Producing laminates composed of lisicon material

Abstract

The invention is concerned with laminates composed of LiSICon material, and production and use thereof. The object of the invention was to specify a membrane for separation of lithium out of contaminated lithium-containing waters, which is comparatively inexpensive and permits good permeance for lithium in electrodialysis operation. This object is achieved by coating a substrate with a LiSICon by way of aerosol-based cold deposition. In this way, a laminate that is of excellent suitability as membrane for electrodialytic lithium deposition owing to its particular material combination is obtained.

Description

[0001] Manufacturing of laminated bodies from LiSICon material

[0002] The invention relates to laminated bodies made of LiSICon material, their production and use.

[0003] Layered bodies are solid objects that contain a number of different materials. In addition, a layered body has a layered structure, meaning it comprises a number of layers arranged one above the other. Each layer is assigned at least one material, which can be found in the respective layer. In the simplest case, each layer is assigned exactly one material, so that the number of layers corresponds to the number of materials. Of course, several materials can also be assigned to a layer. In practice, however, the individual materials are distributed throughout the entire layered body; admittedly with a statistical accumulation within the assigned layers. Consequently, the materials assigned to the respective layer are merely enriched in the layer. In particular, in the boundary region between two superimposed layers, the materials assigned to the adjacent layers occur alongside one another.

[0004] Laminated bodies can take on a wide variety of geometric shapes. In the simplest case, a laminated body has a substantially flat shape, with a plurality of equally flat layers arranged one above the other. Typically, the thickness of the laminated body and the individual layer thicknesses are significantly smaller than the longitudinal and transverse dimensions of the laminated body, so that—ignoring the thickness—the laminated body appears essentially two-dimensional. Of course, laminated bodies can also have more complex shapes. In particular, the thickness of the individual layers can vary.

[0005] Laminated bodies are typically produced by coating a substrate with at least one layer. The laminated body is then composed of at least two layers: a first layer formed by the substrate and the coating as the second layer. The laminated body then comprises the substrate material and the coating material.

[0006] The invention specifically relates to such layered bodies which are at least partially constructed from LiSICon materials, namely LiSICon as substrate material and / or as coating material.

[0007] LiSICon stands for Lithium Super Ionic Conductor. It is a class of inorganic, (glass) ceramic material that is electrically insulated but also possesses intrinsic conductivity for lithium ions. A few years ago, the term LiSICon was only used for a few materials with a specific stoichiometry and crystal structure. However, as more and more materials with similar properties have been discovered or developed, the term LiSICon is now used more generically for (glass) ceramics with intrinsic lithium conductivity. The transport mechanism for lithium is rooted in the crystal structure of this material. Simply put, the lithium ions are "passed through" the crystals. Commercially available LiSICon materials include lithium aluminum titanium phosphate (LATP), lithium aluminum titanium silicon phosphate (LATSP), lithium aluminum germanium phosphate (LAGP), and lithium lanthanum titanium oxide (LLTO).A general introduction to LiSICon materials and their transport mechanism is provided by:.

[0008] Palakkathodi Kammampata et al.: Cruising in ceramics — discovering new structures for all-solid-state batteries — fundamentals, materials, and performances. Ionics 24, 639-660 (2018) DOI: 10.1007 / S11581 -017-2372-7

[0009] Yedukondalu Meesala et al.: Recent Advancements in Li-Ion Conductors for All-Solid-State Li-Ion Batteries. ACS Energy Lett. 2017, 2, 12, 2734-2751 DOI: 10.1021 / acsenergylett.7b00849

[0010] As described in these two review articles, LiSICons can be used as solid-state electrolytes for lithium-ion batteries (LIBs).

[0011] Due to their selective conductivity for lithium ions, LiSICon materials can also be used as membranes for the electrodialytic separation of lithium from lithium-containing waters. The lithium must be present in the mixture in ionic form, for example, as a lithium salt dissolved in water.

[0012] A process for the electrodialytic separation of lithium from seawater is known from WO 2022157624 A1, among others. It uses a LiSICon membrane made of LLTO. Since seawater contains only small amounts of lithium, the membranes must be designed with a correspondingly large surface area to extract lithium economically from the sea. This appears to be feasible with comparatively inexpensive LLTO.

[0013] However, it should also be noted that LLTO has a lower specific conductivity for Li compared to other LiSICons. For a given material thickness, a low intrinsic Li conductivity of the membrane material results in a low permeance of the membrane. Permeance is a measure of the conductivity of the membrane taking into account its thickness. The higher the membrane permeance, the lower the electrical energy required for the dialysis process. LiSICon materials with low intrinsic Li conductivity therefore reduce the permeance of the membrane and increase the energy requirements of the process. While it is theoretically possible to reduce the material thickness of the membrane and thereby increase its permeance again, the thickness of the membrane material cannot fall below a certain minimum for stability reasons.Therefore, the low specific conductivity of the LLTO cannot be compensated for in practice simply by reducing the membrane thickness. This is especially true if the membrane is subject to wear during operation.

[0014] As a result, an LLTO membrane always achieves lower permeance than a LiSICon membrane with higher intrinsic Li conductivity. Therefore, it requires more energy to operate the electrodialysis process.

[0015] The extraction of lithium from the sea using an LLTO membrane therefore appears particularly attractive when inexpensive electrical energy is available at the same time - especially from renewable sources.

