Production of a liquid organic electrolyte metal-ion battery component, and electrochemical cell comprising such a component

Abstract

The subject matter of the present invention is a method for producing such components, the components that can be obtained by this method and the use of these components in the production of a liquid organic electrolyte electrochemical cell.

Description

DESCRIPTION Title of the invention: REALIZATION OF A METAL-ION BATTERY COMPONENT WITH LIQUID ORGANIC ELECTROLYTE, AND ELECTROCHEMICAL CELL COMPRISING SUCH A COMPONENT. Technical field of the invention [1] The present invention relates to the technical field of metal-ion battery components (positive electrode, negative electrode, or separator), obtained by direct extrusion in the form of films, or shaped from composite filaments or composite granules by a fused deposition method. More particularly, the present invention relates to a method for manufacturing such components, the components that can be obtained by this method, and the use of these components in the manufacture of a liquid organic electrolyte electrochemical cell. Technical background [2] The metal-ion (lithium or sodium) battery with liquid organic electrolyte is the technology of choice for many applications (mobile devices, automotive, stationary, aeronautical, etc.) and their large-scale sale encourages researchers to continually increase their performance and develop sustainable and environmentally friendly manufacturing processes. [3] Additive manufacturing (usually referred to by the acronym AM), and in particular the fused deposition modeling (FDM) process (internationally known by the English acronyms FFF for "Fused Filament Fabrication" or FGF for "Fused Granular Fabrication"), is attractive because it allows for design flexibility and solvent-free manufacturing. Using this technology, also called 3D printing, it is possible, on the one hand, to produce three-dimensional battery architectures with larger active areas, which theoretically increase specific capacity at high cycling rates. On the other hand, this technology allows the battery to conform perfectly to the shape of the final object, thus maximizing energy storage capacity. [4] 3D printing a battery requires the production of composite filaments or granules corresponding to the different components: separator, positive and negative electrodes. These composite filaments or granules typically comprise a thermoplastic polymer matrix in which various materials such as materials Electrochemically active, electrically conductive components, ceramic nanoparticles, plasticizers, etc. are added according to their targeted role. [5] After the 3D printing or assembly phase, the battery electrodes and separator must be able to be impregnated with a liquid electrolyte while maintaining their mechanical integrity. However, to date, in the case of a component comprising a single polar thermoplastic polymer WO 2016 / 036607: - either the liquid electrolyte could not penetrate to the core of an electrode printed by FFF: in this case, only the active material on the surface of the electrodes was accessible to the electrolyte making the electrochemical reaction partial and difficult, which resulted in a significant polarization and a very low capacitance on the electrochemical curves; - either the polymer could become impregnated with electrolyte but the mechanical integrity was lost after a few cycles and the battery performance was affected accordingly. [1] Furthermore, the electrode of WO 2016 / 036607 contains at most 50% by weight of electrochemically active material, and typically between 10% and 30% by weight relative to the weight of the polymer. Moreover, international application WO 2019 / 2019202600 also teaches the additive manufacturing of an electrode comprising a single functional polymer, in which the electronically conductive carbon (at a rate of 50 to 70% by weight) and the electrochemically active material are dispersed. [2] The processes taught by international applications WO 2016 / 036607 and WO 2019 / 202600 have the disadvantages of providing electrodes with a limited mass content of electrochemically active material (less than 50%) or electrodes that do not have good mechanical strength or have limited wetting properties by the electrolyte. Description of the invention [3] More specifically, in order to overcome the aforementioned drawbacks, the applicant has developed a process for manufacturing composite filaments, composite films or composite granules for producing components of liquid organic electrolyte metal-ion batteries, said process comprising the steps: a. supplying or preparing at least two thermoplastic polymer compositions, including a first nonpolar polymer composition comprising at least one first nonpolar thermoplastic polymer, said first nonpolar thermoplastic polymer having a melting temperature Tfl and not exhibiting any affinity with the liquid organic electrolyte of said metal-ion battery into which it is intended to be incorporated, and a second polar polymer composition comprising at least one polar thermoplastic polymer, said polar thermoplastic polymer having a melting point Tf2 and exhibiting an affinity for said liquid organic electrolyte, said nonpolar thermoplastic polymer and said first polar thermoplastic polymer being immiscible, b. mixing said at least first and second nonpolar and polar polymer compositions, to form a thermoplastic polymer mixture; c.introducing said composite composition into an extruder, then forming by extrusion composite granules, or composite filaments, or composite films; said extrusion step being carried out at a temperature Te equal to or greater than the melting temperature of said thermoplastic polymer mixture, and preferably 10°C greater than the melting temperature of said thermoplastic polymer mixture; said composite granules or said composite films or said composite filaments thus obtained at Tissue of the extrusion step being made up of a polymer matrix having a co-continuous morphology of said polar thermoplastic polymer and said first non-polar thermoplastic polymer, to ensure the electrochemical function and the mechanical strength. [4] For the purposes of this invention, polymers derived from a given monomer include both homopolymers derived from that single monomer and copolymers derived from that given monomer and at least one other different monomer. [5] For the purposes of this invention, co-continuous morphology means a polymer matrix comprising a mixture of immiscible polymers, each forming a continuous network within the matrix. [6] With regard to step c), if the thermoplastic polymer mixture obtained in step b) consists only of the first and second thermoplastic polymer compositions (without plasticizer-type additives), the melting temperature of the thermoplastic polymer mixture will be the higher of the temperatures Tfl and Tf2. In the presence of a plasticizer, the melting temperature of the thermoplastic polymer mixture may be lower than Tf2. [7] Examples of plasticizers that can be used in the context of the present invention include, in particular, ATBC (Acetyl Tributyl Citrate), PC (propylene carbonate) type plasticizers... [8] The first nonpolar polymer composition comprises a first nonpolar thermoplastic polymer, which ensures the mechanical stability of the component during battery operation. The first nonpolar thermoplastic polymer is inert with respect to the electrolyte. The first polymer composition may, if necessary (if the component is an electrode), include the active material and carbon fillers, thus acting as a host structure and ensuring the mechanical strength of the electrode. [9] As primary nonpolar thermoplastic polymers usable within the framework of the present invention, olefins and mixtures thereof may be cited in particular, and preferably a polypropylene (PP) or a polyethylene (PE).

