Electrochemical device with an improved intermediate membrane between two porous electrodes

Abstract

A solid electrochemical device is presented, comprising: - first (PE1) and second (PE2) electrodes, having planar layer shapes of first and second thicknesses respectively, and - an intermediate membrane (MB) separating the first and second electrodes, the first and second electrodes having respective porosities greater than a threshold, the intermediate membrane having a porosity less than the threshold, wherein the intermediate membrane has at least one first peripheral rim of height (a) greater than or equal to the first thickness to form a first recess for receiving the first electrode. Abstract figure: Figure 5

Description

Title of the invention: Electrochemical device with an improved intermediate membrane between two porous electrodes. Technical field

[0001] This disclosure relates to the field of solid-state electrochemistry and its applications in all electrochemical devices such as fuel cells, electrolyzers, hydrogen or oxygen separators, electrochemical compressors and pumps, or gas sensors. Previous technique

[0002] As illustrated in [Fig.1] relating to the prior art, such devices may have porous electrodes PE1, PE2 separated by a denser intermediate layer, referred to in particular as "dense membrane" below.

[0003] Such an embodiment is described in particular in document EP4198175, which presents an electrolyte whose solid structure is ensured by the intermediate layer, which is denser than the porous electrodes. Current standard manufacturing techniques use yttrium-stabilized zirconia (YSZ) or barium / cerium / yttrium oxide-based oxides (for example, BaCei XYXO3 γ, BaCei x YZrxYYO3 γ, etc.) as the dense layer and porous electrodes that may have a "cermet" type composition (a mixture of ceramic and metal, the ceramic most often being the same material as the dense layer and the metal being nickel).

[0004] In particular, if the respective porosities of electrodes PE1 and PE2 exceed a certain threshold (for example, 30%), it will be understood that the intermediate membrane has a porosity lower than this threshold. Therefore, it is possible to apply infiltrations of selected materials into the first electrode PE1, for example, without these materials contaminating, in principle, the underlying second electrode PE2, because the intermediate membrane MB acts as a barrier to these materials, so that they remain embedded only in the first electrode PE1. Furthermore, it is generally preferable that this membrane MB also be gas-tight (particularly impermeable to air or hydrogen).

[0005] As illustrated in [Fig. 2] relating to the prior art, the infiltration of active materials into at least one of the porous electrodes PE1 is typically carried out. This operation aims to incorporate particles deep within the PE1 electrode, particles designed to impart specific properties (catalytic, electro-catalytic, electrochemical, etc.) to the PE1 electrode for the purpose of its activation. This infiltration can be achieved by spraying a fluid. (for example a liquid LIQ containing such particles) on the upper surface of the first electrode PE1.

[0006] As illustrated in Figure 3 relating to the prior art, once the liquid LIQ has infiltrated the porous electrode PE1 (left-hand side of Figure 3), the density of the intermediate membrane MB forms a barrier to this liquid LIQ. Thus, after evaporation and removal of impurities, the aforementioned particles constituting the active elements EEA remain well confined within the porous electrode PE1 (right-hand side of Figure 3). However, in such a configuration in the sense of the prior art, it is difficult to control the distribution of these electrically active elements EEA, and typically, this distribution in the first electrode PE1 is inhomogeneous (spot near the center of electrode PE1 in the illustrated example).

[0007] This problem of inhomogeneity in the distribution of EEA elements could be overcome by increasing the amount of liquid LIQ sprayed onto the upper surface of the first electrode PE1, as illustrated in the left-hand portion of [Fig. 4]. However, in this case, an excess of liquid containing EEA particles can migrate to the edges of the membrane MB and into the second porous electrode PE2. This then creates a risk of short-circuiting (RCCT) between the first and second electrodes PE1 and PE2, due to the direct connection that these EEA particles can make, thus distributing themselves from the first electrode PE1 to the second electrode PE2.

[0008] More generally, the prior art configuration as illustrated in Figures 1 to 4 often presents problems with the diffusion of unwanted species from one PE1 electrode to the other PE2 electrode, particularly by crossing the edges of the dense MB membrane. For example, during the aforementioned sintering process presented in document EP4198175, the nickel Ni contained in the hydrogen electrode (Cermet) can diffuse during the sintering process and contaminate the different layers of the cell.

