Patent Application
20230361371
The invention relates to a method for recycling a first electrode for a lithium-ion battery, a method for recycling at least one cell of a spent lithium-ion battery, a precursor mixture of an electrode composition for a lithium-ion battery obtained by this electrode recycling, and the electrode composition resulting from this precursor mixture. In particular, the invention applies to a recycling of a starting electrode for a lithium-ion battery and of such a battery allowing obtaining, from this starting electrode, another functional electrode of the same polarity (i.e. anode or cathode) capable of being integrated into a new lithium-ion battery. In particular, the starting electrode may be new and functional (i.e. not yet integrated into a battery and able to operate within this battery), defective (or intended for scrap), or spent (i.e. extracted from a lithium-ion battery at the end of service life).
In a known manner, lithium-ion batteries have a great autonomy of use in electric and hybrid motor vehicles. The popularity of these vehicles has been growing exponentially for years, resulting, with a lag of about five to seven years, in the accumulation of spent lithium-ion batteries, which have been used to power these vehicles.
As described for example in US 7,235,332 B2, the electrodes of lithium-ion batteries are usually manufactured by a coating process comprising steps of dispersing the compounds of the electrode coating in an organic solvent such as N-methyl pyrrolidone (NMP), spreading the obtained dispersion over a metal collector, then evaporating the solvent.
This coating process has many drawbacks from environmental and safety perspectives due to the use of such an organic solvent which, besides its toxicity and its flammability, requires evaporating a large amount thereof. In addition, the dispersion of solid compounds in this solvent according to a very high mass fraction of solid turns out to be delicate, posing problems of sedimentation and coagulation and requiring a dispersion of very good quality. Indeed, the presence of aggregates or impurities can generate coating defects, cracks, bubbles and inhomogeneities in the coated coating.
WO 2015/124835 A2 has suggested preparing a lithium-ion battery electrode coating composition overcoming these drawbacks, by
Currently, it is estimated that 2 million tons of lithium-ion batteries worldwide will be used in 2030. The accumulation of these batteries covers materials that are expensive to buy, such as the metals of the current collectors (typically aluminium or copper), rare materials or else very localised resources, such as the active materials of electrodes including alloys of lithiated oxides of transition metals for the cathodes (for example alloys of nickel, manganese and cobalt or of nickel, cobalt and aluminium) and graphite for the anodes. Hence, it is highly desirable to reuse or recycle all or part of these spent batteries, it being specified that a lithium-ion battery for electric vehicles is considered in Europe to be at the end of its service life when its capacity falls down to 80% of its initial capacity.
Different processes are currently known for recycling the different materials present in a spent lithium-ion battery.
WO 2016/174156 A1 discloses a method for treating spent batteries comprising in particular grinding thereof, then an inactivation of the ground material by drying so as to decompose the binders of the electrode coatings and to minimise the amount of electrolyte in the ground and dried material, which is thus almost electrochemically inert for transport thereof. This method further comprises a separation of the active material of the metallic collector supporting it preferably by sieving by airjet, and a purification by hydrometallurgy of the active materials before recycling thereof.
A major drawback of this method lies in the purification of the active materials by hydrometallurgy which is complex, costly and energy-intensive in particular with high CO2 emissions, and leads to intermediate products which are recycled into electrode coatings by equally costly, energy-intensive steps releasing large amounts of CO2. In addition, this process does not enable recovering the binder for recycling thereof.
US 9,614,261 B2 discloses a method for recycling an electrode material from spent lithium-ion batteries, comprising:
A major drawback of this method lies in its complexity, and in the fact that it requires the use of toxic and expensive organic solvents in large amounts and includes expensive and energy-intensive pyrolysis steps. In addition, the electrochemical performances of electrodes prepared from active materials thus regenerated are not taught in this document.
WO 2018/169830 A1 discloses a method for recycling an anode material of a lithium-ion battery from one or more charged cell(s) of the battery, which comprises in particular the following steps:
A major drawback of this last method lies in the limited electrochemical performances of the obtained electrode material, which is limited to an anode material obtained by reusing the purified anode material.
Another drawback of this last method as well as of all those that prescribe recycling of an electrode material in the form of a dispersion in a solvent such as NMP, is that the recycled materials must be free of traces of insoluble or non-dispersible materials present in a spent lithium-ion battery electrode, like for example traces originating from the passivation layers at the anode-electrolyte interface (SEI for short) or from the cathode-electrolyte interface layers (SCI for short), traces of lithium salts or other materials resulting from a degradation of the electrolyte, or originating from the separator.
