Organics removal combined with in situ thermal-reduction for enhancing the liberation and metallurgy efficiency of LiCoO2 derived from spent lithium-ion batteries

Pre-separation combined with reduction roasting for high-quality recovery of graphite and lithium from spent lithium ion batteries

The recycling of spent lithium ion batteries is of great significance because it contains large amounts of valuable metals. But current recovery methods exhibit limited efficiency in selectively extracting lithium from spent electrode materials and spent graphite becomes metallurgical residues. In this study, we propose a novel recycling flowchart that combines flotation with multi-stage water-leaching to enhance the recovery of graphite and lithium from black mass derived from spent lithium ion batteries. Removal of organics can be conducted by pyrolysis, at the same time, the spent ternary cathode material was decomposed into CoO, NiO, and MnO at a temperature of 600 °C for 60 min using pyrolysis product-derived reductant. The sub-microlevel migration behavior of lithium ions in electrode materials was also examined. The electrode material aggregates were broken up by water crushing, and 38.67 % lithium dissolves into water for recycling. Bubble flotation was used to recycle the excess graphite from the black mass while the residual graphite was used as reductant for the carbothermal reduction. Using the developed scheme, we were able to recover 95.51 % of lithium after carbothermal reduction with 12.31 % carbon residue. Based on basic research, a novel recycling flowchart of spent lithium-ion batteries has been proposed.

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.

Mixed crushing and competitive leaching of all electrode material components and metal collector fluid in the spent lithium battery

Hydrometallurgy is a primary method for recovering cathode electrode materials from spent lithium-ion batteries (LIBs). Most of the current research materials are pure cathode electrode materials obtained through manual disassembly. However, the spent LIBs are typically broken as a whole during the actual industrial recycling which makes the electrode materials combined with the collector fluid. Therefore, the competitive leaching between metal collector fluid and electrode material was examined. The pyrolysis characteristics of the electrode materials were analyzed to determine the pyrolysis temperature. The electrode sheet was pyrolyzed and then crushed for competitive leaching. The effect of pyrolysis was analyzed by XPS. The competitive leaching behavior was studied based on leaching agent concentration, leaching time and leaching temperature. The composition and morphology of the residue were determined to prove the competitive leaching results by XRD-SEM. TG results showed that 500 °C was the suitable pyrolysis temperature. XPS analysis demonstrated that pyrolysis can completely remove PVDF. Li and Co were preferentially leached during the competitive leaching while the leaching rates were 90.10% and 93.40% with 50 min leaching at 70 °C. The Al and Cu had weak competitive leachability and the leaching rate was 29.10% and 0.00%. XRD-SEM analysis showed that Li and Co can be fully leached with residual Al and Cu remaining. The results showed that the mixed leaching of electrode materials is feasible based on its excellent selective leaching properties.

Selective Recovery of Cathode Materials from Spent Lithium-Ion Battery Material with a Near-Room-Temperature Separation

Effective separation of cathode materials from the current collector is a critical step in recycling a spent lithium-ion battery (LIB). This typically necessitates the decomposition or dissolution of the organic binder, poly(vinylidene fluoride) (PVDF), to achieve efficient recovery of cathode materials. However, this process requires a high decomposition temperature, typically between 400 and 600 °C, and can lead to side reactions, such as current collector oxidation/brittleness, decomposition of cathode materials, and formation of metal fluorides. In this study, we propose that non-thermal plasma (NTP) treatment can be used to achieve an extremely high separation of cathode materials and aluminum current collector at near room temperature. Instead of relying on PVDF decomposition, which requires high temperatures, PVDF can be deactivated by partially breaking down long molecular chains with appropriate NTP conditions. With a total treatment time of around 2000 s and an environmental temperature of approximately 80 °C, minor side reactions can be avoided. The separation rate can reach up to 95.69%, and high-quality cathode materials can be obtained with only 0.02 wt % aluminum impurity content. This research could potentially offer a new approach toward minimizing recycling steps and reducing energy consumption in the recycling of spent LIBs. It could also be extended to the recovery of a broader range of electronic wastes.

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.

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.

