Ultrasound-driven sustainable recovery and regeneration of high-purity graphite from spent lithium-ion batteries

Natural graphite (NG) has been attracted as a promising anode material for lithium ion batteries due to its appropriate charge/discharge profile, high reversible capacity and low cost. However, high irreversible capacity and low capacity retention at first cycle have influenced on its practical use. Although low cost is the main advantage of natural graphite, the material cost of natural graphite should be reduced further in order to be used for electric vehicles (EVs) and energy saving systems (ESS). Generally, pristine natural graphite contains various impurities such as Al, Fe, and Si. For commercial use, pristine natural graphite should be refined since the impurities would have a negative effect on both electrolyte and electrode of lithium ion batteries. The purity grade of natural graphite can be classified based on the purification process. As the requirement for high purity increases, more purification steps are needed, resulting in high manufacturing cost. Therefore, the main issue for the application of natural graphite as an anode active material is to use low-purity natural graphite with purification process as less as possible. In this regard, effect of Fe as impurity on the electrochemical performance of the low-purity natural graphite as anode active material for lithium ion batteries was investigated in this study. Natural graphite powders with 5 wt% Fe (05Fe) and 10 wt% (10Fe) were synthesized by combustion method from the raw materials of Fe(III)(NO3)3 9H2O (Alfa Aesar) and high-purity spherical natural graphite (POSCO CHEMTECH) by calcination at 500 °C in air atmosphere. The morphology of the natural graphite powders was observed by scanning electron microscopy (SEM, JSM-5900, JEOL, Japan). The particle size of each powder was measured by a dynamic light scattering method (ELS 6000 zeta potential and particle size analyzer, Otsuka Electronics, Japan). Powder X-ray diffraction (XRD, MAX-2500, RIGAKU, Japan) analysis was conducted using Cu Kα radiation with a wavelength λ = 1.5406 Å. The crystallite sizes (La and Lc) were calculated on the basis of the d002XRD lines by application of the Scherrer’s equation. The crystallinity of the natural graphite powders was investigated by Raman spectroscopy (LabRAM, Horiba Jobin-Yvon, Japan). The concentrations of impurities in the natural graphite were determined by an inductively coupled plasma atomic emission spectrophotometer (ICP-AES). A working electrode paste was fabricated from a mixture of natural graphite with a binder consisting of carboxymethylcellulose (CMC)/styrene-butadiene rubber (SBR) and carbon black (Super-p) as a conductive agent dissolved in D.I. water. The weight ratio of graphite to binder (CMC:SBR:Super-p=2:2:1) was 95:2:2:1. The prepared paste was coated onto 10㎛ Cu foil by using a doctor blade and then dried under vacuum at 120 °C for 12 h. Electrochemical performance was evaluated using CR2032 coin-type cells with a 20 μm thick Cellgard 2300 porous membrane separator and 1 M LiPF6-EC/DMC (1:1 in volume ratio) electrolyte. Lithium metal foil was used as a counter electrode. All of the samples studied in this work were treated by sphericalization and the sphericalized natural graphite maintained a spherical shape after the calcination process at 500 °C for 4 h. All the samples have both hexagonal and rhombohedral phases which are the typical structure of natural graphite. Fe2O3 peaks (JCPDS card #33-0664) were indexed at 2θ = 33.1°, 35.6°, 62.4°, and 63.9°, respectively. The most of Fe2O3particles were located on a surface of natural graphite, based on the EDX mapping and back-scattered electron (BSE) images. The irreversible capacity during the charge-discharge reactions increased with increasing the Fe content. However, the cycle retention of the 05Fe, 10Fe, and NG are comparable. Therefore, it may be possible to use unrefined natural graphite as an anode active material for lithium-ion rechargeable batteries.

A scalable and facile regeneration route is utilized to recover the graphite from a spent lithium-ion battery (LIB). Eco-friendly organic acid is employed as a leaching-curing reagent for the present work. All the unwanted content of elements e.g. Ni, Co, Li, Cu and Al has been completely terminated from the graphite after the purification step without any additional calcination process. The optical, structural and electrochemical properties of as-reclaimed graphite have been studied by several analytical methods. Regenerated graphite is restored to its layered crystal structure along with expansion in the interlayer distance, and the same is confirmed from scanning electron microscopy and X-ray diffraction analysis respectively. Notably, high purity graphite is achieved and tested in its electrochemical storage property in supercapacitor (SC) applications. As an outcome, recreated graphite exhibits a maximum areal capacitance of 285 mF cm−2 at 5 mV s−1. The fabricated symmetric SC demonstrates the superior energy storage performance in terms of durability and higher capacitance (131 mF cm−2) with better capacity retention over several cycles. It is worth mentioning that this curing process is a facile route, consumes lower energy and eco-friendly methodology and thereby may have futuristic extent for the bench scale reclamation of graphite from spent LIBs.