The present invention aims to provide a method for recycling an electrode for a lithium-ion battery including an electrode coating covering a collector, and for recycling a spent lithium-ion battery incorporating such electrodes, which overcomes in particular the aforementioned drawbacks by enabling a direct and low-cost reuse of anode and cathode coatings already deposited over collectors, without complex or energy-intensive steps, for obtaining a new electrode coating having electrochemical properties (i.e. capacity) and cyclability (i.e. retention of capacity after several cycles) that are both satisfactory.
This aim is achieved in that the Applicant has discovered, surprisingly, that if one hot mixes, through aa molten process and without solvent, a lithium-ion battery electrode coating recovered by separation from its current collector, to new ingredients for an electrode of the same polarity comprising a compatible active material, a permanent binder, a sacrificial binder and an electrically-conductive additive, then it is possible to obtain through this direct recycling of the coating a new electrode coating for lithium-ion battery which, after deposition over a new collector, has electrochemical performances and cyclability comparable to those of a new “control” electrode coating also obtained through a molten process and without solvent which comprises identical mass fractions of the same permanent and sacrificial binders and of the same conductive additive but which is devoid of any recycled coating (replaced by the same new active material).
According to an aspect of the invention, a method for recycling a first electrode for a lithium-ion battery, the first electrode including a first collector and a first coating which covers the first collector and which comprises first ingredients comprising a first active material, a first polymeric binder and a first electrically-conductive additive, comprises:
By “hot melt mixing, without solvent” implemented at step b), it should be understood in a known manner in the present description a mixing of the considered polymers in the molten state in the absence of any solvent, which may be carried out at a temperature which is both
It should be noted that this melt mixing of the recovered first coating with the second new ingredients allows, through a subsequent elimination of the sacrificial polymeric binder included in these second ingredients, obtaining current density regimes from C/5 to 3C or 5C, maximum discharge capacities substantially of the same magnitude as those obtained for said new “control” electrode coating of the same polarity and with a similar basis weight, and a cyclability also comparable to that of this new “control” coating (which is also obtained through the solvent-free molten process from the same ingredients used according to the same mass fractions while replacing the first coating-second active ingredient mixture with the second active ingredient alone used according to the same mass fraction as this mixture).
As second active material compatible with said first active material, it is possible to select a second active material which is such that the difference between the respective operating voltages of the first and second active materials is preferably lower than or equal to 0.5 V in absolute value. Preferably, the second active material has a chemical composition identical to that of the first active material.
Advantageously, step a) may be implemented by a separation process selected from among:
It should be noted that this step a) may optionally result in the presence of traces of the current collector in the first coating thus recovered and therefore in the precursor mixture resulting therefrom.
Also advantageously, the recycling method according to the invention may further comprise before step a) a step a0) of providing the first electrode to be recycled, the method possibly having, between steps a0) and b), no step of purification, enrichment, regeneration or pyrolysis of said first coating, the first polymeric binder being kept in the first coating to implement step b).
It should be noted that this absence of a step of purification, enrichment, regeneration or pyrolysis of the first coating in the recycling method according to the invention, which is reflected in particular by the non-elimination of the first binder before recycling, differs from the prior art disclosed in the aforementioned documents.
According to a first embodiment of the invention, the recycling method further comprises, before step a), a step a0) of providing the first electrode to be recycled which is new so that it is not derived from a battery cell, the method having no step of washing the first coating after step a0) and before mixing thereof at step b) with the second ingredients.
It should be noted that this first embodiment relates in particular to a first starting electrode, which may be an anode or a cathode:
According to a second embodiment of the invention, the recycling method further comprises, before step a), a step a0) of providing the first electrode to be recycled which is derived from a spent lithium-ion battery cell, the method further comprising, between steps a0) and a) or between steps a) and b), a step a1) of washing the first coating to extract therefrom almost all of an electrolyte that the spent lithium-ion battery contained in contact with the first electrode, by means of an organic washing solvent which is generally inert with respect to the first polymeric binder and which comprises, for example, dimethyl carbonate.
It should be noted that this second embodiment relates in particular to a substantially spent first starting electrode which may be an anode or a cathode which may still be functional or not (i.e. extracted from a lithium-ion battery which has already completed at least one charge-discharge cycle and which may be at the end of its service life, i.e. not functional because its electrochemical capacity expressed in mAh/g of electrode reaches only 80% of its initial capacity).