[0016] As an alternative source of lithium to seawater, natural Li brines or lithium-containing waters can be used. These are generated as production waste during the production of fresh LIBs or during the recycling of used LIBs. Unlike seawater, such lithium-containing waters contain the coveted lithium in comparatively high concentrations, but also contain disruptive impurities, particularly cations of the following elements: B, Na, Mg, Al, Si, K, Ca, Mn, Fe, Co, Ni, Cu, and C. The alkali and alkaline earth metals are particularly abundant in lithium-containing brines of natural origin, while the other metal cations are found primarily in lithium-containing waters resulting from the reprocessing of used LIBs or from production waste from LIB production. Such streams also often contain carbon compounds originating from adhesives, binders, LIB anode materials, carbon black, or LIB plastic packaging.These can then contain carbon-containing acids, or their cations, but also uncharged organic decomposition products from the upstream steps of LIB recycling.

[0017] Unfortunately, the currently commercially available "phosphate-based" LiSICon materials such as LAGTP, LATSP, or LAGP are quite sensitive to the aforementioned contaminants: Sodium, potassium, calcium, and magnesium ions, in particular, reduce the lithium conductivity of phosphate-based LiSICons as soon as they come into contact with the material. In some cases, LAGTP, LATSP, or LAGP membranes are directly destroyed by these ions. Therefore, lithium-containing waters containing many cationic contaminants cannot be brought into contact with phosphate-based LiSICon membranes without complex pre-treatment (see, for example, US20120103826A1). In particular, the recovery of lithium from the highly contaminated waste streams from LIB production or LIB recycling quickly becomes uneconomical due to these pre-treatment measures.

[0018] While it is possible to use LLTO instead of the sensitive, phosphate-based LiSICon to separate Li from water with a high proportion of cationic impurities, LLTO has a significantly lower specific Li conductivity compared to phosphate-based LiSICons such as LAGTP, LATSP, or LAGP, which in turn increases the energy demand for electrodialysis.

[0019] The selection of the separation-active membrane material for lithium electrodialysis is further complicated by the fact that not all LiSICons that can be produced in the laboratory are also available on an industrial scale and that the prices for these materials are sometimes very high.

[0020] For all these reasons, it is not trivial to identify a LiSICon material that offers a good compromise between acquisition cost, service life and Li conductivity for the separation of Li from contaminated water.

[0021] WO 2019055730 A1 also deals with the separation of lithium from aqueous solutions using LiSICon membranes. Specifically, LLTO, LAGP, or LATP are mentioned. The LiSICon material can be applied to a porous support structure. However, WO 2019055730 A1 does not address the chemical nature of this support structure. Likewise, this document fails to disclose how LiSICon is applied to the support structure.

[0022] In view of this state of the art, the task was to provide a membrane for the separation of lithium from contaminated lithium-containing waters that is comparatively inexpensive and allows good permeance for lithium in electrodialysis operation.

[0023] This task is solved by coating a substrate with a LiSICon material using aerosol-based cold deposition. This method produces a laminated body that, due to its special material combination, is ideally suited as a membrane for electrodialytic lithium deposition. Although the use of laminated bodies as membranes for lithium deposition had already been outlined, no specific technology was specified for producing a membrane with this special material composition.

[0024] The invention therefore relates to a method for producing a laminated body comprising the following non-chronological steps: a) Providing a substrate containing at least one substrate material, wherein the substrate material is selected from the group consisting of the following materials:

[0025] • metallic material M;

[0026] • ceramic material K;

[0027] • glassy material G;

[0028] • polymeric material P;

[0029] • LiSICon with stoichiometry LATSP

[0030] Lil+x+yAlxTi2-xSiyP3-yOl2 (LATSP) where in LATSP: 0.1 <x<0.3 und 0.2<y<0.4;

[0031] • LiSICon with stoichiometry LAGTP

[0032] Lii 4Alo.4(Gei-xTix)i .6 (PO4)3(LAGTP) where in LAGTP: 0 <x<1 ; b) Bereitstellen eines ersten anorganischen Materials in Pulverform, wobei das erste anorganische Material ausgewählt ist aus der Gruppe bestehend aus den folgenden Materialien: o LiSICon mit der Stöchiometrie LAGTP

[0033] Lii4Alo (Gei.xTix)i 6 (PO4)3(LAGTP) where in LAGTP: 0 <x<1 o LiSICon mit der Stöchiometrie LAGP

[0034] Lii+xAlxGe2-x (PÜ4)3 (LAGP) where in LAGP: x=0 or x=0.2 or x=0.4. o LiSICon with stoichiometry LATSP

[0035] Lil+x+yAlxTi2-xSiyP3-yOl2 (LATSP) where in LATSP: 0.1 <x<0.3 und 0.2<y<0.4; o LiSICon mit der Stöchiometrie LLTO

[0036] Li3xLa(2 / 3)-xQ(i / 3)-2xTiO3 (LLTO) where in LLTO: 0 <x<0.16 und wobei das LLTO optional dotiert sein kann mit mindestens einem Dotierelement, welches ausgewählt ist aus der Gruppe bestehend aus den folgenden Dotierelementen: Ag, AI, Zr, Nd, Sr, Ta, Y, Ge, Nb; o LiSICon mit der Stöchiometrie LLZO

