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This article describes two ways to recover valuable and ecologically critical active materials from spent lithium-ion electrodes
and electrode production rejects, using the example of a system containing LiNi0.33Co0.33Mn0.33O2 (NMC) active material and
a polyvinylidene fluoride (PVdF) binder. First, a physical process using thermal treatment and me...
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... Besides, a remarkable amount of energy gets dissipated as heat, limiting comminution capacity at standard rates met by shredding [41]. Pre-treatments based on ball milling [42] and other purely mechanical processes [43][44][45][46] have been explored, also in combination with acids in mechano-chemical processes [28,47,48], significantly increasing metals' recovery by increasing the specific surface area of the detached materials [49] and limiting energy requirements [50]. ...
... Hydrometallurgical and pyrometallurgical processes decompose the PVDF binder, creating HF gas at a high temperature (i.e., 400-500 • C) (Hanisch et al., 2015;Song et al., 2013). Another approach is to weaken the binding forces by forming new bonds between the PVDF binder and an organic solvent (e. g., N-Methyl-2-pyrrolidone, NMP) (Chen et al., 2019;Hanisch et al., 2011). Novel chemical delamination methods have been proposed to minimize reagent costs and/or energy consumption by applying novel "green solvents" for PVDF dissolution. ...
... Examples include a CaO reaction medium (Wang et al., 2019b), a NaSiO 3 and Na 2 CO 3 medium (He et al., 2020); and dissolution in organic solvents, such as Cyrene (Bai et al., 2020a), ethylene glycol (Bai et al., 2020b), oil-based methyl ester solvents (Wang et al., 2020), or molten salt systems, such as eutectic AlCl 3 -NaCl molten salt (Wang et al., 2019a), eutectic choline chloride-glycerol (Wang, M. et al., 2019), or eutectic LiOH-LiNO 3 /-LiOAc-LiNO 3 molten salt (Ji et al., 2021a;Ji et al., 2022). Physical separation methods include agitation, ultrasonication, and pressure washing (Hanisch et al., 2011;He et al., 2015;Ji, Y. et al., 2022;Song et al., 2013). The current performance of delamination generally is evaluated using three factors: (1) separation efficiency (i.e., percent recovery of CAMs); (2) separation time; and (3) purity of recovered material (i.e., or impurity content, which is mainly due to Al contamination). ...
... Thus, current research on the recycling of manufacturing scrap or EoL LiBs focuses on the effective disposal of PVDF with low environmental impact. Several methods such as high-temperature annealing [28][29][30] and dissolving PVDF in organic solvents are used to separate the active materials from the current collector [27]. However, high-temperature annealing can alter the crystal structure and morphology of the active materials. ...
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.
... One option is to decompose PVDF at a high temperature (400-500 • C) (Hanisch et al., 2015;Song et al., 2013) but HF is released. Another option is to weaken binding forces in cathodes by forming new bonds between PVDF and organic solvents, e.g., N-Methyl-2-pyrrolidone (NMP) and N-N-dimethylformamide (DMF), which are volatile and could lead to air pollution Hanisch et al., 2011). Recently, to avoid toxic gas emissions and reduce solid waste, other chemical approaches have been proposed to accelerate the dissolution or decomposition of PVDF and to separate cathode materials from Al foil under an elevated reaction temperature, such as Cyrene at 100 • C (Bai et al., 2020a), ethylene glycol at 160 • C (Bai et al., 2020b), AlCl 3 -NaCl at 160 • C (Wang et al., 2019a), choline chloride-glycerol at 190 • C (Wang et al., 2019c), methyl ester solvents at 190 • C , lithium hydroxide and lithium nitrate at 260 • C (Ji et al., 2021), lithium acetate and lithium nitrate at 300 • C (Ji et al., 2022), and calcium oxide at 300 • C (Wang et al., 2019b). ...