In accordance with said second embodiment, the first coating may further comprise traces of said electrolyte with which the first electrode has been in contact in the spent lithium-ion battery cell, which is an aprotic electrolyte based on Li+ cations, for example a solution of lithium hexafluorophosphate (LiPF6) in an organic solvent such as one or more alkyl carbonate(s) (for example a mixture of ethyl carbonate and dimethyl carbonate as an electrolyte solvent).
It should be noted that the first coating recovered at step a) according to this second embodiment may further comprise all or part of the other insoluble or non-dispersible impurities present in a spent lithium-ion battery electrode, such as traces from passivation layers at the anode-electrolyte interface (SEI) or cathode-electrolyte interface layers (SCI), or traces originating from the separator contained in the cell of the spent lithium-ion battery, given that the melt mixing step b) tolerates the presence of such impurities, unlike wet preparation of electrode coatings typical of the prior art by dispersion in a solvent.
Preferably, the mixing of step b) is carried out according to a mass ratio [first coating / (first coating + second active material)] equal to or higher than 1% and lower than or equal to 65%, which is more preferably inclusively comprised between 5% and 60% and for example between 20% and 55%.
Also preferably and possibly in combination with the ratio hereinabove, the mixing of step b) is carried out according to a mass fraction of all of the first coating and of the second active material in the entirety of said precursor mixture which is inclusively comprised between 55% and 85%, preferably between 60% and 80%.
Also preferably and possibly in combination with all or part of the foregoing, the mixing of step b) is carried out with the sacrificial polymeric binder which is selected from among polyalkene carbonates, step c) being preferably implemented by thermal decomposition, for example in a vat under air or a furnace, under nitrogen.
Still more preferably, the sacrificial polymeric binder, thermally decomposed at step c), comprises at least one poly(alkene carbonate) polyol including end groups more than 50 mol% (and possibly more than 80 mol%) of which comprise hydroxyl functions, the sacrificial polymeric binder possibly comprising:
Advantageously, said at least one poly(alkene carbonate) polyol may be a linear aliphatic diol selected from among poly(ethylene carbonate) diols and poly(propylene carbonate) diols with a weight-average molecular mass Mw comprised between 500 g/mol and 5,000 g/mol, preferably between 700 g/mol and 2,000 g/mol. As example, one could, more advantageously, use a poly(propylene carbonate) diol of the following formula:
According to a variant of the invention, step c) may be implemented by any other process enabling the total or partial extraction of the sacrificial polymeric binder without impacting the rest of the mixture, for example through an extraction by a solvent with as sacrificial binder thus extractable by the liquid process at least one polymer, for example selected from among the group consisting of polyethylene glycols, polypropylene glycols and mixtures thereof.
In general, it should be noted that the elimination of the sacrificial binder at step c) of the method according to the invention is preferably total or almost total, i.e. substantially with no decomposition or extraction residue.
According to another aspect of the invention, the mixing of step b) is carried out with the permanent polymeric binder which may be different from the first polymeric binder, for example with:
As non-halogenated thermoplastic polymer for the permanent binder, it is possible to use an apolar aliphatic polyolefin of the homopolymer or copolymer type (including by definition terpolymers), derived from at least one alkene and optionally in addition to a comonomer other than an alkene, for example selected from among polyethylenes (for example HDPE or LDPE), polypropylenes (PP), polybutenes-1 and polymethylpentenes. Alternatively, this non-halogenated thermoplastic polymer may be a copolymer of ethylene and an acrylate, such as an ethylene-ethyl acrylate polymer, an ethylene-octene, ethylene-butene, propylene-butene or ethylene-butene -hexene copolymer.
As a non-diene rubber for the permanent binder, mention may be made of polyisobutylenes, copolymers of ethylene and of an alpha-olefin such as ethylene-propylene copolymers (EPM) and ethylene-propylene-diene terpolymers (EPDM).
It should be noted that each of the precursor mixture obtained at step b) and the second coating obtained at step c) may in this case comprise, as permanent binders, two polymers belonging to very different families, i.e. a halogenated thermoplastic polymer, on the one hand, and a non-halogenated thermoplastic polymer or an elastomer of the thermoplastic elastomer or rubber type, for example diene, on the other hand, unlike common practice.