[0009] Such problems limit the practical deployment of these technologies in industrial environments. Currently available production methods struggle to create components with a high-quality microstructure and free from such interlayer contamination. The migration of certain elements during high-temperature operation, for example (typically in electrochemical devices such as batteries), can compromise the integrity of the entire electrochemical device, which represents a significant limitation of current methods.

[0010] Furthermore, in the prior art configuration of electrochemical cell stacks as illustrated by way of example in [Fig. 10], misalignment defects may occur between the first electrode PE1 in particular and the membrane (for example, due to a PE1 electrode that is narrower than the MB membrane). This then leads to PBE sealing problems, particularly with regard to gas. Summary

[0011] This disclosure improves the situation.

[0012] The proposed approach aims to overcome all or part of the above problems by introducing a layered manufacturing technique that efficiently separates the reactive layers, thereby improving the purity of each layer and the manufacturing process as a whole.

[0013] A method for manufacturing a solid electrochemical device is then proposed, the device comprising: - the first and second electrodes, having the shapes of flat layers, respectively of first and second thicknesses, and - an intermediate membrane, separating the first and second electrodes, the first and second electrodes having respective porosities greater than a threshold, the intermediate membrane having a porosity less than the threshold, wherein the intermediate membrane has at least a first peripheral rim of height greater than or equal to the first thickness to form a first recess, to receive the first electrode, the process comprising spraying a free surface of the first electrode with a fluid carrying active elements in order to infiltrate said active elements deep into the first electrode and confer chosen properties to the first electrode, the first basin thus forming a barrier to the active elements to prevent contamination of the second electrode.

[0014] Thus, the cup-like shape of the membrane prevents contamination of the second electrode. This technical effect, linked to the particular shape of the membrane, is also achieved both during the spraying step, thus preventing contamination of the second electrode, and during the sintering step of the assembly formed by the membrane and the electrodes, thus preventing diffusion of species between electrodes (for example, metals such as nickel, or others).

[0015] In one embodiment, the process involves the formation of a matrix comprising a precursor of the first electrode, attached to a precursor of the intermediate membrane on a first face, and a precursor of the second electrode, attached to the precursor of the intermediate membrane on a second face, a temperature greater than 1000°C being applied to this matrix to sinter at least partially the materials of the aforementioned precursors.

[0016] For example, sintering can be carried out before spraying (optionally and not necessarily).

[0017] In practice, sintering can be carried out in a furnace at a temperature above 1000°C and preferably above 1200°C.

[0018] The sprayed fluid may be, for example, an aqueous or organic liquid solution containing precursor components of selected electrode properties, as shown, for example, with reference to [Fig. 2]. The aforementioned active elements may typically include at least one element from among a transition metal, a lanthanide, and a rare earth element.

[0019] In one embodiment for example, the process may include, after spraying, the removal of undesirable elements initially present in the fluid, by applying to the first electrode at least a temperature of for example between 750 and 850°C.

[0020] In one embodiment, the precursor of the intermediate membrane can be formed in a solid material by at least one of the following techniques among pressing, machining, casting and drying, 3D printing, of said solid material.

[0021] Of course, other techniques can also be considered.

[0022] The precursor of the first electrode (and possibly of the second electrode) can be deposited on the precursor of the intermediate membrane by a technique of deposition of a porous material including spray, screen printing, casting and drying, of the porous material.

[0023] Here again, of course, other techniques can also be considered.

[0024] A solid electrochemical device is further proposed, comprising: - the first and second electrodes, having the shapes of flat layers, respectively of first and second thicknesses, and - an intermediate membrane, separating the first and second electrodes, the first and second electrodes having respective porosities greater than a threshold, the intermediate membrane having a porosity less than the threshold, in which the intermediate membrane has at least a first peripheral rim of height greater than or equal to the first thickness to form a first basin, to receive the first electrode.

[0025] In one embodiment, the intermediate membrane further includes a second peripheral rim of height greater than or equal to the second thickness to form a second basin, for receiving the second electrode.