Effects of incineration and pyrolysis on removal of organics and liberation of cathode active materials derived from spent ternary lithium-ion batteries

Removing organics via thermal treatment to liberate active materials from spent cathode sheets is essential for recovering lithium-ion batteries. In this study, the effects of incineration, N2 pyrolysis, and CO2 pyrolysis on the removal of organics and liberation of ternary cathode active materials (CAMs) were compared. The results indicated that the organics in the spent ternary cathode sheets comprised a residual electrolyte and polyvinylidene fluoride (PVDF) binder. Moreover, the organics could be removed to promote the liberation of CAMs via incineration, N2 pyrolysis, and CO2 pyrolysis. When the temperature was <200 °C, the chemical properties of the volatilized ester electrolyte remained unchanged during both N2 and CO2 pyrolysis, indicating that the electrolyte can be collected by controlling the pyrolysis temperature and condensation. Furthermore, PVDF binder decomposition occurred at 200-600 °C. The optimal temperatures of incineration, N2 pyrolysis, and CO2 pyrolysis were 550, 500, and 450 °C, respectively, and these treatments increased the liberation efficiency of CAMs from 81.49 % to 98.75 %, 99.26 %, and 97.98 %, respectively. In addition, heat-treated CAMs required less time to achieve adequate liberation. Following three thermal treatment processes, the sizes of the CAM particles were mainly concentrated in the ranges of 0.075-0.1 mm and <0.075 mm. Furthermore, for all types of CAMs examined, the Al concentration decreased from 1.09 % to <0.35 %, which increased the separation efficiency and improved the chemical metallurgical performance.

Lithium-ion battery recycling: a source of per- and polyfluoroalkyl substances (PFAS) to the environment?

Recycling of lithium-ion batteries (LIBs) is a rapidly growing industry, which is vital to address the increasing demand for metals, and to achieve a sustainable circular economy. Relatively little information is known about the environmental risks posed by LIB recycling, in particular with regards to the emission of persistent (in)organic fluorinated chemicals. Here we present an overview on the use of fluorinated substances - in particular per- and polyfluoroalkyl substances (PFAS) - in state-of-the-art LIBs, along with recycling conditions which may lead to their formation and/or release to the environment. Both organic and inorganic fluorinated substances are widely reported in LIB components, including the electrodes and binder, electrolyte (and additives), and separator. Among the most common substances are LiPF6 (an electrolyte salt), and the polymeric PFAS polyvinylidene fluoride (used as an electrode binder and a separator). Currently the most common LIB recycling process involves pyrometallurgy, which operates at high temperatures (up to 1600 °C), sufficient for PFAS mineralization. However, hydrometallurgy, an increasingly popular alternative recycling approach, operates under milder temperatures (<600 °C), which could favor incomplete degradation and/or formation and release of persistent fluorinated substances. This is supported by the wide range of fluorinated substances detected in bench-scale LIB recycling experiments. Overall, this review highlights the need to further investigate emissions of fluorinated substances during LIB recycling and suggests that substitution of PFAS-based materials (i.e. during manufacturing), or alternatively post-treatments and/or changes in process conditions may be required to avoid formation and emission of persistent fluorinated substances.

Extraction of precious metals from used lithium-ion batteries by a natural deep eutectic solvent with synergistic effects

As the demand for lithium-ion batteries rises, the growing quantity of waste produced from lithium-ion battery electrode materials becomes an issue of concern. We propose a novel approach for effectively extracting precious metals from cathode materials that address the problem of secondary pollution and high energy consumption that arise from the conventional wet recovery process. The method employs a natural deep eutectic solvent (NDES) composed of betaine hydrochloride (BeCl) and citric acid (CA). The leaching rates of manganese (Mn), nickel (Ni), lithium (Li), and cobalt (Co) in cathode materials may reach 99.2 %, 99.1 %, 99.8 %, and 98.8 %, respectively, due to the synergy of strong coordination ability (Cl^-) and reduction (CA) in NDES. This work avoids the use of hazardous chemicals while achieving total leaching in a short period (30 min) at a low temperature (80 °C), achieving an efficient and energy-saving aim. It reveals that NDES has a high potential for recovering precious metals from cathode materials and offers a viable, environmentally friendly method of recycling used lithium-ion batteries (LIBs).