[0010] The first nonpolar polymer composition may also include a second nonpolar thermoplastic polymer selected from saturated (e.g., olefin copolymers) or unsaturated (e.g., polystyrene or SBR) nonpolar elastomers and / or mixtures thereof. A polypropylene-based elastomer (PBE) is preferred as the second nonpolar polymer. This second nonpolar polymer provides greater flexibility to the final component (which may be in filament form, preferably windable filament), while also being inert with respect to the electrolyte.

[0011] The second polar polymer composition includes a polar thermoplastic polymer, which exhibits an affinity for the electrolyte, promoting the impregnation of the battery component and the diffusion of lithium ions within its structure.

[0012] Examples of polar polymers that can be used in the context of the present invention include esters such as polycaprolactone (PCL), ethers such as POE (polyethylene oxide), carbonates, polyamides, polycaprolactone (PCL) and PVDF (polyvinylidene fluoride).

[0013] According to a first embodiment of the process according to the invention, the first and second polymer compositions may be solventized. In this case, the first nonpolar polymer composition will further comprise a nonpolar solvent, and the second polar composition will further comprise a polar solvent. Step b) of mixing the first and second nonpolar and polar polymer compositions may then advantageously be carried out for a period of between 1 and 30 minutes and at the higher of the two solution temperatures after complete dissolution of said polar and nonpolar polymers in their respective solvents. Said nonpolar and polar thermoplastic polymers will have been previously dissolved in their respective solvents, advantageously for a period of between 30 minutes and 24 hours. In the particular case of this embodiment In implementation, the process according to the invention shall further comprise, between said steps b) of mixing and c) of extrusion, a step b') of spreading said composite composition on a flat surface so as to form a composite film, followed by a step b”) of drying, said composite film being then cut into pieces during a cutting step b'”) intended to be inserted into said extruder.

[0014] Examples of non-polar solvents that can be used in the context of the present invention to dissolve non-polar polymers include, but are not limited to, solvents whose resulting dipole moment is zero, such as hydrocarbons and carbon tetrachloride.

[0015] Polar solvents that can be used in the context of the present invention to dissolve polar polymers include, but are not limited to, solvents whose resulting dipole moment is non-zero, such as dichloromethane, N-methyl-2-pyrrolidone (NMP) and acetone.

[0016] According to a second embodiment of the process according to the invention, the first and second non-polar and polar polymer compositions may be solvent-free and introduced separately or in a mixture into the extruder to carry out step b) of mixing.

[0017] If the metal-ion battery component with liquid organic electrolyte that is to be produced is an electrode, the process according to the invention can be used to produce composite filaments, composite films, or composite granules from a thermoplastic polymer blend of at least two immiscible thermoplastic polymers, an electrochemically active material, and electronically conductive carbon (introduced during step b) of the mixing process). It should be noted that the active materials must operate within the electrochemical stability window of the two thermoplastic polymers. Another alternative would be to introduce these fillers into the nonpolar polymer solution (first embodiment of the process according to the invention) or directly with the nonpolar polymer (solvent-free route) during the extrusion step.

[0018] In the case of a positive electrode, the electrochemically active material may be a compound chosen from among olivine structure compounds such as LiFePO4, lamellar compounds of the type LiMCh or NaMCh (with M designating a metallic element among Co, Ni, Mn, Al alone or mixture), oxides, sulfides, NaSICON structure compounds, and spinel structure compounds of the type LiMmCU, whether they are stoichiometric, over-stoichiometric or under-stoichiometric in metal ion.

[0019] In the case of a negative electrode, a compound chosen from the following compounds, taken alone or in combination, may be used as an electrochemically active material. mixture: carbon, I^TisO, metallic and intermetallic compounds, alloys, silicon, oxides, sulfides.

[0020] As an electronically conductive carbon, carbon nanofibers (usually referred to by the acronym CNF) and / or carbon nanotubes (usually referred to by the acronym CNT) and / or carbon black may advantageously be used in the context of the present invention.

[0021] If the component of the liquid organic electrolyte metal-ion battery to be produced is a separator, the process according to the invention can be used to produce composite filaments, composite films, or composite granules from a thermoplastic polymer blend of at least two immiscible thermoplastic polymers free of electrochemically active material and electronically conductive carbon. Advantageously, such a blend of at least two immiscible thermoplastic polymers may further comprise an electrochemically inactive and insulating material, for example, silica, to increase the mechanical strength and / or wettability of the separator by the electrolyte.

