COMPLEX ELECTROCHEMICAL CELL AND ITS USES

Abstract

Complex electrochemical cell and its uses. The present invention relates to a complex electrochemical cell (complex MEA) that integrates one or more individual electrochemical cells, based on ceramic and metal materials, which are connected together (e.g., in parallel and / or series arrangements), in such a way as to minimize electrical losses and allow cell control strategies that make operation more flexible, while maintaining maximum energy efficiency and adaptability to external operating requirements.

Description

COMPLEX ELECTROCHEMICAL CELL AND ITS USES The present invention relates to a complex electrochemical cell (complex MEA) that integrates one or more individual electrochemical cells, based on ceramic and metal materials, which are connected together (e.g., in parallel and / or series arrangements), in such a way as to minimize electrical losses and allow cell control strategies that make operation more flexible, while maintaining maximum energy efficiency and adaptability to external operating requirements. BACKGROUND OF THE INVENTION Solid oxide-based electrochemical cells (SOCs) are electrochemical conversion devices composed of a ceramic membrane-electrolyte with selective transport of oxygen ions or protons, and two electrodes on either side of the electrolyte that enable the half-reactions of gaseous compounds and adsorbed species. For practical application, electrochemical cells are connected in series in groups, to form modules or stacks, which have the appropriate geometry for the entry and exit of fluids, for the electrical interconnection between cells, and for the sealing between cells and the outside of the stack. Segmented series designs involve connecting multiple electrochemical cell units in series to increase the total voltage output while proportionally decreasing the electrical current. This configuration allows for increased operating voltage while maintaining power output. An example is the series-segmented design (developed by Mitsubishi) for tubular solid oxide fuel cells, particularly their "SEG-CELL" technology, a type of solid oxide fuel cell (SOFC) architecture that uses segmented electrochemical cells connected in series. The SEG-CELL design aims to improve the overall efficiency and reliability of SOFC systems. However, this technology (of serial segmented designs) has limitations, such as only allowing one-dimensional designs, losing flexibility in current collection and limiting interconnectivity between cells, so that external or internal adjustment of interconnectivity between cells is not possible, and so that it does not allow control of the cell's operating regime. The complex electrochemical cell of the invention, comprising one or more individual electrochemical cells connected in series and / or in parallel, allows overcoming the aforementioned limitations (design, flexibility, poor interconnectivity, control of the operating regime), in addition to providing further improvements such as greater thermal management, reliability, performance, and scalability. DESCRIPTION OF THE INVENTION The present invention relates to a complex electrochemical cell (complex MEA) comprising one or more individual electrochemical cells connected in series and / or parallel, with a specific geometry and composition, referring to their layers and sublayers, that provides advantages related to design, flexibility, interconnectivity, operating regime control, thermal management, reliability, performance, and scalability. The complex electrochemical cell (MEA) of the invention may also comprise various integrated elements providing additional advantages, as will be seen throughout the description. Finally, the invention relates to the use of the complex electrochemical cell (MEA) of the invention for the generation of hydrogen gas (H2) or synthesis gas from electrolysis and co-electrolysis, respectively, or for the conversion of hydrocarbons. A first aspect of the invention relates to a complex electrochemical cell, characterized in that it comprises: - a porous support (A) with a porosity between 20-80%, composed of a material selected from a metallic and / or ceramic material, - a layer (D) comprising at least two electrochemical cells, connected in series and / or in parallel, placed on the porous support (A), where each cell is composed of at least: or a porous functional anodic layer (AL), composed of materials selected from fluorites, zirconium and / or yttrium oxides, undoped or doped barium zirconates, Fe, Ce, Zr, Cr, Ti, Mn or Mo-based perovskites; and metals or alloys of Ni, Fe, Ag, Cu, Au or Pt, or combinations thereof, preferably having a thickness between 0.25 µm and 10 µm, and preferably wherein said porous functional anodic layer (AL) has an electronic conductivity of less than 0.1 S / cm and an ionic conductivity to protons or to oxygen ions of less than 1·10-4 S / cm a porous functional cathodic layer (CL), composed of materials selected from metal nitrides, manganite, zirconium oxide, cerium or yttrium and combinations thereof, perovskite-type structure of alkaline earth elements and / or rare earths and / or transition metals; or metals or alloys of Pd, or Ag, or Au, or Nb, or V, or Ni, or W, or Ta; or combinations thereof, preferably having a thickness between 0.5 µm and 30 µm, and preferably wherein said porous functional cathodic layer (CL) has an electronic conductivity greater than 0.1 S / cm and an ionic conductivity (to protons or to oxygen ions) greater than 1·10-4 S / cm; an electrolyte layer (EL) that is at least partially positioned between and in contact with the anodic layer (AL) and the cathodic layer (CL), wherein the layer is composed of materials selected from undoped or rare-earth-doped bismuth oxide or Nb or Ta or combinations thereof; undoped or partially substituted fluorite-type zirconium oxide and / or cerium oxide with a fluorite-type crystal structure, or zirconium oxide and / or cerium oxide with a fluorite-type crystal structure, or zirconate or cerium oxide with a fluorite-type crystal structure, or zirconate or cerium oxide with a fluorite-type crystal structure, or zirconate or cerite with a fluorite-type crystal structure, or zirconate or cerite, or barium oxide ...lanthanide tungstates, preferably the lanthanide being selected from lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium, apatites, lanthanide sesquioxides, preferably the lanthanide being selected from lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium, lanthanum niobates, Ce- and La-based pyrochlorides, barium indates, graphene oxide (CGO), or combinations thereof, preferably having a thickness between 0.25 µm and 10 µm, preferably where the electrolyte layer (EL) is impermeable to gases with a hydrogen leakage rate less than 5·10-3 mbar·L / s and exhibits an ionic conductivity to protons or oxygen ions greater than 1·10-4 S / cm; or an electrical interconnection (IC) layer in contact with at least the anodic layer (AL) of an individual cell with the (CL) and / or (CCL) layer of at least one other individual cell composed of materials selected from a mixture of silver (Ag) and mixtures of at least two components selected from SiO2, Al2O3, B2O3, BaO, BaSiAl, ZnO, CaO, SrO, ZrO2, TiO2, Na2O, or K2O, preferably having a thickness between 0.25 µm and 50 µm, and preferably where said electrical interconnection (IC) layer is impermeable to gases (with a hydrogen leakage rate of less than 5·10-3 mbar·L / s), and exhibits an electronic conductivity greater than 0.5 S / cm and or a sealing dielectric layer (SI), composed of materials selected from mixtures of at least two components selected from SiO2, Al2O3, B2O3, BaO, BaSiAl, ZnO, CaO, SrO, ZrO2, TiO2, Na2O, or K2O, preferably with a thickness between 0.5 µm and 200 µm, preferably the sealing dielectric layer (SI) has an electronic conductivity of less than 1·10-6 S / cm and is impermeable to gases with a hydrogen leakage rate of less than 5·10-3 mbar·L / s, and is preferably in contact with an interconnection layer (IC), an electrolyte layer (EL), and an anodic layer (AL). According to the invention, "porous support" is defined as a support material on which at least one other layer is placed, comprising a porosity of at least 20% with respect to the total volume of the support. The "porosity" of a layer or material according to the invention is understood to be the percentage (%) of its internal volume where there is no material, relative to the total volume of the material; that is, the percentage of "empty" volume within the material or layer. Therefore, porosity is quantitatively expressed as a percentage by volume. The porosity according to the present invention has been measured by scanning electron microscopy (SEM) and is defined as the area of ​​the observed image of the material of interest that exhibits holes or voids, relative to the total area mapped in the image obtained by optical microscopy (in %). To measure both the area exhibiting holes or voids and the total image area, the software of the SEM instrument itself was used. The porosity reported in the present invention is the average porosity obtained from a total of 5 to 10 images for the same material.Other alternative techniques for measuring porosity would be optical microscopy (OM), X-ray tomography (XR), mercury intrusion, or Archimedes' method (pycnometry). "Thickness" according to the invention is defined as the thickness of the material along the Z-axis. The thickness (in µm) according to the invention was measured using scanning electron microscopy (SEM or TEM) by direct measurement. Other alternative techniques for measuring thickness would be the use of a micrometer, a profilometer, or X-ray tomography. An element "doped" with another element is defined as one that has been replaced in the material's microstructure by at least 0.5 mol% of the other element. The molar percentage of doping according to the invention was measured by weighing the precursors of the starting chemical elements. Other alternative techniques for measuring the molar percentage of doping include ICP (Inductively Coupled Plasma), X-ray fluorescence, and EDS-SEM microanalysis. According to the invention, "gas permeability" is defined as the amount of gas that passes per unit time through a layer of material of a given thickness, expressed, for example, in