable alternative for the reductive acid leaching of valuable metals from spent LIBs due to its high efficiency, application maturity, environmental friendliness, and low cost.

Study on the thermal reduction effect of organic components in spent ternary lithium battery cathode active materials

To improve the adhesion between cathode materials and current collector, and increase the electronic conductivity among electroactive substances, a certain proportion of conductive agents (acetylene black) and agglomerant (PVDF) are usually added in the battery manufacturing process. However, these conductive agents have negative effects on the recovery of cathode materials by pyrolysis or calcination. Recognizing this issue, a method based on the concept of "treating spent with spent" was developed in this paper. Organic matters contained in cathode active materials functioned as the reduction reagents, which can reduce the valence state of transition metals, resulting in the breakdown of the strong chemical bond and the stable layered structure of cathode materials. In this study, the thermal reduction effect of different organic components on cathode active materials was analyzed respectively to evaluate the reduction function of each component. XRD, XPS and ICP-MS were used to compare and analyze changes of phase, element compound state and ion leaching efficiencies of different cathode materials before and after thermal reduction under different amounts of reducing agents. The results show that both PVDF and acetylene black reduced the high-valent metals to low-valent oxides or elemental substances, demonstrating their thermal reduction capabilities. Comparisons of the XRD, XPS analysis and ion leaching results of thermal reduced products suggest that acetylene black has a stronger thermal reduction ability than that of PVDF. The results also show that the reduction of the high nickel cathode material (NCM811) is easier than that of the low nickel cathode material (NCM111).

An overview of global power lithium-ion batteries and associated critical metal recycling

The rapid development of lithium-ion batteries (LIBs) in emerging markets is pouring huge reserves into, and triggering broad interest in the battery sector, as the popularity of electric vehicles (EVs)is driving the explosive growth of EV LIBs. These mounting demands are posing severe challenges to the supply of raw materials for LIBs and producing an enormous quantity of spent LIBs, bringing difficulties in the areas of resource allocation and environmental protection. This review article presents an overview of the global situation of power LIBs, aiming at different methods to treat spent power LIBs and their associated metals. We provide a critical review of power LIB supply chain, industrial development, waste treatment strategies and recycling, etc. Power LIBs will form the largest proportion of the battery industry in the next decade. The analysis of the sustainable supply of critical metal materials is emphasized, as recycling metal materials can alleviate the tight supply chain of power LIBs. The existing significant recycling practices that have been recognized as economically beneficial can promote metal closed-loop recycling. Scientific thinking needs to innovate sustainable and cost-effective recycling technologies to protect the environment because of the chemicals contained in power LIBs.

Literature Review, Recycling of Lithium-Ion Batteries from Electric Vehicles, Part I: Recycling Technology

During recent years, emissions reduction has been tightened worldwide. Therefore, there is an increasing demand for electric vehicles (EVs) that can meet emission requirements. The growing number of new EVs increases the consumption of raw materials during production. Simultaneously, the number of used EVs and subsequently retired lithium-ion batteries (LIBs) that need to be disposed of is also increasing. According to the current approaches, the recycling process technology appears to be one of the most promising solutions for the End-of-Life (EOL) LIBs—recycling and reusing of waste materials would reduce raw materials production and environmental burden. According to this performed literature review, 263 publications about “Recycling of Lithium-ion Batteries from Electric Vehicles” were classified into five sections: Recycling Processes, Battery Composition, Environmental Impact, Economic Evaluation, and Recycling & Rest. The whole work reviews the current-state of publications dedicated to recycling LIBs from EVs in the techno-environmental-economic summary. This paper covers the first part of the review work; it is devoted to the recycling technology processes and points out the main study fields in recycling that were found during this work.

