Recycling of cathode material from spent lithium-ion batteries: Challenges and future perspectives

Direct Regeneration of Degraded LiFePO4 Cathode via Reductive Solution Relithiation Regeneration Process

The rapid growth of electronic devices, electric vehicles, and mobile energy storage has produced large quantities of spent batteries, leading to significant environmental issues and a shortage of lithium resources. Recycling spent batteries has become urgent to protect the environment. The key to treating spent lithium-ion batteries is to implement green and efficient regeneration. This study proposes a recycling method for the direct regeneration of spent lithium iron phosphate (LFP) batteries using hydrothermal reduction. Ascorbic acid (AA) was used as a low-cost and environmentally friendly reductant to reduce Fe3+ in spent LiFePO4. We also investigated the role of AA in the hydrothermal process and its effects on the electrochemical properties of the regenerated LiFePO4 cathode material (AA-SR-LFP). The results showed that the hydrothermal reduction direct regeneration method successfully produced AA-SR-LFP with good crystallinity and electrochemical properties. AA-SR-LFP exhibited excellent electrochemical properties, with an initial discharge specific capacity of 144.4 mAh g-1 at 1 C and a capacity retention rate of 98.6% after 100 cycles. In summary, the hydrothermal reduction direct regeneration method effectively repairs the defects in the chemical composition and crystal structure of spent LiFePO4. It can be regarded as a green and effective regeneration approach for spent LiFePO4 cathode materials.

Crystal phase and nanoscale size regulation utilizing the in-situ catalytic pyrolysis of bamboo sawdust in the recycling of spent lithium batteries

Current Li-ion battery (LIB) recycling methods exhibit the disadvantages of low metal recovery efficiencies and high levels of pollution and energy consumption. Here, products generated via the in-situ catalytic pyrolysis of bamboo sawdust (BS) were utilized to regulate the crystal phase and nanoscale size of the NCM cathode to enhance the selective Li extraction and leaching efficiencies of other valuable metals from spent LIBs. The catalytic effect of the NCM cathode significantly promoted the release of gases from BS pyrolysis. These gases (H2, CO, and CH4) finally transformed the crystal phase of the NCM cathode from LiNixCoyMnzO2 into (Ni-Co/MnO/Li2CO3)/C. The size of the spent NCM cathode material was reduced approximately 31.7-fold (from 4.1 μm to 129.2 nm) after roasting. This could be ascribed to the in-situ catalytic decomposition of aromatic compounds generated via the primary pyrolysis of BS into C and H2 on the surface of the cathode material, resulting in the formation of the nanoscale composite (Ni-Co/MnO/Li2CO3)/C. This process enabled the targeted control of the crystal phase and nanoscale size of the material. Water leaching studies revealed a remarkable selective Li extraction efficiency of 99.27 %, and sulfuric acid leaching experiments with a concentration of 2 M revealed high extraction efficiencies of 99.15 % (Ni), 93.87 % (Co), and 99.46 % (Mn). Finally, a novel mechanism involving synergistic thermo-reduction and carbon modification for crystal phase regulation and nanoscale control was proposed. This study provides a novel concept for use in enhancing the recycling of valuable metals from spent LIBs utilizing biomass waste and practices the concept of "treating waste with waste".

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.

Preoxidation and Prilling Combined with Doping Strategy to Build High-Performance Recycling Spent LiFePO4 Materials

Direct regeneration has gained much attention in LiFePO4 battery recycling due to its simplicity, ecofriendliness, and cost savings. However, the excess carbon residues from binder decomposition, conductive carbon, and coated carbon in spent LiFePO4 impair electrochemical performance of direct regenerated LiFePO4. Herein, we report a preoxidation and prilling collaborative doping strategy to restore spent LiFePO4 by direct regeneration. The excess carbon is effectively removed by preoxidation. At the same time, prilling not only reduces the size of the primary particles and shortens the diffusion distance of Li+ but also improves the tap density of the regenerated materials. Besides, the Li+ transmission of the regenerated LiFePO4 is further improved by Ti4+ doping. Compared with commercial LiFePO4, it has excellent low-temperature performance. The collaborative strategy provides a new insight into regenerating high-performance spent LiFePO4.