[0037] Li7La3(Zr, D)2OI2(LLZO) wherein in LLZO the dopant D is selected from the group consisting of the following dopants: Hf, Ce, Ru; c) providing a carrier gas; d) dispersing the first inorganic material in the carrier gas so that an aerosol stream is obtained, e) placing the substrate in an evacuated space in which an absolute pressure of 0.1 kPa to 1 kPa and a temperature of 15°C to 25°C prevail; f) exposing the substrate placed in the evacuated space to the aerosol stream so that at least one layer containing the first inorganic material is deposited on the substrate; g) obtaining a layered body comprising the substrate and at least the aforementioned layer in which the first inorganic material is enriched, wherein the aforementioned layer is deposited on the substrate. The method according to the invention operates according to the principle of aerosol-based cold deposition.It enables the coating of a substrate made of metal, ceramic, glass, or polymer with LiSICon materials. In particular, the process described here allows the production of a layered body composed of two different LiSICon materials: This is achieved by coating a substrate made of a first LiSICon material with a second LiSICon material. The process also allows a porous substrate made of a non-lithium-conductive material to be coated with an intrinsically lithium-conductive LiSICon layer. Such a layered body is well suited as a membrane for the deposition of Li. +Cations from lithium-containing waters. The advantage of using a LiSICon layered body instead of a monolithic membrane in the context of lithium electrodialysis is that the advantages of different LiSICons can be combined in the layered body. A layered body can be configured so that the mechanical stability of the membrane is ensured by the substrate, while selectivity is achieved with a thin LiSICon coating. The thin layer thickness allows the use of insensitive and inexpensive LLTO without significantly limiting the overall permeance of the membrane. It is also possible to apply a thin protective layer of LLTO to phosphate-based LiSICon, which has high lithium conductivity, to protect the sensitive phosphate from contamination.In this way, better solutions can be realized in complex application situations with a LiSICon layered body than with a membrane made of only one LiSICon material.

[0038] The LiSICon layer body is produced using aerosol-based cold deposition.

[0039] In aerosol-based cold deposition (also called aerosol deposition method, ADM), a substrate is exposed to a high-energy aerosol jet in a vacuum. This jet contains a carrier gas and a powder dispersed within it. The powder is deposited on the surface of the substrate. This causes a layer to grow on the substrate in which the powder material is concentrated.

[0040] A basic description of aerosol-based cold deposition can be found in:

[0041] Sozak, M., Nazarenus, T., Exner, J. et al. Room temperature manufacture of dense NaSICON solid electrolyte films for all-solid-state-sodium batteries. J Mater Sci 58, 10108-101 19 (2023). https: / / doi.org / 10.1007 / s10853-023-08642-w

[0042] It is also mentioned here that this process is also suitable for the deposition of LAGP and LATP on various substrates. However, Sozak et al. do not provide a concrete description of such a process; rather, in the cited article, they report how they coated a stainless steel or aluminum substrate with a NaSICon material. A further description of aerosol-based cold deposition can be found in DE102018003289A1, and an associated apparatus for carrying out the process is disclosed in DE102020005738A1.

[0043] An alternative process of aerosol-based cold deposition was described by Ilka-Verena Luck in her presentation NEXT-GENERATION COATING APPLICATIONS BY AEROSOL DEPOSITION at the International Thermal Spray Conference and Exposition on May 23, 2023 in Quebec, Canada.

[0044] The invention further relates to a laminated body comprising a substrate made of metal, ceramic, glass, polymer, or LiSiCon and a coating made of LAGTSP, LAGTP, LAGP, or LLTO. Such a laminated body can be produced by the method according to the invention.

[0045] Such a laminated body is ideally suited as a membrane for separating mixtures of substances, particularly for the electrodialytic separation of lithium from lithium-containing waters. This use is a further subject of the invention.

[0046] Preferred developments of the method according to the invention, the laminated body according to the invention and its use are set out in the subclaims.

[0047] In particular, it was found that LATSP substrates can be coated particularly well using aerosol-based cold deposition with LLTO, LAGTP, or LAGP powders if these powders have a microcrystalline structure. Inorganic materials produced by flame pyrolysis, such as Aerosil® from Evonik, possess this microcrystalline structure. However, due to their structure and particle size, these materials are unsuitable for the ADM process, as the small and light particles are entrained by the gas flow and do not possess sufficiently high kinetic energy to enable layer buildup on the substrate.

[0048] It has been found that these microcrystalline, pyrogenically produced compounds can be used in the ADM process if they are calcined after production and, after calcination, milled to the correct agglomerate size for the ADM process. Calcination of the pyrogenically produced particles ideally takes place at a temperature between 500°C and 1000°C, particularly preferably between 550°C and 800°C, with treatment at this temperature lasting between a few minutes and several hours. Treatment times of several hours do not negatively affect the process, but are not necessary. After calcination, grinding takes place in mills suitable for achieving the desired particle size with a median X 50.0 of 1 to 3 pm, combined with an X 990 of 10 pm (for example, classifying mills such as a Jet Mill or Pulvis from Hosokawa).When applied in this form using ADM, high layer quality and good ionic conductivity, combined with good layer adhesion, are achieved, particularly when using lithium-conductive materials.

[0049] The ion transfer from one material to the next material also does not experience any increased resistance, so that the overall ion conduction has very good conductivities due to a multi-layer material combination.

[0050] Thus, the combination of ADM technology and the tailor-made ceramic pyrogenically produced particles as described is ideal for the production of thin lithium conductive layers from a wide variety of LiSICon materials and material combinations.