units of mbar·L / s. Permeability can be measured for different types of gases (e.g., hydrogen, oxygen, etc.) under specific pressure and temperature conditions. According to the invention, a material is defined as "impermeable" or "permeable" to a certain gas or gases if its gas permeability is below or above, respectively, the value of 10⁻³ or 10⁻⁴ mbar·L / s for H₂ or He, under conditions of 25 °C and 0.25–1 barg. The "permeability" to gases according to the invention has been measured using the measuring equipment "Pfeiffer Vacuum ASM 340 W, Helium Leak Detector Wet Version, Touch Screen Display, Configurable I / O Interface Board, 200-240 V, 50 / 60 Hz JSVA02A2MH9A".Other alternative techniques for measuring the molar % of doping would be Inductively coupled plasma (ICP), Scanning electron microscopy / Energy dispersive spectroscopy (SEM / EDS), X-ray fluorescence or X-ray photoelectron spectroscopy. As a reference value for permeability in the present invention, Helium (He) has been used in the quality control measurement. According to the invention, "electronic conductivity" is defined as the ability of a material to allow the passage of electrons or other electron carriers. Electrical or electronic conductivity according to the invention is measured in Ω / cm at 700 °C. According to the invention, electrical or electronic conductivity has been measured using voltammetry (AC or DC) with the measurement parameters of electric current, applied voltage or electric field, frequency, temperature, and partial pressure of O₂ or H₂O. According to the invention, "ionic conductivity" or "electrical conductivity" is defined as the ability of a material to allow the passage of certain ions (e.g., protons or oxygen ions). Ionic conductivity according to the invention is measured in S / cm at 700 °C. The invention specifies that ionic conductivity is measured using voltammetry (DC or AC) as a function of the partial pressure of O₂ at operating temperatures, with the measurement parameters being electric current, applied voltage or electric field, frequency, temperature, and partial pressure of O₂ or H₂O. Other alternative techniques for measuring this conductivity include O₂ or H₂ permeability, electrochemical relaxation techniques, etc. The "size of microparticles or nanoparticles" according to the invention is defined as the average diameter of the microparticles or nanoparticles along all axes, assuming that the particles are spherical. The size of the microparticles (µm) or nanoparticles (nm) in the present invention is reported in micrometers or nanometers, respectively. According to the invention, the size of the microparticles or nanoparticles has been measured by scanning electron microscopy (SEM), in which case the particle size would be defined as the average diameter of the particles observed in the same SEM image, this being the average of the horizontal and vertical diameters of the observed particles (assuming that the particles are spherical, although since they are not, the horizontal and vertical diameters will likely be different). Alternatively, this particle size could be measured using techniques other than SEM, such as "Dynamic Light Scattering (DLS)", using suspensions in a liquid, usually water. According to the invention, a "layer adjacent to another" is defined as a layer that is in direct contact with another without the presence of an additional intermediate layer. The term "degraded" in this memory has its usual meaning, that is, a smooth or progressive transition effect between different materials or properties, such as porosity or ionic or electronic conductivity. The complex electrochemical cells of the invention can have a planar geometry or take the form of 3D structures, such as cylindrical geometry or corrugated planes. In the latter case, the XY plane is distributed on a circumference and the Z axis is radial. They can also consist of segmented designs arranged in series and / or in parallel. In a preferred embodiment of the present invention, it further comprises a porous current collector (CCL) layer, preferably with a thickness between 0.25 µm and 200 µm, composed of materials selected from strontium lanthanum manganite (LSM), strontium lanthanum chromite (LSC), strontium lanthanum cobalt ferrite (LSCF), uncoated nickel or nickel coated with strontium lanthanum manganite (LSM) or strontium lanthanum chromite (LSC), uncoated stainless steels or stainless steels coated with strontium lanthanum manganite (LSM) or strontium lanthanum chromite (LSC), silver (Ag) or gold (Au) or platinum (Pt) or their alloys, Cu and / or Ni and / or Ag and / or Au and / or Fe and / or Co alloys, Inconel or Hastelloy alloys, lanthanum chromite (LaCrO3) undoped or doped with Y, Al, Fe, Mn, lanthanum manganite (LaMgO3) with Sr, Y, Al, Ca, Fe, Mn, Mg and / or Mn and / or Co and / or Cu spinels, Cu2MnO4, or combinations thereof, and preferably placed partially on a porous cathodic layer (CL) and partially on an electrical interconnection layer (IC). Regarding the porous support (A) that forms part of the first aspect of the complex electrochemical cell of the invention, it is made of a material or materials resistant to high temperatures and mechanically and chemically compatible with the constituent materials of the other functional layers. In the particular case where the porous support (A) is made of metallic alloys, the two main advantages are (1) the significant reduction in the thickness of the support allows the electrochemical cells (MEAs or Membrane-Electrode Assemblies) to be smaller and lighter, and (2) the use of a metallic support (of high strength), instead of a ceramic support (more brittle) is advantageous in terms of mechanical strength, thermal properties and cost. Preferably, the porous support has uniform dimensions in both width and length, i.e., a uniformity of size along the XY plane. Preferably, the 2 electrochemical cells are electrically interconnected to the porous support (A) Regarding the sublayers that comprise layer (D), it should be noted that layer (D) comprises: - at least one porous anodic functional layer (AL) that preferably has an electronic conductivity greater than 0.1 S / cm (at 700 °C), and an ionic conductivity to protons or oxygen ions greater than 1·10-4 S / cm (at 700 °C). - at least one electrical interconnection (IC) layer, preferably impermeable to gases by having a permeability of less than 10-3-10-4 mbar·L / s for H2 or He, under conditions of 25 °C temperature and 0.25-1 barg pressure, and having an electronic conductivity greater than 1 S / cm (at 700 °C), all for thicknesses of the (IC) layer between 0.5-250 µm. - at least one electrolyte (EL) layer preferably impermeable to gases by having a permeability of less than 10-3-10-4 A mbar·L / s for H2 or He, under conditions of 25 °C temperature and 0.25-1 barg pressure, and / or has an ionic conductivity to protons or to the oxygen ion of at least 10-4 S / cm (at 700 °C). - at least one porous functional cathodic layer (CL) that preferably has an electronic conductivity greater than 0.1 S / cm (at 700 °C) and an ionic conductivity to protons or oxygen ions greater than 1·10-4 S / cm (at 700 °C), all for layer (CL) thicknesses between 0.5-100 µm. - at least one porous current collector (CCL) layer, preferably exhibiting an electronic conductivity greater than 5 S / cm, for CCL layer thicknesses between 0.25-200 µm, and - at least one sealing dielectric layer (SI) that is preferably impermeable to gases by having a permeability of less than 10-3-10-4 mbar·L / s for H2 or He, under conditions of 25 °C temperature and 0.25-1 barg pressure, and / or has an electronic conductivity of less than 10-6 S / cm (at 700 °C), all for layer thicknesses (IC) between 0.5-250 µm. Preferably, the (IC) layer is electrically connected to the (AL) layer of an individual cell with the (CL) and / or (CCL) layer of another individual cell / s. The cathodic layer (CL) integrated into the plurality of electrochemical cells (D) has the primary function of carrying out the electrochemical reaction of oxygen activation, either by reduction of O2 or oxidative evolution of H2O and O2. In this case, this porous cathodic layer (CL) is generally composed of a mixed conductor of electrons and oxygen ions in the solid state, preferably including alkaline earth elements, rare earth elements, or transition metals such as iron and cobalt in its crystalline structure. These oxides are oxygen-deficient in their structure, and thanks to these oxygen vacancies in their lattice, the diffusion of the oxygen ion and activation of O2 through the crystalline structure is possible. Furthermore, in the cathodic layer (CL) the use of non-oxide ceramics (e.g. titanium nitrides) or hydrogen-permeable alloys (e.g. Pd, V, Nb, Ta alloys). The current collector layer (CCL) integrated into the plurality of electrochemical cells (D) has the primary function of collecting and distributing the electrical current generated within the cell. These collectors are preferably made of materials with high conductivity (electronic and / or ionic) and high corrosion resistance at operating temperatures (in solid oxide cells), which can range from 600 to 1000 °C. It should be noted that the choice of current collector material depends on several factors, such as the specific design of the solid oxide cell (SOC), the operating conditions, and the desired balance between performance and cost. Furthermore, according to the first aspect of the invention, the sublayers of layer (D) can be made of highly varied materials, and for example, can therefore comprise a crystalline phase of selected structures such as fluorite, perovskite, spinel, or pyrochlore, or combinations thereof. A particular embodiment refers to a more specific distribution of the sublayers of layer (D), where in addition to the above-mentioned conditions regarding the positioning of the anodic layer (AL), the electrolyte layer (EL), the cathodic layer (CL), and the electrical interconnection layer (IC), the following additional positioning conditions between layers are also met: - at least one porous functional anodic layer (AL) is located on the porous support (A), - at least one electrical interconnection (IC) layer is located on a porous functional anodic layer (AL), - at least one electrolyte layer (EL) is located partially on the porous support (A) and