Contact-electro-catalysis (CEC)

Contact-electro-catalysis (CEC) is an emerging field that utilizes electron transfer occurring at the liquid-solid and even liquid-liquid interfaces because of the contact-electrification effect to stimulate redox reactions. The energy source of CEC is external mechanical stimuli, and solids to be used are generally organic as well as in-organic materials even though they are chemically inert. CEC has rapidly garnered extensive attention and demonstrated its potential for both mechanistic research and practical applications of mechanocatalysis. This review aims to elucidate the fundamental principle, prominent features, and applications of CEC by compiling and analyzing the recent developments. In detail, the theoretical foundation for CEC, the methods for improving CEC, and the unique advantages of CEC have been discussed. Furthermore, we outline a roadmap for future research and development of CEC. We hope that this review will stimulate extensive studies in the chemistry community for investigating the CEC, a catalytic process in nature.

Resource recovery and regeneration strategies for spent lithium-ion batteries: Toward sustainable high-value cathode materials

Traditional cathode recycling methods have become outdated amid growing concerns for high-value output and environmental friendliness in spent Li-ion battery (LIB) recycling. Our study presents a closed-loop approach that involves selective sulfurization roasting, water leaching, and regeneration, efficiently transforming spent ternary Li batteries (i.e., NCM) into high-performance cathode materials. By combining experimental investigations with density functional theory (DFT) calculations, we elucidate the mechanisms within the NCM-C-S roasting system, providing a theoretical foundation for selective sulfidation. Utilizing in situ X-ray diffraction techniques and a series of consecutive experiments, the study meticulously tracks the evolution of regenerating cathode materials that use transition metal sulfides as their primary raw materials. The Li-rich regenerated NCM exhibits exceptional electrochemical performance, including long-term cycling, high-rate capabilities, reversibility, and stability. The closed-loop approach highlights the sustainability and environmental friendliness of this recycling process, with potential applications in other cathode materials, such as LiCoO2 and LiMn2O4. Compared with traditional methods, this short process approach avoids the complexity of leaching, solvent extraction, and reverse extraction, significantly increasing metal utilization and Li recovery rates while reducing pollution and resource waste.

Zinc-Bromine Batteries: Challenges, Prospective Solutions, and Future

Zinc-bromine batteries (ZBBs) have recently gained significant attention as inexpensive and safer alternatives to potentially flammable lithium-ion batteries. Zn metal is relatively stable in aqueous electrolytes, making ZBBs safer and easier to handle. However, Zn metal anodes are still affected by several issues, including dendrite growth, Zn dissolution, and the crossover of Br species from cathodes to corrode anodes, resulting in self-discharge and fast performance fading. Similarly, Br2 undergoes sluggish redox reactions on cathodes, which brings several issues such as poor reaction kinetics, the highly corrosive nature of Br species leading to corrosion of separators and poisoning of anodes, and the volatile nature of Br species causing increased internal pressures, etc. These issues are compounded in flowless ZBB configuration as no fresh electrolyte is available to provide extra/fresh reaction species. In this review, the factors controlling the performance of ZBBs in flow and flowless configurations are thoroughly reviewed, along with the status of ZBBs in the commercial sector. The review also summarizes various novel methodologies to mitigate these challenges and presents research areas for future studies. In summary, this review will offer a perspective on the historical evolution, recent advancements, and prospects of ZBBs.

The Foreseeable Future of Spent Lithium-Ion Batteries: Advanced Upcycling for Toxic Electrolyte, Cathode, and Anode from Environmental and Technological Perspectives

With the rise of the new energy vehicle industry represented by Tesla and BYD, the need for lithium-ion batteries (LIBs) grows rapidly. However, owing to the limited service life of LIBs, the large-scale retirement tide of LIBs has come. The recycling of spent LIBs has become an inevitable trend of resource recovery, environmental protection, and social demand. The low added value recovery of previous LIBs mostly used traditional metal extraction, which caused environmental damage and had high cost. Beyond metal extraction, the upcycling of spent LIBs came into being. In this work, we have outlined and particularly focus on sustainable upcycling technologies of toxic electrolyte, cathode, and anode from spent LIBs. For electrolyte, whether electrolyte extraction or decomposition, restoring the original electrolyte components or decomposing them into low-carbon energy conversion is the goal of electrolyte upcycling. Direct regeneration and preparation of advanced materials are the best strategies for cathodic upcycling with the advantages of cost and energy consumption, but challenges remain in industrial practice. The regeneration of advanced graphite-based materials and battery-grade graphite shows us the prospect of regeneration of anode. Furthermore, the challenges and future development of spent LIBs upcycling are summarized and discussed from technological and environmental perspectives.