[0051] A particularly preferred embodiment of the invention provides for the first inorganic material to be used in a doped powder form. The powder is doped with a lithium salt. Doping in this context means that the individual particles of the powder made of the first inorganic material (LiSICon) are coated or at least spiked with the lithium salt on their surface. The internal structure of the LiSICon (crystal structure / stoichiometry) remains unaffected. The motivation for this doping is to give the individual LiSICon particles an extra portion of lithium, namely in the form of the lithium salt on the surface of the particles. It has been shown that when LiSICon material is exposed to high temperatures, lithium is lost from the crystal lattice, so that the conductivity for Li +-cations decreases. In the ADM process, the LiSICon particles in the aerosol stream acquire high kinetic energy. This is converted into heat energy when the particles impact the substrate. The LiSICon particles heat up, which can cause Li to be lost from the LiSICon. However, if the particles now bring an extra portion of lithium in the form of lithium salt, the lithium missing in the crystal lattice of the LiSICon is replaced by lithium originating from the lithium salt, as the lithium salt also decomposes under high energy influences. As a result, doping the powder with the lithium salt ensures that the first inorganic material retains its intrinsic conductivity for Li. + -cations are not lost too much through the ADM process.

[0052] The following lithium salts are suitable for doping the first inorganic material: lithium nitrate (LiNOs), lithium nitrate trihydrate (LiNOs • 3H2O), lithium hydroxide (LiOH), lithium oxide (U2O), lithium peroxide (U2O2), lithium nitrite (UNO2), lithium carbonate (U2CO3), and lithium bicarbonate (CHLiOs). Lithium nitrate is particularly preferred for doping the first inorganic material.

[0053] The LiSICon powder is doped using a wet-chemical process: A solution of the lithium salt is prepared in an organic solvent. Ethanol, for example, is a suitable organic solvent. The lithium salt solution is then mixed with the undoped LiSICon powder to form a dispersion. The organic solvent is then removed from the dispersion, for example, by drying. Spray drying is the most suitable method. This produces a powder doped with lithium salt.

[0054] This wet-chemical doping method combines particularly well with the pyrogenic production of LiSICon powder: The calcined LiSICon powder is dispersed in the lithium salt solution before or after grinding and then dried. The dried, now doped powder can then be further ground if necessary. This produces the first inorganic material, which is then applied to the substrate using the aerosol stream.

[0055] The sub-process for providing the first inorganic (LiSICon) material for use in the ADM process therefore preferably comprises the following steps: b1) pyrolytic production of a precursor powder from LiSICon material; b2) calcining the precursor powder; ba) providing an undoped powder in the form of the calcined precursor powder; b3) grinding the calcined precursor powder; bb) providing a solution containing at least one organic solvent and at least one lithium salt dissolved therein; bc) preparing a dispersion by dispersing the undoped powder in the solution; bd) removing the solvent from the dispersion by drying or spray drying; be / b4) obtaining a doped powder as the first inorganic material in powder form.

[0056] It is irrelevant whether the grinding of the calcined precursor powder takes place before or after its doping.

[0057] The pyrolytic production of precursor powder from LiSICon material is generally known and is disclosed, among other things, in WO 2023 / 078790 A1. For example, Example 3 of this document describes the pyrolytic production of LAGTP powder. A powdered LiSICon with the stoichiometry LATP was produced pyrolytically in Example 1 of WO 2023 / 078790 A1.

[0058] Calcination, as described above, is necessary to agglomerate the fine LiSICon material produced during pyrolysis. Without calcination, the pyrolytically produced LiSICon powder would have a particle size far too fine to be successfully processed by aerosol-based cold deposition. Since during calcination, the particles also grow into agglomerates that are too large for the intended purpose, the calcined powder is further ground and, if necessary, sieved to finally achieve the desired particle size distribution. In this way, a powdered LiSICon material is obtained through pyrolytic production of the precursor powder from LiSICon material, calcination and grinding of the calcined powder, and optional sieving and doping. This powdered LiSICon material has the following particle size distribution: median size X50.0 from 1 pm to 3 pm

[0059] Particle size with Qo=O.99 (X99,o) of 10 pm.

[0060] Both quantities are determined according to ISO 9276-5:2005(E). The median size Xso.o is often referred to as the Dso value in particle technology.

[0061] A LiSICon powder with this particle size distribution is ideal for coating a substrate in an ADM process. This allows a laminated body with one or more layers of LiSICon material to be constructed based on the substrate. Table 1 contains preferred embodiments of the laminated body, for the production of which the substrate material and the inorganic materials are selected according to the table rows:

[0062] Table 1 : Embodiments

[0063] The embodiments marked with an asterisk * in Table 1 are not according to the invention.

[0064] M stands for a metallic material, K for a ceramic material, G for a glassy material, and P for an organic polymer material. These acronyms represent LiSICon materials with the corresponding stoichiometry. "na" stands for "not applicable," which in this table means that no third layer is present in this embodiment.

[0065] Metallic materials include pure metals such as Fe, Cr, Ni, Cu, Al, Mg or alloys such as steel, non-ferrous metals or light metals.

[0066] Ceramic materials include all types of oxide, carbide and nitride ceramics, in particular this includes zirconium oxide, aluminum oxide, titanium dioxide, silicon dioxide, silicon carbide and silicon nitride.

[0067] Glass-like materials can be all types of glass, especially those that exhibit good stability at low and high pH values. The glasses are preferably inorganic glasses, especially silicate or borate glasses.

[0068] LiSICon materials are ceramic materials. Some LiSICon materials exist in a glassy state, meaning they are both ceramic and glassy.

[0069] Materials made of organic polymers can consist of polyolefins, such as polypropylene (PP) or polyethylene (PE). They can also consist of polyimides (PI), polyamides (PA), polyesters (PES), polyurethanes (PU), polyvinyl chlorides (PVC), and polyacrylates, as well as polyphenylene sulfide, polyetherimide, polysulfone, polyethersulfone, and other so-called high-performance polymers. Copolymers can also be used, such as copolymers of acrylonitrile, butadiene, and styrene, although their composition can vary widely. The embodiments shown in Table 1 are therefore based on ordered pairs, where the left entry represents the first inorganic material and the right entry represents the second inorganic material.

