Sustainable recovery of valuable metals from spent lithium-ion batteries using DL-malic acid: Leaching and kinetics aspect

Recycling and Reuse of Spent LIBs: Technological Advances and Future Directions

Recovering valuable metals from spent lithium-ion batteries (LIBs), a kind of solid waste with high pollution and high-value potential, is very important. In recent years, the extraction of valuable metals from the cathodes of spent LIBs and cathode regeneration technology are still rapidly developing (such as flash Joule heating technology to regenerate cathodes). This review summarized the studies published in the recent ten years to catch the rapid pace of development in this field. The development, structure, and working principle of LIBs were firstly introduced. Subsequently, the recent developments in mechanisms and processes of pyrometallurgy and hydrometallurgy for extracting valuable metals and cathode regeneration were summarized. The commonly used processes, products, and efficiencies for the recycling of nickel-cobalt-manganese cathodes (NCM/LCO/LMO/NCA) and lithium iron phosphate (LFP) cathodes were analyzed and compared. Compared with pyrometallurgy and hydrometallurgy, the regeneration method was a method with a higher resource utilization rate, which has more industrial application prospects. Finally, this paper pointed out the shortcomings of the current research and put forward some suggestions for the recovery and reuse of spent lithium-ion battery cathodes in the future.

Toward Circular Energy: Exploring Direct Regeneration for Lithium-Ion Battery Sustainability

Lithium-ion batteries (LIBs) are rapidly developing into attractive energy storage technologies. As LIBs gradually enter retirement, their sustainability is starting to come into focus. The utilization of recycled spent LIBs as raw materials for battery manufacturing is imperative for resource and environmental sustainability. The sustainability of spent LIBs depends on the recycling process, whereby the cycling of battery materials must be maximized while minimizing waste emissions and energy consumption. Although LIB recycling technologies (hydrometallurgy and pyrometallurgy) have been commercialized on a large scale, they have unavoidable limitations. They are incompatible with circular economy principles because they require toxic chemicals, emit hazardous substances, and consume large amounts of energy. The direct regeneration of degraded electrode materials from spent LIBs is a viable alternative to traditional recycling technologies and is a nondestructive repair technology. Furthermore, direct regeneration offers advantages such as maximization of the value of recycled electrode materials, use of sustainable, nontoxic reagents, high potential profitability, and significant application potential. Therefore, this review aims to investigate the state-of-the-art direct LIB regeneration technologies that can be extended to large-scale applications.

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.

Toward Sustainable All Solid-State Li-Metal Batteries: Perspectives on Battery Technology and Recycling Processes

Lithium (Li)-based batteries are gradually evolving from the liquid to the solid state in terms of safety and energy density, where all solid-state Li-metal batteries (ASSLMBs) are considered the most promising candidates. This is demonstrated by the Bluecar electric vehicle produced by the Bolloré Group, which is utilized in car-sharing services in several cities worldwide. Despite impressive progress in the development of ASSLMBs, their avenues for recycling them remain underexplored, and combined with the current explosion of spent Li-ion batteries, they should attract widespread interest from academia and industry. Here, the potential challenges of recycling ASSLMBs as compared to Li-ion batteries are analyzed and the current progress and prospects for recycling ASSLMBs are summarized and analyzed. Drawing on the lessons learned from Li-ion battery recycling, it is important to design sustainable recycling technologies before ASSLMBs gain widespread market adoption. A battery-recycling-oriented design is also highlighted for ASSLMBs to promote the recycling rate and maximize profitability. Finally, future research directions, challenges, and prospects are outlined to provide strategies for achieving sustainable development of ASSLMBs.