According to another aspect of the invention, each of the first electrode and the second electrode is:
As explained hereinabove, it should be noted that the second active material is selected so as to be compatible with the first active material preferably by means of the aforementioned criterion of absolute value of the difference of the respective operating voltages of these two active materials lower than or equal to 1 V, and still more preferably also by the fact that the two active materials belong to the same chemical family (for example graphite for an anode, an alloy comprising at least the same metals for the cathode second active material).
As first and second active material(s), it is also possible to use other active inorganic fillers capable of enabling insertion/deinsertion of lithium for the lithium-ion battery electrodes, comprising lithiated polyanionic compounds or complexes such as a phosphate of a lithiated metal M of formula LiMPO4 coated with carbon (for example C-LiFePO4), a lithiated titanium oxide of formula Li4Ti5O12, or any other active material known to a person skilled in the art for cathodes (for example LiCoO2, LiMnO4) or anodes.
As electrically-conductive additive(s), it is possible to use, for example, a conductive carbon black, for example a high-purity one, an expanded graphite, graphene, carbon nanofibers, carbon nanotubes or a mixture of at least two of these.
According to another feature of the invention, the method may comprise between steps b) and c) the following steps:
A method according to the invention for recycling at least one cell of a spent lithium-ion battery including a packaging or an envelope, comprising the following steps:
It should be noted that step (i) consists in disassembling all or part of the spent battery, for example at the end of its service life (i.e. when its capacity is reduced to 80% at most of its initial capacity) to remove its packaging and recover the electrodes (collectors and affixed electrode coatings included) impregnated in electrolyte and the separators, and that step (ii) of recycling at least one of the two electrodes of the or each cell consists in implementing the aforementioned steps a), b) and c) of the recycling method presented hereinabove in the particular case where the or each electrode to be recycled originates from a spent lithium-ion battery which involves implementing the aforementioned step a1).
A precursor mixture according to the invention of an electrode coating composition for a lithium-ion battery, the composition being obtained by a method according to the invention for recycling a first electrode as defined hereinabove, wherein the precursor mixture comprises the product of a hot reaction, through a molten process and without solvent, of:
It should be noted that this precursor mixture is not only characterised by the fact that it comprises a sacrificial polymeric binder and is devoid of solvent, but also that it is directly derived from scraping of the first coating of the first current collector.
According to another aspect of the invention, this precursor mixture may be such that the sacrificial polymeric binder is selected from among polyalkene carbonates, the polymeric binder comprising, for example, at least one poly(alkene carbonate) polyol including end groups more than 50 mol% of which comprise hydroxyl functions.
Advantageously, this precursor mixture may also be such that:
As explained hereinabove, it should be noted that this combination of permanent binders with very different chemical structures, i.e. a halogenated thermoplastic polymer, on the one hand, and a non-halogenated thermoplastic polymer or an elastomer selected from among thermoplastic elastomers and rubbers, for example a diene rubber, on the other hand, differs from the prior art consisting in particular of the aforementioned documents (cf. for example WO 2018/169830 A1 which teaches the use of one same PVDF binder for the new electrode coating).
According to another feature of the invention which may depend, or not, on the aforementioned chemical structures of said first binder and of said permanent binder, this precursor mixture may be such that the first electrode is derived from a spent lithium-ion battery, the first coating which is derived therefrom then further comprising traces of an electrolyte that the spent lithium-ion battery contained in contact with the first electrode and which is an aprotic electrolyte based on Li+ cations, for example a solution of lithium hexafluorophosphate (LiPF6) in an organic solvent such as one or more alkyl carbonate(s).
An electrode composition according to the invention for a lithium-ion battery comprises the product of a total or partial thermal decomposition reaction of a precursor mixture according to the invention as defined hereinabove, and preferably said composition comprises:
It should be noted that this electrode composition finally obtained which forms the new electrode coating according to the invention obtained by the aforementioned recycling could be characterised not only by the aforementioned combination of several permanent binders with very different chemical structures, but also by the fact that it could comprise impurities originating from a spent lithium-ion battery, such as these electrolyte traces of or other elements of the battery.
It should also be noted that an electrode composition according to the invention may also comprise a plurality of different yet compatible active materials, as explained hereinabove.