[0022] The process according to the invention allows, up to step c), the production of composite films or composite filaments and composite granules. To produce a metal-ion battery component with an organic electrolyte from composite films, or from composite filaments or granules obtained in step c), a preferred variant of the process according to the invention may further comprise an additional step d).

[0023] If the products obtained at the end of step c) are in the form of composite filaments or composite granules, the additional step d) will be a 3D printing step to produce, by FFF or FGF, a metal-ion battery component with liquid organic electrolyte of the electrode type (positive or negative) or separator.

[0024] If the products obtained at the end of step c) are in the form of composite films, the additional step d) will be an assembly step to produce from these composite films a metal-ion battery with liquid organic electrolyte (for example the following configurations button cell, pouch cell, prismatic cell, cylindrical cell).

[0025] The present invention also relates to a metal-ion battery component with liquid organic electrolyte that can be obtained by the preferred variant of the process according to the invention.

[0026] Preferably, the proportion of electrochemically active material in the battery component according to the invention may be at least 50% by weight relative to the weight of said component, and can reach up to 65% by weight in the case of components in filament form and 75% in the case of components in granule form.

[0027] The process according to the invention thus allows the production of custom batteries with a shape that can be adapted, on demand, to the object that they must power.

[0028] Integration into the object, compared to a conventional battery, allows, depending on the applications, for space savings, maximization of storage capacities, or a much more satisfactory aesthetic appearance.

[0029] The present invention also relates to an electrochemical cell comprising at least one battery component according to the invention.

[0030] Other advantages and features of the present invention will result from the following description, given by way of non-limiting example and made with reference to the accompanying figures and examples. Brief description of the figures

[0031] The following examples illustrate the invention, in conjunction with the figures discussed above, without however limiting its scope: [Fig 1]: Figure 1 schematically represents the different stages of the solvent-based production process of a positive electrode filament for a Li-ion battery according to the first embodiment of the process according to the invention; [Fig 2]: Figure 2 schematically represents the different stages of the dry process for producing a positive electrode filament for a Li-ion battery according to the second embodiment of the process according to the invention (solvent-free process, first variant); [Fig 3]: Figure 3 schematically represents the different stages of the dry process for producing a positive electrode filament for a Li-ion battery according to the second embodiment of the process according to the invention (solvent-free process, second variant); [Fig 4]: Figure 4 schematically represents the different stages of the dry process of producing a positive electrode filament for a Li-ion battery using a semi-industrial twin-screw extruder, according to the second embodiment of the process according to the invention (solvent-free process, second variant); [Fig 5]: Figure 5 includes backscattered electron scanning microscopy images of the surface of the electrode disk of Example 1: the image on the left a) showing the tray face, and the image on the right b) the nozzle face; [Fig 6]: Figure 6 includes scanning electron microscopy images (or SEM images) taken on a cross-section of the printed electrode disk from Example 2; [Fig 7]: Figure 7 includes scanning electron microscopy images (or SEM images) taken on a cross-section of the printed electrode disk from Example 3; [Fig 8]: Figure 8 includes scanning electron microscopy images (or SEM images) taken on a cross-section of the printed electrode disk from Example 4: this electrode disk shows in its core PCL / LTO (white grains) / CNF (Long tube) / PBE and PP (dark background); [Fig 9]: Figure 9 shows the specific capacities as a function of the number of cycles of a cell cycled at room temperature containing the printed disc obtained in example 1 as the working electrode, metallic lithium as the counter electrode and a fiberglass separator impregnated with the electrolyte LiPF6 (IM) in CE (ethylene carbonate): CDE (diethyl carbonate) (1:1 mass ratio) [Fig 10]: Figure 10 shows the specific capacities as a function of the number of cycles of a cell cycled at 25°C, containing the printed disc obtained in Example 2 as a working electrode, metallic lithium as a counter electrode and a fiberglass separator impregnated with the electrolyte LiPF6 (IM) in CE:CDM (dimethyl carbonate) (3:7 mass ratio); [Fig 11]: Figure 11 shows the specific capacities as a function of the number of cycles of a cell cycled at 25°C, containing the printed disc obtained in example 3 as the working electrode, metallic lithium as the counter electrode and a fiberglass separator impregnated with the electrolyte LiPF6 (IM) in CE:CDM (3:7 mass ratio); [Fig 12]: Figure 12 shows the specific capacities as a function of the number of cycles of a cell cycled at 25°C, containing the printed disc obtained in Example 4 as the working electrode, metallic lithium as the counter electrode and a fiberglass separator impregnated with the electrolyte LiPF6 (IM) in CE:CME (methyl and ethyl carbonate) (3:7 mass ratio). [Fig 13]: Figure 13 shows the specific capacities as a function of the number of cycles of a cell cycled at 25°C, containing the printed disc obtained in Example 5 as the working electrode, metallic lithium as the counter electrode and a fiberglass separator impregnated with the electrolyte LiPF6 (IM) in CE:CME (methyl and ethyl carbonate) (3:7 mass ratio). [Fig 14]: Figure 14 shows the conductivity value of a printed separator of the PP / PCL polymer blend (50 / 50 mass ratio) impregnated with the LiPF6 (IM) electrolyte in CE / CME (3 / 7 mass ratio), compared to the values ​​obtained in a fiberglass separator and a commercial PP separator; [Fig 15]: Figure 15 schematically illustrates the main steps in preparing composite discs from filament prepared by the solvent method; the disc contains only one PLA type thermoplastic polar polymer; [Fig 16]: Figure 16 shows the evolution of specific capacities as a function of the number of cycles of a cell cycled at room temperature containing a printed disc based on the positive active material Graphite (+PLA, PEGDME500, graphite, C45) as the working electrode, metallic lithium as the counter electrode and a fiberglass separator impregnated with the electrolyte LiPF6 (IM) in EC:DEC (1:1 mass ratio); [Fig 17]: Figure 17 shows transmission electron microscopy images of a section made on a negative electrode filament comprising: on part (a) small particles of CSP carbon black dispersed in PLA (grey background), and on part b) a higher magnification image in a region close to a graphite particle (circled in red); [Fig 18]: Figure 18 is a scanning electron microscopy image of cracks observed in the negative electrode of Example 4 after cycling. EXAMPLES