[0070] (LATSP, LAGTP)

[0071] (LATSP, LAGP)

[0072] (LAGTP, LAGP)

[0073] (LATSP, LLTO)

[0074] (LAGTP, LLTO)

[0075] (M, LATSP)

[0076] (M, LAGTP)

[0077] (M, LAGP)

[0078] (M, LLTO)

[0079] (K, LAGTP)

[0080] (K, LAGP)

[0081] (K, LLTO)

[0082] (G, LAGTP)

[0083] (G, LAGP)

[0084] (G, LLTO)

[0085] (P, LAGTP)

[0086] (P, LAGP)

[0087] (P, LLTO)

[0088] Further embodiments are based on an additional layer of LLTO.

[0089] What all designs have in common is that the LiSICon material with the highest resistance to alkali and alkaline earth ions in the respective combination is applied as the last layer.

[0090] The particularly preferred embodiments are based on three ordered pairs, in which the left entry represents the first inorganic material and the right entry represents the second inorganic material.

[0091] (LATSP, LAGTP);

[0092] (LATSP, LAGP);

[0093] (LATSP, LLTO);

[0094] Further particularly preferred embodiments are based on an additional coating of LLTO, resulting in a three-layer structure. Ideally, the substrate materials are porous. Porous means that the substrate has pores. The pores should in particular be accessible from the outside and, furthermore, preferably be interconnected. The substrate is therefore preferably open-pored. A substrate in textile form, in particular a textile fabric, is porous in this sense because pores form between the fibers of the textile. Textile fabrics include woven fabrics, knitted fabrics, scrims, felts, or nonwovens. In addition to a textile form, substrates that derive their porosity from a grain structure, such as sintered bodies, are also suitable. Sintered bodies are composed of grains that are partially fused at their grain boundaries.Because the fusion is only partial, the grain boundaries of a sintered body are still visible. Pores form between the grain boundaries.

[0095] As already described, the substrate can consist of a metal, a ceramic, an organic polymer, or a glass-like material. Among the class of metallic substrates, porous sintered metals, metal foams, expanded metals, perforated sheets, metal fleeces, or fine metal fabrics (gauze) are particularly suitable. Organic substrate materials are preferably in textile form, i.e., as a textile sheet with organic fibers, in particular as a fleece made of fibers consisting of the desired substrate material. Alternatively, organic substrate materials can be used as a film. Ceramic materials are preferably used as flat sintered ceramics. Glass-like materials can either be cast as flat glass or as glass frit by fusing glass grains. Glass frits are advantageously porous.LiSICon materials are typically shaped using sol-gel technology or by sintering corresponding LiSICon powders. Since porous substrates can be produced from LiSICon material by sintering LiSICon powders, this method is preferred. LiSICon powder is preferably sintered under mechanical pressure and the influence of an electric current (spark plasma sintering). The processes described here are state-of-the-art. The substrates obtained in this way are commercially available. In particular, commercially available organic or inorganic ultrafiltration membranes, glass frits, or sintered metal frits can be used as porous substrates.

[0096] It can also be advantageous to use a composite that combines ceramic and organic materials as a substrate. Examples of this include composite bodies such as those disclosed in EP 3669974 B1. If such a composite body is used as a substrate, the substrate accordingly contains several substrate materials.

[0097] The average pore size of the substrate should be less than 10 pm, in particular less than 1 pm, and most preferably less than 0.2 pm. This enables good impregnation of the substrate with a liquid electrolyte, in particular with an aqueous catholyte of an electrodialysis cell. This is described in more detail below. Furthermore, it is advantageous if the average pore size of the substrate is smaller than the median size X50.0 of the powder of the first inorganic material (LiSICon) applied to the substrate. This allows a continuous coating of LiSICon material to be applied to the porous substrate, making the laminated body fluid-tight overall. If the powder is finer than the pores, it cannot be ruled out that some pores may remain unsealed despite coating with the ADM process. The laminated body would then be permeable to fluids and could no longer be used as a highly selective membrane.Therefore, it is preferred if the particle size distribution of the powder made from the first inorganic (LiSICon) material is adjusted so that its median size X50.0 is larger than the average pore size of the porous substrate. The particle size distribution of the powder is most easily adjusted by grinding the first inorganic material. Grinding can take place in several stages. If necessary, sieving and / or classifying steps should be provided before or after the individual grinding stages. These steps are preferably carried out in a combination of a mill and an air classifier. In the sieving or classifying steps, the oversize particles are separated so that they can be returned to the grinding process and / or the undersize particles, which do not correspond to the desired particle size distribution, are removed.

[0098] The mean pore size is determined using gas flow porometry as described below using a Porolux 1000 (porometer, Eke, Belgium). For this purpose, a circular sample with a diameter of 25 mm is punched out of the material to be analyzed, dried at 100 °C for 1 hour in a drying cabinet to remove moisture from the pores, and then immediately immersed in the wetting liquid Porefil® to ensure that all existing pores are filled with this liquid. The sample is then degassed by briefly applying a vacuum (150 mbar or 15 kPa) in a desiccator to ensure that all pores are filled with Porefil®. The degassed sample is placed in the sample holder of the measuring device, and the sample holder is screwed shut.