One-step recovery of cobalt from ammonia-ammonium carbonate system via pressurized ammonia distillation

Ammonia leaching of Co-bearing resources has attracted attention due to its selectivity to cobalt and mild leaching conditions. However, in ammonia leach liquor, cobalt and ammonia are complexed stably, which undoubtedly increases the difficulty of preparing cobalt products from the solution. In this study, ammonia distillation process was proposed and studied to recover cobalt from NH₃-(NH₄)₂CO₃ system. First, the E-pH diagram of Co-NH₃-CO₃^2--H₂O system was drawn, and the possibility of preparing cobalt products from the solution was discussed. Then, by comparing atmospheric and pressurized ammonia distillation processes, it was found that the microspherical Co₃O₄ product can be obtained directly through pressurized ammonia distillation. Furtherly, the effects of parameters on this process and the formation mechanism of Co₃O₄ were investigated systematically. Over 99% of cobalt could be recovered in one step under optimal conditions. Finally, CoCO₃ products with different morphologies were also obtained directly by adding the reducing agent during pressurized ammonia distillation, and the cobalt recovery rate was hardly affected. The evaporated ammonia and residual solution can be recycled. This work realizes the one-step preparation of cobalt products and provides a new perspective on cobalt recovery from ammoniacal solution.

Recover value metals from spent lithium-ion batteries via a combination of in-situ reduction pretreatment and facile acid leaching

The pretreatment of cathode material before leaching is crucial in the spent lithium-ion battery hydro-metallurgical recycling. Here research demonstrates that in-situ reduction pretreatment could dramatically improve the leaching efficiencies for valuable metals from cathodes. Specifically, calcination under 600 °C without oxygen using alkali treated cathode can induce in-situ reduction and collapse of oxygen framework, which is ascribed to the carbon inherently contained in the sample and promote the following efficient leaching without external reductants. The leaching efficiencies of Li, Mn, Co and Ni can remarkably reach 100%, 98.13%, 97.27% and 97.37% respectively. Characterization methods, such as XRD, XPS and SEM-EDS, were employed and revealed that during in-situ reduction, high valence metals such as Ni³⁺, Co³⁺, Mn⁴⁺ can be effectively reduced to lower valence states, conducive to subsequent leaching reactions. Moreover, leaching processes of Ni, Co and Mn fit well with the film diffusion control model, and the reaction barrier is in accordance with the order of Ni, Co and Mn. In comparison, it is observed that Li was leached with higher efficiency regardless of the various pretreatments. Lastly, an integral recovery process has been proposed and economic assessment demonstrates that in-situ reduction pretreatment increases the benefit with a negligible cost increase.

Recycling of valuable metals from spent lithium-ion batteries by self-supplied reductant roasting

The massive spent lithium-ion batteries (LIBs) need to be recycled due to their increasing decommission in recent years. This paper aims to propose an effective process that uses self-supplied reductant roasting and acid leaching to recover Lithium, Nickle, Cobalt and Manganese from spent LIBs. In the absence of external carbon resources, the waste membrane from spent LIBs was used as the reductant in the self-supplied reductant roasting. A thermodynamic analysis was conducted to judge the possible reduction reaction between the cathode material and waste membrane. Then, the effects of roasting temperature, roasting time and membrane dosage on the crystal structure and phase transformation of roasting products were investigated and optimized. After the roasting process, the valence state of metals in the cathode material decreased and the structure became loose and porous. Moreover, the layer structure of the cathode material was transformed into groups of Li₂CO₃, Ni, Co, NiO, CoO and MnO. Further, the reduction effect of cathode powders under each roasting condition was verified under the same leaching conditions. After leaching for 30 min, the leaching efficiencies of Li, Ni, Co and Mn were over 99% under the optimum roasting conditions. Finally, economic assessments proved that the proposed process is profitable. The whole process demonstrates an effective and positive way for recycling spent LIBs and making full use of their waste membrane, which promotes resource recovery and environmental protection.

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.