... Besides chemical delamination, mechanical forces via e.g. agitation and ultrasonication, can assist chemical reagents to improve the separation of cathode materials (Hanisch et al., 2011;He et al., 2015;Song et al., 2013). For example, combining organic solvents and ultrasound increases the peel-off efficiency at least six times than that of using organic solvent alone (He et al., 2015). ...
Recycling cathode materials from spent lithium-ion batteries has the potential to reduce damages to the environment and human health due to hazardous waste treatment, and mitigate supply risks of raw materials. Related political incentives or regulations have led to increased research and development efforts on cathode recycling. Promising approaches include direct recycling and hydrometallurgical processes, where delamination is the first step after collection of cathodes. In this study, we examined a pressure washing system’s ability to harvest cathode materials. A high-pressure water jet provides strong forces to overcome the adhesion provided by organic binders. Four factors (water pressure, distance between nozzle and cathode, incident angle of water jet, and nozzle type) were investigated using a 3⁴⁻¹ fractional factorial design to screen important parameters and find the optimal conditions. Compared with other delamination processes where chemical reagents and heating are involved, the chemical-free pressure washing system can achieve separation in a few seconds (∼74 min/m²) at room temperature, which remarkably improves the efficiency of delamination. The particle size of recycled products (D50 of 31.87 μm) is significantly reduced without Al contamination from current collectors or morphological damages. In addition, three types of recycled cathode materials were used as inputs for the acid leaching process. High leaching efficiencies of lithium (>90 %) and cobalt (>85 %) suggest that the pressure washing system could be a practical, economical, and eco-friendly pretreatment process to harvest cathode materials.
... The resulting material showed promising electrochemical properties for reuse as cathode material, with a first charge of 130.8 mAh/g and a first discharge of 127.2 mAh/g [119]. Hanisch et al. (2011) reintroduced recycled materials as components of new batteries. The aluminum current collector was separated by thermal and mechanical treatments, and a chemical process allowed for compound recovery. ...
... The aluminum current collector was separated by thermal and mechanical treatments, and a chemical process allowed for compound recovery. LiNi 0.33 Co 0.33 Mn 0.33 O 2 electrodes were successfully recovered and applied in new battery cells [120]. obtained LiNi 1/3 Mn 1/3 Co 1/3 O 2 as a coprecipitation product. ...
Lithium-ion batteries (LIBs) containing graphite as anode material and LiCoO2, LiMn2O4, and LiNixMnyCozO2 as cathode materials are the most used worldwide because of their high energy density, capacitance, durability, and safety. However, such widespread use implies the generation of large amounts of electronic waste. It is estimated that more than 11 million ton of LIBs waste will have been generated by 2030. Battery recycling can contribute to minimizing environmental contamination and reducing production costs through the recovery of high-value raw materials such as lithium, cobalt, and nickel. The most common processes used to recycle spent LIBs are pyrometallurgical, biometallurgical, and hydrometallurgical. Given the current scenario, it is necessary to develop environmentally friendly methods to recycle batteries and synthesize materials with multiple technological applications. This study presents a review of industrial and laboratory processes for recycling spent LIBs and producing materials that can be used in new batteries, energy storage devices, electrochemical sensors, and photocatalytic reactions.
... Regarding the dissolution approach, two methods are widely utilized to remove PVDF. The first method is based on the solubility of PVDF in polar solvents, with N-methyl-2-pyrrolidone (NMP), for example, shown to be quite effective (Hanisch et al., 2011;Zhang et al., 2016). However, its use may be strictly limited under regulations and guidences such as the Registration, Evaluation, Authorisation, and Restriction of Chemicals (European Chemical Agency, 2020). ...