partially on the anodic layer (AL), being in turn in contact with an electrical interconnection layer (IC), - at least one porous functional cathode layer (CL) is located partially on the electrolyte layer (EL) and partially on an electrical interconnection layer (IC), - at least one porous current collector (CCL) layer is placed partially over a porous cathode layer (CL) and partially over an electrical interconnection (IC) layer; - at least one sealing dielectric layer (SI) is in contact with an interconnection layer (IC), with an electrolyte layer (EL), and with an anodic layer (AL). The segmented design of the complex electrochemical cell according to the first aspect of the invention (which can be in series and / or in parallel) offers several general advantages over conventional electrochemical cells: - Improved thermal management: The segmented design allows for better control of temperature distribution within the stack. By dividing the cell into smaller segments, it becomes easier to manage and control thermal gradients throughout the cell. This minimizes thermal stress and ensures a more uniform temperature distribution, resulting in increased performance and durability. - Increased reliability: The segmented design (in series and / or parallel) helps mitigate the effects of potential cracks or defects in individual cells. If a single cell experiences a failure, the impact on the overall stack performance is limited to that segment, while the remaining cells can continue operating. This segmented architecture improves the overall reliability and operational stability of the system. - Flexible operation: Segmented solid oxide electrochemical cells offer flexibility in terms of operation and maintenance. They allow for easier replacement of individual cells or segments within the cell, reducing downtime and simplifying maintenance procedures. This feature is especially advantageous for large-scale SOC systems, where replacing the entire stack in the event of a localized failure is impractical. - Scalability: The segmented design allows for scalability, as it can increase the system's power and / or current while maintaining a consistent cell design. This scalability makes series-segmented cells suitable for a wide range of applications, from small-scale residential systems to large-scale power generation plants in the case of SOFC fuel cells. In general, the proposed segmented design (in series and / or in parallel) in the complex electrochemical cell improves the performance, reliability, and flexibility of solid oxide cells, addressing some of the challenges associated with temperature distribution and improving the robustness of the system. Additionally, the complex electrochemical cell according to the first aspect of the invention, with the particular distribution of the sublayers of the layer (D) named above, also offers specific functions or advantages over conventional electrochemical cells: For the same cell power (whether in series, parallel, or mixed configurations), it is possible to reduce by a factor of n (where n is the number of individual cells in series in the circuit, typically between 10 and 100) the magnitude of the electrical current passing through the cell that must make contact in a complex cell stack with a bipolar plate. This minimizes the effect of contact resistances and parasitic ohmic resistances, making it possible to increase energy efficiency and minimize failures due to electrical contact losses. Furthermore, this allows the cell stacks of this type of cell to achieve voltages n times higher than those of conventional cells, making it possible to use conventional power electronics equipment that is less expensive and more efficient. The proposed cell architecture makes it possible to combine various types of electrolytes, allowing for the adjustment of the amount of protons and oxygen ions circulating between the two gas chambers. This enables the adjustment of the H2 and O2 content of the gas streams exiting the chambers on both sides of the complex electrochemical cell. This offers advantages in the process where it is integrated, reducing (i) the need for additional gas stream conditioning units for downstream use, and (ii) the associated energy cost of those units. - Greater operational flexibility, by enabling external adjustment of the complex electrochemical cell to various electrical track connection configurations, which activate different current paths. This allows (1) better control of cell operation, (2) adjustment in the XY plane of heat evolution and the extent of certain electrocatalytic and / or catalytic reactions. - Greater control of cell operation, as it allows for cell diagnostics, by being able to obtain information on individual cells, temperature or other operating parameters, depending on the architecture of the particular implementation chosen. One embodiment according to the first aspect of the invention relates to the number of individual electrochemical cells comprising the complex electrochemical cell, specifically that layer (D) integrates at least two individual electrochemical cells placed on a porous support (A). A particular embodiment of the specific case of two individual electrochemical cells on a porous support is shown in Figure 5. The use of at least two electrochemical cells provides the advantage that when electrically connected in series, the current passing through the complex cell is reduced proportionally to the number of individual cells, while the voltage is increased proportionally, thus enabling more efficient electrical management and reducing contact and ohmic losses related to current management.Using a porous support (A) for each individual electrochemical cell provides the advantage that gases can access the electrode and thus undergo an electrochemical transformation. In another embodiment according to the first aspect of the invention, the complex electrochemical cell further comprises lateral electrical connections (F) for connecting the electrochemical cell to cables, plates, and / or interconnectors. These lateral electrical connections (F) of the complex electrochemical cell provide the advantage of facilitating external control of the connectivity between individual cells, allowing connection between complex cells in a stack without requiring the bipolar plate to have firm contact along the surface of the complex cell, and also the advantage of allowing interconnection / multiplexing between cells from the outside (e.g., allowing the cell to be coupled to a power electronics system). In another embodiment according to the first aspect of the invention, the porous support (A) comprises materials selected from spinels, forsterites, perovskites, magnesium oxides, cerium oxides doped (e.g., with at least one lanthanide metal), zirconium oxides doped (e.g., with at least Y, Mg, Sc and / or a lanthanide metal), titanium oxides, aluminum nitrides, refractory alloys or superalloys, metallic alloys such as temperature-resistant metallic alloys, iron alloys, stainless steels, clays, silicates of Al or Mg or Ti or Fe or of alkali or alkaline earth elements, or combinations thereof, such as the material known as forsterite. These particular materials for the porous support (A) provide thermal stability and a coefficient of thermal expansion compatible with the other layers of the complex electrochemical cell. Given these conditions, the use of lightweight materials (with lower gravimetric density) is advantageous as they reduce mechanical problems in the stacking of multiple complex cells in assemblies (stacks), preferably in materials based on MgO, Mg, Ti, Si and Al, etc. In the particular case of porous supports (A) based on metallic alloys, the two main advantages are (1) the significant reduction in the thickness of the support allows the cells to be smaller and lighter, and (2) the use of a metallic support (high strength) versus ceramic (brittle) is advantageous in terms of mechanical strength, thermal properties and cost. In a further preferred embodiment of the porous support (A), the porous support (A) comprises a material selected from magnesium oxide (MgO), yttrium-doped zirconium oxide (3YSZ), forsterite, aluminum magnesium spinels (MgAl2O4), iron perovskite, ferritic stainless steels such as (e.g., P434L, ITM, or Crofer APU22), or combinations thereof. These particular materials for the porous support (A) provide the advantage of having adequate mechanical, thermochemical, and thermal shock resistance, containing no critical material (CRM), and exhibiting thermal expansion behavior compatible with the other materials of the complex cell. In another preferred embodiment, the porous support (A) has a flat geometry with or without engraved "flowfield" type reliefs, tubular, corrugated flat, or corrugated tube. In another embodiment relating to the porous support (A) according to the first aspect of the invention, the porous support (A) has been subjected to a heat treatment step at temperatures between 600 °C and 1200 °C. This heat treatment can be performed on the porous support (A) before the assembly of the complex electrochemical cell of the invention, or it can also be performed on the complex electrochemical cell once the porous support (A) has already been assembled together with the layer (D). This heat treatment stage at temperatures between 600 and 1200 °C (specific to the porous support) after the shaping of the porous support (A) provides the advantage of eliminating any organic matter present in the deposited layers, thereby sintering and chemically bonding the inorganic particles together. Sintering in this context means thermal compression through high-temperature recrystallization mechanisms, which is achieved by heat treatment at the appropriate temperature in specific gaseous atmospheres, conventionally air. Heat treatment is necessary to activate and structure the inks of the cell components. An exception is PVD-deposited components, which may not require specific heat treatment. The shaping of the porous support (A) according to the invention can be carried out by a technique selected from uniaxial or isostatic pressing, extrusion or calendering, tape casting (using a doctor blade or roll-to-roll), conventional casting, dip coating, spin coating, roller coating or screen printing, physical vapor deposition, sputtering, electron beam