Synergistic strengthening mechanisms of mechanical activation-microwave reduction for selective lithium extraction from spent lithium batteries

Carbothermal reduction of cathode materials is an effective method to selectively extract lithium carbonate, both mechanical activation and microwave heating can enhance thermal reduction of mixed electrode materials. However, the mechanism of enhanced lithium extraction has not been fully revealed. This study attempts to uncover the synergistic strengthening mechanisms of mechanical activation-microwave reduction from the aspects of material structure, dielectric properties, reduction kinetics and lithium recovery rate. Mechanical activation induces amorphization and structural defects. The enhanced dielectric properties of materials and the induced hotspots/arc plasmas are also responsible for the enhancement of the reduction reaction. The average dissociation activation energy in the activated sample is 18.0 kJ·mol^-1, which is 20.3 kJ·mol^-1 lower than that of unactivated sample. The model-free method reveals that the carbothermic reduction process can be divided into three stages: (I) initial stage (α < 0.4(0.6)): the activation energy gradually decreases with the formation of strong microwave acceptor-reduction products; (II) transitional stage (0.4(0.6) < α < 0.7): the increase in mass transfer resistance leads to gradual increase in activation energy. Mechanical activation shortens the transitional reaction stage; (III) later reaction stage (α > 0.7), the decrease in activation energy may be attributed to the enhanced microwave absorption and CO reduction. The model-fitting method reveals that after mechanical activation, the reaction kinetic changes from reaction-order model to Ginstling-Brounshtein diffusion model. The optimized lithium extraction process parameters were: activation 300 rpm for 1.5 h, reduction temperature 550 °C. The research results can provide theoretical support for the enhanced extraction of cathode materials.

Repurposing of spent lithium-ion battery separator as a green reductant for efficiently refining the cathode metals

Developing green and high-efficient pyrometallurgy processes to recycle precious metals from spent lithium-ion batteries (LIBs) is of great importance for resource sustainability and environmental protection. Herein, a novel reduction roasting approach relying on spent LIB separator to refine the spent cathode is proposed. The efficiency of repurposing separator as a reductant for roasting the spent LiCoO₂ cathode and the underlying mechanisms were investigated. After the separator-mediated roasting at 500 °C for 2 h, Li⁺ leaching efficiency of the cathode reached 93.2 %, >2.6 times higher than those after roasting without reductant (25.2 %) or with benchmark reductant graphite (26.1 %). Under the separator-added roasting condition, the cathode was converted to the desired products, CoO and Li₂CO₃. Based on the analysis of in-situ reaction using thermogravimetric/differential scanning calorimetry and pyrolysis gas species identification, the separator-mediated reduction roasting of cathode was composed of two stages, i.e., reducing gas generation due to separator pyrolysis, followed by the reducing gas mediated LiCoO₂ reduction. During the process, the generated C₂H₄ and CO dominated the reduction. The use of co-existing separator to recover precious metals from spent LIBs is an effective and sustainable strategy to maximize the utilization of spent LIBs.

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).

Synergistic effect of ultrasonication and sulfate radical on recovering cobalt and lithium from the spent lithium-ion battery

Ultrasonication has been mechanically applied widely in the recycling of spent lithium-ion (SLI) batteries while its influence on chemical pathways has barely been reported. In this study, ultrasonication and sulfate radicals were used in a coupling system to obtain efficient recoveries of Co and Li from SLI batteries. The synergistic effect of ultrasonication and sulfate radicals on recycling was quantitatively analysed by significance analysis and surface responses in a central composite design. The employment of persulfate significantly affected the whole recycling process during the sonication. Factors including acoustic time, operating powers, and temperature all had a significant effect on the recoveries of Co and Li. The maximum recovery efficiencies of Co and Li of 97.33% and 99.25%, respectively, and the minimum loss rate of Al of 4.13% were simultaneously obtained by the fitting predictor. The optimal combination of factors for the sonication system included an acoustic time (min) of 5.5, an operating power (W) of 168, a temperature (°C) of 86, and a ratio of cathode foil to S-solution (mg/mL) of 1:60. A moiety of cathode active material was directly separated from the aluminium collector by sulfate radical-related reactions. Co and Li cations dissolved from LiCoO₂ by carbon dioxide radicals were reprecipitated by excess oxalate. The research demonstrated the positively synergistic influence caused by ultrasonication and sulfate radicals on achieving efficient recoveries of Co and Li from SLI batteries, explicitly expanding the technical choices for the recycling procedure.