[0032] The raw materials of the polymer compositions (polar, non-polar polymers, polar and non-polar solvents), the electrochemically active material and the electronically conductive carbon, as well as the equipment used (extruder and 3D printer) are detailed below.

[0033] Raw materials First polymer composition - first non-polar polymers: polypropylene (PP) - Second nonpolar polymers: polyolefin-based elastomer (PBE) - nonpolar solvents: cyclohexane; Second polymer composition - polar polymers: polyethylene oxide (POE), polycaprolactone (PCL) - polar solvents: dichloromethane Electrochemically active material (or active substance): - LiFePCri (usually referred to by the acronym LFP, particle size D50: 2-6 um) -Li4TisOi2 (usually referred to by the acronym LTO). Electronically conductive carbon: - mixture of carbon nano fibers (usually referred to by the acronym CNF: 100 nm wide x 20-200 µm long) and carbon nanotubes (usually referred to by the acronym CNT: 9.5 nm wide x 1.5 µm long); - nano carbon fibers (CNF: 100 nm wide x 20-200 um long) - Carbon black (C45)

[0034] Materials - laboratory extruder marketed under the trade name HAAKE MiniLab III, by the company Thermo Fischer Scientific, - Semi-industrial twin-screw extruder marketed under the trade name Process 11 by ThermoFisher Scientific, - 3D printer marketed under the trade name Original Prusa i3 MK3 3D by the company Prusa; - single-screw extruder under the trade name Filabot Original, by the company Filabot Triex LLC, USA). EXAMPLE 1: Solvent-based production of a positive electrode disc for a Li-ion battery according to the first embodiment of the process according to the invention

[0035] In this example, a positive electrode disc for a Li-ion battery is produced by 3D printing according to the first embodiment of the process according to the invention.

[0036] An extruder for manufacturing the filament is fed with pieces of a solvent-prepared composite film. This film consists of two thermoplastic polymers, the inert polypropylene (PP) polymer with respect to the electrolyte and poly(ethylene oxide) responsible for transporting the electrolyte within the electrode by impregnation, the active material LiFcPCU (D50 particle size: 2-6 µm) and two electronically conductive carbons of the nanofiber (CNF: 100 nm wide x 20-200 µm long) and nanotube (CNT; 9.5 nm wide x 1.5 µm long) type, in the following mass percentages: PP: 33%, POE: 13%, LiFePO4: 49%, CNF: 2.5%, CNT: 2.5%.

[0037] The fabrication of the composite film (as illustrated in Figure 1) comprises the following steps: the PP and POE polymers are first dissolved separately in cyclohexane at 110°C and dichloromethane at room temperature, respectively. The two solutions are then mixed, and the fillers (carbon followed by LiFePO4) are added. The mixture is spread onto a glass plate. After drying, the thin film is cut into pieces, which are then fed into the extruder.

[0038] The 2 mm diameter filament is obtained using a laboratory extruder equipped with two co-rotating screws, at a temperature of 190°C. The residence time of the material in the extruder (7 cm 3 The process takes approximately 15 minutes and the screw rotation speed is 50 rpm. The resulting filament has an electronic conductivity of approximately 9 x 10⁻¹⁰ 2 S / cm.

[0039] It feeds a printer (Original Prusa i3 MK3 3D) whose nozzle and bed temperature is respectively 260 and 100 °C, for printing the disc 12.7 cm in diameter and 170 iim thick.

[0040] Analysis of the images (see Figure 5) of the printed disc surfaces obtained by scanning electron microscopy in backscattered electron mode clearly demonstrates the immiscible nature of the polymers. The LiFePO4 (LFP) active material particles and the conductive carbon particles are located exclusively within the PP polymer.

[0041] The printed disc is cycled in an electrochemical cell comprising this working electrode facing a counter electrode based on metallic lithium and a fiberglass separator impregnated with the liquid electrolyte. This consists of lithium salt LiPFe (IM) solubilized in a mixture of CE (ethylene carbonate) and CDE (diethyl carbonate), with a mass ratio of 1:1.

[0042] The cell is cycled at room temperature, at a constant current between 2.6 and 4V versus Li + / Li°. The capacities calculated per gram of LFP active material, obtained at a C / 40 (150 mAh / g) and C / 20 (130 mAh / g) regime, are close to the theoretical capacity of LFP of 170 mAh / g, as illustrated by Figure 9. EXAMPLE 2: Dry process fabrication of a positive electrode disc for a Li-ion battery according to the second embodiment of the process according to the invention (solvent-free process, first variant)

[0043] This example describes the steps for the dry processing of a positive electrode disc for a Li-ion battery according to the second embodiment of the process according to the invention (as illustrated in Figure 2).