deposition, suspension spraying, and / or thermal spraying, including plasma spraying and spray pyrolysis; 3D printing, stereolithography, inkjet printing, laser drilling, and combinations thereof. Generally, the manufacturing process includes at least one heat treatment to achieve mechanical strength of the part. Another embodiment of the invention relates to the number of individual electrochemical cells comprising the complex electrochemical cell, specifically that the layer (D) integrates a plurality of individual electrochemical cells interconnected in series (1xn or nx1 array, where n is any integer) or a plurality of individual electrochemical cells interconnected in series and parallel in array form (nxn array, where n is any integer), placed on one or more porous supports (A), where each cell is placed on a porous support (A) in the case of more than one porous support (A). Another more preferred embodiment according to the first aspect of the invention relates to the number of individual electrochemical cells comprising the complex electrochemical cell, specifically that the layer (D) integrates nine individual electrochemical cells interconnected in series (1x9 array), or twenty-five individual electrochemical cells interconnected in series and parallel in array form (5x5), placed on one or more porous supports (A), where each cell is placed on a porous support (A) in the case of there being more than one porous support (A). The series distribution of 9 individual electrochemical cells, as a 1x9 array, has the advantage that the cell as a whole has a voltage 9 times higher and a current 9 times lower, which reduces electrical losses related to high currents (in contacts and current distributors) and allows voltages 9 times higher in the stack, which allows the use of more efficient and lower cost electrotechnical equipment (such as inverters). The combined series and parallel distribution of 5 cells in series x 5 cells in parallel, comprising a total of 25 electrochemical cells arranged as a 5x5 array, provides the advantage that, in general, it allows for higher voltages to be achieved, and flexibility when choosing the interconnection between cells, allowing (i) cells or paths to be bypassed when faults are diagnosed and (ii) the configuration to be adjusted to have suitable behavior, for example when high enthalpy reactions are carried out (such as hydrocarbon reforming or NH3 cracking), in combination with the exothermic evolution associated with the electrochemical operation of the cell. Another embodiment according to the first aspect of the invention relates to the porous functional cathodic sublayer (CL) of the layer (D), specifically that the porous functional cathodic layer (CL) comprises a material selected from La0.6Sr0.4CoO3-, La0.6Sr0.4CoO3, Ba0.5Sr0.5Fe0.2Co0.8O3-, ferrites, nickelates, rare-earth or gadolinium-doped cerium oxide with spinel-like structure, cobalt-free spinel-like materials, mixture of yttria zirconia oxide (8YSZ) and lanthanum strontium manganite (LSM), or scandium-doped zirconium oxide. These oxides or materials have the advantage of having a high oxygen deficiency in their structure and, thanks to these oxygen vacancies in their network, they make the diffusion mechanism of the oxygen ion and activation of O2 through the crystal structure even more efficient. The symbol signifies the oxygen deficiency of the material, and is called oxygen substoichiometry, being equal to the oxygen vacancy content. For example, in the chemical formula Ba0.5Sr0.5Fe0.2Co0.8O3-, it refers to the variability of the oxygen atoms in its chemical formula, and the value of in this can be a non-integer value between -0.1 and 1. Another embodiment according to the first aspect of the invention relates to the porous functional anodic sublayer (AL) of layer (D), specifically that the porous functional anodic layer (AL) is at least a fluorite based on doped or undoped cerium oxide or zirconium oxide; and / or mixtures with metals selected from Ni, Al, Cu, Fe, Co, Pd, Mn, Mo, Cr; yttrium zirconium oxide (8YSZ), a mixture of 8YSZ and nickel, scandium-doped zirconium oxide, a mixture of nickel and cerium-yttrium-doped barium zirconate (BZCY), or combinations thereof. These particular materials provide the advantage of high activity in the electrochemical reaction of oxygen oxidation, the H2 evolution reaction, water decomposition, or hydrocarbon reforming. Another embodiment according to the first aspect of the invention relates to the porous functional anodic sublayer (AL) and / or the porous functional cathodic layer (CL) of layer (D), specifically that the material or materials of the porous functional anodic layer (AL) and / or the porous functional cathodic layer (CL) have an average particle size in the range of 0.1 to 3 µm. These particle sizes provide the advantage of having a larger surface area available for carrying out electrochemical reactions and, therefore, reducing the polarization resistance and the associated overpotential, thereby enabling the achievement of higher current densities. Another embodiment according to the first aspect of the invention relates to the porous functional anodic sublayer (AL) and / or the porous functional cathodic layer (CL) of layer (D), specifically that the surface of the porous functional anodic layer (AL) and / or the porous functional cathodic layer (CL) is coated with nanoparticles (electrocatalyst nanoparticles with electrode-like compositions) smaller than 75 nm. Non-limiting examples of nanoparticles for coating the porous functional anodic layer (AL) are nickel (Ni), palladium (Pd), or platinum (Pt) nanoparticles. Non-limiting examples of nanoparticles for coating the porous functional cathodic layer (CL) are O2, Pr3O7, PrNiO4, BaLaCoO4, or La0.6Sr0.4Co3- nanoparticles.This coating with nanoparticles smaller than 75 nanometers provides the advantage of having a larger surface area available to carry out electrochemical reactions and, therefore, reduce polarization resistance and the associated overpotential, allowing higher current densities to be achieved. Another embodiment according to the first aspect of the invention relates to the electrolyte (EL) sublayer of layer (D), specifically that the electrolyte (EL) layers of at least two of the electrochemical cells that form part of the complex electrochemical cell have different compositions. The fact that at least two of the electrolyte (EL) layers have different compositions provides the advantage that (i) in the case of compositions with different ionic character (H+ vs. O-2), it allows for appropriate adjustment of the H and O species in the different gas streams, for example, by adjusting the H2O content or H2 / CO ratios; and (ii) in the case of having the same ionic character, it allows for adjusting the electrochemical properties of the cell based on the position of each individual cell in the reaction coordinates of the gas reaction circuit, thus enabling optimal cell performance at each stage of the gas reaction.In other words, having at least two electrolyte (EL) layers of different compositions allows for complex cells that can precisely perform the extraction of oxygen ions and the injection of protons (what is usually called co-ionic or dual ionic character), which allows for more convenient electrochemical reactions and the obtaining of gases more selectively and with compositions tailored for different applications. Preferably, at least one of the electrolyte (EL) layer compositions carries mostly protons, while at least one other electrolyte (EL) layer composition carries mostly oxygen ions. As an illustrative example, in the particular case of co-electrolysis, the fact that the complex cell has two electrolyte (EL) layers of different composition allows co-ionic transport through the electrolytes of the complex cell, facilitating the conversion of water in situ to regenerate hydrogen during the hydrogenation of CO2 and, simultaneously, allows changing the equilibrium to promote the formation of synthetic hydrocarbons. Another embodiment according to the first aspect of the invention also relates to the electrolyte sublayer (EL) of layer (D), but specifically to its composition being selected from lanthanide tungstates, zirconium oxide and / or cerium oxide with fluorite-type crystal structure substituted by Y, Sc, Gd, La, Pr, Sm, Nd, Er, Eu, Yb, and / or Tb and their combinations, yttrium zirconium oxide (8YSZ), scandium-doped zirconium oxide, cerium-yttrium-doped barium zirconate or cerate (BZCY), barium zirconate or cerate doped at 10-20 mol% with Gd, Y, Sc, Eu, Yb and their combinations;or zirconium and / or cerium oxide where the cerium and / or zirconium respectively are substituted in a molar ratio of between 10% and 30%, preferably between 10% and 20%, by at least one element selected from among Y, Sc, Gd, La, Pr, Sm, Nd, Er, Eu, Yb, and / or Tb and combinations thereof, the latter having the advantage of exhibiting improved proton conductivities compared to those of the first aspect of the invention, particularly a proton conductivity greater than 0.00025 S / cm at 700°C;A mixture of 8YSZ and BZCY, Ce0.8G0.9O1.9, porous La0.6Sr0.4CoO3 perovskite, apatites based on Ca, Al, Si, or Ge, or combinations thereof. These particular materials have the advantage of exhibiting improved proton conductivities compared to those of the first aspect of the invention, with proton conductivities of at least 5 × 10⁻⁵ S / cm, which allows the complex cell to operate at higher current densities, thus improving its performance. Particularly preferred as the electrolyte (EL) layer material is barium cerate or zirconate doped (10–20 mol%) with at least one element selected from Gd, Y, Sc, Eu, Yb, and combinations thereof, which have a perovskite-type crystal structure and a proton conductivity greater than 0.01 S / cm at 700°C. Another embodiment relating to the electrolyte layer (EL) according to the first aspect of the invention relates to at least one electrolyte layer (EL) comprising at least two juxtaposed layers of different compositions, and wherein at least one of the juxtaposed layers has an ionic conductivity greater than 5 × 10⁻⁵ S / cm. This has the advantage that, for the individual electrolytic cell, juxtaposed layers can be placed, each with greater or lesser electronic or ionic conductivity to the desired ions, thus enabling