Recycling of LiFePO4 cathode materials from spent lithium-ion batteries through ultrasound-assisted Fenton reaction and lithium compensation

Efficient exfoliation of cathode materials from current collectors for their direct regeneration is the typical bottleneck during spent lithium ion batteries (LIBs) recycling due to the strong adhesion of PVDF (polyvinylidene fluoride) binders. Ultrasound-assisted Fenton reaction was innovatively applied for the selective removal of PVDF binders to recover cathode materials of LiFePO₄ from current collectors and the recovered LiFePO₄ was regenerated through lithium compensation, targeting for the in-situ recycling of cathode materials from spent LIBs. Experimental results suggest that the PVDF binders were adequately degraded by hydroxyl radical (·OH) generated from Fenton's reagent with reinforcement of ultrasound, and about 97% cathode materials can be scrubbed from Al foils under optimized conditions. Detailed analytical results support that the cathode materials peeled off from current collectors are free from contamination of effluent, and the recovered LiFePO₄ can be directly re-fabricated as new cathode materials through lithium compensation with little reduction of electrochemical performances. And the tentative mechanism investigation for pathway of ·OH generation and chemical reactions indicates that ·OH generated from Fenton's reagent with the reinforcement of ultrasound can effectively degrade PVDF binders. This work can be a green and efficient candidate for the in-situ recycling of cathode materials of LiFePO₄ from spent LIBs.

A novel method for carbon removal and valuable metal recovery by incorporating steam into the reduction-roasting process of spent lithium-ion batteries

Oxygen-free roasting could efficiently achieve the recovery of valuable metals from spent lithium-ion batteries (LIBs), but the roasted products have the drawbacks of a high carbon (C) content and a complex separation process. Hence, in this study, a new method incorporating steam (H₂O) into the reduction-roasting recovery process of spent LIBs (steam roasting) was proposed to realize carbon removal and valuable metal recovery simultaneously. The influence of steam on the reduction-roasting process of spent LiNi_0.6Co_0.2Mn_0.2O₂ batteries (NCM) was investigated through experimental methods and thermodynamic analysis. The results indicated that the addition of steam could dramatically facilitate the decomposition and reduction process of spent NCM, and the carbon removal efficiency could reach 84%. H₂O only acted on the reaction process of the anode material, and the main component C could be efficiently gasified by steam to produce hydrogen (H₂) and carbon monoxide (CO), which could significantly accelerate the reduction process of CoO and NiO. The optimal conditions for valuable metal recovery and carbon removal were a H₂O/C mole ratio of 5:1 and a reduction-roasting temperature of 1123 K. After steam roasting, the magnetic recovery efficiencies of Co and Ni were as high as 90% and 93%, respectively. The final recovery products were Co, Ni, and Li₂CO₃ with high purities. Therefore, this study is expected to provide a novel approach to achieve efficient disposal and recovery of metals from spent LIBs.

Highly efficient re-cycle/generation of LiCoO2 cathode assisted by 2-naphthalenesulfonic acid

The explosively growing demand for electrical energy is generating a great deal of spent lithium-ion batteries (LIBs). Therefore, a simple and effective strategy for the sustainable recycling of used batteries is urgently needed to minimize chemical consumption and to reduce the associated environmental pollution. In this work, 2-naphthalenesulfonic acid is innovatively proposed for the highly-selective recovery of valuable metals. Impressively, lithium and cobalt are simultaneously separated through a single-step process, in which 99.3% of lithium is leached out as Li⁺ enriched solutions while 99% of cobalt is precipitated as cobalt-naphthalenesulfonate. The obtained lithium enriched solutions are recovered as Li₂CO₃. The cobalt-naphthalenesulfonate with high purity (99%) is ready to be transformed into Co₃O₄, and then generated into LiCoO₂ by reacting with the above-obtained Li₂CO₃. The cathode material LiCoO₂ with micro/nanostructures exhibits excellent electrochemical properties. Characterization results confirm the coordination structure of the extracted cobalt complex (Co(NS)2•6H₂O). Finally, compared to other selective metal extraction techniques, this strategy avoids additional separation and purification processes, thus improving the recycling efficiency. Overall, this route can be extended to selectively extract valuable metals from other types of cathode materials in spent LIBs as a sustainable approach.