Recovery of Li2CO3 from Spent LiFePO4 by Using a Novel Impurity Elimination Process

The large-scale implementations of lithium iron phosphate (LFP) batteries for energy storage systems have been gaining attention around the world due to their quality of high technological maturity and flexible configuration. Unfortunately, the exponential production of LFP batteries is accompanied by an annual accumulation of spent batteries and a premature consumption of the lithium resource. Recycling souring critical battery materials such as Li₂CO₃ is essential to reduce the supply chain risk and achieve net carbon neutrality goals. During the recovery of Li₂CO₃, impurity removal is the most crucial step in the hydrometallurgy process of spent LiFePO₄, which determines the purity of Li₂CO₃. By investigating and comparing the results of impurity elimination from the purified Li⁺-containing liquids with strong and weak alkalis under identical pH conditions, respectively, a strategy based on an alkali mixture has been proposed. The purified Li⁺-containing liquid was, thereafter, concentrated and sodium carbonate was added in order to precipitate Li₂CO₃. As a result, a high purity Li₂CO₃ (99.51%) of battery grade was obtained. LiFePO₄ prepared with the recovered Li₂CO₃ and FePO₄ as raw materials also displayed a comparative high capacity and stable cycle performance to the commercial product and further verified the electrochemical activity of the recovered materials.

Recycling of All-Solid-State Li-ion Batteries: A Case Study of the Separation of Individual Components Within a System Composed of LTO, LLZTO and NMC

With the current global projection of over 130 million electric vehicles (EVs), there soon will be a need for battery waste management. Especially for all-solid-state lithium-ion batteries (lithium ASSBs), aspects of waste management and circular economy have not been addressed so far. Within such ASSBs, the use of solid-electrolytes like garnet-type Li_6.5 La₃ Zr_1.5 Ta_0.5 O₁₂ (LLZTO) may shift focus on strategies to recover not only the transition metal elements but also elements like La/Zr/Ta. In this work, we present a two-step recycling approach using citric acid as the leaching agent to separate and recover the individual components of a model cell comprising of Li₄ Ti₅ O₁₂ (LTO) anode, Li_6.5 La₃ Zr_1.5 Ta_0.5 O₁₂ (LLZTO) garnet electrolyte and LiNi_1/3 Mn_1/3 Co_1/3 O₂ (NMC) cathode. We observe that by adjusting the concentration of citric acid, it was possible to separate the materials from each other without strong mixing of individual phases and also to maintain their principle performance characteristics. Thus, the process developed has a potential for upscaling and can guide towards considering separation capability of battery components in the development of lithium ASSBs.

Comprehensive insights into the gallic acid assisted bioleaching process for spent LIBs: Relationships among bacterial functional genes, Co(III) reduction and metal dissolution behavior

Despite the growing demand for resource recovery from spent lithium-ion batteries (LIBs) by bioleaching, low Co leaching efficiency has hindered the development and application of this technology. Therefore, a novel process was designed, combining gallic acid (GA) and mixed culture bioleaching (MCB), to enhance the removal of metals from spent LIBs. Results indicated that the GA + MCB process achieved 98.03% Co and 98.02% Li leaching from spent LIBs, simultaneously reducing the biotoxicity, phytotoxicity and leaching toxicity of spent LIBs under optimal conditions. The results of mechanism analysis demonstrated that functional microorganisms adapted to the leaching system through various strategies, including oxidative stress reduction, DNA damage repair, heavy metal resistance and biofilm formation, maintaining normal physiological activities and the continuous production of biological acid. The biological acid erodes the surface of waste LIBs, causing some Co and a large amount of Li to be released, while also increasing the contact area between GA and Co(III). Therefore, GA is beneficial for reducing insoluble Co(III), forming soluble Co(II). Finally, biological acid can effectively promote Co(II) leaching. Collectively, the results of this study provide valuable insight into the simultaneous enhancement of metal extraction and the mitigation of environmental pollution from spent LIBs.