the selective passage of electrons and different types of ions through the electrolyte layer (EL).For example, one of the juxtaposed electrolyte (EL) layers can primarily transport protons, while the other juxtaposed layer of the electrolyte (EL) layer can primarily transport oxygen ions, thus ensuring the transport of both protons and oxygen ions across the electrolyte (EL) layer of the individual electrolytic cell. Furthermore, placing two juxtaposed layers allows one layer to act as a "shielding layer" for the other, and vice versa, within the atmosphere of the other layer. Another embodiment relating to at least one electrical interconnection layer (IC), comprises silver (Ag) as a high conductivity metal greater than 1S / cm of said layer (IC). In another embodiment referring to the (CL) and (CCL) layers, the porous functional cathode layer (CL) has the same composition as the porous current collector layer (CCL). Another embodiment relating to the addition of a ceramic dielectric material layer (B) relates to the complex electrochemical cell further comprising at least one porous ceramic dielectric material layer (B), preferably with electronic conductivity less than 10-6 S / cm, placed on the porous support (A), wherein the presence of layer (B) implies that the sublayers (AL) and (EL) of layer (D) are on and in contact respectively with layer (B) (instead of on and in contact with the porous layer (A) respectively), wherein layer (B) preferably has a thickness between 0.2 µm and 20 µm, and wherein layer (B) is composed of materials selected from yttrium-doped zirconium oxide (3YSZ), Sc-doped ZrO2, Al, Mg, or rare earths; TiO2, Sr titanates or rare earths, alumina, Mg and Al spinel, MgO, CaO, forsterite, porcelain, rare earth aluminates, and combinations thereof. This layer (B) is preferably uniform in length and width along the XY axis. An electronic conductivity of layer (B) of less than 10-6 S / cm prevents electron leakage through support A, thus preventing the loss of functionality of the circuit connecting the individual cells of layer D. Additionally, layer (B) also acts as a barrier to the diffusion of chemical elements from layers C and / or D, preventing, as a non-limiting and illustrative example, the diffusion of Cr. Another advantage of adding a layer (B) on the porous support (A) is that this layer (B) reduces the roughness and pore size compared to that of the pure porous support (A), thus facilitating the subsequent deposition of other layers, such as a dielectric porous layer (C) which will be defined below. Another embodiment also relates to the addition of a porous layer (C), specifically that the complex electrochemical cell further comprises at least one porous layer (C) formed by two or more juxtaposed layers of dielectric porous material, wherein said at least two layers are selected from the at least one anodic layer (AL), the at least one electrolyte layer (EL), the at least one cathodic layer (CL), and the at least one current collector layer (CCL), where: - the porous dielectric layer (C) integrates electrically conductive tracks (PCE) that define an electrical circuit and allow the electrical connection of said electrical circuit to the adjacent layer (D), - the porous dielectric layer (C) is in contact with the layer that integrates the set of electrochemical cells (D), and - the porous dielectric layer (C) has a thickness between 2 µm and 200 µm, and - the dielectric porous layer (C) has a porosity between 20% and 60%. The porous dielectric layer (C) has an electronic conductivity of less than 10⁻⁶ S / cm and is preferably made of ceramic material. The electrically conductive tracks of the aforementioned embodiment of layer (C) preferably have an electronic conductivity greater than 0.5 S / cm. These characteristics of the porous dielectric layer (C) and its arrangement in the complex electrochemical cell according to the above embodiment provide several advantages: on the one hand, the good adhesion of the layer (C) to the cell thanks to the intermediate layer (B), and on the other hand the fact that the conductive tracks of the layer (C) are able to define an electrical circuit for the interconnection between individual elements of the layer (D) and optionally with elements of the side contacts (F), thus allowing the layer (C) to perform the function that a printed circuit board (PCB) would do. A printed circuit board (PCB), in electronic systems, is a rigid structure containing electrical circuits formed by embedded metal surfaces called traces and larger areas of metal called planes, separated from each other by dielectric material (electrical insulator). Electronic components, such as chips, resistors, diodes, etc., are soldered to the board onto metal pads, which connect to the circuits on the board. This allows the components to be interconnected to achieve specific functionalities in conventional electronic devices, such as household appliances, computers, or telephones. The distribution of traces and dielectric material on the PCB is conventionally arranged in planes to achieve complex interconnections. In a preferred embodiment of the above embodiment, referring to the porous dielectric layer (C), the at least one porous dielectric layer (C) is located between the layer (D) and the support (A), where the presence of layer (C) implies that the sublayers (AL) and (EL) of layer (D) are on and in contact with layer (C), respectively; instead of on and in contact with the porous layer (A), respectively. In this particular case, layer (C) is referred to as layer (E). This specific positioning of layer (C) between layer (D) and the porous support (A) facilitates the manufacturing and compactness of the cell, since layer C is deposited on the surface of the support (A) and is the basis for the deposition and subsequent thermal consolidation of the sublayers of layer (D). Ideally, the materials of the different layers that make up the electrochemical cell array should have a similar expansion profile; that is, they should expand and contract in a coordinated manner to prevent cracks, breaks, buckling, or other defects in the final assembly. If two materials do not have the same expansion or thermal dilation profile, their joint will experience mechanical stress, and the assembly may fail mechanically during heating or cooling processes. Furthermore, the materials of the different layers of the complex electrochemical cell, which integrates the array of individual electrochemical cells, are preferably thermochemically compatible, that is, that both components in contact, for example the support and a functional layer, present a similar expansion profile as a function of temperature and that interdiffusion of elements and chemical reaction between the materials of both layers does not take place at high temperatures to give rise to new crystalline phases, which can result in the generation of defects and / or rupture of the membrane, and loss of conduction properties. Another embodiment according to the first aspect of the invention relates to additional elements integrated into the complex electrochemical cell, specifically that the complex electrochemical cell comprises at least one of the following elements integrated into either of the layers (C) and / or (D): - elements for temperature measurement selected from thermistors or calibratable resistive layers, - Elements for the electrochemical measurement of water or oxygen concentration in the gas phase, based on selective electrodes or semiconductors whose electronic or ionic conductivity depends on the concentration of the gaseous species. Measurements in these devices are based on determining the cell impedance, the EMF voltage, and iV (voltamperometric) curves. - Diodes that allow control of the direction of the electric current between individual electrochemical cells, typically semiconductors based on carbides or nitrides of semimetals, and / or - MOSFET-type active switching elements between individual electrochemical cells selected from solid-state transistors and relays. All these elements allow for better control and in-situ calibration of the cell's operating parameters to achieve greater efficiency in the electrochemical processes carried out by the cell, such as the production of hydrogen or synthesis gas by electrolysis or co-electrolysis respectively. A second aspect of the invention therefore relates to the use of the complex electrochemical cell of the invention, for example, for the production of H2 from water vapor electrolysis; or for example, for the production of synthesis gas from the co-electrolysis of water vapor and CO2. Throughout the description and claims, the word "comprises" and its variants are not intended to exclude other technical features, additives, components, or steps. For those skilled in the art, other objects, advantages, and features of the invention will become apparent partly from the description and partly from the practice of the invention. The following examples and figures are provided for illustrative purposes and are not intended to limit the scope of the present invention. BRIEF DESCRIPTION OF THE FIGURES Figure 1.- Cross section of the complex cell consisting of: (A) a porous support, (B) a porous layer of a ceramic dielectric material, (D) a layer integrating an array of individual electrochemical cells, and (C) an integrated circuit layer containing electrically conductive tracks and electrically insulating dielectric material. Figure 2.- Cross section of the complex cell consisting of: (A) a porous support, (B) a porous layer of a ceramic dielectric material, (D) a layer integrating an array of individual electrochemical cells, (C) and (E) integrated circuit layers containing electrically conductive tracks and electrically insulating dielectric material. Figure 3.- Cross section of the complex cell consisting of: (A) a porous support, (B) a porous layer of a ceramic dielectric material, and (D) a layer that integrates an array of individual electrochemical cells. Figure 4.- Cross section of the complex cell consisting of: (A) a porous support, and (D) a layer that integrates an array of individual electrochemical cells. Figure 5.