Cathode Scrap Research Articles

Influence of green solvents on the recovery of cathode active materials from electrode scraps: A comparative study

Direct recycling of cathode materials from spent Li-ion batteries (LIBs) or electrode scraps necessitates the efficient recovery of active materials from the aluminum foil. The variability in electrode types and recovery processes across previous studies complicates the comparative assessment of the recovery performance of green solvents. In this study, we evaluated the performance of three green solvents—triethyl phosphate (TEP), dihydrolevoglucosenone (Cyrene), and propylene carbonate (PC)—in recovering valuable active materials from industrial-grade cathode scraps. Using ultrasonication, we developed a standardized, energy-efficient recovery process that eliminated the need for conventional stirring and achieved complete cathode delamination from the aluminum foil. Furthermore, we successfully recovered the used green solvents after the process, ensuring their reuse and supporting a circular economy. The recovered materials retained their original morphology, chemical composition, and crystalline structure; however, the presence of surface impurities varied significantly depending on the green solvent used. These impurities had a considerable impact on the electrochemical performance of the recovered materials. TEP and PC yielded high-purity active materials and aluminum foils suitable for reuse or direct recycling, while Cyrene resulted in substantial residues of PVDF/solvent, requiring additional post-processing. Additionally, the recyclability of these green solvents was influenced by their solubility power for PVDF. This study provides valuable insights into the green solvent-based recycling process, laying the groundwork for future sustainable practices in LIB recycling.

An economical and closed-loop hydrometallurgical method to prepare battery-grade iron phosphate from delithiated LiFePO4 cathode scrap

The economical recovery of Fe and P poses a significant challenge in the comprehensive recovery of spent LiFePO4 batteries. A novel approach for the preparation of battery-grade FePO4·2H2O from iron phosphate residue by H3PO4 leaching and precipitation without alkali addition was proposed in this study. Under the optimized conditions of H3PO4 concentration of 6 mol L−1, liquid-solid ratio of 7.5 mL g−1, leaching temperature of 75 °C, and leaching time of 180 min, the leaching rates of 99.2% and 98.0% were achieved for Fe and P, respectively. During the leaching process, first dissolved Fe and P will recombine to form FePO4·2H2O, whereas the complete dissolution of FePO4·2H2O requires an increase in leaching temperature. Subsequently, 93.5% of Fe in the leaching solution can be precipitated as FePO4·2H2O at dilution ratio of 3.5, temperature of 90 °C, and crystallization time of 4 h. The mother liquor can be employed as a leaching agent after simple evaporation; thus, the closed-loop hydrometallurgical method avoids wastewater emissions. The LiFePO4/C cathode materials synthesized from FePO4·2H2O precursors exhibited an initial discharge capacity of 157.6 mAh g−1 at 0.1 C. After 100 cycles at 1 C, the reversible specific capacity remained 136.2 mAh g−1 with a capacity retention rate of 100%. This study presents an economical and environmental-friendly method for recycling iron phosphate residue, which is promising to address a crucial problem in the comprehensive recovery of spent LiFePO4 batteries.

Selective recovery of lithium from spent lithium-ion batteries via mild hydrothermal driven Lewis acid-base reaction in aqua solution

Selective metal recovery from spent lithium-ion batteries has attracted wide attention since a high recovery rate and minimized environmental impact can be expected. However, either high temperature or high chemical consumption in order to realize effective lithium recovery is required, as the cathode inherent with high physiochemical stability, especially when the cobalt content is high (e.g. LiCoO2). Herein, we discover that Lewis acids in cathode scraps induce phase transition from LiCoO2 to Co(CoO2)2 and Li+, thus realizing fully selective recovery of lithium in a mild environment. Since Lewis acids are produced from scraps, the chemical consumption is reduced. Meanwhile, relying on the mild phase transition caused by Lewis acids, the morphology of the waste are maintained in the Co(CoO2)2 products, resulting in a comparable electrochemical performance with commercial Co3O4 anode materials. Consequently, a closed-loop route for recycling cathode scrap is established at mild conditions with low cost and environmental impact.

Recycling of NCA cathode material from end-of-life LiBs via Glycerol-triacetate solvent -based separation

Currently, a challenging task for recycling both spent lithium-ion batteries and cathode scrap is the separation of cathode materials from the current collector. A promising and efficient recovery method is to use an organic solvent to dissolve the organic polyvinylidene difluoride (PVDF) binder to recover both cathode materials and aluminum foil. However, the use of toxic solvents hinders its practical application in recycling the large amounts of cathode scrap generated during the manufacturing process. The proposed solvent-based separation process uses glycerol triacetate, a bio-derived green solvent. This study investigates a closed-loop recovery process that recovers cathode materials, including Al foil and PVDF binder, from cathode scrap. Using the glycerol triacetate solvent, a closed-loop recycling process was developed. The glycerol triacetate separation process provides a sustainable platform for the recovery and reuse of electrodes, thereby contributing to battery recycling efforts.