[0044] The filament (2 mm diameter) is manufactured using a laboratory extruder equipped with two co-rotating screws. The extrusion temperature is set at 200°C, and the material's residence time in the extruder is 7 cm. 3 ) is approximately 15 minutes and the screw rotation speed is 50 rpm.

[0045] The extruder is fed with the following components: two thermoplastic polymers in granular form, polypropylene (PP), which is inert with respect to the electrolyte, and polycaprolactone (PCL), which carries the electrolyte to the electrode by impregnation; the active material LiFePCL (D50 particle size: 2-6 µm); and an electronically conductive carbon nanofiber (CNF: 100 nm wide x 20-200 µm long), in the following mass percentages: PP: 23.7%, PCL: 15.8%, LiFePCL: 55%, CNF: 5.5%. The introduction of these components into the extruder at 215°C was carried out in two stages. The PP and PCL granules are introduced first to ensure the homogeneity of the molten polymer mixture, followed by the homogeneous mixture of fillers, LiFcPCL and carbon. These two powders are pre-mixed for 10 hours in a container with zirconia beads subjected to three-dimensional movement.

[0046] The filament thus obtained has an electronic conductivity of approximately 8.3 S / m.

[0047] It feeds a printer (Original Prusa i3 MK3 3D) whose nozzle and bed temperature is respectively 220 and 100 °C, for printing the 12.5 cm diameter and 200 um thick disc.

[0048] Analysis of the images (see figure 6) taken at the heart of the electrode, by scanning electron microscopy shows a venous morphology of the PCL, in particular a vein of PCL (in red on the left) in an LFP matrix (white grains) / CNF (in green on the left) / PP (dark background).

[0049] The printed disc is cycled in an electrochemical cell comprising this working electrode facing a counter electrode based on metallic lithium and a fiberglass separator impregnated with the liquid electrolyte. This consists of lithium salt LiPFe (IM) solubilized in a mixture of CE (ethylene carbonate) and CDM (dimethyl carbonate), with a mass ratio of 3:7.

[0050] Once assembled, the cell undergoes a 24-hour storage period at 47°C to allow the electrolyte to saturate the electrode. It is then cycled at 25°C with a constant current between 2.6 and 4V versus Li + / Li°. The capacities calculated per gram of LFP active material, obtained at a regime of C / 40 (156 mAh / g) and C / 20 (146 mAh / g), C / 10 (138 mAh / g) are close to the theoretical capacity of LFP of 170 mAh / g, as illustrated by figure 10. EXAMPLE 3: Dry process fabrication of a positive electrode disc for a Li-ion battery according to the second embodiment of the process according to the invention (solvent-free process, second variant)

[0051] This example describes the steps for the dry production of a positive electrode disc for a Li-ion battery according to the second embodiment of the process according to the invention (as illustrated in Figure 3).

[0052] In order to produce a filament that can be wound under industrial conditions, the polymer (polypropylene) which is inert with respect to the electrolyte is partially replaced by an elastomer (2 eme variant of the second embodiment of the process according to the invention).

[0053] The filament (2 mm diameter) is manufactured using a laboratory extruder equipped with two co-rotating screws. The extrusion temperature is set at 215°C, and the residence time of the material in the extruder is 7 cm. 3) is approximately 15 minutes and the screw rotation speed is 50 rpm.

[0054] The extruder is fed with three thermoplastic polymers in pellet form: polypropylene (PP), which is inert with respect to the electrolyte; a polyolefin (PBE) elastomer, which provides greater flexibility to the final filament and is also inert with respect to the electrolyte; and polycaprolactone (PCL), which completes this mixture and is responsible for delivering the electrolyte to the electrode by impregnation. LFP active material and a carbon nanofiber (CNF: 100 nm wide x 20-200 µm long) are incorporated in the following mass percentages: PP: 17.775%, PBE: 5.925%, PCL: 15.8%, LFP: 55%, CNF: 5.5%.

[0055] The introduction of these components into the extruder was carried out in two stages. The PP, PBE, and PCL granules were introduced first to ensure the homogeneity of the molten polymer mixture, followed by the homogeneous mixture of fillers, LiFcPCh and carbon. These two powders were pre-mixed for 10 minutes in a container of zirconia beads subjected to three-dimensional movement.

[0056] The filament thus obtained has an electronic conductivity of approximately 4.84 S / m.

[0057] It feeds a 3D printer whose nozzle and bed temperatures are respectively 220 and 50 °C, for printing the 12.5 cm diameter and 200 iim thick disc.

[0058] Analysis of the images (see figure 7) taken at the heart of the electrode, by scanning electron microscopy, shows PCL outgrowths in an LFP / CNF / PP and PBE matrix.

[0059] The printed disc is cycled in an electrochemical cell comprising this working electrode facing a counter electrode based on metallic lithium and a fiberglass separator impregnated with the liquid electrolyte. The electrolyte used is a mixture of LiPFe (1 mol / L), CE (ethylene carbonate) and CDM (dimethyl carbonate) with a mass ratio of 3:7.