[0099] The determination of the pore radius distribution is based on the measuring principle of capillary flow porometry. The sample, which has been soaked with the wetting liquid and degassed, is subjected to a gradually increasing inert gas pressure (nitrogen) in the measuring cell, and the pore diameters corresponding to the applied pressure are emptied by the gas pressure. The flow rate of the gas is recorded as the pressure increases. In the continuous pores, an exchange of the wetting liquid with nitrogen takes place. This continues until the relevant pore area has been covered, i.e., until even the smallest pores in the measuring area are free of liquid. The pressure in the measuring cell is then reduced again, and the measurement is repeated on the now dry sample. The pore size distribution is calculated from the difference between the wet curve and the dry curve.The porometry measurements provide information about the largest pore radii present (so-called "bubble point"), as well as the most common and smallest pore diameters. The use of porous substrate materials is particularly advantageous when the laminated body is to be used as a membrane in the electrodialytic separation of lithium from lithium-containing water. In such an application, the laminated body used as a membrane is installed in an electrochemical cell in such a way that the layer containing the LiSICon material is in contact with the lithium-containing water. The substrate is therefore facing away from it. Instead, the substrate is in contact with the catholyte of the electrochemical cell, in which the separated lithium accumulates during electrodialysis (the lithium is dissolved in the lithium-containing water as Li). +cation, which migrates through the LiSICon material towards the cathode according to the electrical potential prevailing in the electrochemical cell. The Li + Cations therefore accumulate in the cell's catholyte during electrodialysis. The catholyte is usually an aqueous solution. In order for the catholyte to retain the Li + To absorb cations, it must be in contact with the LiSICon material, which delivers the lithium cations to the catholyte. To ensure high permeance of the membrane for lithium, a particularly large contact area must be ensured between the LiSICon material and the catholyte. Because the catholyte infiltrates the pores of the substrate, the porosity of the substrate increases the contact area between the LiSICon material and the catholyte and thus also the permeance of the membrane. This increased permeance, in turn, has a positive effect on the efficiency of electrodialysis.

[0100] If the substrate is a LiSiCon material, the porosity of the substrate is not absolutely necessary to enable the application of the laminated body as a membrane in the electrodialytic separation of lithium from lithium-containing waters. It is merely desirable in the interest of increasing efficiency. However, if the substrate is a material that does not have conductivity for lithium cations, this material must be porous, because otherwise the Li + Cations cannot enter the catholyte. As a result, the substrate in lithium electrodialysis must not be impermeable to lithium: It becomes permeable, for example, through its intrinsic conductivity as a LiSICon material or through its porous structure, which can be impregnated with catholyte. Of course, the substrate can also combine both properties.

[0101] If the laminate has a purpose other than the function of a membrane in electrodialytic lithium separation, the substrate can also be lithium-tight and, in particular, free of pores.

[0102] In the context of the electrodialytic separation of lithium from lithium-containing waters, which contain cationic impurities in addition to lithium cations, such as cations of the elements B, Na, Mg, Al, Si, K, Ca, Mn, Fe, Co, Ni, Cu, and C, it is recommended to use a three-layer membrane constructed as follows: a porous substrate, a first coating made of a first LiSICon material, and a second coating made of a second LiSICon material on top of the first coating. The second LiSICon material is less sensitive to cationic impurities than the first LiSICon material. Since the second coating is exposed to cationic impurities during membrane operation, the second coating made of the less sensitive material protects the first coating.The first LiSICon material enriched in the first coating can have a higher specific Li conductivity than the second LiSICon material enriched in the second coating. This makes the membrane more selective overall. Likewise, the second LiSICon material can be cheaper than the first LiSICon material, making the membrane cheaper overall. It is also conceivable to choose different layer thicknesses s of the respective LiSICon layers: The thickness si of the first layer containing the first inorganic material can be greater than the thickness S2 of the second layer containing the second inorganic material. This makes sense when the first inorganic material is more expensive than the second. Of course, in other situations, it may be useful to choose S2 greater than si.

[0103] For these reasons, a three-layer composite used as a membrane in Li separation preferably has a second coating of LLTO. The first coating can be made of LAGTP, LAGP, or LATSP. All materials discussed here can be used as substrates, as long as they are in porous form. The corresponding material combinations are listed in Table 1.

[0104] If LLTO is used as a coating material, it is optionally possible to use doped LLTO. It is known that the Li conductivity of LLTO can be increased by doping with a doping element. The following elements can be considered for doping LLTO: Ag, Al, Zr, Nd, Sr, Ta, Y, Ge, Nb. A method for doping LLTO with aluminum, more specifically with Al 3+ , was presented by Huang Yi et al:

[0105] Huang Y., He L., Zhu X.: Low temperature synthesis of Lio 33Lao 55TiO3solid electrolyte with Al 3+ doping by a modified Pechini method. (2022) Ionics, 28 (4), pp. 1739 - 1751 DOI: 10.1007 / sl 1581-021-04422-1

[0106] In contrast to the doping of the particles with lithium salt, the doping of LLTO with the doping elements Ag, Al, Zr, Nd, Sr, Ta, Y, Ge, Nb is a doping at the crystal level.

[0107] Another doped LiSICon, which can be used as the first inorganic material for coating in the context of the invention, is doped LLZO:

[0108] Li7La3(Zr, D)2OI2(LLZO)

[0109] The dopant D of LLZO is optionally Hf, Ce or Ru. A method for the preparation of appropriately doped LLZO is described by Lee, Han Uk et al.: Lee HU, Han S., Lee DG, Ko H., Lee J., Im WB, Song T., Choi J., Cho SB: Isovalent multi-component doping strategy for stabilizing cubic-Li?La3Zr2Oi2 with excellent Li mobility. Chemical Engineering Journal, 471 , art. no. 144552. DOI: 10.1016 / j.cej.2023.144552 Unlike the doping of the particles with lithium salt, the doping of LLZO with the dopants Hf, Ce or Ru is a doping at the crystal level.