Roll-to-roll solvent-free manufactured electrodes for fast-charging batteries

Roll-to-roll solvent-free manufactured electrodes for fast-charging batteries

Material and Waste Flow Analysis for Environmental and Economic Impact Assessment of Inorganic Acid Leaching Routes for Spent Lithium Batteries’ Cathode Scraps

With the development trend and technological progress of lithium batteries, the battery market is booming. This means that the demand for lithium batteries has increased significantly, resulting in a large number of discarded lithium batteries. The consumption of plenty of lithium batteries may lead to the scarcity and expending of relevant raw material metal resources, as well as serious heavy metal environmental pollution. Therefore, it is of great significance to recycle valuable metal resources from discarded lithium batteries. The proper recycling of these valuable metals can reduce the shortage of mineral resources and environmental hazards caused by a large number of scrapped vehicle batteries. Recently, different systematic approaches have been developed for spent lithium battery recovery. However, most of these approaches do not account for the hidden costs incurred from various processing steps. This work is determined by the concept of material flow cost accounting (MFCA). Hence, in this research, a MFCA-based approach is developed for the leaching process of spent lithium batteries recovery, taking into consideration the hidden costs embedded in process streams. In this study, hydrochloric acid had the worst leaching efficiency due to its high solid-to-liquid ratio and the lowest acid concentration, so it was excluded in the first stage selection. It takes TWD 16.03 and TWD 24.10 to leach 10 g of lithium battery powder with sulfuric acid and nitric acid, respectively. The final sulfuric acid was the acid solution with the highest leaching efficiency and relatively low cost among inorganic acids.

Effective stripping and reutilization of LiFePO4 cathode waste from retired lithium ion batteries

The recycling of retired lithium ion batteries (LIBs) plays a vital role in alleviating the energy crisis and preventing secondary pollution. However, the unstable properties of waste materials greatly restricts the reuse of recycled materials in the industrial energy domain. Herein, we applied water as stripping solvent to effectively dispose of lithium iron phosphate (LiFePO4) cathode scrap. The results showed that the stripping rate of cathode scrap could reach more than 92%, and the recycling did not give rise to any impact on the structure of the cathode material under optimized condition. The molar ratios of elements were signed as n (Li): n (Fe): n (P) = 5 : 4.6: 4.95 by inductively coupled plasma emission spectroscopy (ICP-OES) and energy disperse spectroscopy (EDS). The Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) showed that the PVDF was completely invisible after sintering. The LiFePO4 materials calcined at different temperature for 10 h under argon atmosphere showed excellent constant current charge-discharge performance and good cycle life, which reflected the stability of the olivine structure. The LiFePO4 cathode material directly calcined at 650 °C for 10 h exhibited the best charge-discharge specific capacity with a high Coulombic efficiency of 99.2%. Cyclic voltammetry (CV) tests showed that the re-sintered LiFePO4 material had a less redox polarized potential compared with the retired LiFePO4 material. The non-structure-damaging recycling mode also provides a green and effective direction for the recovery and recyclability of retired LiFePO4.

Gas exchange-driven carbothermal reduction for simultaneous lithium extraction from anode and cathode scraps

Recovering lithium resources from spent lithium-ion batteries offer a significant opportunity to address the issue of lithium scarcity. The preferential extraction of lithium from cathode materials by reduction roasting has been widely researched, but the simultaneous extraction of lithium from cathode and cathode scrap has not been reported. Thus, we investigated the feasibility and advantages of lithium extraction from spent LiNi1/3Co1/3Mn1/3O2 batteries by carbothermal reduction reaction with spent anode graphite. Under optimal conditions, the lithium recovery rate reached more than 90%, and the selectivity reached 100%. Then, with the help of TG-MS and other characterization techniques, the mechanism of lithium migration and transformation caused by gas exchange during the roasting process was elucidated. We hope that the results of this study will provide a new opportunity for the industrial recycling of spent lithium-ion batteries through this technology for the simultaneous extraction of lithium from anode and cathode scraps.