[0026] The height of at least one of the first and second edges can typically be between 0.1 micron and 1 millimeter. Its width can be between a few millimeters and a few centimeters, for example with a first and / or second electrode width typically between 10 and 50 cm (according to usual industrial formats).

[0027] The intermediate membrane can, for its part, be of a thickness between a few microns and a few millimeters (preferably between 3 microns and 3 mm).

[0028] At least one of the first and second rims may be rectangular in shape, or even circular.

[0029] In one embodiment, the porosity of the first and second electrodes can be between a few hundred nanometers and a few tens of microns.

[0030] The intermediate membrane can, for its part, be made of a ceramic that is airtight to at least one gas among air and hydrogen.

[0031] In such an embodiment, the device may further comprise at least a first plate for enclosing the first electrode in a sealed space and thus delimited by the first plate and the first peripheral rim, which forms a sealed shoulder (reference EPLT of [Fig.9] discussed later).

[0032] In such an embodiment, the first containment plate can be electrically conductive and configured to be interconnected with a homologous plate of another electrochemical device (as illustrated in [Fig.9]).

[0033] As illustrated in [Fig.9], the first rim can be of the same width as the second rim.

[0034] In an embodiment retaining the usual dimensions of the prior art, the first rim can be wider than the second rim, to retain the sealing shoulder despite different electrode widths (the second electrode being for example narrower than the first).

[0035] In one embodiment, the first electrode can then be configured to be in contact with air and the second electrode can be configured to be in contact with hydrogen, in an application of the device as an air / hydrogen fuel cell typically.

[0036] The first electrode at least can be made of a material comprising at least one element among an oxide, a metal, a perovskite, a double perovskite, a mixture of ceramic and metal (Cermet).

[0037] The intermediate membrane can be made of a material comprising at least one element among yttrium-stabilized zircon and / or scandium, a barium-cerium-yttrium mixture, a ceramic and metal mixture (Cermet).

[0038] According to one of the possible traces of the above process on the electrochemical device, the first electrode at least has active elements, infiltrated in depth, while the intermediate membrane is devoid of these active elements. Brief description of the drawings

[0039] Other features, details and advantages will become apparent from the detailed description below, and from the analysis of the accompanying drawings, in which, in addition to Figures 1 to 4 and 10 relating to the prior art and discussed above:

[0040] Figure 5 illustrates a cross-sectional view of the solid electrolyte cell with an intermediate H-shaped membrane structure according to one embodiment,

[0041] Figure 6 illustrates a cross-sectional view of the solid electrolyte cell according to Figure 5, with a well-homogeneous infiltration of the active elements EEA into the first electrode PE1, according to an advantage of the present description.

[0042] Figure 7 illustrates a top view of the solid electrolyte cell as defined in Figure 5, in an embodiment where the first electrode PE1 in particular is rectangular in shape,

[0043] Figure 8 illustrates a top view of the solid electrolyte cell as defined in Figure 5, in an embodiment where the first electrode PE1 in particular is circular in shape,

[0044] Fig. 9 illustrates an example of stacking solid electrochemical cells as defined in this description, the peripheral rim of the H-dense membrane forming a sealed shoulder allowing the different PE1, PE2 electrodes that each stacked cell may contain to be properly compartmentalized.

[0045] Fig. 11 illustrates a series of steps of an example of a manufacturing process for a solid electrochemical device as defined in this description. Description of the implementation methods

[0046] With reference to [Fig. 5], the present description relates to a solid electrochemical device comprising first and second electrodes PE1 and PE2, having substantially planar layer shapes and first and second thicknesses, respectively. These first and second thicknesses may be substantially equal, as illustrated in the example in [Fig. 5]. The solid electrochemical device further comprises an intermediate membrane MB, separating the first and second electrodes PE1 and PE2.

[0047] The first and second electrodes PE1, PE2 have respective porosities exceeding a threshold (for example, 30% or more of "holes" without electrode material), while the intermediate membrane MB has a porosity below this threshold. In another expression of porosity (defined by the size of the "holes" without material in the electrode), the porosity of the first and second electrodes can range from a few hundred nanometers (constituting the aforementioned threshold) to a few tens of micrometers. Thus, the porosity of the dense membrane MB can be less than a few hundred nanometers.