Separation of cathode particles and aluminum current foil in Lithium-Ion battery by high-voltage pulsed discharge Part I: Experimental investigation

To enable effective reuse and recycling processes of spent lithium-ion batteries (LiBs), here we develop a novel electrical method based on a high-voltage pulsed discharge to separate cathode particles and aluminum (Al) foil. A cathode particle sample was mechanically separated from a LiB, cut into 30-mm × 80-mm test pieces, and subjected to a high-voltage electrical pulse discharge from either end in water. At a voltage of 25 kV, 93.9% of the cathode particles separated from the Al foil. These particles were easily recovered by sieving at 2.36 mm because the Al foil retained its shape. Some Al contaminated the particles owing to generation of hot plasma and subsequent shock waves; however, the Al concentration in the recovered cathode particles was limited to 2.95%, which is low enough to allow for further cobalt and nickel recovery by hydrometallurgical processing. The results of heat balance calculations obtained from the current waveforms suggested that polyvinylidene fluoride, the main component of the adhesive in the cathode particle layers, melted and lost its adhesion through Joule heating of the Al foil at the maximum current of 19.0 kA at 25 kV. Almost 99% of the recovered cathode particles maintained their chemical composition and form after separation, and therefore could potentially be directly reused in LiBs.

Recycling of LiCoO2 cathode material from spent lithium ion batteries by ultrasonic enhanced leaching and one-step regeneration

A novel process for recycling of spent LiCoO₂ cathode materials has been developed. The novel process comprises an ultrasonic enhanced leaching and one-step regeneration of LiCoO₂ materials with spray drying method. The ultrasonic is novelly applied for effectively improving leaching process of spent LiCoO₂ materials in the system of DL-malic acid and H₂O₂. The leaching efficiencies of 98.13% for Li and 98.86% for Co were presented under the optimal condition of 1.5 mol/L DL-malic acid with 3 vol% H₂O₂, the solid/liquid ratio of 4 g/L, ultrasonic power of 95 W, temperature of 80 °C and leaching time of 25 min. Based on kinetic analysis, the ultrasonic enhanced leaching process is mainly controlled by the diffusion control model. Meanwhile, the product of Co(C₄O₅O₅)₂ formed on particles surface of spent LiCoO₂ materials during ultrasonic enhanced leaching process, which is provided from reaction mechanism analysis of scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). Finally, the regenerated LiCoO₂ materials are regenerated in one step by spray drying from leaching solution, which present good electrochemical performance.

A high-performance regenerated graphite extracted from discarded lithium-ion batteries

Lithium-ion batteries based on G-A-T-SGT@C anode display high specific capacity, excellent rate capability and outstanding cycling performance.

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.

Investigation of the Physico-Chemical Properties of the Products Obtained after Mixed Organic-Inorganic Leaching of Spent Li-Ion Batteries

Lithium-ion batteries are currently one of the most important mobile energy storage units for portable electronics such as laptops, tablets, smartphones, etc. Their widespread application leads to the generation of large amounts of waste, so their recycling plays an important role in environmental policy. In this work, the process of leaching with sulfuric acid for the recovery of metals from spent Li-ion batteries in the presence of glutaric acid and hydrogen peroxide as reducing agents is presented. Experimental results indicate that glutaric-acid application improves the leaching performance compared to the use of just hydrogen peroxide under the same conditions. Obtained samples of leaching residues after mixed inorganic-organic leaching were characterized with Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, and X-ray diffraction.

Recovery of Co, Li, and Ni from Spent Li-Ion Batteries by the Inorganic and/or Organic Reducer Assisted Leaching Method

The battery powder (anodic and cathodic mass) manually separated from spent Li-ion batteries used in laptops was subjected to acidic reductive leaching to recover the Co, Li, and Ni contained in it. In the laboratory experiments, 1.5 M sulfuric acid was used as the leaching agent and the reducing agents were 30% H2O2 solution or/and glutaric acid. Glutaric acid is a potential new reducing agent in the leaching process of spent lithium-ion batteries (LIBs). The influence of the type of the used reducer on obtained recovery degrees of Co, Li, and Ni as well as the synergism of the two tested reducing compounds were analyzed. As a result, it was determined that it is possible to efficiently hydrometallurgically separate Co, Li, and Ni from battery powder into solutions. The highest recovery degrees of the investigated metals (Co: 87.85%; Li: 99.91%; Ni: 91.46%) were obtained for samples where two reducers, perhydrol and glutaric acid, were added, thus confirming the assumed synergic action of H2O2 and C5H8O4 in a given reaction environment.

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.