[0060] Once assembled, the cell undergoes a 24-hour storage period at room temperature to allow the electrolyte to saturate the electrode. It is then cycled at 25°C, with a constant current between 2.8 and 4V versus Li + / Li°. The capacities are calculated per gram of active material of LiFcPCU, they are obtained at a regime of C / 40 (165 mAh / g), C / 20 (149 mAh / g) and C / 10 (143 mAh / g), C / 5 (131.5mAh / g), C / 2 (102mAh / g) and C / 10 (143 mAh / g), as illustrated by figure 11. EXAMPLE 4: Dry process fabrication of a negative electrode disc for a Li-ion battery according to the second embodiment of the process according to the invention

[0061] This example describes the steps for the dry processing of a negative electrode disc for a Li-ion battery according to the second embodiment of the process according to the invention (as illustrated in Figure 3).

[0062] In order to produce a windable filament, the polymer (polypropylene) which is inert with respect to the electrolyte is partially replaced by an elastomer (2 eme variant of the second embodiment of the process according to the invention).

[0063] The filament (2 mm diameter) is manufactured using a laboratory extruder equipped with two co-rotating screws. The extrusion temperature is set at 215°C, and the residence time of the material in the extruder is 7 cm. 3 ) is approximately 15 minutes and the screw rotation speed is 50 rpm.

[0064] The extruder is fed with three thermoplastic polymers in pellet form: polypropylene (PP), which is inert with respect to the electrolyte; a polyolefin (PBE) elastomer, which provides greater flexibility to the final filament and is also inert with respect to the electrolyte; and polycapro lactone (PCL), which completes this mixture to deliver the electrolyte to the electrode by impregnation. LTO active material and a carbon nanofiber (CNF: 100 nm wide x 20-200 µm long) are incorporated, according to the following mass percentages: PP: 15.642%, PBE: 7.821%, PCL: 15.8%, LTO: 55%, CNF: 5.5%.

[0065] The introduction of these components into the extruder was carried out in two stages. The PP, PBE, and PCL granules were introduced first to ensure the homogeneity of the mixture. molten polymers are used, and then a homogeneous mixture of fillers, LTO and carbon, is added. These two powders are pre-mixed for 10 minutes in a container containing zirconia beads subjected to three-dimensional movement.

[0066] The filament thus obtained has an electronic conductivity of approximately 3.91 S / m.

[0067] It feeds a printer (Original Prusa i3 MK3 3D) whose nozzle and bed temperature is respectively 220 and 50 °C, for printing the 12.5 cm diameter and 200 iim thick disc.

[0068] Analysis of the images (see figure 8) taken at the heart of the electrode, by scanning electron microscopy, shows a venous morphology of the PCL.

[0069] The printed disc is cycled in an electrochemical cell comprising this working electrode facing a counter electrode based on metallic lithium and a fiberglass separator impregnated with the liquid electrolyte. This consists of lithium salt LiPFe (IM) solubilized in a mixture of CE (ethylene carbonate) and CME (methyl ethyl carbonate), with a mass ratio of 3:7.

[0070] Once assembled, the cell undergoes a 24-hour storage period at room temperature to allow the electrolyte to saturate the electrode. It is then cycled at 25°C, with a constant current between 1 and 2V versus Li + / Li°. The capacities calculated per gram of LTO active material are obtained at a regime of C / 40 (136 mAh / g), C / 20 (129 mAh / g), C / 10 (110 mAh / g), C / 5 (70 mAh / g), C / 2 (20 mAh / g), and C / 10 (110 mAh / g), as illustrated by Figure 12. EXAMPLE 5: Dry production of a negative electrode disc for a Li-ion battery according to the second embodiment of the process according to the invention

[0071] This example describes the steps for the dry processing of a negative electrode disc for a Li-ion battery according to the second embodiment of the process according to the invention (as illustrated in Figure 4).

[0072] In order to produce a filament that can be wound under industrial conditions, the polymer (polypropylene) which is inert with respect to the electrolyte is partially replaced by an elastomer in a larger quantity than in example 4 (2 eme variant of the second embodiment of the process according to the invention).

[0073] The filament (2 mm diameter) with a final composition of PP / PBE / PCL / LTO / CNF / CNT (by mass percentages 11.85 / 11.85 / 15.8 / 55 / 2.75 / 2.75) is manufactured using a semi-industrial extruder equipped with two co-rotating screws. The extrusion temperature is set at 215°C. The screw torque is set at 6 Nm.

[0074] The extruder is first fed with three thermoplastic polymers in pellet form: polypropylene (PP), which is inert with respect to the electrolyte; a polyolefin (PBE) elastomer, which provides greater flexibility to the final filament and is also inert with respect to the electrolyte; and polycaprolactone (PCL), which completes this mixture to deliver the electrolyte to the electrode by impregnation. The resulting polymer filament is then cut into pellets.

[0075] These granules are mixed with the active material LTO and two carbons, one of nanofiber type (CNF: 100 nm wide x 20-200 µm long), the other of nanotube type (CNT: 9.5 nm wide x 1.5 µm long). The mixing of 50 g of materials is carried out for 100 minutes, in a container containing zirconia beads subjected to three-dimensional movement.

[0076] The mixture is fed back into the extruder. The filament thus obtained feeds a printer (Original Prusa i3 MK3 3D) whose nozzle and bed temperature is respectively 220 and 50 °C, for printing the disc 12.5 cm in diameter and 200 iim thick.