[0048] In particular, the intermediate membrane MB has at least one first peripheral rim of height a (reference "a" in [Fig. 5]) greater than or equal to the thickness of the first electrode PE1 to form a first recess for the first electrode PE1. Thanks to this arrangement, and as illustrated in [Fig. 6], it is possible to infiltrate as many particles as desired into the layer formed by the first electrode PE1 without these particles (containing EEA active elements) reaching the second electrode PE2, located beneath the dense membrane MB, by diffusion (compared to the prior art situation illustrated in [Fig. 4] discussed earlier). Thus, the risks of short circuits (reference RCCT in [Fig. 4]) are limited.Furthermore, the distribution of these EEA particles in the first porous electrode PE1 can advantageously be homogeneous (at least in comparison to the prior art situation illustrated in [Fig.3] previously discussed).

[0049] The intermediate membrane MB may further comprise a second peripheral rim of height b (reference “b” in [Fig. 5]) greater than or equal to the thickness of the second porous electrode PE2 to form a second recess for the second electrode PE2. Such an embodiment makes it possible to carry out a similar step of infiltrating EEA particles by spraying a fluid containing such particles onto the free surface of the second electrode PE2, again without risk of contaminating the first electrode PE1.

[0050] In the example illustrated in [Fig. 5], the height a of the first rim and the height b of the second rim are substantially equal. Nevertheless, such an embodiment allows for variations. For example, in the case of a cell stack in the prior art sense illustrated in [Fig. 10], the layers forming the first (upper) and second (lower) electrodes may have different respective thicknesses (the upper layer being thinner, for example, than the lower layer). In this case, it may be advantageous to provide a dense membrane MB whose first rim has a different height a (lower, for example) than the height b of the second rim (i.e.: a ​

[0051] However, on the other hand, a cell structure that is symmetrical as illustrated in [Fig. 9] (with, in particular, a=b) ensures, among other things, a homogeneous heat distribution within the cell during its operation, without local "hot spots". Furthermore, such symmetry promotes the mechanical stability of the assembly during the sintering step.

[0052] Typically, the height a, b of at least one of the first and second rims can be between 0.1 micron and 1 millimeter. Furthermore, at least one of the first and second rims can have a width (reference "f" in [Fig. 7]) between a few millimeters and a few centimeters, for example between 3 millimeters and 5 centimeters. In the configuration illustrated in this [Fig.7], at least one of the first and second rims (here the upper rim at the periphery of the first PE1 electrode) is rectangular in shape.

[0053] Alternatively, and as illustrated in [Fig. 8], at least one of the first and second rims (here, the upper rim delimiting the first electrode PE1) is circular. In this typical embodiment, the circular rim can be between a few millimeters and a few centimeters wide (preferably between 3 millimeters and 5 centimeters). In the rectangular geometry configuration of [Fig. 7], as in the circular geometry configuration of [Fig. 8], the first and second electrodes can be between 10 and 50 cm wide, which is entirely consistent with the usual dimensions of industrial solid-state electrochemical devices.

[0054] These dimensional data can be considered in conjunction with those of the MB membrane. Typically, the intermediate membrane can be between a few microns and a few millimeters thick (preferably between 3 µm and 3 mm). Such an embodiment, with a porosity typically less than a few hundred nanometers, ensures in particular that the dense MB membrane acts as an effective barrier against the passage of gases (as will be seen in the embodiment example of [Fig. 9] described later) while allowing ion transport for the efficient operation of solid-state electrochemical devices such as, for example, fuel cells and electrolyzers.