Separation of cathode particles and aluminum current foil in lithium-ion battery by high-voltage pulsed discharge Part II: Prospective life cycle assessment based on experimental data

This series of papers addresses the recycling of cathode particles and aluminum (Al) foil from positive electrode sheet (PE sheet) dismantled from spent lithium-ion batteries (LIBs) by applying a high-voltage pulsed discharge. As concluded in Part I of the series (Tokoro et al., 2021), cathode particles and Al foil were separated in water based on a single pulsed power application. This separation of LIB components by pulsed discharge was examined by means of prospective life cycle assessment and is expected to have applications in LIB reuse and recycling. The indicators selected were life cycle greenhouse gas (LC-GHG) emissions and life cycle resource consumption potential (LC-RCP). We first completed supplementary experiments to collect redundant data under several scale-up circumstances, and then attempted to quantify the uncertainties from scaling up and progress made in battery technology. When the batch scale of pulsed discharge separation is sufficiently large, the recovery of cathode particles and Al foil from PE sheet by pulsed discharge can reduce both LC-GHG and LC-RCP, in contrast to conventional recycling with roasting processes. Due to technology developments in LIB cathodes, the reuse of positive electrode active materials (PEAM) does not always have lower environmental impacts than the recycling of the raw materials of PEAM in the manufacturing of new LIB cathodes. This study achieved a proof of concept for resource consumption reduction induced by cathode utilization, considering LC-GHG and LC-RCP, by applying high-voltage pulsed discharge separation.

Structure Recovery and Recycling of the Used LiCoO2 Cathode Material

The large number of lithium batteries have been retiring from the market of energy storage. Thus, the recycling of the used electrode materials is becoming urgent. In this study, the industrial machinery processing was used to recover the crystal structure of the waste LiCoO 2 materials with the combination of small-scale equipment repair technology. The results show that the crystal parameters of the repaired LiCoO 2 material become small, the unit cell volume is reduced, and the crystal structure tends to be stable. The Co-O bond length of 1.9134 nm, O-Co-O bond angle of 94.72º, the (003) interplanar spacing of 0.467 nm indicate the excellent recovery level of the repaired LiCoO 2 . In addition, the electrochemical performance of the repaired LiCoO 2 material is greatly improved, compared with the waste material. The capacity of the repaired electrode material can be maintained at 120 mAh g -1 after 100 cycles at the current density of 0.2 C. The promising rate performance of the repaired electrode material demonstrates the stable structure. This research work provides a large-scale method for the direct recovery of LiCoO 2 with the reduction of unnecessary energy and reagent consumption, which will be beneficial to the environmental protection.

Direct recovery of degraded LiCoO2 cathode material from spent lithium-ion batteries: Efficient impurity removal toward practical applications

Regenerating cathode material from spent lithium-ion batteries (LIBs) permits an effective approach to resolve resource shortage and environmental pollution in the increasing battery industry. Directly renovating the spent cathode materials is a promising way, but it is still challenging to efficiently remove all of the complex impurities (such as binder, carbon black, graphite and current collectors) without destroying the material structure in the electrode. Herein, a facile strategy to directly remove these impurities and simultaneously repair the degraded LiCoO₂ by a target healing method is reported. Specifically, by using an optimized molten salt system of LiOH-KOH (molar ratio of 3:7) where LiNO₃ and O₂ both serve as oxidants, the impurities can be completely removed, while the structure, composition and morphology of degraded LiCoO₂ can be successfully repaired to commercial level based on a two-stage heating process (300 °C for 8 h and 500 °C for 16 h, respectively), resulting in a high recovery rate of approximately 100% for cathode material. More importantly, the regenerated LiCoO₂ exhibits a high reversible capacity, good cycling stability and excellent rate capability, which are comparable with commercial LiCoO₂. This work demonstrates an efficient approach to recycle and reuse advanced energy materials.