Eco-Friendly Organic Acid-Assisted Mechanochemical Process for Metal Extraction from Spent Lithium-Ion Batteries

This work represents a combination of mechanochemistry with eco-friendly low-cost natural organic acids to recover metal ions from spent lithium-ion battery (LIB) cathode materials. The effects of various reaction parameters on the metal extraction efficiency during the mechanochemical process were investigated. The results showed that under the optimal recovery conditions, that is, 2 mL of H2O2, mass ratio of LiCoO2 (LCO) to alginic acid of 1:10, rotation speed of 500 rpm, and grinding time of 4 h, the recovery efficiencies of Li and Co were 97.58 and 98.59%, respectively. The reaction mechanism of the mechanochemical process was discussed and verified. LCO combines with alginic acid and converts into water-soluble alginate under the action of a mechanical force and a reducing agent, and the metal ions are extracted and recovered in the subsequent water leaching process. In addition, the preliminary environmental and economic evaluation of the recycling process was assessed. The mechanochemical route proposed in this work can achieve green, efficient, and low-cost recovery of cathode scrap, which is a prospective guideline for the future industrial recycling of spent LIBs.

Recycling of waste power lithium-ion batteries to prepare nickel/cobalt/manganese-containing catalysts with inter-valence cobalt/manganese synergistic effect for peroxymonosulfate activation

Developing a high-efficiency peroxymonosulfate (PMS) activator is of great significance for the elimination and mineralization of organic contaminants. Herein, a catalyst (LiNi0.5Co0.2Mn0.3O2, NCM) was constructed using the cathode scrap of spent lithium-ion battery (LIB) for activation of PMS to remove Rhodamine B (RhB). The excellent catalytic capacity of NCM-650 was observed, as RhB was completely removed after 25 min. The NCM-650/PMS process could function effectively over a broad pH scope with favorable reusability and adaptability. The non-radical channels (singlet oxygen and mediated charge transfer) played a dominant role in the removal of RhB. Several reactive radical species (sulfate radicals, hydroxyl radicals and superoxide radicals) also facilitated the degradation of RhB, where the Co2+ and Mn4+ on the surface served as active sites to activate PMS. The synergistic effect of inter-valence cobalt and manganese in the catalyst was the predominant medium during the whole reaction process. According to the intermediates identified by High performance liquid chromatograph-mass spectrometry (HPLC-MS) and the analysis of density function theory (DFT) calculations, N-de-ethylation, chromophore cleavage, ring opening, and mineralization were regarded as the primary decomposition pathways. This research provided a novel perspective on the potential application of waste LIBs for the effective activation of PMS.

In Situ Electrochemical Regeneration of Degraded LiFePO4 Electrode with Functionalized Prelithiation Separator

AbstractLithium‐ion batteries (LIBs) are in great demand for their impressive successes in serving people's daily life. Concomitantly, recycling the retired LIBs has also aroused the enthusiasm of widespread studies due to its great significance in the sustainable development of LIBs. Among the spent LIBs, LiFePO4 (LFP) is the main force because of its widespread use in electric vehicles and grids due to its stability and favorable price. However, considering the low cost of LFP manufacture as well as the abundance of Fe and P, traditional metallurgy processes are not economically feasible for recycling LFP because of high energy consumption and tedious steps. Here, this work proposes a green recycling method to directly regenerate the degraded LFP electrode via an in situ electrochemical process with a functionalized prelithiation separator. Compared with the existing recycling strategies for LFP batteries, the proposed method takes full advantage of the degraded cathode scraps without destroying the original structure, greatly reducing the cost of the remanufacture of the cathode electrodes simply via a prelithiation technique.

Sustainable Recycling of Cathode Scrap towards High‐Performance Anode Materials for Li‐Ion Batteries

AbstractPollution from spent batteries is causing an environmental crisis, driving the development of innovative recycling and upcycling methods. Conventional recycling technologies are plagued by the technical barriers of high pollution, low efficiency, and poor product utilization. Herein, an innovative and sustainable method is reported of in situ selective and precise recycling of cathode scrap into high value‐added transition metal oxides, as well as in‐depth verification of their suitability as lithium‐ion batteries (LIBs) anodes. The recycled ZnMn2O4 material exhibits extremely high discharge specific capacity and performs well at high rates. This unique selective conversion technology, attributed to the co‐octahedral retention conversion, can be applied to obtain a variety of anode materials from aged cells. A successful demonstration of the reconversion of waste LiMn2O4 and LiCoO2 to obtain transition metal oxide materials provides the possibility of further efficient green recycling approaches for large‐scale applications.