Other features, advantages and details of the present invention will appear upon reading the following description of several embodiments of the invention, provided for illustrative and non-limiting purposes with reference to the appended drawings, among which:
Electrode coating compositions according to the invention, “control” ones not in accordance with the invention, have been prepared by implementing the following protocol of melt mixing, shaping, deposition over a collector then elimination of the sacrificial binder, starting from recycled first electrode coatings in order to obtain second coating compositions according to the invention and not in accordance with the invention, and starting from new ingredients in order to obtain “control” electrode coating compositions.
To obtain each of these electrode compositions, each precursor mixture has been processed by a molten process and without solvent in a “Haake Polylab OS” type internal mixer, with a capacity of 69 cm3 and at a temperature comprised between 60° C. and 75° C.
Then, the precursor mixtures thus obtained have been shaped by calendering at room temperature (22° C.) using a “Scamex” external cylinder mixer until reaching an electrode coating thickness of 600 µm. Afterwards, these precursor mixtures have been calendered again at 70° C. in order to reach a thickness of 50 µm to 150 µm.
Then the precursor mixtures thus calendered have been deposited over a metal current collector using a sheet calender at 70° C. The used collector has been made of aluminium coated with carbon for the cathodes based on an active material made of an NMC alloy, and of copper for the anodes based on graphite.
Afterwards, each precursor mixture previously deposited over the corresponding current collector has been placed in a ventilated vat or a furnace, in order to extract the sacrificial polymeric binder therefrom, by subjecting each precursor mixture to a heat treatment in a vat under ambient air in a first test, or under an inert atmosphere in a second test (in a rotary furnace under nitrogen, with a nitrogen flow rate of 1 L/min).
In both cases, this heat treatment consisted of a temperature ramp from 50° C. to 250° C. then of an isotherm for 30 min at 250° C. for the evaporation of the sacrificial binder.
The electrodes thus prepared have been cut out with a die cutter (diameter 16 mm, surface area 2.01 cm2), then weighed. The mass of active material has been determined by subtracting the mass of the bare current collector prepared according to the same conditions (heat treatments). The electrodes thus cut have been placed in a furnace directly connected to a glove box, then they have been dried at 100° C. under vacuum for 12 hours before transferring them to the glove box (under an argon atmosphere at 0. 1 ppm H2O and 0.1 ppm O2).
Afterwards, for each prepared electrode forming an anode or cathode to be tested, a button cell (CR1620 format) has been assembled using a metallic lithium counter-electrode, a “Cellgard 2500” separator and a LiPF6 EC/ DMC (50/50% by mass) battery grade electrolyte.
The batteries thus obtained have been characterised on a “Biologic VMP3” potentiostat. To this end, charge/discharge cycles at constant current between 1 V and 10 mV for the anodes and between 4.0 V and 2.5 V for the cathodes have been carried out.
As regards the anodes (based on graphite), the galvanostatic measurements of electrochemical capacity have been carried out at current densities of C/5, C/2, C, 2C and 5C, while considering the mass of active material and a theoretical capacity of 372 mAh/g. As regards the cathodes (based on an NMC alloy), the galvanostatic measurements have been carried out at current densities of C/5, C/2, C, 2C and 3C, while considering the mass of active material and a theoretical capacity of 200 mAh/g.
In order to compare the performances of the different systems, the capacities upon the fifth discharge (disinsertion of lithium) for the anodes and the charge for the cathodes have been assessed, at each current density. Then, the button cells have been cycled at the constant current density of C/5 for the anodes and C/2 for the cathodes, in order to quantify the cyclability of the tested electrodes. The potential terminals for each electrode have been kept.
Two precursor mixtures of anodes according to the invention have been prepared, respectively intended to form two compositions according to the invention 11, 11′ of second anode coatings, by implementing the following steps:
As regards the “control” anode, it has been obtained by depositing over the same collector made of copper a “control” anode coating C1 derived from a “control” precursor mixture consisting of the same anode new second ingredients and their respective amounts as for the precursor mixtures of the compositions 11 and 11′, except that this “control” precursor mixture was devoid of the recycled first coating with instead and in the same amount the same active material consisting of graphite.
Table 1 hereinafter details the ingredients and the formulation of the precursor mixture of each composition I1, I1′ according to the invention.
Table 2 hereinafter details the ingredients and the formulation of the precursor mixture of the “control” composition C1 according to the invention.
Table 3 hereinafter gives an account of the capacitive performances obtained at the C/5 to 5C regimes for the anodes incorporating the compositions I1, I1′ according to the invention and the “control” composition C1, respectively.