- Cross section of the complex cell consisting of: (A) a porous support, and (D) a layer integrating two individual electrochemical cells connected in series, each of which is formed by: (AL) porous anodic layer, (EL) gas-impermeable electrolyte layer, (CL) porous cathodic layer, (CCL) porous current collection layer, and (IC) gas-impermeable electrical interconnection layer. Figure 6.- Evolution of voltage as a function of current density for a complex electrochemical cell composed of 10 x 10 cells (as in example 1), in which the individual cells are connected in two ways (See Figure 7): (I) 10 blocks of 10 adjacent cells connected in parallel and the 10 blocks are connected in series. (II) 20 blocks of 5 adjacent cells connected in parallel and the 20 blocks are connected in series. Figure 7.- Schematic of the connection of 100 individual cells in two different configurations: (left) 10 blocks of 10 adjacent cells connected in parallel and the 10 blocks are connected in series; and (right) 20 blocks of 5 adjacent cells connected in parallel and the 20 blocks are connected in series. Figure 8.- Diagram of an individual electrochemical cell that are integrated into the layer (D) which is formed by: (AL) porous anodic layer, (EL) gas impermeable electrolyte layer, (CL) porous cathodic layer, (CCL) porous current collection layer, (IC) gas impermeable electrical interconnection layer, and (SI) gas impermeable electrical insulating seal layer. Figure 9.- Simple equivalent electrical circuit of an individual electrochemical cell. Figure 10.- Diagram of a (1 x 9) array of individual electrochemical cells that are integrated into the (D) layer and are electrically connected in series. Figure 11.- Diagram of a (5 x 5) array of individual electrochemical cells (a total of 25 cells) that are integrated into the (D) layer and are electrically connected in series. Figure 12.- Top view of a complex electrochemical cell showing the arrangement of the lateral electrical connections (outer frame) around the (D) and (A) layers (see Figure 4). EXAMPLES The invention will now be illustrated by examples of the complex electrochemical cell according to the claims, as well as its features. Example 1 A composite electrochemical cell, according to the scheme in Figure 1, composed of: (1) a support (A) made of 3YSZ material: thickness (350 µm), porosity (50%), average pore size (2 µm) and particles (5 µm). Manufactured by tape-casting, (2) a layer (B) of 3YSZ: thickness (15 µm), porosity (40%), average pore size (0.25 µm) and particles (0.5 µm). This interlayer has the function of reducing surface roughness and pore size to improve the deposition of layer (C), and (3) an assembly / plurality of juxtaposed dielectric layers (C) of integrated circuit containing 100 porous conductive tracks of electronic conductivity greater than 0.5 S / cm, lateral tracks that are not in contact with each other, and connect each of the layers (AL) of each individual cell with contact points of the lateral connections of layer (F), allowing the measurement of the potential difference between the different cells, which is advantageous for the diagnosis of the operation and real-time control of the complex cell's functioning. Layer (C) has a composition of 3YSZ as a dielectric and Ni as an electronic conductor for the electrically conductive tracks. In turn, the complex electrochemical cell comprises an array (10x10) of individual electrochemical cells composed of the following layers (D): a. a porous functional anodic layer (AL) formed by a mixture (50%-50% by volume) of 8YSZ and Ni, having thickness (10 µm), porosity (30%), average pore size (0.25 µm) and particles (0.5 µm), b. an electrolyte (EL) layer formed by the ionic material 8YSZ, which has a thickness (5 µm) and porosity of less than 2%, c. a porous functional cathodic layer (CL) formed by a mixture (50%-50% by volume) of 8YSZ and LSM, having thickness (15 µm), porosity (30%), average pore size (0.25 µm) and particles (0.5 µm), and d. a current collector layer made of Cu2MnO4 material that has thickness (75 µm), porosity (45%), average pore size (2 µm) and particle size (5 µm). The individual cells are electrically connected by means of a gas-impermeable electrical interconnection layer (IC) with a permeability of 10⁻³ to 10⁻⁴ mbar·L / sa for H₂ and He gases, 20 µm thick, composed of a mixture of Ag (0.5–2 µm) and a BaSiAl glass-ceramic material. This layer connects the anodic layer (AL) of one cell to the current-collecting layer (CCL) of an adjacent cell. In this way, a dense, continuous layer is created by interleaving electrolyte and electrical interconnection layers, preventing the passage of gas in contact with the porous support (A). Alternatively, if a layer (E) of porous MgO electrical insulator (30% porosity by volume) and 5 µm thick is added to the complex electrochemical cell of example 1, the complex electrochemical cell represented by Figure 2 would be obtained. If, on the other hand, the complex electrochemical cell of example 1 does without the juxtaposed electrical layers (C), then the configuration of the complex electrochemical cell is represented by Figure 3; while if, in addition, the interlayer (B) is also omitted, the resulting electrochemical cell would be that represented in Figure 4. If to this last complex electrochemical cell (composed of layers (A) and (D)), represented by Figure 4, lateral connections (F) are additionally added, which are connected to the electrical cables that go to the power and control source, where said lateral connections (F) are of composition 3YSZ and Ni, with a thickness of 10 µm and 5 mm in width, in an outer frame made of 3YSZ and Ni and with a width of 1 cm, placed just around the layers (A) and (D), the complex electrochemical cell represented schematically by Figure 12 is obtained. Example 2 Electrochemical cell composed according to example 1, wherein the electrolyte and electrodes contain the ionic conducting material Sc-doped ZrO2, instead of 8YSZ. Example 3 Electrochemical cell composed according to example 2, wherein the electrolyte layer (EL) comprises an additional upper interlayer of the material Ce0.8G0.9O1.9, with a thickness of 250 nm, and the functional cathode layer (CL) is composed of the porous perovskite La0.6Sr0.4CoO3. Example 4 Electrochemical cell composed according to example 1, wherein there are individual cells interleaved with two different types of electrolytes (EL) based on two different ceramic compounds (8YSZ and BZCY), and different functional anode layers (AL) (Ni / 8YSZ and Ni / BZCY), wherein the (EL) and (AL) layers are 10 µm and 10 µm, respectively. Example 5 Electrochemical cell composed according to example 4 in which the electrolyte layers (EL) have an upper interlayer of graphene oxide (CGO), 250 nm thick, and the functional cathode layer (CL) is composed of the porous La0.6Sr0.4CoO3 perovskite with a thickness of 15 µm. Example 6 A complex electrochemical cell formed by a porous support like that of example 1, on which a layer (D) is mounted that integrates two individual electrochemical cells (2x1 matrix), and where the composition and characteristics of each of the sublayers of layer (D) are those mentioned for the sublayers of example 1, these sublayers being: - 2 porous anodic layers (AL), one for each individual electrochemical cell. - 2 electrolyte layers (EL), one for each individual electrochemical cell. - 2 porous cathodic layers (CL), one for each individual electrochemical cell. - 2 porous current collection layers (CCL), one for each individual electrochemical cell, and - 1 electrical interconnection layer, shared by both individual electrochemical cells. A schematic of the complex electrochemical cell of Example 6 can be seen in Figure 5. Example 7 Example 7 refers to when the layer (D) according to the invention comprises only a single electrochemical cell. This cell with its corresponding sublayers is shown schematically in Figure 8, without yet being mounted on the porous support (A). This electrochemical cell only comprises one sublayer of each of the layers that make up the (D) layer, these being the (AL) , (EL) , (CL) , (CCL) , (IC) , and (SI) , its composition and characteristics being analogous to those indicated for said sublayers in example 1. Figure 9 represents the electrical circuit equivalent to the individual electrochemical cell of this example 7 (Figure 8). Example 8 Assembly of 9 electrochemical cells as in Example 8, electrically connected in series (as a 1x9 array), on a porous substrate (A) of composition and characteristics as in Example 1, where each individual electrochemical cell comprises one of each of the sublayers of layer (D) mentioned in Example 8, the 9 cells being integrated into layer (D). A schematic of the configuration according to Example 8 is shown in Figure 10. Example 9 An analogous example to that in Figure 8, but with 25 individual electrochemical cells mounted in 5 rows and 5 columns (5x5 matrix), where the rows represent the electrical connection of the individual electrochemical cells in series, while the columns represent their electrical connection in parallel. A schematic of the configuration according to Example 9 is shown in Figure 11. Layer (D), especially its electrolyte sublayer (EL) of layer (D), comprises rare earth ortho-niobiates and ortho-tantalates, rare earth tungstates (e.g., lanthanides), rare earth sesquioxides (e.g., lanthanides) undoped or alkaline earth doped, rare earth molybdates, cerium and lanthanum pyrochlorides, Ca, Al, Si, or Ge-based apatites, undoped or rare earth doped bismuth oxide or Nb or Ta or combinations thereof, rare earth phosphate or combinations thereof, zirconium oxide and / or cerium oxide with fluorite-type crystal structure undoped or partially substituted by Y, Sc, Gd, La, Pr, Sm, Nd, Er, Eu, Yb, and / or Tb; undoped or Ce, Gd, Y, Sc, Eu and / or Yb doped barium zirconate or cerate; cerium oxide-based fluorites; perovskites containing Ba, Zr, Ce, G, La, Sr, Y, Co or Yb; lanthanum niobates, barium indates, graphene oxide (CGO), or combinations thereof.These materials provide adequate ionic conductivity, expansion coefficient, and chemical compatibility with the other materials in the adjacent layers. The layer (D), especially its porous cathodic sublayer (CL), comprises Pd, Nb, V, Ni, Mo, W, metal nitrides or carbides or combinations thereof. The layer (D), especially its porous anodic sublayer (AL) and / or its current collector sublayer (CCL), comprises Cu, Ni, Ag, Au, Fe, Co, metal nitrides or carbides, or combinations thereof.