Efficient utilization of scrapped LiFePO4 battery for novel synthesis of Fe2P2O7/C as candidate anode materials

With the increasing retirement of LiFePO4 batteries, state-of-the-art recycling strategies have drawn widespread attention for sustainable resource development. However, critical issues, such as tedious procedures and improper disposal of hazardous wastes, need to be solved urgently and efficiently. Generally, the recovery of lithium is emphasized during the recycling process, yet the relatively low valuable Fe/P compounds are rarely concerned, which are considered as hazardous materials. Herein, a simplified and economical method is developed to treat spent lithium-ion batteries (LIBs) by utilizing LiFePO4 cathode scraps as the raw precursors to fabricate novel anode material Fe2P2O7. Specifically, thermodynamic analysis confirms the feasibility of the selective extraction of lithium and synchronous separation of Li/Fe/Al elements. Under the optimal experimental parameters, the leaching efficiency of lithium can reach up to 98.84% and that of Fe/Al is below 1%, demonstrating the superior selectivity of lithium. Significantly, the waste leaching slag FePO4 is flexibly utilized to regenerate Fe2P2O7, which is applied as a novel anode material for LIBs and exhibits satisfactory rate capability and competitive long-term cycling stability (reversible capacities of 147.2 mAh g−1 at 1.0 A g−1 after 500 cycles with an excellent retention of 88.55%). This presented strategy takes full advantages of spent batteries by recycling the valuable fragments and turning solid waste into value-added anode materials simultaneously. It is convinced that the potential “waste to treasure” approach provides an environmental-friendly technology to reutilize the spent LIBs, which achieves the interdisciplinary of resource recycling and energy storage area.

Sustainable recycling of LiCoO2 cathode scrap on the basis of successive peroxymonosulfate activation and recovery of valuable metals

Increasing demand and waste of lithium-ion batteries (LIBs) has adversely affected resources and the environment. Multistage utilization of spent LIBs is essential to their sustainable development. Here, we propose a simple recycling method of LiCoO2 cathode scrap, based on the first use of the cathode scrap as a catalyst to degrade organic pollutants via peroxymonosulfate activation, and subsequent recovery of valuable metals from the used catalyst. Compared with pristine LiCoO2, the LiCoO2 cathode scrap exhibits excellent catalytic performance due to the active sites generated, such as the vacancy generation and electronic structure modulation by the degradation of LiCoO2 during the continuous lithiation and delithiation processes. The removal efficiency of cathode scrap to the o-phenylphenol exceeds 98% within 60 min, and the degradation efficiency is still above 95% after the 10th use because its unique sandwich and porous structure ensure the stability and recyclability. After multiple catalytic reactions, due to the generation of crack, the separation of the sandwich structure, and further degradation of active materials, the leaching efficiency of transition metals from the cathode scrap in deep eutectic solvent is promoted. 86% of lithium and 95% of cobalt are leached from the used catalyst respectively. This study provides a promising strategy for the sustainable development of LIBs and promotes the utilization of spent LIBs in multiaspect.

Sustainable recycling of cathode scraps via Cyrene-based separation

Separation of cathode materials from the current collector remains a challenging task for the recycling of both spent lithium-ion batteries and cathode scraps. Dissolving the organic binder polyvinylidene difluoride (PVDF) with an organic solvent to recover both cathode materials and Al foils is an efficient and promising method. However, the use of toxic solvents limits their practical application in recycling large amounts of cathode scraps generated during the manufacturing process. Cyrene, a bioderived green solvent, is proposed here for a solvent-based separation process. This study investigated a closed-loop recovery process to reclaim cathode materials, Al foils, and PVDF binder from cathode scraps. Additionally, the reuse of the Cyrene solvent led to a circular recycling process. The Cyrene-based separation process embraces a sustainable electrode recovery and reuse platform and paves the way for battery recycling.

Recycling the Cathode Scrap of Spent Lithium-Ion Batteries as an Easily Recoverable Peroxymonosulfate Catalyst with Enhanced Catalytic Performance

The cathode in spent lithium-ion batteries (LIBs) has intrinsic properties and a unique sandwich-like structure and contains transition metals. Moreover, the transition metal-based catalysts freque...