[0077] The printed disc is cycled in an electrochemical cell comprising this working electrode facing a counter electrode based on metallic lithium and a fiberglass separator impregnated with the liquid electrolyte. This consists of lithium salt LiPFe (IM) solubilized in a mixture of CE (ethylene carbonate) and CME (methyl ethyl carbonate), with a mass ratio of 3:7.

[0078] Once assembled, the cell undergoes a 24-hour storage period at room temperature to allow the electrolyte to saturate the electrode. It is then cycled at 25°C, with a constant current between 1 and 2V versus Li + / Li°. The capacities calculated per gram of LTO active material are obtained at a regime of C / 40 (140.3 mAh / g), C / 20 (138 mAh / g), C / 10 (134.3 mAh / g), C / 5 (129.2 mAh / g), C / 2 (110.1 mAh / g), and C / 10 (135.2 mAh / g), as illustrated by Figure 13. It is thus noted that the industrial process leads to a strong improvement in the performance of the printed electrode at a rapid cycling regime (comparison Figure 12 and Figure 13 C / 5 and C / 2). EXAMPLE 6: Dry process fabrication of a Li-ion battery separator in accordance with i er / 2 eme embodiment of the process according to the invention.

[0079] In this example, a Li-ion battery separator disc is made by FFF (3D printing).

[0080] The filament (2 mm diameter) is manufactured using a laboratory extruder (HAAKE MiniLab III, Thermo Scientific) equipped with two co-rotating screws. The extrusion temperature is set at 215°C, and the residence time of the material in the extruder is 7 cm. 3 ) is approximately 15 minutes and the screw rotation speed is 50 rpm.

[0081] The extruder is fed with two thermoplastic polymers in pellet form, the non-polar polymer PP (polypropylene) and the polar polymer PCL (polycaprolactone) in the following mass percentages: PP: 60%, PCL: 40%.

[0082] The filament obtained feeds a 3D printer (Original Prusa i3 MK3 3D) whose nozzle and bed temperature is respectively 220 and 50 °C, for printing the disc 12.5 cm in diameter and 200 iim thick.

[0083] This printed separator is impregnated with the liquid electrolyte composed of lithium salt LiPFe (IM) solubilized in a mixture of CE and CME, with a mass ratio of 3:7, then introduced into an electrochemical cell to measure the ionic conductivity at 25°C.

[0084] The ionic conductivity obtained is 1.87 x 10⁻¹⁰ 4 S / cm, a value close to the conductivities obtained in a commercial polypropylene separator (thickness 25 µm, porosity 50%) and in a fiberglass separator, of 1.2 x 10⁻¹⁰⁻¹ 3 and 3.1 10' 3 S / cm respectively. COMPARATIVE EXAMPLE EC1: 1 single polymer (PLA)

[0085] In this example, a negative electrode disc for a Li-ion battery is produced by 3D printing using the fused filament fabrication (FFF) process. The extruder used to manufacture the filament is fed with pieces of a solvent-prepared composite film. This example illustrates the problems encountered when introducing a single polar thermoplastic polymer into the component.

[0086] The film is made of a thermoplastic polymer, PLA (polylactic acid), and the active ingredient graphite (TIMREX SLS graphite: 1.5 m 2 g -1 (d50=14µm, d90=26µm, supplied by Timcal), of a Carbon Super P type electronic conductor (62 m 2 / g), and the plasticizer PEGDME500 (Poly(ethylene glycol) dimethyl ether molar mass -500) in the following mass percentages: PLA: 33%, PEGDME500: 13%, graphite: 49%, C45: 5%. The plasticizer is added to provide a minimum of flexibility to the filament to make it printable; without plasticizer, this film is very brittle.

[0087] The manufacturing of the composite film involves the following steps: the PLA polymer is dissolved for 2 hours in dichloromethane at room temperature, then the plasticizer and fillers (C45 carbons and graphite) are added. These two powders, C45 and graphite, are previously mixed, for 10 hours, in a container containing zircon beads subjected to three-dimensional movement.

[0088] The mixture is spread on a glass plate. After drying, the thin film is cut into pieces, which are then fed into the extruder (as illustrated in Figure 15).

[0089] The 2 mm diameter filament is manufactured using a single-screw extruder (Filabot Original), at a temperature of 190°C.

[0090] The printed disc is cycled in an electrochemical cell comprising this working electrode facing a counter electrode based on metallic lithium and a fiberglass separator impregnated with the liquid electrolyte. This consists of lithium salt LiPFe (IM) solubilized in a mixture of CE (ethylene carbonate) and CDE (diethyl carbonate), with a mass ratio of 1:1.

[0091] Once assembled, the cell undergoes a 24-hour storage period at room temperature to allow the electrolyte to saturate the electrode. The cell is then cycled at room temperature, with a constant current between 2.6 and 4V versus Li + / Li°.

[0092] We observe that, on the one hand, the capacitance increases steadily during the first 6 cycles (Figure 16), indicating a difficult and gradual impregnation of the electrode disk. On the other hand, the capacitances calculated per gram of active material (graphite), obtained at different operating regimes, are much lower than the theoretical capacitance of graphite of 372 mAh / g. This is explained by discontinuous electron percolation pathways due to the low carbon / polymer volume ratio (Figure 17).