Claims

1. Complex electrochemical cell, characterized in that it comprises: - a porous support (A) with a porosity between 20-80%, composed of a material selected from a metallic and / or ceramic material, - a layer (D) comprising at least two electrochemical cells connected in series and / or in parallel, placed on the porous support (A), where each cell is composed of at least: or a porous functional anodic layer (AL), composed of materials selected from fluorites, zirconium and / or yttrium oxides, undoped or doped barium zirconates, perovskites based on Fe, Ce, Zr, Cr, Ti, Mn or Mo; and metals or alloys of Ni, Fe, Ag, Cu, Au or Pt, or combinations thereof, preferably having a thickness between 0.25 µm and 10 µm; or a porous functional cathodic layer (CL), composed of materials selected from metal nitrides, manganite, zirconium oxide, cerium or yttrium and their combinations, perovskite-type structure of alkaline earth elements and / or rare earths and / or transition metals; or metals or alloys of Pd, or Ag, or Au, or Nb, or V, or Ni, or W, or Ta; or combinations thereof, preferably having a thickness between 0.5 µm and 30 µm; or an electrolyte layer (EL) located at least partially between the anodic layer (AL) and the cathodic layer (CL) and in contact with both layers, wherein the layer is composed of materials selected from undoped or rare-earth-doped bismuth oxide or Nb or Ta or combinations thereof; undoped or partially substituted fluorite-type zirconium oxide and / or cerium oxide with a fluorite-type crystal structure, or zirconium oxide and / or cerium oxide with a fluorite-type crystal structure, or zirconate or cerium oxide with a fluorite-type crystal structure, or zirconate or cerium oxide with a fluorite-type crystal structure, or zirconate or cerium oxide with a fluorite-type crystal structure, or zirconate or cerite-doped barium oxide, or ... lanthanide tungstates, apatites, lanthanide sesquioxides, lanthanum niobates, Ce and La-based pyrochlores, barium indates, graphene oxide (CGO), or combinations thereof, preferably having a thickness between 0.25 µm and 10 µm; or an electrical interconnection (IC) layer in contact with at least the anodic layer (AL) of an individual cell with the (CL) and / or (CCL) layer of at least one other individual cell, composed of materials selected from a mixture of a metal with a conductivity greater than 1 S / cm, and mixtures of at least two components selected from SiO2, Al2O3, B2O3, BaO, BaSiAl, ZnO, CaO, SrO, ZrO2, TiO2, Na2O, or K2O, preferably with a thickness between 0.25 µm and 50 µm; 1. A sealing dielectric layer (SI), composed of materials selected from mixtures of at least two components selected from SiO2, Al2O3, B2O3, BaO, BaSiAl, ZnO, CaO, SrO, ZrO2, TiO2, Na2O, or K2O, preferably with a thickness between 0.5 µm and 200 µm.