[0110] Another advantage of aerosol-based cold deposition is that this process allows for the creation of very thin layers. The layer containing the first inorganic material is preferably less than 10 μm thick, most preferably less than 1 μm. These thin layers of LiSICon material enable particularly high permeance when the layered body is used as a membrane. Until now, it was not possible to produce LiSICon membranes with a thickness of less than 10 μm. If the layered body has two layers of LiSICon material, both layers can have a thickness in this range.

Claims

Patent claims 1 . A method for producing a laminated body comprising the following non-chronological steps: a) providing a substrate containing at least one substrate material; b) providing a first inorganic material in powder form; c) providing a carrier gas; d) dispersing the first inorganic material in the carrier gas to obtain an aerosol stream; e) placing the substrate in an evacuated space in which an absolute pressure of 0.1 kPa to 1 kPa and a temperature of 15°C to 25°C prevail; f) subjecting the substrate placed in the evacuated space to the aerosol stream so that at least one layer containing the first inorganic material is deposited on the substrate; g) obtaining a laminated body comprising the substrate and at least the aforementioned layer in which the first inorganic material is enriched, wherein the aforementioned layer is deposited on the substrate; characterized in that the substrate material is selected from the group consisting of the following materials:. • metallic material M; • ceramic material K; glass-like material G; polymeric material P; LiSICon with stoichiometry LATSP Lil+x+yAlxTi2-xSiyP3-yOl2 (LATSP) where in LATSP: 0.1 <x<0.3 und 0.2<y<0.4; • LiSICon with stoichiometry LAGTP Lii 4Alo.4(Gei-xTix)i .6 (PO4)3(LAGTP) where in LAGTP: 0 <x<1 und dass das erste anorganische Material ausgewählt ist aus der Gruppe bestehend aus den folgenden Materialien: o LiSICon mit der Stöchiometrie LAGTP Lii4Alo (Gei.xTix)i 6 (PO4)3(LAGTP) where in LAGTP: 0 <x<1 o LiSICon mit der Stöchiometrie LAGP Lii+xAlxGe2-x (PO4)3(LAGP) where in LAGP: x=0 or x=0.2 or x=0.

4. o LiSICon with stoichiometry LATSP Lil+x+yAlxTi2-xSiyP3-yOl2 (LATSP) where in LATSP: 0.1 <x<0.3 und 0.2<y<0.4; o LiSICon with stoichiometry LLTO Li3xLa<2 / 3)-xn(i / 3)-2xTiO3 (LLTO) where in LLTO: 0 <x<0.16 und wobei das LLTO optional dotiert sein kann mit mindestens einem Dotierelement, welches ausgewählt ist aus der Gruppe bestehend aus den folgenden Dotierelementen: Ag, AI, Zr, Nd, Sr, Ta, Y, Ge, Nb; o LiSICon mit der Stöchiometrie LLZO Li7La3(Zr, D)2OI2(LLZO) wherein in LLZO the dopant D is selected from the group consisting of the following dopants: Hf, Ce, Ru.

2. The method according to claim 1, wherein the carrier gas contains oxygen and is provided at a pressure of 5 kPa to 50 kPa.

3. Method according to claim 1 or 2, characterized by a relative movement between the aerosol stream and the substrate, wherein the relative movement extends in the plane of the substrate and wherein the speed of the relative movement is between 1 mm / s and 10 mm / s.

4. The method according to claim 1, 2 or 3, wherein the substrate material and the first inorganic material form an ordered pair selected from the group consisting of the following ordered pairs: (LATSP, LAGTP) (LATSP, LAGP) (LAGTP, LAGP) (LATSP, LLTO) (LAGTP, LLTO) (M, LATSP) (M, LAGTP) (M, LAGP) (M, LLTO) (K, LAGTP) (K, LAGP) (K, LLTO) (G, LAGTP) (G, LAGP) (G, LLTO) (P, LAGTP) (P, LAGP) (P, LLTO) where the left entry of the ordered pairs represents the substrate material and the right entry of the ordered pairs represents the first inorganic material.

5. The method according to claim 1, 2 or 3, wherein the substrate material and the first inorganic material form an ordered pair selected from the group consisting of the following ordered pairs: (LATSP, LAGTP); (LATSP, LAGP); (LATSP, LLTO); where the left entry of the ordered pairs represents the substrate material and the right entry of the ordered pairs represents the first inorganic material.

6. Method according to one of claims 1 to 5, characterized in that the substrate is porous.

7. The method according to claim 6, characterized in that the substrate has an average pore width d determined according to the method defined in the description, wherein the average pore width d is between 0 and 10 pm or between 0 and 1 pm or between 0 and 0.2 pm.

8. A method according to any one of claims 1 to 7, characterized in that the first inorganic material is provided with the following particle size distribution: Median size Xso.o from 1 pm to 3 pm Particle size with Qo=0.99 (X99,o) of 10 pm. Both sizes determined according to ISO 9276-5:2005(E).

9. Process according to claims 7 and 8, characterized in that the mean pore size d is smaller than the median size Xso.o.

10. The method according to any one of claims 1 to 9, wherein step b) providing a first inorganic material in powder form comprises at least the following substeps: b1) pyrolytic production of a precursor powder; b2) calcining the precursor powder; b3) grinding the calcined precursor powder; b4) obtaining the first inorganic material in powder form.