[0093] After cycling, the electrode disc tends to crumble due to the gelation of the PL A polymer with the electrolyte (Figure 18). This disc has two major drawbacks: slow electrolyte impregnation, loss of its mechanical integrity during cycling, and poor electron percolation leading to low electrochemical performance.

Claims

CLAIMS

1. A method of manufacturing composite filaments, composite films or composite granules for a liquid organic electrolyte metal-ion battery component, said method comprising the steps of: a. providing or preparing at least two thermoplastic polymer compositions, including a first apolar polymer composition comprising a first apolar thermoplastic polymer, said first apolar thermoplastic polymer having a melting temperature Tfl and not having an affinity with the liquid organic electrolyte of said metal-ion battery in which it is intended to be integrated, and a second polar polymer composition comprising a polar thermoplastic polymer, said polar polymer having a melting temperature Tf2 and having an affinity with said liquid organic electrolyte, said apolar thermoplastic polymer and said first polar thermoplastic polymer being immiscible, b.mixing said at least first and second apolar and polar polymer compositions, to form a thermoplastic polymer mixture; c. introducing said composite composition into an extruder, then forming by extrusion composite granules, or composite filaments or films; said extrusion step being carried out at a temperature Te equal to or higher than the temperature of said thermoplastic polymer mixture; said composite granules, or said composite films or said composite filaments thus obtained at Tissue of the extrusion step being constituted by a polymer matrix having a co-continuous morphology of said polar thermoplastic polymer and said first apolar thermoplastic polymer.

2. A method according to claim 1, wherein said apolar polymer is chosen from olefins, and mixtures thereof, and preferably is a polypropylene (PP) or a polyethylene (PE).

3. Method according to any one of claims 1 and 2, according to which said first polymer composition comprises at least one second apolar thermoplastic polymer chosen from saturated or unsaturated elastomeric apolar polymers and / or their mixtures, and preferably a polyolefin-based elastomer (PBE).

4. A method according to any one of claims 1 to 3, wherein said polar thermoplastic polymer is selected from esters, ethers, carbonates, polyamides, and PVDF.

5. A method according to any one of claims 1 to 4, wherein: said first apolar polymer composition further comprises an apolar solvent and said second polar polymer composition further comprises a polar solvent; step b) of mixing the first and second apolar and polar polymer compositions is carried out for a period of between 1 minute and 30 minutes and at the higher of the temperatures of the two solutions after complete dissolution of said apolar and polar polymers in their respective solvents; said method further comprises, between said steps b) of mixing and c) of extrusion, a step b') of spreading said composite composition on a flat surface so as to form a composite film, followed by a step b”) of drying, said composite film then being cut into pieces during a cutting step b'”) intended to be inserted into said extruder.

6. Method according to claim 5, in which the apolar solvent is a solvent whose resulting dipole moment is zero, and preferably chosen from hydrocarbons, carbon tetrachloride.

7. A method according to claim 5 or 6, wherein the polar solvent is a solvent whose resulting dipole moment is non-zero, and preferably chosen from dichloromethane, N-methyl-2-pyrrolidone (NMP) and acetone.

8. A method according to any one of claims 1 to 4, wherein said first apolar polymer compositions and second polar polymer compositions are solvent-free and are introduced separately or as a mixture into the extruder to carry out mixing step b).

9. Method according to any one of claims 1 to 8, according to which an electrochemically active material and electronically conductive carbon are introduced during step b) of mixing into the thermoplastic polymer mixture.

10. The method of claim 9, wherein said liquid organic electrolyte metal-ion battery component is a positive electrode and said electrochemically active material is selected from compounds of olivine structure such as LiFePO4, lamellar compounds of the LiMO2 or NaMO2 type with M designating a metallic element from Co, Ni, Mn, Al alone or mixed), oxides, sulfides, compounds of NaSICON type structure, and compounds of spinel structure of the LiMn2O4 type, whether stoichiometric, super-stoichiometric or sub-stoichiometric in metal ion.

11. The method of claim 9, wherein said liquid organic electrolyte metal-ion battery component is a negative electrode and said electrochemically active material is selected from the following compounds alone or in mixture: carbon, Li4Ti5O12, metallic and intermetallic compounds, alloys, silicon, oxides and sulfides.

12. A method according to any one of claims 9 to 11, wherein the electronically conductive carbon comprises carbon nanofibers (CNF) and / or carbon nanotubes (CNT) and / or carbon black.

13. A method according to any one of claims 1 to 8, wherein said liquid organic electrolyte metal-ion battery component is a separator and said thermoplastic polymer blend is free of electrochemically active material and electronically conductive carbon and optionally contains fillers.

14. Method according to claim 13, according to which an electrochemically inactive and insulating material, and preferably silica, is introduced during step b) of mixing.

15. Method according to any one of claims 1 to 14, further comprising a 3D printing step for producing from composite filaments or composite granules, a metal-ion battery component with liquid organic electrolyte.

16. A method according to any one of claims 1 to 14, further comprising a step of assembling composite films, for manufacturing a liquid organic electrolyte metal-ion battery component.

17. A liquid organic electrolyte metal-ion battery component obtainable by a method as defined in any one of claims 15 and 16.

18. Component according to claim 17, wherein the level of electrochemically active material is at least 40% by weight relative to the weight of said component.

19. An electrochemical cell comprising at least one component as defined in any one of claims 17 or 18.

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