[0055] Thus, for example, in an application of the electrochemical device as an air / hydrogen fuel cell, the intermediate membrane can be made of a ceramic that is airtight to at least one gas, such as air or hydrogen. Referring to [Fig. 9], which illustrates such an embodiment, a dense membrane among dense membranes MBi (for example, the membrane located at the very top of [Fig. 9]) can carry a first upper electrode PE1, which is enclosed by an upper plate PIFA. This is a final interconnecting plate of the assembly, designed to be in contact with air on its lower surface. Indeed, this PIFA plate is configured to allow a gas such as air to flow through its lower slotted openings. The porous upper electrode PE1 can thus interact with the flowing air.In contrast, the underlying dense membrane remains airtight, and advantageously this first PIFA plate allows the first PE1 electrode to be enclosed in a sealed space delimited by the first PIFA plate and the first upper peripheral rim of the membrane, this rim then forming a sealed EPLT shoulder on which the lower part of the PIFA plate can rest.

[0056] Similarly, the membrane among the dense membranes MBi, located at the very bottom of [Fig. 9], can carry a second lower electrode PE2, which is enclosed by a lower plate PIFH. This is a final interconnecting plate of the assembly, designed to be in contact with hydrogen via its upper surface. Indeed, this PIFH plate is configured to allow the circulation (through its lower slotted openings viewed in a plane perpendicular to that of [Fig. 9]) of a gas such as hydrogen. In this example, it will be understood that air flows in a direction perpendicular to the plane of [Fig. 9] on the surface of electrode PE1, while hydrogen flows in a direction parallel to the plane of [Fig. 9] on the surface of electrode PE2. The porous lower electrode PE2 can interact with the hydrogen thus circulating.In contrast, the overlying dense membrane remains hydrogen-tight, and advantageously this second PIFH plate allows the second PE2 electrode to be enclosed in a sealed space delimited by the second PIFH plate and the second lower peripheral rim of the membrane, this lower rim then forming a sealed EPLT shoulder in contact with the upper part of the PIFH plate.

[0057] This realization and its advantages extend of course to all the intermediate plates interconnected with each other and referenced PIHA on the [Fig.9], the dense membranes MBi all having rims forming EPLT shoulders that are airtight to the circulating gases.

[0058] In particular, each electrochemical device of the assembly in [Fig.9] comprises, in addition to first and second electrodes PE1, PE2 separated by a dense membrane MBi, a pair of containment plates: - an upper plate carrying air and in contact with the first electrode PE1, and - a lower plate carrying hydrogen and in contact with the second electrode PE2.

[0059] Each of these PIHA containment plates is electrically conductive and configured to be interconnected with a counterpart plate of another electrochemical device.

[0060] In the example in [Fig. 9], the first (upper) rim is the same width as the second (lower) rim, because in this example the upper electrode PE1 and lower electrode PE2 are the same width. Alternatively, however, the upper electrode PE1 may be narrower than the lower electrode PE2 (as in the prior art illustrated in [Fig. 10]), and in this case, the first (upper) rim of the membrane may be wider than the second (lower) rim to retain the manufacturing methods of the electrodes in the prior art, for example, but adapting the shape of the intermediate membrane to these manufacturing methods.

[0061] On the other hand, without at least the upper edge of the dense membrane MBi forming a sealed shoulder with the air in the [Fig.9], PBE sealing problems may occur due to the space left open between an interconnecting plate in contact with the air (for example the upper plate PIFA) and the edges of the first electrode PE1, or even the edges of the intermediate membrane MBi.

[0062] Figure 11 illustrates an example of a manufacturing process for a solid electrochemical device as described herein. As an example of a first step SI, the material forming a precursor of the intermediate membrane MB may be pressed to give it an H-shaped form (cross-sectional view) as illustrated in particular in Figures 5 and 6, discussed earlier. More generally, the precursor of the intermediate membrane may be formed in a solid material by at least one of the following techniques: pressing, but also possibly machining, casting and drying, or even 3D printing of the aforementioned solid material.

[0063] Then, during an S2 step, it can be deposited: - a precursor of the first PE1 electrode on a superior surface of the MB membrane, and - a precursor of the second PE2 electrode on a lower surface of the membrane.

[0064] At this S2 step, the precursor of the first electrode at least (and / or of the second electrode) can be deposited on the precursor of the intermediate membrane by a technique of deposition of a porous material such as spray, screen printing, casting and drying, or other, of the aforementioned porous material.