MnCO3 Cuboids from Spent LIBs: A New Age Displacement Anode to Build High-Performance Li-Ion Capacitors

The advantage of hybridizing battery and supercapacitor electrodes has succeeded recently in designing hybrid charge storage systems such as lithium-ion capacitors (LICs) with the benefits of higher energy than supercapacitors and more power density than batteries. However, sluggish Li-ion diffusion of battery anode is one of the main barriers and hampers the development of high-performance LICs. Herein, is introduced a new conversion/displacement type anode, MnCO₃ , via effectively recycling spent Li-ion batteries cathodes for LICs applications. The MnCO₃  cuboids are regenerated from the spent LiMn₂ O₄  cathodes by organic acid lixiviation process, and hydrothermal treatment displays excellent reversibility of 535  mAh g^-1  after 50  cycles with a Coulombic efficiency of >99%. Later, LIC is assembled with the regenerated MnCO₃  cubes in pre-lithiated form (Mn⁰  + Li₂ CO₃ ) as anode and commercial activated carbon (AC) as the cathode, delivering a maximum energy density of 169.4 Wh kg^-1  at 25 °C with ultra-long durability of 15,000 cycles. Even at various atmospheres like -5 and 50 °C, this LIC can offer a energy densities of 53.8 and 119.5 Wh kg^-1 , respectively. Remarkably, the constructed AC/Mn⁰  + Li₂ CO₃ -based LIC exhibits a good cycling performance for a continuous 1000 cycles with >91% retention invariably for all temperature conditions.

Challenges in Recycling Spent Lithium-Ion Batteries: Spotlight on Polyvinylidene Fluoride Removal

In the recycling of retired lithium-ion batteries (LIBs), the cathode materials containing valuable metals should be first separated from the current collector aluminum foil to decrease the difficulty and complexity in the subsequent metal extraction. However, strong the binding force of organic binder polyvinylidene fluoride (PVDF) prevents effective separation of cathode materials and Al foil, thus affecting metal recycling. This paper reviews the composition, property, function, and binding mechanism of PVDF, and elaborates on the separation technologies of cathode material and Al foil (e.g., physical separation, solid-phase thermochemistry, solution chemistry, and solvent chemistry) as well as the corresponding reaction behavior and transformation mechanisms of PVDF. Due to the characteristic variation of the reaction systems, the dissolution, swelling, melting, and degradation processes and mechanisms of PVDF exhibit considerable differences, posing new challenges to efficient recycling of spent LIBs worldwide. It is critical to separate cathode materials and Al foil and recycle PVDF to reduce environmental risks from the recovery of retired LIBs resources. Developing fluorine-free alternative materials and solid-state electrolytes is a potential way to mitigate PVDF pollution in the recycling of spent LIBs in the EV era.

Acid-free extraction of valuable metal elements from spent lithium-ion batteries using waste copperas

A large amount of hazardous spent lithium-ion batteries (LIBs) is produced every year. Recovery of valuable metals from spent LIBs is significant to achieve environmental protection and alleviate resource shortages. In this study, a green and facile process for recovery of valuable metals from spent LIBs by waste copperas was proposed. The effects of heat treatment parameters on recovery efficiency of valuable metals and the redox mechanism were studied systematically through phase transformation behavior and valence transition. At low temperature (≤460 °C), copperas reacted with lithium on the outer layer of LIBs preferentially, but the reduction of transition metals was limited. As the temperature rose to 460-700 °C, the extraction efficiency of valuable metals was greatly enhanced due to the generation of SO₂, and the gas-solid reaction proceeded much fast than the solid-solid reaction. In the final stage (≥700 °C), the main reactions were the thermal decomposition of soluble sulfates and the combination of decomposed oxides with Fe₂O₃ to form insoluble spinel. Under the optimum roasting conditions, i.e., at a copperas/LIBs mass ratio of 4.5, and a roasting temperature of 650 °C and roasting time of 120 min, the leaching efficiencies of Li, Ni, Co and Mn were 99.94%, 99.2%, 99.5% and 99.65%, respectively. The results showed that valuable metals can be selectively and efficiently extracted from the complex cathode materials by water leaching. This study used waste copperas as an aid to recover metals and provided an alternative technical route for green recycling of spent LIBs.