The growing demand for lithium-ion batteries (LIBs) has led to significant environmental and resource challenges, such as the toxicity of LIBs’ waste, which pose severe environmental and health risks, and the criticality of some of their components. Efficient recycling processes are essential to mitigate these issues, promoting the recovery of valuable materials and reducing environmental pollution. This review explores the application of electrodialysis in the process of recycling LIBs to contribute to the principles of circular hydrometallurgy. The article is structured to provide a comprehensive understanding of the topic, starting with an overview of the environmental and resource challenges associated with manufacturing LIBs. Then the current recycling processes are presented, focusing on hydrometallurgical methods. The concept of circular hydrometallurgy is introduced, emphasizing sustainable resource recovery. The electrodialysis technique is described in this context, highlighting its integration into the process of recycling LIBs to separate and recover valuable metals. Finally, the article addresses the challenges and limitations of the electrodialysis technique, such as energy consumption and system optimization, and identifies areas for future research and development. Through this analysis, the review aimed to contribute to advancing the development of more sustainable and efficient LIB recycling technologies, ensuring a safer and more environmentally friendly approach to the management of batteries’ lifecycle.

With increased use of Lithium-Ion Batteries (LIBs) and the scarcity of some of their components, their recycling and the recovery of their metals have become essential. In this work, an indirect bioleaching process was designed to solubilise metals from LIB black mass using biogenic acid generated in a stirred tank bioreactor. The biogenic acid was used in addition to H2O2 as a reductant for improved solubilisation, and influential factors including pulp density, temperature, and concentration of H2O2 were optimised. The best results were achieved at 55°C, with a pulp density of 7.5% (w/v) and 0.5% (v/v) H2O2, which resulted in 82% Li, 32% Ni, 24% Co and 21% Mn solubilisation in 5min of the process. However, over time transition metals in the leachate did not remain in solution, due to their adsorption onto the carbon content of the black mass. To selectively recover solubilized Co, Ni, Mn, and Li from the leachate, a combined process of electrowinning and precipitation was applied to the leachate, leading to the successful electroplating of Co, Ni and Mn with 100%, 100% and 97.2% of solubilised metals respectively, while 40% of the Li was recovered by precipitation following the addition of sodium carbonate. These results constitute a promising step toward closing the loop for the sustainable selective recovery of critical metals used in LIB manufacturing and suggest the next targets to improved bioleaching efficiency.

Sustainable recovery and resynthesis of electroactive materials from spent Li-ion batteries to ensure material sustainability

Recycling has become an absolute necessity. Spent Lithium-ion batteries (LIBs) are hazardous waste but a potential source of purified minerals. The industrial focus on LIB recycling is mostly centered on costly and scarce cathode materials recovery. Graphite is often overlooked as it fails to generate useful revenue. Herein, the waste LIBs are recycled following an all-components-recovery route that minimizes cross-contamination. However, the surface of the recovered graphite is covered with solid electrolyte interphase (SEI) formed during its first life application. Solvent wash followed by thermal treatment revives graphite for second-life applications. Three important things to consider here are the interaction of solvent media with the preformed SEI, the role of leftover SEI in forming the second-life SEI, and the effect of regenerated SEI on second-life electrochemistry. Therefore, the nature of the solvent plays a vital role in the overall process. Utilizing water is the go-to alternative but the obtained electrochemistry from water-washed graphite is below the mark. Organic solvent dimethyl carbonate (DMC) modifies the chemical composition of the interphase in such a way that it improves second-life electrochemistry. Strong inorganic acid HCl results in the highest carbon purity and makes recovered graphite suitable for non-electrochemical applications too. Electrochemically superior DMC-washed graphite is repurposed into a dual-ion full cell that delivers an average voltage of 4.5 V and an energy density of 110 Wh kg-1. Figure 1

Supercritical fluid technology is a promising approach for sustainable and efficient resource recovery (especially fluorinated binders and electrolytes) from end-of-life lithium ion batteries with significant economic and environmental perspectives.

The widespread adoption of lithium-ion batteries (LIBs) in various applications has led to an increasing demand for efficient and environmentally sustainable recycling processes. This necessity stems from the broader goal of establishing a sustainable and circular economy for LIBs while simultaneously addressing the challenges within the supply chain.One of the primary challenges in LIB recycling lies in the retrieval of valuable materials from end-of-life LIBs or electrode scraps in an environmentally benign manner. In particular, reclaiming the high purity of cathode active materials is a critical step to further development of direct recycling. The recovered materials need to be binder- and carbon black-free while retaining their inherent characteristics, including morphology, crystallinity, and electrochemical activity.Traditional methods for solvent-based cathode recovery involve energy-intensive processes and often employ hazardous solvents, leading to environmental concerns and safety issues. In response, recent studies have proposed several green solvents as environmentally friendly and economically viable alternatives for sustainable cathode recovery processes.In this study, we conduct a comprehensive comparative analysis of various green solvents to assess their efficiency in recovering cathode materials from electrode scraps. We employ an ultrasound-assisted recovery process using different green solvents to compare the characteristics of the recovered cathode active materials in terms of morphology, purity, surface characteristics, and electrochemical performance. By evaluating the key challenges and advantages of each green solvent, we aim to provide valuable insights into the development of solvent-based cathode recovery.