[0065] Thus, the process may include the formation of a matrix during this step S2. This matrix initially comprises a precursor of the first electrode, attached to a precursor of the intermediate membrane on one face, and a precursor of the second electrode, attached to the precursor of the intermediate membrane on a second face. The term "precursor" is used here to designate the state of the materials before the sintering step.

[0066] Then, during a step S3, the temperature of the assembly can be increased to sinter the entire structure. A temperature above 1000°C (preferably around 1200°C in a furnace, for example) can be applied to the aforementioned matrix to at least partially sinter the precursor materials.

[0067] Sintering can be carried out before the LIQ fluid spraying step. However, alternatively, sintering can be carried out before spraying.

[0068] In the example of [Fig. 11], the process continues with step S4 of spraying a surface left free of the first electrode at least PE1 with a fluid LIQ, The active element carrier allows these active elements (EEAs) to penetrate deeply into the precursor of the first electrode PE1, thus imparting the desired properties to the first electrode. The upper basin formed by the membrane's rim then acts as a barrier to the active elements (EEAs), preventing contamination of the second electrode PE2. The LIQ fluid can be an aqueous or organic liquid solution, carrying precursor components that define the electrode's properties. Following the spraying, a step S5 may be implemented to remove aqueous and / or organic components, or other components of the liquid solution other than the active elements (EEAs) initially present in the LIQ fluid, by applying a temperature of at least 750 to 850°C to the first electrode PE1.Next, in step S6, one or more of the cells thus obtained can be interconnected by gluing each electrode to an interconnecting plate, as previously described with reference in particular to [Fig.9].

[0069] It should be noted that the annealing step S5 does not actually need to be formally carried out before the interconnection of the cell thus obtained in step S6. Indeed, in electrochemical devices operating at high temperatures such as fuel cells for example, the operating temperature can be close to 800°C so that the evacuation of undesirable elements after spraying by the LIQ fluid can simply take place during the operation of the device.

[0070] Regarding the materials used, the first electrode at least PE1 (and / or the second electrode PE2) can be made of a material comprising at least one element among an oxide, a metal or metal oxide, a perovskite, a double perovskite, a mixture of ceramic and metal (Cermet).

[0071] The intermediate membrane MB can be made of a material comprising at least one element among yttrium-stabilized zircon and / or scandium, a barium-cerium-yttrium mixture, a ceramic and metal mixture (Cermet).

[0072] According to a trace of implementation of the process within the meaning of this description on the electrochemical device obtained, the first electrode at least PE1 (and / or the second electrode PE2) has active elements EEA, infiltrated in depth, while the intermediate membrane is comparatively devoid of these active elements EEA.

[0073] These EEA active elements may typically include at least one element from among a transition metal, a lanthanide, a rare earth.

[0074] The use of an H-shaped membrane precursor, even before the S3 sintering step, allows, when nickel oxide NiO is used for sintering as in the document cited above EP4198175, to minimize the amount of NiO to be used as a sintering aid because the H shape already provides strength to the precursor matrix.

[0075] Furthermore, by using this H-shaped architecture, it is possible to replace this composition with another metal oxide (such as ZnO, CuO, etc.), thereby preventing the accumulation and agglomeration of NiO, and of Ni nanoparticles after subsequent reduction, at grain boundaries and, more specifically, at the junction points between the intermediate membrane and the electrodes. Such an accumulation of redox-sensitive Ni nanoparticles presents a risk to the mechanical stability and chemical tolerance of the electrolyte material, for example, a risk of coking (a degradation phenomenon through surface oxidation and carbon accumulation). In addition, nickel nanoparticles increase the resistance of the electrolyte grain boundaries, which reduces the conductivity and therefore the overall faradaic efficiency of the entire electrochemical device.

[0076] Avoiding this contamination by nickel, in addition to contamination by EEA elements likely to generate short circuits between the first and second electrodes, are all advantages that can be provided by the object of the present description.

[0077] This disclosure is not limited to the forms of embodiment described above, only by way of example, but encompasses all the variants that a person skilled in the art may consider within the framework of the protection sought.