Amino Acid Leaching of Critical Metals from Spent Lithium-Ion Batteries Followed by Selective Recovery of Cobalt Using Aqueous Biphasic System

To reduce the exploitation of mine resources and decrease the harm to the environment caused by urban electronic wastes, the recovery of critical metals in secondary resources is crucial. In this study, we have successfully developed an eco-friendly process to integrate the leaching and separation of cobalt (Co) from a spent lithium-ion battery (LIB) cathode using an amino acid-based aqueous biphasic system (ABS). We, for the first time, demonstrated a simple method for leaching a LIB cathode using only amino acids. In addition, we have investigated the leaching mechanism using the typical cathode active material lithium cobalt oxide (LiCoO₂). Then, the Co was selectively extracted by a biphasic system (amino acid-PPG400-H₂O). This novel process has an excellent prospect in the field of spent-battery recycling because of its eco-friendly and process-simplified advantages.

E-waste recycled materials as efficient catalysts for renewable energy technologies and better environmental sustainability

Waste from electrical and electronic equipment exponentially increased due to the innovation and the ever-increasing demand for electronic products in our life. The quantities of electronic waste (e-waste) produced are expected to reach 44.4 million metric tons over the next five years. Consequently, the global market for electronics recycling is expected to reach $65.8 billion by 2026. However, electronic waste management in developing countries is not appropriately handled, as only 17.4% has been collected and recycled. The inadequate electronic waste treatment causes significant environmental and health issues and a systematic depletion of natural resources in secondary material recycling and extracting valuable materials. Electronic waste contains numerous valuable materials that can be recovered and reused to create renewable energy technologies to overcome the shortage of raw materials and the adverse effects of using non-renewable energy resources. Several approaches were devoted to mitigate the impact of climate change. The cooperate social responsibilities supported integrating informal collection and recycling agencies into a well-structured management program. Moreover, the emission reductions resulting from recycling and proper management systems significantly impact climate change solutions. This emission reduction will create a channel in carbon market mechanisms by trading the CO2 emission reductions. This review provides an up-to-date overview and discussion of the different categories of electronic waste, the recycling methods, and the use of high recycled value-added (HAV) materials from various e-waste components in green renewable energy technologies.

Synthesis of fatty acid-based ammonium ionic liquids and their application for extraction of Co(II) and Ni(II) metals ions from aqueous solution

Leaching of cobalt and nickel into diverse water streams has become an environmental hazard and is continuously impacting human health through the food chain. Solvent extraction is the most widely accepted for separating these metals, but traditional extractants employed in conjunction with molecular diluents often lack selectivity and caused major environmental hurdles. Therefore, the development of cost-effective, environmentally friendly technologies for recovering these heavy metals has been strongly encouraged in recent years. Herein, two halogens free, low viscous, biocompatible fatty acid-based hydrophobic ionic liquids (ILs), i.e., methytrioctylammonium oleate, methytrioctylammonium linoleate were synthesized, analytically characterized and employed for recovery of cobalt, Co(II) and nickel, Ni(II) from their aqueous solutions. Extraction behaviour of Co(II) and Ni(II) was further evaluated by varying equilibrium time, ILs molar concentration, metal loading, and temperature. Thermodynamic parameters such as enthalpy change and Gibbs free energy change were also studied during extraction process. Slope analysis suggested that the extraction mechanism was an exothermic process that followed ion-transfer from the aqueous phase to the organic phase. Results showed that both fatty acid based-ILs were found to be capable of extracting >99% of Co(II) and Ni(II) from aqueous solutions at 298 K, in 15 min of shaking time using a 1:1 (org: aq.) ratio at low concentrations of 2.5-10 g L^-1. Furthermore, for methyltrioctylammonium oleate IL, Co(II) extraction was selectively preferred over Ni(II) extraction when the metal concentration was increased to above to 10 g L^-1. The stripping results showed that 2 M H₂SO₄, and 2 M HCl successfully stripped out >99% of Co(II) and Ni(II) from the organic phase, respectively compared to HNO₃.

A green and sustainable strategy toward lithium resources recycling from spent batteries

Recycling lithium from spent batteries is challenging because of problems with poor purity and contamination. Here, we propose a green and sustainable lithium recovery strategy for spent batteries containing LiFePO₄, LiCoO₂, and LiNi_0.5Co_0.2Mn_0.3O₂ electrodes. Our proposed configuration of "lithium-rich electrode || LLZTO@LiTFSI+P3HT || LiOH" system achieves double-side and roll-to-roll recycling of lithium-containing electrode without destroying its integrity. The LiTFSI+P3HT-modified LLZTO membrane also solves the H⁺/Li⁺ exchange problem and realizes a waterproof protection of bare LLZTO in the aqueous working environment. On the basis of these advantages, our system shows high Li selectivity (97%) and excellent Faradaic efficiency (≥97%), achieving high-purity (99%) LiOH along with the production of H₂. The Li extraction processes for spent LiFePO₄, LiNi_0.5Co_0.2Mn_0.3O₂, and LiCoO₂ batteries is shown to be economically feasible. Therefore, this study provides a previously unexplored technology with low energy consumption as well as high economic and environmental benefits to realize sustainable lithium recycling from spent batteries.