Hydrometallurgical Regeneration of LiMn2O4 Cathode Scrap Material and Its Electrochemical Properties

AbstractThe main researches focus on the recovery of metal elements in lithium manganate and not consider regenerating the cathode scrap materials. In this study, first, the polyvinylidene fluoride (PVDF) binder is removed by a combination of solvent dissolution and heat treatment. PVDF is easily separated by dissolving in an N‐methyl‐2‐pyrrolidone solution at a heating temperature of 60 °C, stirring time of 50 min, and solid solution ratio of 80 g⋅L−1. The dissolution rate of the scrap material achieves 86.70 % under optimal conditions. Further, using inductively coupled plasma spectroscopy to define the Li and Mn metal contents, and the LiMn2O4 cathode material is regenerated by a hydrometallurgical method. At the optimum calcination conditions of 500 °C for 12 h, electrochemical performance show that there are obvious charge and discharge platforms in the charge/discharge curves, and high first‐cycle discharge capacity is 123.7 mAh g−1 (3.0–4.3 V and 0.1 C), after 50 cycles, it decrease to 83.2 mAh g−1.

Pyrometallurgically regenerated LiMn2O4 cathode scrap material and its electrochemical properties

Recycling cathode materials from lithium-ion battery scraps can play a significant role in reducing environmental contamination and resource depletion. In this study, we employed pyrometallurgical techniques to regenerate LiMn2O4 cathode materials from recovered cathode scraps. First, the binder was removed under optimal conditions by a heating and stirring method to maximize the dissolution rate of the cathode scrap materials. Next, inductively coupled plasma spectroscopy was used to define the Li and Mn contents, and finally, the LiMn2O4 cathode material was regenerated by a pyrometallurgical method. After calcination under the optimum conditions of 500 °C for 12 h, electrochemical performance testing revealed obvious charge and discharge platforms in the charge/discharge curves; further, a high first-cycle discharge capacity was observed at 136.6 mAh·g-1 (3.0–4.3 V and 0.1 C), which decreased to 93 mAh·g-1 after 50 cycles. This process is low-cost and environmentally friendly, with the potential for recovering other cathode scrap materials.

Selective recovery of Li and FePO4 from spent LiFePO4 cathode scraps by organic acids and the properties of the regenerated LiFePO4

To recycle the sharply growing spent lithium-ion batteries and alleviate concerns over shortages of resources, particularly Li, is still an urgent issue. In this work, an organic acids based leaching approach at room temperature is proposed to recover Li and FePO4 from spent LiFePO4 cathode powder. The coexistent metal ions, Cu and Al, have also been investigated. Citrus fruit juices, rich in organic acids, such as citric acid and malic acid, have been used as leaching agents in this work. Among lemon, orange and apple, lemon juice shows the best leaching effect based on its suitable pH of the reaction system. Under the optimized conditions, the leaching rates of Li, Cu and Al can reach up to 94.83%, 96.92% and 47.24%, while Fe and P remain as low as 4.05% and 0.84%, respectively. Li2CO3 and FePO4 can be recovered from the leachate and the leaching residue, respectively. The recovered FePO4 was used to prepare new cathode material LiFePO4. The crystalline carbon, present in the spent LiFePO4 cathode scraps, has a significant effect on the electrochemical performances of the regenerated LiFePO4. The regenerated LiFePO4 cathode material delivered a comparable discharge capacity of 155.3 mAh g−1 at 0.1C and rate capacity to the fresh LiFePO4. For the cycling stability, it displays capacity retention of 98.30% over 100 cycles at 1 C with a fading rate of 0.017% per cycle. The proposed organic acids-based recycling strategy is much benign for recycling the spent LiFePO4 cathode materials.

Corrosion and Alloy Engineering in Rational Design of High Current Density Electrodes for Efficient Water Splitting

AbstractAlongside rare‐earth metals, Ni, Fe, Co, Cu are some of the critical materials that will be in huge demand thanks to growth in clean‐energy sector. Herein scrap stainless steel wires (SSW) from worn‐out tires are employed as a support material for catalyst integration in the hydrogen evolution reaction (HER). In addition, SSW by corrosion engineering is exercised as an in situ formed freestanding robust electrode for the oxygen evolution reaction (OER). By superficial corrosion of SSW, inherent active species are unmasked in the form of Ni/FeOOH nanocrystallites displaying efficient water oxidation by reaching 500 mA cm−2 at low overpotential (η500) of 287 mV in 1 m KOH. Similarly, cathode scrap SSW with active (alloy) coatings of MoNi4 catalyzes the HER at η‐200 = 77 mV, with a low activation energy (Ea = 16.338 kJ mol−1) and high durability of 150 h. Promisingly, when used in industrial conditions, 5 m KOH, 343 K, these electrodes demonstrate abnormal activity by yielding high anodic and cathodic current density of 1000 mA cm−2 at η = 233 mV and η = 161 mV, respectively. This work may inspire researchers to explore and reutilize high‐demand metals from scrap for addressing critical material shortfalls in clean‐energy technologies.