[0078] A cross-flow gas flow configuration (known as "cross-flow") has been illustrated in Figure 9 (and in Figure 10 for comparison). However, other configurations are also possible. For example, there is also a "counter-flow" configuration where the gases flow in opposite directions.

[0079] More generally, although an application for co-catalytic ceramic membrane reactors has been described above, this architecture is applicable to all electrochemical devices (especially high-temperature ones such as fuel cells and electrolyzers), hydrogen or oxygen separators, catalytic and / or electrochemical reactors, electrochemical compressors and pumps, all configured as simple units or stacks, and gas sensors.

Claims

Demands

1. A method for manufacturing a solid electrochemical device, the device comprising: - first (PE1) and second (PE2) electrodes, having planar layer shapes, respectively of first and second thicknesses, and - an intermediate membrane (MB), separating the first and second electrodes, the first and second electrodes having respective porosities greater than a threshold, the intermediate membrane having a porosity less than the threshold, wherein the intermediate membrane has at least a first peripheral rim of height (a) greater than or equal to the first thickness to form a first basin, for receiving the first electrode (PE1),The process comprises spraying (S4) a free surface of the first electrode (PE1) with a fluid (LIQ) carrying active elements to infiltrate said active elements (EEA) deep into the first electrode (PE1) and impart chosen properties to the first electrode, the first basin forming a barrier to the active elements to prevent contamination of the second electrode (PE2).

2. A method according to claim 1, comprising the formation (S2) of a matrix comprising a precursor of the first electrode, attached to a precursor of the intermediate membrane on a first face, and a precursor of the second electrode, attached to the precursor of the intermediate membrane on a second face, a temperature greater than 1000°C being applied (S3) to said matrix to sinter at least partially the materials of said precursors.

3. The method according to claim 2, wherein the sintering is carried out before spraying.

4. A method according to any one of claims 2 and 3, wherein the precursor of the intermediate membrane is formed in a solid material by at least one of the techniques among pressing, machining, casting and drying, 3D printing, of said solid material.

5. A method according to any one of claims 2 to 4, wherein the precursor of the first electrode at least is deposited on the precursor of the intermediate membrane by a technique of deposition of a porous material including spraying, screen printing, casting and drying, of the porous material.

6. Solid electrochemical device, comprising: - first (PE1) and second (PE2) electrodes, having planar layer shapes, respectively of first and second thickness, and - an intermediate membrane (MB), separating the first and second electrodes, the first and second electrodes having respective porosities greater than a threshold, the intermediate membrane having a porosity less than the threshold, wherein the intermediate membrane has at least a first peripheral rim of height (a) greater than or equal to the first thickness to form a first basin, for receiving the first electrode.

7. Device according to claim 6, wherein the intermediate membrane (MB) further comprises a second peripheral rim of height (b) greater than or equal to the second thickness to form a second cup, for receiving the second electrode (PE2).

8. Device according to any one of claims 6 and 7, wherein the height (a, b) of at least one of the first and second rims is between 0.1 micron and 1 millimeter.

9. Device according to any one of claims 6 to 8, wherein the intermediate membrane has a thickness (c) between a few microns and a few millimeters.

10. Device according to any one of claims 6 to 9, wherein at least one of the first and second rims (f) is of a width between a few millimeters and a few centimeters.

11. Device according to any one of claims 6 to 10, wherein the porosity of the first and second electrodes is between a few hundred nanometers and a few tens of micrometers.

12. Device according to any one of claims 6 to 11, wherein the intermediate membrane (MB) is made of a ceramic that is airtight to at least one gas among air and hydrogen.

13. Device according to claim 12, further comprising at least a first plate for enclosing the first electrode in a sealed space delimited by the first plate and the first peripheral rim, which forms a sealed shoulder (EPLT).

14. Device according to claim 13, wherein the first containment plate (PIHA) is conductive and configured to be interconnected with a counterpart plate (PIHA) of another electrochemical device.

15. Device according to any one of claims 6 to 14, wherein the first electrode (PE1) at least comprises active elements (EEA), infiltrated in depth, while the intermediate membrane (MB) is devoid of said active elements.

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