Hydrometallurgical enhanced liberation and recovery of anode material from spent lithium-ion batteries

The efficient recycling of spent anode material (SAM) from spent lithium-ion batteries (LIBs) is generally critical in terms of electronic waste recyclingas well as increasing resource shortage and environmental problems. This research reported a novel and green method to recycle lithium, copper foil, and graphite from SAM by water leaching treatment. The results indicated that 100% of graphite was exfoliated from the anode material and 92.82% leaching efficiency of lithium was obtained under the optimal conditions of 80 °C, 60 g/L, 300 rpm, and 60 min, respectively. This finding revealed that the SAM got a full liberation characteristic due to the removal of binder, which produced an ideal leaching lithium efficiency rivaling the acids' performance. The mechanism of the liberation of SAM and lithium leaching is presented based on the analysis of results. The graphite was purified and recovered after water leaching treatment. Besides, lithium was recovered in the form of lithium carbonate (Li₂CO₃)_, and the copper foil was recovered in a sheet. This study endeavors to develop an economical and environmentally feasible plan to recycle graphite, copper, and lithium from SAM.

A critical review of current technologies for the liberation of electrode materials from foils in the recycling process of spent lithium-ion batteries

Proper disposal of spent lithium-ion batteries is beneficial for the resource recycling and pollution elimination. Full liberation of electrode materials, including the liberation between electrode material and current collector (copper/aluminum foils) and the liberation among electrode material particles, is the pivotal precondition for improving the recovery efficiency of electrode materials. In this article, authors attempt to carry out a summary of current technologies used in the liberation of electrode materials derived from spent lithium-ion batteries. However, specialized studies about the liberation of electrode materials are insufficient at present. This research clearly shows that: (1) Organic binder must be removed so as to improve the liberation and metallurgy efficiency of electrode materials; (2) A collaboration of varied technologies is the necessary process to achieve high liberation efficiency between electrode materials and copper/aluminum foils; (3) Pyrolysis may be a recommended technology for removal of organic binder because part of pyrolysis products can be recovered. Finally, an alternative recycling flowchart of spent LIBs is proposed.

Hydrometallurgical recycling of EV lithium-ion batteries: Effects of incineration on the leaching efficiency of metals using sulfuric acid

The growing demand for lithium-ion batteries will result in an increasing flow of spent batteries, which must be recycled to prevent environmental and health problems, while helping to mitigate the raw materials dependence and risks of shortage and promoting a circular economy. Combining pyrometallurgical and hydrometallurgical recycling approaches has been the focus of recent studies, since it can bring many advantages. In this work, the effects of incineration on the leaching efficiency of metals from EV LIBs were evaluated. The thermal process was applied as a pre-treatment for the electrode material, aiming for carbothermic reduction of the valuable metals by the graphite contained in the waste. Leaching efficiencies above 70% were obtained for Li, Mn, Ni and Co after 60 min of leaching even when using 0.5 M sulfuric acid, which can be linked to the formation of more easily leachable compounds during the incineration process. When the incineration temperature was increased (600-700 °C), the intensity of graphite signals decreased and other oxides were identified, possibly due to the increase in oxidative conditions. Higher leaching efficiencies of Mn, Ni, Co, and Li were reached at lower temperatures of incineration (400-500 °C) and at higher leaching times, which could be related to the partial carbothermic reduction of the metals.

Recent advances in pretreating technology for recycling valuable metals from spent lithium-ion batteries

In recent years, the amount of spent lithium-ion batteries (LIBs) increase sharply due to the promotion of new energy vehicles and the limited service life. Recycling of spent LIBs has attracted much attention because of the serious environmental pollution and high economic value. Although some established techniques have been presented in spent LIBs recycling process, but most of them focus on cathode material recycling due to its high economic value. Therefore, preparation of high purity cathode material by a proper pretreating technology is an important procedure. In this paper, the technologies used in the pretreating process of spent LIBs are summarized systematically from three main points of discharging procedure, liberation, and separation. The collaborative application of multi-technologies is the key to realize efficient pretreating process, which can lay the foundation for the subsequent metallurgical process. In addition, an alternative pretreating flowchart of spent LIBs is proposed based on the multi-process collaboration. Pretreating procedures in this process are mainly based on the physical property difference, and they include "Discharging-Shredding-Crushing-Sieving-Separation".