2. A complex electrochemical cell according to claim 1, further comprising a porous current collector (CCL) layer, preferably with a thickness between 0.25 µm and 200 µm, composed of materials selected from strontium lanthanum manganite (LSM), strontium lanthanum chromite (LSC), strontium lanthanum cobalt ferrite (LSCF), uncoated or strontium lanthanum manganite (LSM) or strontium lanthanum chromite (LSC) coated nickel, uncoated or strontium lanthanum manganite (LSM) or strontium lanthanum chromite (LSC) coated stainless steels, silver (Ag) or gold (Au) or platinum (Pt) or their alloys, Cu and / or Ni and / or Ag and / or Au and / or Fe and / or Co alloys, Inconel or Hastelloy alloys, lanthanum chromite (LaCrO3) undoped or doped with Y, Al, Fe, Mn, lanthanum manganite (LaMnO3) with Sr, Y, Al, Ca, Fe, Mn, Mg and / or Mn and / or Co and / or Cu spinels, Cu2MnO4, or combinations thereof, and preferably placed partially on a porous cathodic layer (CL) and partially on an electrical interconnection layer (IC). 3.A complex electrochemical cell according to claim 1 or 2, further comprising side electrical connections (F) for connecting the electrochemical cell to cables, plates, and / or interconnectors.

4. A complex electrochemical cell according to claim 1 to 3, wherein the porous support (A) comprises materials selected from spinels, forsterites, perovskites, magnesium oxides, cerium oxides doped with at least one lanthanide metal, zirconium oxides doped with at least Y, Mg, Sc and / or a lanthanide metal, titanium oxides, aluminum nitrides, refractory alloys or superalloys, temperature-resistant metal alloys, iron alloys, stainless steels, clays, silicates of Al or Mg or Ti or Fe or of alkali or alkaline earth elements, or combinations thereof. 5.A complex electrochemical cell according to claim 4, wherein the porous support (A) comprises a material selected from magnesium oxide (MgO), yttrium-doped zirconium oxide (3YSZ), forsterite, aluminum magnesium spinels (MgAl2O4), iron perovskite, ferritic stainless steels P434L, ITM, or Crofer APU22, or combinations thereof.

6. A complex electrochemical cell according to claims 1 to 5, wherein the porous support (A) has a flat geometry with or without engraved "flowfield" reliefs, a tubular geometry, a corrugated flat geometry, or a corrugated tube geometry.

7. Electrochemical cell according to any of claims 1 to 6, wherein the porous functional cathodic layer (CL) comprises a material selected from La0.6Sr0.4CoO3-, La0.6Sr0.4CoO3, Ba0.5Sr0.5Fe0.2Co0.8O3-, ferrites, nickelates, rare-earth or gadolinium-doped cerium oxide with a spinel-type structure, a mixture of yttria zirconia oxide (8YSZ) and lanthanum strontium manganite (LSM), or scandium-doped zirconium oxide.

8. Electrochemical cell according to any of claims 1 to 7, wherein the material or materials of the porous functional anode layer (AL) is at least a fluorite based on doped or undoped cerium oxide or zirconium oxide; and / or mixtures with metals selected from Ni, Al, Cu, Fe, Co, Pd, Mn, Mo, Cr; zirconium yttrium oxide (8YSZ), mixture of 8YSZ and nickel, scandium-doped zirconium oxide, mixture of nickel and cerium-yttrium-doped barium zirconate (BZCY), or combinations thereof. 9.An electrochemical cell according to any one of claims 1 to 8, wherein the material or materials of the porous functional anode layer (AL) and / or the porous functional cathode layer (CL) have an average particle size in the range of 0.1 to 3 µm.

10. An electrochemical cell according to any one of claims 1 to 9, wherein the surface of the porous functional anode layer (AL) and / or the porous functional cathode layer (CL) is coated with nanoparticles smaller than 75 nm.

11. A complex electrochemical cell according to claims 1 to 10, wherein the electrolyte (EL) layers of at least two of the electrochemical cells comprising the complex electrochemical cell are of different compositions. 12.Complex electrochemical cell according to claims 1 to 11, wherein at least one of the electrolyte layers (EL) has a composition selected from lanthanide tungstates, zirconium oxide and / or cerium oxide with fluorite-type crystal structure substituted by Y, Sc, Gd, La, Pr, Sm, Nd, Er, Eu, Yb, and / or Tb and combinations thereof, yttrium zirconium oxide (8YSZ), scandium-doped zirconium oxide, cerium-yttrium-doped barium zirconate or cerate (BZCY), barium zirconate or cerate doped 10-20 mol% with Gd, Y, Sc, Eu, Yb and combinations thereof; or zirconium and / or cerium oxide where the cerium and / or zirconium respectively are substituted in a ratio of between 10% and 30% molar, preferably between 10% and 20%, by at least one element selected from Y, Sc, Gd, La, Pr, Sm, Nd, Er, Eu, Yb, and / or Tb and combinations thereof; mixture of 8YSZ and BZCY, Ce0.8G0.9O1.9, perovskite La0.6Sr0.4CoO3 porous, apatites based on Ca, Al, Si, or Ge, or combinations thereof.

13. Complex electrochemical cell according to any of claims 1 to 12, wherein the electrolyte layer (EL) comprises at least two juxtaposed layers of different composition, and wherein at least one of the juxtaposed layers has an ionic conductivity greater than 1 × 10⁻⁴ S / cm.

14. Complex electrochemical cell according to any of claims 1 to 13, wherein the electrical interconnection layer (IC) comprises silver (Ag) as a high-conductivity metal greater than 1 S / cm.

15. Complex electrochemical cell according to any of claims 1 to 14, wherein the porous functional cathode layer (CL) has the same composition as the porous current collector layer (CCL). 16.A complex electrochemical cell according to any one of claims 1 to 15, wherein the complex electrochemical cell further comprises at least one porous layer of ceramic dielectric material (B), placed on the porous support (A), wherein the presence of layer (B) implies that the sublayers (AL) and (EL) of layer (D) are on and in contact with layer (B), respectively, wherein layer (B) preferably has a thickness between 0.2 µm and 20 µm, and wherein layer (B) is composed of materials selected from yttrium-doped zirconium oxide (YSZ), Sc-doped ZrO2, Al-doped Mg or rare-earth elements; TiO2, Sr or rare-earth titanates, alumina, Mg and Al spinel, MgO, CaO, forsterite, porcelain, rare-earth aluminates, and combinations thereof. 17.A complex electrochemical cell according to any one of claims 1 to 16, wherein the complex electrochemical cell further comprises at least one porous dielectric layer (C) formed by two or more juxtaposed layers of porous dielectric material, wherein: - the porous dielectric layer (C) incorporates electrically conductive tracks (PCE) that define an electrical circuit and allow the electrical connection of said electrical circuit to the adjacent layer (D), - the porous dielectric layer (C) is in contact with the layer that integrates the electrochemical cell assembly (D), and - the porous dielectric layer (C) has a thickness between 2 µm and 200 µm, and - the porous dielectric layer (C) has a porosity between 20% and 60%. 18.A complex electrochemical cell according to claim 17, characterized in that at least one porous dielectric layer (C) is located between layer (D) and the support (A), and wherein the presence of layer (C) implies that the sublayers (AL) and (EL) of layer (D) are located on and in contact with layer (C) respectively. 19.A complex electrochemical cell according to any one of claims 1 to 18, comprising at least one of the following elements integrated into any of layers (C) and / or (D): - elements for temperature measurement selected from thermistors or calibratable resistive layers, - elements for the electrochemical measurement of the concentration of water or oxygen in the gas phase, based on selective electrodes or semiconductors whose electronic or ionic conductivity depends on the concentration of the gaseous species, - diodes that allow control of the direction of the electric current between individual electrochemical cells based on semimetal carbides or nitrides, and / or - MOSFET-type active switching elements between individual electrochemical cells selected from solid-state transistors and relays. 20.Use of the complex electrochemical cell described according to claims 1 to 19 for the production of H2 from the electrolysis of water vapor.

21. Use of the complex electrochemical cell described according to claims 1 to 20 for the production of synthesis gas from the co-electrolysis of water vapor and CO2.

Images