Recycling of waste lithium-ion batteries via a one-step process using a novel deep eutectic solvent

Deep eutectic solvents (DESs) possess excellent solubility and selectivity, making them suitable for extracting valuable metals and serving as a green alternative in the recycling process. This work introduces a low-viscosity DES consisting of dimethylthetin, oxalic acid, and water for the comprehensive recovery of cathode materials from LIBs. Leaching parameters such as ratio (1:1), leaching temperature (60 °C), and reaction time (15 min) for were systematically optimized, resulting in a selective separation efficiency of 99.98 % for lithium ions. Furthermore, in-situ regeneration of the precursor can be achieved during the leaching process. Charge-discharge tests indicate that the initial charge and discharge capacities of the regenerated battery are 166.8 mAh/g and 138.4 mAh/g, respectively. The DES demonstrates stability and can be easily recycled by replenishing the consumed components. This proposed strategy facilitates the reintroduction of nonrenewable resources into the supply chain and reduces the environmental impact of heavy metals, aligning with the principles of a circular economy.

Comparative life cycle analysis of critical materials recovery from spent Li-ion batteries

The development of new generations of electric vehicles is expected to drive the growth of lithium-ion batteries in the global market. Life Cycle Assessment (LCA) method was utilized in this study to evaluate the environmental impacts of various hydrometallurgical processes in critical materials recovery from lithium-ion battery (LIB) cathode powder. The main objective of this work was to fill the knowledge gap regarding the environmental sustainability of various processes in LIB recycling and to generate a comprehensive comparison of the environmental burdens caused by numerous hydrometallurgical methods. According to this investigation, leaching with acetic acid, formic acid, maleic acid, and DL-malic acid demonstrates lower environmental impacts compared to lactic acid, ascorbic acid, succinic acid, citric acid, trichloroacetic acid, and tartaric acid. Among inorganic acids, nitric acid and hydrochloric acid show higher environmental impacts compared to sulfuric acid. Furthermore, the results of this study indicate that leaching with some organic acids such as citric, succinic, ascorbic, trichloroacetic, and tartaric acids leads to higher negative environmental impacts in most environmental categories compared to inorganic acids like sulfuric and hydrochloric acid. Therefore, not all organic acids utilized in the leaching of critical and strategic materials from cathode powder can enhance environmental sustainability in the recycling process. The results of the solvent extraction study as a downstream process of leaching show that sodium hydroxide, organic reagents, and kerosene have the highest environmental impact among all inputs in this process. Generally, solvent extraction has a greater environmental impact compared to the leaching process.

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.

Progress, Key Issues, and Future Prospects for Li-Ion Battery Recycling

The overuse and exploitation of fossil fuels has triggered the energy crisis and caused tremendous issues for the society. Lithium-ion batteries (LIBs), as one of the most important renewable energy storage technologies, have experienced booming progress, especially with the drastic growth of electric vehicles. To avoid massive mineral mining and the opening of new mines, battery recycling to extract valuable species from spent LIBs is essential for the development of renewable energy. Therefore, LIBs recycling needs to be widely promoted/applied and the advanced recycling technology with low energy consumption, low emission, and green reagents needs to be highlighted. In this review, the necessity for battery recycling is first discussed from several different aspects. Second, the various LIBs recycling technologies that are currently used, such as pyrometallurgical and hydrometallurgical methods, are summarized and evaluated. Then, based on the challenges of the above recycling methods, the authors look further forward to some of the cutting-edge recycling technologies, such as direct repair and regeneration. In addition, the authors also discuss the prospects of selected recycling strategies for next-generation LIBs such as solid-state Li-metal batteries. Finally, overall conclusions and future perspectives for the sustainability of energy storage devices are presented in the last chapter.

Discharge of lithium-ion batteries in salt solutions for safer storage, transport, and resource recovery