The growing demand of electric vehicles and rapid consumption of rechargeable lithium-ion batteries (LIBs) require recycling of spent cathode active materials (CAMs) to reduce hazardous wastes and supply raw materials to LIB production. To separate CAMs from the cathode, direct calcination of polyvinylidene fluoride (PVDF) binder is widely applied, which leads to high energy consumption and release of toxic hydrogen fluoride. It is desirable to have an environmentally friendly and effective alternative to traditional direct calcination. In this study, five lithium salts, LiOAc (lithium acetate), LiNO3, LiCl, Li2CO3, and Li2SO4, were deployed and compared for their performance in recycling CAMs. A peel-off efficiency of up to 98.5% was achieved at a LiOAc to LiNO3 molar ratio of 3:2, salt to cathode mass ratio of 10:1, and temperature of 300 °C at a holding time of 30 min. This system avoids corrosive chemicals and minimizes particle agglomeration of recycled products. Compared with sodium salt systems (NaOAc-NaNO3) or direct calcination, the LiOAc-LiNO3 system prevented high reaction temperature or further lithium loss, and minimized crystal structure and morphological changes. A decomposition mechanism of PVDF through adsorption of HF and fluorine substitution was proposed.
... The solubility behavior of PVDF in 46 solvents and their Hansen solubility parameters are investigated [49]. Four effective solvents are widely used in LIBs recycling to remove PVDF: Nmethyl-2-pyrrolidone (NMP), N-N-dimethylformamide (DMF), N-N dimethylacetamide (DMAC), and N-N-dimethyl sulfoxide (DMSO) [50][51][52][53]. These four solvents (NMP, DMF, DMAC, and DMSO) and ethanol are compared in terms of separating cathode materials from cathode to recycle LiCoO 2 [54]. ...
... Thermal treatment is widely used to remove residues of PVDF and graphite/acetylene black. PVDF is decomposed in the temperature range of 350-600°C [50,62,63], and carbon is decomposed in the temperature range of 600-800°C [65,73]. The TGA curves of electrode components are shown in Figure 7. ...
Lithium-ion battery (LIB)-based electric vehicles (EVs) are regarded as a critical technology for the decarbonization of transportation. The rising demand for EVs has triggered concerns on the supply risks of lithium and some transition metals such as cobalt and nickel needed for cathode manufacturing. There are also concerns about environmental damage from current recycling and disposal practices, as several spent LIBs are reaching the end of their life in the next few decades. Proper LIB end-of-life management can alleviate supply risks of critical materials while minimizing environmental pollution. Direct recycling, which aims at recovering active materials in the cathode and chemically upgrading said materials for new cathode manufacturing, is promising. Compared with pyrometallurgical and hydrometallurgical recycling, direct recycling has closed the material loop in cathode manufacturing via a shorter pathway and attracted attention over the past few years due to its economic and environmental competitiveness. This paper reviews current direct recycling technologies for the cathode, which is considered as the material with the highest economic value in LIBs. We structure this review in line with the direct recycling process sequence: cathode material collection, separation of cathode active materials from other components, and regeneration of degraded cathode active materials. Methods to harvest cathode active materials are well studied. Efforts are required to minimize fluoride emissions during complete separation of cathode active materials from binders and carbon. Regeneration for homogeneous cathode is achieved via solid-state or hydrothermal re-lithiation. However, the challenge of how to process different cathode chemistries together in direct recycling needs to be solved. Overall, the development of direct recycling provides the possibility to accelerate the sustainable recycling of spent LIBs from electric vehicles.
... In the thermal treatment process, graphite can be removed by oxidation to form CO/CO 2 (Lombardo et al., 2020;Sun et al., 2019;Xiao et al., 2017). The current collector and the cathode material can be effectively separated from the heat-treated material through further processing, such as ball milling, vibration, and flotation (Hanisch et al., 2011;Wu et al., 2017). ...