Recycling of cathode material from spent lithium ion batteries using an ultrasound-assisted DL-malic acid leaching system

Herein, a novel process involving ultrasound-assisted leaching developed for recovering Ni, Li, Co, and Mn from spent lithium-ion batteries (LIBs) is reported. Carbonate coprecipitation was utilized to regenerate LiNi_0.6Co_0.2Mn_0.2O₂ from the leachate. Spent cathode materials were leached in DL-malic acid and hydrogen peroxide (H₂O₂). The leaching efficiency was investigated by determining the contents of metal elements such as Li, Ni, Co, and Mn in the leachate using atomic absorption spectrometry (AAS). The filter residue and the spent cathode materials were examined using Fourier transform infrared (FTIR) and scanning electronic microscopy. The leaching efficiencies were 97.8% for Ni, 97.6% for Co, 97.3% for Mn, and 98% for Li under the optimized conditions (90 W ultrasound power, 1.0 mol/L DL-malic acid, 5 g/L pulp density, 80 °C, 4 vol% H₂O₂, and 30 min). The leaching kinetics of the cathode in DL-malic acid are in accordance with the log rate law model. The electrochemical analysis indicates that the LiNi_0.6Co_0.2Mn_0.2O₂ regenerated at pH 8.5 has good electrochemical performance. The specific capacity of the first discharge at 0.1 C is 168.32 mA h g^-1 at 1 C after 50 cycles with a capacity retention of 85.0%. A novel closed-loop process to recycle spent cathode materials was developed, and it has potential value for practical application and for contributing to resource recycling and environmental protection.

Reduction-ammoniacal leaching to recycle lithium, cobalt, and nickel from spent lithium-ion batteries with a hydrothermal method: Effect of reductants and ammonium salts

Some inevitable issues of the acid leaching method used to recycle spent lithium-ion batteries (LIBs), such as toxic gas emission, excessive acid-base consumption, inferior metal selectivity and equipment corrosion, have gradually emerged and restricted the promotion and development of this method. It is therefore essential to develop a sustainable closed-loop recycling technology (reduction-ammoniacal method) for spent LIBs. In this study, the effects of various species of ammonia, ammonium salts and reductants on the leaching of Li, Co, Ni, Mn and Al from spent LIBs were investigated with a hydrothermal method. An increase of the electrode potential of the reductant greatly accelerated the selective leaching of Li, Co and Ni, which agreed with the thermodynamic analysis results. The standard electrode potentials of the LiNi_xCo_yMn_1-x-yO₂ (NCM) materials were also determined by using approximate calculations. When using (NH₄)₂SO₃ as a reductant in a one-step leaching process, 100% Co, 98.3% Ni and 90.3% Li were extracted into the ammonia-ammonium chloride solutions. From the kinetics analysis, the surface chemical reaction shrinking core model was found to control the leaching behavior of Li, Co, and Ni in the reduction-ammoniacal leaching process. A shell-core structure was composed of a product layer, a diffusion layer of the solid core and an unreacted core. Species in the product layer reduced the leaching efficiencies of Li, Co, and Ni. The results obtained for this hydrothermal reduction-ammoniacal method applied to recycle spent LIBs provide insights for the design of a high-speed, exceptionally selective, closed-loop recycling technique.

Manganese-based multi-oxide derived from spent ternary lithium-ions batteries as high-efficient catalyst for VOCs oxidation

Valuable metals such as manganese, cobalt, nickel and copper are recycled from spent ternary lithium-ions batteries (LiBs) and are considered as the active metal precursor to prepare based-manganese multi oxide for VOCs oxidation. The results of characterization analysis indicate that the catalyst from spent LiBs shows larger specific surface area of 26.80 m²/g as well as abundant mesoporous structures on the surface, higher molar ratio of Mn⁴⁺/Mn³⁺ (0.70) and O_latt/O_ads (1.68), better low-temperature reductivity and stronger intensity of weak acid sites in comparison with those of pure manganese oxides. The evaluation experiments show that the catalyst from waste exhibits more excellent catalytic performance of toluene combustion in comparison with pure manganese oxides. Furthermore, the presence of considerable amount of lithium and aluminum ions can severely weaken the catalytic activity while the co-existence of nickel, cobalt and copper ions contribute a lot to facilitate the catalytic behavior. In-situ DRIFT study implies that the introduction of lithium, aluminum, nickel, copper and cobalt into pure manganese oxides can facilitate toluene conversion to various extents, following the consecutive steps via benzyl species, benzoyl oxide species, benzaldehyde species, benzoate species and the primary intermediates are benzoate species.