The use of lithium-ion batteries (LIBs) has grown in recent years, making them a promising source of secondary raw materials due to their rich composition of valuable materials, such as Cobalt and Nickel. Recycling LIBs can help reduce fossil energy consumption, CO₂ emissions, environmental pollution, and consumption of valuable materials with limited supplies. On the other hand, the hazards associated with spent LIBs recycling are mainly due to fires and explosions caused by unwanted short-circuiting. The high voltage and reactive components of end-of-life LIBs pose safety hazards during mechanical processing and crushing stages, as well as during storage and transportation. Electrochemical discharge using salt solutions is a simple, quick, and inexpensive way to eliminate such hazards. In this paper, three different salts (NaCl, Na₂S, and MgSO₄) from 12% to 20% concentration are investigated as possible candidates. The effectiveness of discharge was shown to be a function of molarity rather than ionic strength of the solution. Experiments also showed that the use of ultrasonic waves can dramatically improve the discharge process and reduce the required time more than 10-fold. This means that the drainage time was reduced from nearly 1 day to under 100 minutes. Finally, a practical setup in which the tips of the batteries are directly immersed inside the salt solution is proposed. This creative configuration can fully discharge the batteries in less than 5 minutes. Due to the fast discharge rates in this configuration, sedimentation and corrosion are also almost entirely avoided.

Organic acid-based linear free energy relationship models for green leaching of strategic metals from spent lithium-ion batteries and improvement of leaching performance

Water-soluble organic acids (e.g., acetic acid, acrylic acid, and ascorbic acid), as green leachants, have been applied to leach strategic metals (Ni, Li, Mn, and Co) from spent lithium-ion batteries (LIBs). Organic acid-based linear free energy relationship models were developed and simulated to predict the feasibility of the leaching efficiency for each of the strategic metals based on in silico calculated descriptors. The developed models, with accuracy (R²) of 0.747-0.831, reveal that hydrogen bond acidity of organic acids promotes the leaching efficiency, whereas molecular volume or excess molar refraction inhibits the efficiency. Furthermore, toxicity (lethal dose 50%) of organic acids was discussed along with the predicted leaching efficiency to explore more green and efficient organic acids. Considering both toxicity and leaching efficiency, citric acid was selected as a green and efficient leachant. To more improve the leaching performance (rate and efficiency) of citric acid, glucose as a green reductant and microwave treatment were additionally applied. Under the selected conditions, the leaching efficiencies after 1 h for Ni, Li, Mn, and Co were enhanced up to 98.3%, 99.1%, 98.7%, and 97.7%, respectively.

A green process for recycling and synthesis of cathode materials LiMn2O4 from spent lithium-ion batteries using citric acid

In the process of recycling spent lithium-ion batteries, citric acid is only used as a chelating agent to resynthesize new cathode materials by a sol-gel process or as a precipitant to separate Mn ions and Li ions.

Cobalt Recovery from Li-Ion Battery Recycling: A Critical Review

The increasing demand for Li-ion batteries for electric vehicles sheds light upon the Co supply chain. The metal is crucial to the cathode of these batteries, and the leading global producer is the D.R. Congo (70%). For this reason, it is considered critical/strategic due to the risk of interruption of supply in the short and medium term. Due to the increasing consumption for the transportation market, the batteries might be considered a secondary source of Co. The outstanding amount of spent batteries makes them to a core of urban mining warranting special attention. Greener technologies for Co recovery are necessary to achieve sustainable development. As a result of these sourcing challenges, this study is devoted to reviewing the techniques for Co recovery, such as acid leaching (inorganic and organic), separation (solvent extraction, ion exchange resins, and precipitation), and emerging technologies—ionic liquids, deep eutectic solvent, supercritical fluids, nanotechnology, and biohydrometallurgy. A dearth of research in emerging technologies for Co recovery from Li-ion batteries is discussed throughout the manuscript within a broader overview. The study is strictly connected to the Sustainability Development Goals (SDG) number 7, 8, 9, and 12.