A Minireview on the Regeneration of NCM Cathode Material Directly from Spent Lithium-Ion Batteries with Different Cathode Chemistries

Research on the regeneration of cathode materials of spent lithium-ion batteries for resource reclamation and environmental protection is attracting more and more attention today. However, the majority of studies on recycling lithium-ion batteries (LIBs) placed the emphasis only on recovering target metals, such as Co, Ni, and Li, from the cathode materials, or how to recycle spent LIBs by conventional means. Effective reclamation strategies (e.g., pyrometallurgical technologies, hydrometallurgy techniques, and biological strategies) have been used in research on recycling used LIBs. Nevertheless, none of the existing reviews of regenerating cathode materials from waste LIBs elucidated the strategies to regenerate lithium nickel manganese cobalt oxide (NCM or LiNixCoyMnzO2) cathode materials directly from spent LIBs containing other than NCM cathodes but, at the same time, frequently used commercial cathode materials such as LiCoO2 (LCO), LiFePO4 (LFP), LiMn2O4 (LMO), etc. or from spent mixed cathode materials. This review showcases the strategies and techniques for regenerating LiNixCoyMnzO2 cathode active materials directly from some commonly used and different types of mixed-cathode materials. The article summarizes the various technologies and processes of regenerating LiNixCoyMnzO2 cathode active materials directly from some individual cathode materials and the mixed-cathode scraps of spent LIBs without their preliminary separation. In the meantime, the economic benefits and diverse synthetic routes of regenerating LiNixCoyMnzO2 cathode materials reported in the literature are analyzed systematically. This minireview can lay guidance and a theoretical basis for restoring LiNixCoyMnzO2 cathode materials.

Bioelectrochemical systems in aid of sustainable biorefineries for the production of value-added products and resource recovery from wastewater: A critical review and future perspectives

Bioelectrochemical systems (BES) have the potential to be used in a variety of applications such as waste biorefinery, pollutants removal, CO₂ capture, and the electrosynthesis of clean and renewable biofuels or byproducts, among others. In contrast, many technical challenges need to be addressed before BES can be scaled up and put into real-world applications. Utilizing BES, this review article presents a state-of-the-art overall view of crucial concepts and the most recent innovative results and achievements acquired from the BES system. Special attention is placed on a hybrid approach for product recovery and wastewater treatment. There is also a comprehensive overview of waste biorefinery designs that are included. In conclusion, the significant obstacles and technical concerns found throughout the BES studies are discussed, and suggestions and future requirements for the virtual usage of the BES concept in actual waste treatment are outlined.

The Efficiency of Black Mass Preparation by Discharge and Alkaline Leaching for LIB Recycling

Lithium-ion batteries (LIBs) are dangerous to recycle, as they pose a fire hazard when cut and contain various chemical hazards. If recycled safely, LIBs provide a rich secondary source for metals such as lithium and cobalt, while reducing the environmental impact of end-of-life LIBs. Discharging the spent LIBs in a 5 wt.% NaCl electrolyte at room temperature enables their safe dismantling. A sludge was observed to form during the LIB discharging, with a composition of 34.9 wt.% Fe, 35 wt.% O, 17.7 wt.% Al, 6.2 wt.% C, and 4.2 wt.% Na. The average electrolytic solution composition after the first discharge cycle contained only 12.6 mg/L Fe, 4.5 mg/L Li, 2.5 mg/L Mn, and trace amounts of Ni and Co. Separating the active cathode powder from the aluminum cathode with a 10 wt.% NaOH leach produced an aqueous filtrate with an Al metal purity of 99.7%. The leach composition consisted of 9558 mg/L Al, 13 mg/L Li, 8.7 mg/L Co, and trace amounts of Mn and Ni. The hydrometallurgical sample preparation processes in this study enables the production of a pure black mass with less than 0.05 wt.% Co, 0.2 wt.% Li, 0.02 wt.% Mn, and 0.02 wt.% Ni losses from the active cathode material.