325
327
203
327
325
144
329
325
185
These results show that, surprisingly, the electrochemical performances of the anodes I1 and I1′ according to the invention derived from spent anodes of different disassembled lithium-ion batteries (respectively “Dell 1” and “Dell 2”) via the recycling of the corresponding anode coatings, are of the same magnitude at regimes from C/5 to 5C as the performances of the “control” anode C1 obtained with the same amounts of the corresponding new ingredients (including the same graphitic active material, instead of mixing thereof with the first coating). In addition, the performance of the anodes according to the invention I1, I1′ was sometimes higher to that of the “control” anode C1, as shown by the capacities measured at C/2 and C.
Cathode precursor mixtures respectively intended to form two compositions according to the invention I2, I2′ and two compositions not in accordance with the invention C2′, C2″ have been prepared by implementing the following steps:
As regards the “control” cathode C2, it has been obtained by depositing over the same aluminium collector a “control” cathode coating derived from a “control” precursor mixture, consisting of the same cathode new second ingredients and their respective amounts as for the precursor mixtures of the compositions I2, I2′, C2′, C2″, except that this “control” precursor mixture of C2 was devoid of the recycled first coating with instead and according to the same amount the same active ingredient consisting of NMC 622.
The compositions I2, I2′, C2, C2′, C2″ have further been calendered again to obtain coatings having a volumetric porosity of 38%. Tables 4-8 hereinafter detail the precursor mixtures used for these compositions.
Table 4 details the ingredients and the formulation of the precursor mixture of the preferred cathode composition I2 according to the invention.
Table 5 details the ingredients and the formulation of the precursor mixture of the “control” composition C2 according to the invention.
Table 6 details the ingredients and the formulation of the precursor mixture of the other composition I2′ according to the invention.
Table 7 details the ingredients and the formulation of the precursor mixture of the composition C2′ not in accordance with the invention.
Table 8 hereinafter details the ingredients and the formulation of the precursor mixture of the other composition C2″ not in accordance with the invention.
Thus, the cathode coatings I2, I2′, C2, C2′, C2″ have been successfully shaped, which had a surface area of about 25 cm2 and a basis weight substantially comprised between 21 and 25 mg/cm2. These cathodes have remained cohesive after elimination of the sacrificial binder at 250° C., and have withstood die cutting satisfactorily.
Table 9 hereinafter gives an account of the capacitive performances obtained at the regimes C/5 to 3C for the cathodes incorporating the compositions I2, I2′, C2, C2′, C2″.
These results show that, surprisingly, the electrochemical performances of the cathodes I2 and I2′ according to the invention derived from new commercial cathodes through recycling of the corresponding cathode coatings, are of the same magnitude at regimes from C/5 to C (and possibly to 2C for the cathode I2) as the performances of the “control” cathode C2 obtained with the same amounts of the corresponding new ingredients (including the same NMC type active material instead of mixing the latter with the first coating).
More specifically, the performance of the cathode I2 of the invention with a mass ratio [1st coating / (1st coating + 2nd active material)] of 25%, a preferred embodiment of the invention, has always been higher than that of the “control” cathode » C2, as shown by the capacities measured at regimes from C/5 to 3C (cf. the capacity of the cathode I2 increased by more than 220% at this high regime of 3C compared to the cathode C2).
As regards the cathode I2′ of the invention, these results show that the recycling of the first cathode coating (according to a mass ratio of about 50% with respect to the 1st coating-2nd active material set) allows substantially preserving the capacity values at regimes from C/5 to C, even though it penalises them at higher regimes of 2C and 3C.
As shown in the graph of
As regards the cathodes C2′ and C2″ not in accordance with the invention, Table 9 hereinabove shows that the integration of about 80% and more by mass of recycled first coating in the 1st coating-2nd active material set degrades the electrochemical performance, especially at current densities higher than 1C (cf. the non-acceptable capacities obtained at the regimes 2C and 3C).
And as shown in the graph of
However, it should be noted that the selection of a mass fraction of the second permanent binder higher than that used in the aforementioned examples and/or a different particle size distribution of the agglomerates resulting from the recycled first coating could allow improving the cohesion of these agglomerates even more and thus improving the capacities of the obtained electrodes.
| Number | Date | Country | Kind |
|---|---|---|---|
| FR20 09896 | Sep 2020 | FR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/FR2021/051689 | 9/29/2021 | WO |