Electric car battery: An overview on global demand, recycling and future approaches towards sustainability

Li-ion batteries are daily present in our electronic devices. These batteries are used in electric and hybrid vehicles supporting the current agreements to decrease greenhouse gas emissions. As a result, the electric vehicle demand has increased in the world. As Li-ion batteries are composed of critical metals in which there is a risk of interruption of supply in the medium term, recycling is the key to a sustainable future without internal combustion vehicles. Understanding the current scenario and future perspectives is important for strategies of new battery design, recycling routes and reverse logistics, as well as policies for sustainable development. This paper presents an overview of current and future vehicles used worldwide. An increase from 1.3 to 2 billion vehicles is expected worldwide until 2030; an outstanding demand will occur mainly in BRICS countries. The data demonstrated a correlation between the number of vehicles in use and GDP. Patents and processes designed for recycling Li-ion batteries and the new developments on pyro-, hydro-, and bio-metallurgical routes have been revised. The manuscript describes the importance and benefits of recycling as regards the supply of critical metals and future trends towards a circular economy.

Recycling and Direct-Regeneration of Cathode Materials from Spent Ternary Lithium-Ion Batteries by Hydrometallurgy: Status Quo and Recent Developments : Economic recovery methods for lithium nickel cobalt manganese oxide cathode materials

The cathodes of spent ternary lithium-ion batteries (LIBs) are rich in nonferrous metals, such as lithium, nickel, cobalt and manganese, which are important strategic raw materials and also potential sources of environmental pollution. Finding ways to extract these valuable metals cleanly and efficiently from spent cathodes is of great significance for sustainable development of the LIBs industry. In the light of low energy consumption, ‘green’ processing and high recovery efficiency, this paper provides an overview of different recovery technologies to recycle valuable metals from cathode materials of spent ternary LIBs. Development trends and application prospects for different recovery strategies for cathode materials from spent ternary LIBs are also predicted. We conclude that a highly economic recovery system: alkaline solution dissolution/calcination pretreatment → H2SO4 leaching → H2O2 reduction → coprecipitation regeneration of nickel cobalt manganese (NCM) will become the dominant stream for recycling retired NCM batteries. Furthermore, emerging advanced technologies, such as deep eutectic solvents (DESs) extraction and one‐step direct regeneration/recovery of NCM cathode materials are preferred methods to substitute conventional regeneration systems in the future.

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.

Countercurrent leaching of Ni, Co, Mn, and Li from spent lithium-ion batteries

This study focuses on a countercurrent leaching process (CLP) for the dissolution of high-value metals from cathode active material of spent lithium-ion batteries (LIBs). Its main aim is to improve the effective utilization of acid during leaching and allow for the continuous operation of the entire CLP by adjusting the process parameters. The overall recovery of lithium (Li), cobalt (Co), nickel (Ni), and manganese (Mn) was 98%, 95%, 95%, and 92%, respectively; the acid utilization of the leaching process exceeded 95% under optimum conditions. The optimum conditions for first stage leaching were 70 g/L solid-liquid (S/L) ratio at 40°C for 30 minutes, and 2.0 M sulfuric acid, 100 g/L S/L ratio, 7 g/L starch, at 85°C for 120 minutes for second stage leaching. After five bouts of circulatory leaching, more than 98% Li, 95% Co, 95% Ni, and 92% Mn were leached under the same leaching conditions. Furthermore, we introduced the Avrami equation to describe metal leaching kinetics from spent LIBs, and determined that the second stage leaching process was controlled by the diffusion rate. In this way, Li, Ni, Co, and Mn can be recovered efficiently and the excess acid in the leachate can be reused in this hydrometallurgical process, potentially offering economic and environmental benefits.

Study on the process of harmless treatment of residual electrolyte in battery disassembly

Residual electrolyte is the main pollution source in the lithium ion battery disassembly process. A practical detoxified approach is studied using the lithium hexafluorophosphate in the decommissioned power battery with dimethyl carbonate as a solvent. The pH measurement, Fourier transform infrared spectroscopy, micromorphology and phase structure characterization techniques showed that the process in this study is capable of removing lithium hexafluorophosphate from decommissioned power batteries, while controlling the proper ratio of NaOH can also completely precipitate F^- into CaF₂ crystal and allows recycling of the organic solvents. This process scheme of residual electrolyte treatment effectively reduces environmental pollution during the decommissioned power batteries recycling process, and has the benefit of resource reuse for valuable elements.