The production of lithium-ion batteries (LIBs) is increasing rapidly because of their outstanding physicochemical properties, which ultimately leads to an increasing amount of spent lithium-ion batteries reaching their end-of-life (EOL). Pretreatment of the discarded batteries is an indispensable part of recycling spent lithium-ion batteries. The batteries contain toxic chemicals and high-value metals that must be recycled to promote environmental protection and sustainability. This paper provides an overview of the current pretreatment methods employed in the recycling of spent LIBs. In particular, the article reviews various options (mechanical, chemical, and thermal pretreatment options) that can be adopted for the pretreatment of spent lithium-ion batteries and puts forward the recommendations for future research and development that will enable more efficient and cleaner technologies for recycling spent LIBs. The review emphasizes the safe pretreatment of the spent LIBs and provides an overview of the consequences of the individual pretreatment steps on the recyclability of the materials to be recovered, and LiCoO2 was chosen as the reference as most studies in the literature focus on LiCoO2 cathode materials. However, discussions on other battery chemistries have also been incorporated into the scope of the review.
... Solvent dissolution utilizes the dissolubility of PVDF in organic solvents to obtain CAMs and aluminum foil. Organic solvents, such as N-methyl-2-pyrrolidone (NMP) (Hanisch et al., 2011;, and N-N-dimethylformamide (DMF) (Song et al., 2013), have been used to dissolute PVDF. The volatilization of toxic organic solvents limits their applications in large-scale systems. ...
The cathode material is the focus of end-of-life lithium-ion battery recycling due to its high value. Cathode-to-cathode direct recycling avoids the need to change the cathode material to other metal forms, which could have significant economic and environmental advantages. A process that separates the cathode layer from current collector and recovers the active cathode materials is highly desirable as this facilitates the following regeneration step. In the present work, eutectic mixtures of lithium compounds are studies as an efficient and environmentally friendly approach for the separation and recovery of active cathode materials. Three commonly used inorganic lithium compounds i.e. LiCl, LiNO3, and LiOH, and their binary eutectic systems are investigated. It is found that LiOH-LiNO3 eutectic system has the highest peel-off efficiency. At temperature of 260 °C with 30 min holding time and salts/cathode electrode mass ratio of 10:1, up to 98.3% of cathode active materials can be recovered. The recovered cathode materials show minimal change and destruction on chemical composition, crystal structure, and morphology. Results suggest that LiOH-LiNO3 eutectic system can facilitate the decomposition of polyvinylidene fluoride binder and capture the HF released. The process based on eutectic systems of lithium compounds provides an alternative binder removal approach to organic solvents, and offers re-lithiation benefit without introducing impurities. It has the potential to promote direct recycling and sustainable recycling of spent lithium-ion batteries.
... [49][50][51][52][53] We expect that the PVDF used in commercial cells may also differ slightly in molecular weight or structure (e. g., a PVDF copolymer, such as PVDF-HFP (poly(vinylidene fluoride-co-hexafluoropropylene)), or poly(vinylidene fluoride-co-chlorotrifluoroethylene) (PVDF-CTFE). [49,50] While pure NMP has been used previously to remove PVDF from composite films, [29,30,42,54] we found that the addition of more volatile THF allowed us to readily remove solvent. Thus, a THF : NMP (50 : 50 v/v) binary solvent mixture was used for all subsequent PVDF recovery experiments. ...
Here, we investigate the recovery and reuse of polyvinylidene fluoride (PVDF) binders from both homemade and commercial cathode films in Li ion batteries. We find that PVDF solubility depends on whether the polymer is an isolated powder or cast into a composite film. A mixture of tetrahydrofuran:N‐methyl‐2‐pyrrolidone (THF : NMP, 50 : 50 v/v) at 90 °C delaminates composite cathodes from Al current collectors and yields pure PVDF as characterized by 1H nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), wide‐angle X‐ray scattering (WAXS), and scanning electron microscopy (SEM). PVDF recovered from Li ion cells post‐cycling exhibits similar performance to pristine PVDF. These data suggest that PVDF can be extracted and reused during Li ion battery recycling while simultaneously eliminating the formation of HF etchants, providing an incentive for use in direct cathode recycling. The structure, purity, and reuse of polyvinylidene fluoride binder recovered from spent lithium‐ion battery cathodes have been investigated.