Recovery of Metals from Waste Lithium Ion Battery Leachates Using Biogenic Hydrogen Sulfide

Lithium ion battery (LIB) waste is increasing globally and contains an abundance of valuable metals that can be recovered for re-use. This study aimed to evaluate the recovery of metals from LIB waste leachate using hydrogen sulfide generated by a consortium of sulfate-reducing bacteria (SRB) in a lactate-fed fluidised bed reactor (FBR). The microbial community analysis showed Desulfovibrio as the most abundant genus in a dynamic and diverse bioreactor consortium. During periods of biogenic hydrogen sulfide production, the average dissolved sulfide concentration was 507 mg L−1 and the average volumetric sulfate reduction rate was 278 mg L−1 d−1. Over 99% precipitation efficiency was achieved for Al, Ni, Co, and Cu using biogenic sulfide and NaOH, accounting for 96% of the metal value contained in the LIB waste leachate. The purity indices of the precipitates were highest for Co, being above 0.7 for the precipitate at pH 10. However, the process was not selective for individual metals due to simultaneous precipitation and the complexity of the metal content of the LIB waste. Overall, the process facilitated the production of high value mixed metal precipitates, which could be purified further or used as feedstock for other processes, such as the production of steel.

Comprehensive characterization on Ga (In)-bearing dust generated from semiconductor industry for effective recovery of critical metals

Gallium (indium)-bearing dust generated from semiconductor industry is an important secondary resource for critical metal recycling. However, the diverse and distinct physicochemical natures of such waste material have made its recycling less effective, e.g. low extraction rate and complex treatment procedures. This research is devoted to gaining in-depth knowledge of the physical and chemical properties of such waste, including the chemical composition, physical phases, particle size distribution and chemical-thermal properties with a series of technologies. As a consequence, the occurrence and distribution of GaN and metallic indium phases are found to be crucial to efficient metal recycling. The thermal-chemical behavior shows that continuous oxidation occurred in the air atmosphere, indicating that heat-treatment followed by acid leaching is feasible to improve their recycling efficiencies. This process is able to leach 80.35% of gallium and 95.78% of indium with one-step operation. Furthermore, different treatment strategies for the waste material are preliminarily evaluated and discussed for the aim of metal recovery. The results show that gallium can be selectively recycled with recycling rate of 89.59% using alkaline leaching. With this research, the understanding on the recyclability of different metals and possibilities of selective recovery can be improved. It provides guidelines during the stage of decision-making for critical metal recycling in order to achieve efficient resource circulation.

A process for combination of recycling lithium and regenerating graphite from spent lithium-ion battery

Recycling lithium and graphite from spent lithium-ion battery plays a significant role in mitigation of lithium resources shortage, comprehensive utilization of spent anode graphite and environmental protection. In this study, spent graphite was firstly collected by a two-stage calcination. Secondly, under the optimal conditions of 1.5 M HCI, 60 min and solid-liquid ratio (S/L) of 100 g·L^-1, the collected graphite suffers simple acid leaching to make almost 100% lithium, copper and aluminum in it into leach liquor. Thirdly, 99.9% aluminum and 99.9% copper were removed from leach liquor by adjusting pH first to 7 and then to 9, and thenthe lithium was recovered by adding sodium carbonate in leach liquor to form lithium carbonate with high purity (>99%). The regenerated graphite is found to have high initial specific capacity at the rate of 37.2 mA·g^-1 (591 mAh·g^-1), 74.4 mA·g^-1 (510 mAh·g^-1) and 186 mA·g^-1 (335 mAh·g^-1), and with the high retention ratio of 97.9% after 100 cycles, it also displays excellent cycle performance at high rate of 372 mA·g^-1. By this process, copper and lithium can be recovered and graphite can be regenerated, serving as a sustainable approach for the comprehensive utilization of anode material from spent lithium-ion battery.