Pyrolysis characteristics of cathode from spent lithium-ion batteries using advanced TG-FTIR-GC/MS analysis

Thermal treatment offers an alternative method for the separation of Al foil and cathode materials during spent lithium-ion batteries (LIBs) recycling. In this work, the pyrolysis behavior of cathode from spent LIBs was investigated using advanced thermogravimetric Fourier transformed infrared spectroscopy coupled with gas chromatography-mass spectrometer (TG-FTIR-GC/MS) method. The fate of fluorine present in spent batteries was probed as well. TG analysis showed that the cathode decomposition displayed a three-stage process. The temperatures of maximum mass loss rate were located at 470 °C and 599 °C, respectively. FTIR analysis revealed that the release of CO₂ increased as the temperature rose from 195 to 928 °C. However, the evolution of H₂O showed a decreasing trend when the temperature increased to above 599 °C. The release of fluoride derivatives also exhibited a decreasing trend, and they were not detected after temperatures increasing to above 470 °C. GC-MS analysis indicated that the release of H₂O and CO displayed a similar trend, with larger releasing intensity at the first two stages. The evolution of 1,4-difluorobenzene and 1,3,5-trifluorobenzene also displayed a similar trend-larger releasing intensity at the first two stages. However, the release of CO₂ showed a different trend, with the largest release intensity at the third stage, as did the release of 1,2,4-trifluorobenzene, with the release mainly focused at the temperature of 300-400 °C. The release intensities of 1,2,4-trifluorobenzene and 1,3,5-trifluorobenzene were comparable, although smaller than that of 1,4-difluorobenzene. This study will offer practical support for the large-scale recycling of spent LIBs.

Environmental impact of spent lithium ion batteries and green recycling perspectives by organic acids - A review

The huge usage of rechargeable batteries in electronics has added to a recurrent problem worldwide in generating tonnage of spent lithium-ion batteries (LIBs). The inadequacy of the resources of the depleting critical metals has also been described in vogue. The environmental assessment of the life cycle of the LIBs has been elucidated vis-a-vis the effects of raw material supply, transportation, and recycling. Based on the available work for recycling technologies, this review also attempts to elicit the various methods practiced in discharging/dismantling, classification, and separation of components followed by metal recovery. The authors have reviewed the major developments in the area of recycling of cathode material by using various acids for extraction of metals from spent LIBs, compared the merits and demerits of acids used and presented a comprehensive outlook to the processes formulated vis-à-vis imperative need for using green techniques. The necessity for benign recycling methods is stressed upon to alleviate the need for high temperature and oxidative acid leaching conditions. The various green lixiviants (organic acids) attempted to extract metals from spent LIBs have been discussed in detail with respect to the mechanism, efficacies as well as the various factors (selectivity, cost, etc.) that govern the use of organic acids in battery recycling. It was ascertained that the GHG emissions to extract Co using organic acids stand 1/8 of that using an inorganic acid leaching process. Efforts need to be envisaged in separating the leached metals from these lixiviants ensuring economics and environmental benefits.

Kinetic Modelling of the Coproduction Process of Fumaric and Malic Acids by Rhizopus arrhizus NRRL 1526

The production of organic acids by biotechnological processes has experienced a notable impulse with the advent of first and second generation biorefineries and the need of searching for renewable and sustainable feedstock, such as biomass. Fumaric acid is a promising biomonomer for polyamide production and a well-known acidulant and preservative in food and feed industries. Malic acid is a well-known food acidulant with a high market share. The biotechnological Fumaric and Malic acid production via fungi of the Rhizopus genus is being explored nowadays as a process for the valorization of food and food-related waste to obtain food ingredients and key platform chemicals of the so-called biochemical biorefinery. In this work, a preliminary study is performed to find reproducible conditions for the production of the acids by Rhizopus arrhizus NRRL 1526 by controlling fungi morphology and inoculum conditions. Afterwards, several production runs are performed to obtain biomass, glucose, and acid concentration data at different processing time values. Finally, an unstructured, unsegregated model including a logistic-type equation for biomass and potential-type equations for the substrate and the products is fitted to experimental data. We find that the production of the organic acids is mainly non-associated with fungal growth.