11. A method according to claim 10, characterized in that the calcination takes place at a temperature between 500°C and 1000°C or at a temperature between 550°C and 800°C, and that the calcination takes place over a period of time from 1 minute to 300 minutes.

12. The method according to any one of the preceding claims 1 to 11, characterized in that the first inorganic material is doped with at least one lithium salt, wherein the lithium salt is selected from the group consisting of the following lithium salts: lithium nitrate, lithium nitrate trihydrate, lithium hydroxide, lithium oxide, lithium peroxide, lithium nitrite, lithium carbonate, lithium hydrogen carbonate.

13. The method according to claim 12, characterized in that step b) providing a first inorganic material in powder form; comprises the following substeps: ba) providing an undoped powder; bb) providing a solution containing at least one organic solvent and at least the lithium salt dissolved therein; bc) preparing a dispersion by dispersing the undoped powder in the solution; bd) removing the solvent from the dispersion by drying or by spray drying; be) obtaining a doped powder.

14. A method according to at least claims 11 and 13, wherein the undoped powder is calcined precursor powder and wherein the doped powder is the first inorganic material in powder form.

15. The method according to any one of claims 1 to 14, further comprising the additional steps: h) Providing a second inorganic material in powder form; i) Dispersing the second inorganic material in the carrier gas so that a further aerosol stream is obtained; j) Exposing the already coated substrate placed in the evacuated space to the further aerosol stream so that at least one further layer containing the second inorganic material is deposited on the aforementioned layer containing the first inorganic material; k) Obtaining a laminated body comprising the substrate, the aforementioned layer in which the first inorganic material is enriched, and the further layer in which the second inorganic material is enriched, wherein the further layer is deposited on the aforementioned layer.

16. A laminated body comprising a substrate containing at least one substrate material and at least one layer applied to the substrate in which a first inorganic material is enriched, characterized in that the substrate material is selected from the group consisting of the following materials: • metallic material M; • ceramic material K; • glassy material G; • polymeric material P; • LiSICon with stoichiometry LATSP Lil+x+yAlxTi2-xSiyP3-yOl2 (LATSP) where in LATSP: 0.1 <x<0.3 und 0.2<y<0.4; LiSICon with the stoichiometry LAGTP Lii 4AI04(Gei-xTix)i 6 (PO4)3 (LAGTP) where in LAGTP: 0 <x<1 und dass das erste anorganische Material ausgewählt ist aus der Gruppe bestehend aus den folgenden Materialien: o LiSICon mit der Stöchiometrie LAGTP Lii 4Alo.4(Gei-xTix)i .6 (PO4)3(LAGTP) where in LAGTP: 0 <x<1 o LiSICon mit der Stöchiometrie LAGP Lii+xAlxGe2-x (PO4)3(LAGP) where in LAGP: x=0 or x=0.2 or x=0.

4. o LiSICon with stoichiometry LATSP Lil+x+yAlxTi2-xSiyP3-yOl2 (LATSP) where in LATSP: 0.1 <x<0.3 und 0.2<y<0.4; o LiSICon mit der Stöchiometrie LLTO Li3xLa(2 / 3)-xQ(i / 3)-2xTiO3 (LLTO) where in LLTO: 0 <x<0.16 und wobei das LLTO optional dotiert sein kann mit mindestens einem Dotierelement, welches ausgewählt ist aus der Gruppe bestehend aus den folgenden Dotierelementen: Ag, AI, Zr, Nd, Sr, Ta, Y, Ge, Nb; o LiSICon mit der Stöchiometrie LLZO Li7La3(Zr, D)2OI2(LLZO) wherein in LLZO the dopant D is selected from the group consisting of the following dopants: Hf, Ce, Ru.

17. A laminated body according to claim 16, wherein the substrate material and the first inorganic material form an ordered pair selected from the group consisting of the following ordered pairs: (LATSP, LAGTP) (LATSP, LAGP) (LAGTP, LAGP) (LATSP, LLTO) (LAGTP, LLTO) (M, LATSP) (M, LAGTP) (M, LAGP) (M, LLTO) (K, LAGTP) (K, LAGP) (K, LLTO) (G, LAGTP) (G, LAGP) (G, LLTO) (P, LAGTP) (P, LAGP) (P, LLTO) where the left entry of the ordered pairs represents the substrate material and the right entry of the ordered pairs represents the first inorganic material.

18. A laminated body according to claim 17, characterized by a further layer in which a second inorganic material is enriched, the further layer being applied to the aforementioned layer.

19. A laminated body according to any one of claims 16 to 18, obtainable by a process according to any one of claims 1 to 15.

20. Laminated body according to one of claims 16 to 19, characterized by a flat shape and / or by a porous substrate.

21. Laminated body according to one of claims 16 to 20, wherein the layer in which the first inorganic material is enriched and / or the layer in which the second inorganic material is enriched has a layer thickness s which is greater than 0 pm, characterized in that layer thickness s is less than 10 pm or less than 1 pm.

22. Use of a laminated body according to one of claims 16 to 21 as a membrane for the electrodialytic separation of lithium from lithium-containing waters.

23. Use according to claim 22, characterized by the presence of cationic impurities in the lithium-containing waters, wherein the cationic Impurities are cations of elements selected from the group consisting of B, Na, Mg, Al, Si, K, Ca, Mn, Fe, Co, Ni, Cu, C 24. Use according to claim 22 or 23, characterized by the presence of anionic impurities in the lithium-containing waters, wherein the anionic impurities are anions selected from the group consisting of sulfate, hydrogen sulfate, carbonate, hydrogen carbonate, hydroxide, chloride, fluoride.