BACKGROUNDThe recycling of spent lithium‐ion batteries (LIBs) is crucial for resource conservation and environmental sustainability, particularly due to the valuable metals they contain, such as cobalt and lithium. This study focuses on developing an ion‐exchange method for cobalt recovery from waste LIB solutions, using a mesoporous silica derivative of carbamoyl sulfamic acid (PST‐SA) as the adsorbent.RESULTSThe batch method for adsorption experiments identified the most effective conditions: a pH of 8, 0.08 g PST‐SA, and a shaking time of 60 min, at room temperature. These experiments demonstrated a remarkable cobalt uptake capacity of 270.70 mg g−1, highlighting PST‐SA's exceptional adsorption capabilities. Additionally, thermodynamic studies revealed the adsorption process to be both endothermic and spontaneous, enhancing our understanding of its chemically reactive mechanisms.CONCLUSIONSThe practical application of PST‐SA, particularly when processing spent LIBs, showcases its real‐world utility. The efficient separation of cobaltous oxalate and lithium phosphate into pure forms emphasizes PST‐SA's potential in recycling and resource recovery. Given its cost‐effectiveness and strong adsorption capacity, PST‐SA stands out as an excellent solution for the removal of Co(II) from discarded LIBs, promoting sustainable material recovery practices. © 2024 Society of Chemical Industry (SCI).

Enhanced lithium recovery from simulated lithium-ion battery (LIB) leachate using supported liquid membrane contactors: effects of organophosphorus extractants and real-time wetting monitoring.

Sustainable recovery: Life cycle assessment for lithium-ion battery recycling.

Sustainable recovery Co3O4-based catalysts from spent lithium-ion batteries for preferential CO oxidation.

In response to the energy crisis and to achieve low-carbon goals, lithium-ion batteries (LIBs) have rapidly become widespread in consumer electronics, electric vehicles, and renewable energy storage. This leads to a surge in the number of spent lithium-ion batteries (S-LIBs). However, if S-LIBs are not handled properly, this will pose serious environmental and health risks. This review highlights the critical need for integrating pollution control into S-LIBs recycling processes to achieve sustainable resource recovery and critically examines pollution control strategies across S-LIBs recycling processes. Pretreatment (discharge, disassembly, separation) releases microplastics, volatile organic compounds (VOCs), and fluorine/phosphorus gases from decomposed LiPF6. Hydrometallurgy generates acidic wastewater, while pyrometallurgy emits CO2, NOx, SO2, and heavy metal aerosols. Direct regeneration risks secondary pollution via chemical residues. These guidelines contribute to enhancing S-LIBs recycling techniques and advancing sustainable development within the field. In conclusion, achieving sustainable S-LIBs recycling involves the development of cost-efficient, non-toxic leaching agents, such as organic acids, and implementing closed-loop processes to minimize waste.

The rapid growth of electric vehicle (EV) market promotes the mass production of lithium-ion batteries. However, the battery production is subjected to high cost and serious environmental issues. Effective and efficient end-of-use lithium-ion battery (LIB) management should be carried out to enhance sustainable development, following the principles of the triple bottom line and circular economy. From the life cycle perspective, battery refurbishing and material recovery are the two major end-of-use options to recover the value of spent batteries. The refurbishing of spent batteries can extend the battery useful life and make full use of battery remaining functional value. Material recycling can recover the battery materials for a new life cycle. However, there still exist many barriers that should be investigated to ensure the success of end-of-use battery recovery. The review covered the pathways to present a full view of end-of-use battery recovery, identified the key bottlenecks in different dimensions, and discussed the strategies for specific scenarios. Industrial practice and pilot projects associated with the two end-of-use options are summarized. In the end, analysis and research suggestions are provided to facilitate the establishment of a sustainable circular battery recovery system.

The accelerating accumulation of spent lithium‐ion batteries (LIBs) poses both a promising resource opportunity and a pressing recycling challenge. While pyrometallurgical and hydrometallurgical recycling routes are technologically mature, they are energy‐ and reagent‐intensive, generate secondary pollution, and fail to preserve cathode structures for direct reuse. In contrast, electrochemical recycling is emerging as a transformative alternative, leveraging electricity as a clean and tunable “reagent” to enable indirect recycling via metal dissolution and selective recovery, and direct regeneration via relithiation under mild conditions. This approach offers high efficiency in recovery and short technology chain while significantly reducing chemical consumption and waste generation. However, its industrial deployment remains in early stages due to stability and scalability challenges. This work systematically evaluates key electrochemical strategies: electrochemical leaching, direct electrodeposition, selective ion separation, direct electrochemical relithiation, and molten‐salt electrochemical strategies. Beyond summarizing recent advances, we critically examine how interfacial design, including slurry‐electrode interactions, side‐reactions, mediator and membrane stability, affects efficiency, selectivity, and durability, as well as reactor design for the scale‐up production. We also assess techno‐economic feasibility and scale‐up bottlenecks, and outline a forward‐looking roadmap integrating operando characterization, interfacial design, and continuous‐flow reactors to advance low‐carbon, scalable electrochemical recycling for a circular LIB supply chain.