A new model of trajectory in eddy current separation for recovering spent lithium iron phosphate batteries

Eddy current separation (ECS) is an environment-friendly technology for separating nonferrous metallic particles whose size was from 2 mm to 10 mm. No wastes are generated in ECS. ECS quality of nonferrous metals from solid wastes is rather low in the production practice of spent lithium iron phosphate (LFP) batteries recovering. Repeating separation even manual sorting is required in the production. The traditional method of falling point prediction based on eddy current mechanics uses equivalent acceleration to replace separation motion curves. These curves have low precision and are unsuitable for predicting the motion trajectory of small particle size of sorted materials. In this work, eddy current separation of positive and negative plates in a crushed product of spent lithium iron phosphate battery is used as an example to establish the force and kinematics models of different materials in the eddy current separation. An iterative method, rather than average speed method, is used to improve the accuracy of the model. Displacement interval replaces disengagement angle as a separating index to improve the model's intuitiveness and practical guidance. In the range of 2-20 mm, test results are consistent with simulation results. The copper and aluminium foils at a magnetic roller speed of 800r/min can be separated to a maximum particle size ratio of 1.72, and the maximum particle size ratio of copper and positive electrode sheets can be large. This paper provided an environmental-friendly and effective technology for separating nonferrous metals from crushed spent LFP batteries.

Eddy current separation for recovering aluminium and lithium-iron phosphate components of spent lithium-iron phosphate batteries

With the rapid development of the electric vehicle market since 2012, lithium-iron phosphate (LFP) batteries face retirement intensively. Numerous LFP batteries have been generated given their short service life. Thus, recycling spent LFP batteries is crucial. However, published information on the recovery technology of spent LFP batteries is minimal. Traditional separators and separation theories of recovering technologies were unsuitable for guiding the separation process of recovering metals from spent LFP batteries. The separation rate of the current method for recovering spent LFP batteries was rather low. Furthermore, some wastewater was produced. In this study, spent LFP batteries were dismantled into individual parts of aluminium shells, cathode slices, polymer diaphragms and anode slices. The anode pieces were scraped to separate copper foil and anode powder. The cathode pieces were thermally treated to reduce adhesion between the cathode powder and the aluminium foil. The dissociation rate of the cathode slices reached 100% after crushing when the temperature and time reached 300℃ and 120 min, respectively. Eddy current separation was performed to separate nonferrous metals (aluminium) from aluminium and LFP mixture. The optimized operation parameters for the eddy current separation were feeding speed of 1 m/s and magnetic field rotation speed of 4 m/s. The separation rate of the eddy current separation reached 100%. Mass balance of the recovered materials was conducted. Results showed that the recovery rate of spent LFP can reach 92.52%. This study established a green and full material recovery process for spent LFP batteries.

Maleic, glycolic and acetoacetic acids-leaching for recovery of valuable metals from spent lithium-ion batteries: leaching parameters, thermodynamics and kinetics

Environmentally friendly acid-leaching processes with three organic acids (maleic, glycolic and acetoacetic) were developed to recover valuable metals from the cathodic material of spent lithium-ion batteries (LiCoO₂). The leaching efficiencies of Li and Co by the maleic acid were 99.58% and 98.77%, respectively. The leaching efficiencies of Li and Co by the glycolic acid were 98.54% and 97.83%, while those by the acetoacetic acid were 98.62% and 97.99%, respectively. The optimal acid concentration for the maleic acid-, glycolic acid- and acetoacetic acid-leaching processes were 1, 2 and 1.5 mol l^-1, respectively, while their optimal H₂O₂ concentrations were 1.5, 2 and 1.5 vol%, respectively. The optimal solid/liquid ratio, temperature and reaction time for the leaching process of the three organic acids was the same (10 g l^-1, 70°C, 60 min). The thermodynamic formation energy of the leaching products and the Gibbs free energy of the leaching reactions were calculated, and the kinetic study showed that the leaching processes fit well with the shrinking-core model. Based on the comparison in the leaching parameters, the efficacy and availability of the three acids is as follows: maleic acid > acetoacetic acid > glycolic acid.

Combined mechanical process recycling technology for recovering copper and aluminium components of spent lithium-iron phosphate batteries

The recycling processes of spent lithium iron phosphate batteries comprise thermal, wet, and biological and mechanical treatments. Limited research has been conducted on the combined mechanical process recycling technology and such works are limited to the separation of metal and non-metal materials, which belongs to mechanical recovery. In this article the combined mechanical process recycling technology of spent lithium iron phosphate batteries and the separation of metals has been investigated. The spent lithium iron phosphate batteries monomer with the completely discharged electrolyte was subjected to perforation discharge. The shell was directly recycled and the inner core was directly separated into a positive electrode piece, dissepiment, and negative electrode piece. The dissociation rate of the positive and negative materials reached 100.0% after crushing when the temperature and time reached 300 °C and 120 min. The crushed products were collected and sequentially sieved after the low-temperature thermal treatment. Then, nonferrous metals (copper and aluminium) were separated from the crushed spent lithium iron phosphate batteries by eddy current separation with particle size -4 + 0.4. The optimised operation parameters of eddy current separation were fed at speeds of 40 r min^-1, and the rotation speed of the magnetic field was 800 r min^-1. The nonferrous metals of copper and aluminium were separated by the method of pneumatic separation. The optimal air speed was 0.34 m s^-1 for the particle-size -1.6 + 0.4 mm and 12.85-14.23 m s^-1 for the particle-size -4 + 1.6 mm. The present recycling process is eco-friendly and highly efficient and produces little waste.

Lithium battery reusing and recycling: A circular economy insight

Driven by the rapid uptake of battery electric vehicles, Li-ion power batteries are increasingly reused in stationary energy storage systems, and eventually recycled to recover all the valued components. Offering an updated global perspective, this study provides a circular economy insight on lithium-ion battery reuse and recycling.

Enhancement in leaching process of lithium and cobalt from spent lithium-ion batteries using benzenesulfonic acid system

Recycling of valuable metals from spent lithium ion batteries (LIBs) is of great significance considering the conservation of metal resources and the alleviation of potential hazardous effects on environment. Thus, the present work focuses on enhancing the efficiency of leaching process for the recovery of cobalt and lithium from the cathode active materials of spent LIBs. In this study, benzenesulfonic acid (C₆H₅SO₃H) with a reducing agent hydrogen peroxide (H₂O₂) was innovatively used as leaching reagents, and the operating variables were optimized to obtain higher leaching efficiencies. Results show the optimized leaching recovery of 99.58% Li and 96.53% Co was obtained under the conditions of 0.75 M benzenesulfonic acid, 3 vol% H₂O₂, a solid to liquid (S/L) ratio of 15 g/L, 500 rpm stirring speed, and 80 min leaching time at 90 °C. Moreover, a new kinetic model was introduced to describe the leaching kinetics of LiCoO₂ from the cathode material. The apparent activation energies E_a for leaching of lithium and cobalt are 41.06 and 35.21 kJ/mol, respectively, indicating that the surface chemical reaction is the rate-controlling step during this leaching process. Further, the proposed recovery mechanism for spent cathode material was raised by analyzing the experimental results and characterizing the morphological and chemical state (i.e. SEM-EDS, XPS and XRD) of raw material and leaching residues. In comparison with the previous leaching process, this research was found to be efficient, low energy consumption, and environmental friendly.

Recovery of valuable metals from LiNi0.5Co0.2Mn0.3O2 cathode materials of spent Li-ion batteries using mild mixed acid as leachant

A novel hydrometallurgical process for recycling LiNi_0.5Co_0.2Mn_0.3O₂ cathode materials harvested from spent Li-ion batteries (LIBs) is established in this work. The cathode material LiNi_0.5Co_0.2Mn_0.3O₂ is dissolved in a mixed acid containing phosphoric acid (leaching agent) and citric acid (leaching agent and reductant). Using 0.2 M phosphoric acid and 0.4 M citric acid with a solid to liquid (S/L) ratio of 20 g/L at 90 °C for 30 min, the proposed method results in a leaching efficiency of ca. 100% for Li, 93.38% for Ni, 91.63% for Co, and 92.00% for Mn, respectively. Kinetics of the leaching process is well described by the Avrami equation. It is found that the leaching process is controlled by surface chemical reactions, and the apparent activation energies (kJ/mol) are 45.83 for Li, 83.01 for Ni, 81.38 for Co and 92.35 for Mn, respectively. With aids of various advanced characterizations methods, including UV-Vis, FT-IR and TOC, we find that there are a great deal of citrates and a small amount of dihydrogen phosphates in the mixed acid leachate. This leaching method enjoys advantages of low acid consumption, short leaching time and no need to add extra reductant.

Electrochemical study of specially designed graphene-Fe3O4-polyaniline nanocomposite as a high-performance anode for lithium-ion battery

In this work, an anode material with improved thermal stability, charge capacity, charge capacity retention, energy density, cyclic performance, operation safety, reversible capacity, and rate capability was synthesized for battery applications. The graphene-magnetite-polyaniline (Gr-Fe3O4-PANI) nanocomposites (NCs) are believed to deliver outstanding performance owing to the collective effect of the layered graphene (Gr) and magnetite (Fe3O4) hollow rods (HRs), as well as the better conductivity of polyaniline (PANI). The Gr-Fe3O4-PANI NCs easily enable the insertion and deinsertion of Li+, the passage of ions in the electrode, fast kinetics of Li+, and low volume expansion. Gr-Fe3O4-PANI NC was prepared by polymerizing aniline in the presence of already prepared Fe3O4 HRs, then dispersing in Gr. Fe3O4 HRs were synthesized by a hydrothermal route. Electrochemical properties were investigated by galvanostatic charge-discharge analysis and cyclic voltammetry. A lithium-ion battery (LIB) based on the Gr-Fe3O4-PANI exhibited a superior reversible current capacity of 1214 mA h g-1, excellent power capability, low volume expansion, high cycling stability and 99.6% coulombic efficiency over 250 cycles.

Recovery of value-added products from cathode and anode material of spent lithium-ion batteries

Herein we report a low cost and eco-friendly approach for the recovery of metals from cathode and anode materials of mobile phone spent lithium-ion batteries (LIBs). Li-based metal oxide and graphite were efficiently separated from their respective foils and used for lixiviation. Acetic acid (CH₃COOH) and water were used as lixiviants for the recovery of metals from cathode and anode materials respectively. It was found that with 3 M Acetic acid and 7.5 vol% H₂O₂ as reducing agent 99.9% Li, 98.7% Co, and 99.5% Mn were leached out from cathode material in 40 min at 70 °C and a pulp density of 20 g/L. Besides the cathode leaching, Li was also extracted from anodic material graphite using water as a solvent and further recovered as solid Li₂CO₃ (99.7% Li). The kinetic evaluation of the cathode lixiviate process was studied using three different shrinking-core kinetic Models and established that the reaction follows the product layer diffusion controlled mechanism. From the cathode leach liquor, 99% Co was recovered as metal sulfide by controlled sulfide precipitation with 99.2% purity, and subsequently, MnCO₃ and Li₂CO₃ were obtained with the purity of 98.7% and 99.4%, respectively. The purity of the salts revealed that these products recovered from spent LIBs might be utilized in the electrochemical energy-storage applications. In addition, this recycling process would promote the sustainable development of the battery industry.

Toward sustainable and systematic recycling of spent rechargeable batteries

A comprehensive and novel view on battery recycling is provided in terms of the science and technology, engineering, and policy.