Electrochemical cell and method for producing hydrogen and oxygen from water

Abstract

The present invention relates to an electrochemical cell and a method for producing hydrogen and oxygen from water. The electrochemical cell according to the present invention makes it possible to carry out electrochemical reactions for a long period of time at temperatures of 120°C to 200°C and pressures of up to 3 MPa (30 bar), even under harsh chemical conditions (for example, a KOH mass fraction of up to 35% in the electrolyte). The method according to the present invention makes it possible to produce hydrogen and oxygen from water at temperatures of 120°C to 200°C and pressures of up to 3 MPa (30 bar), even under harsh chemical conditions (for example, a KOH mass fraction of up to 35% in the electrolyte).

Description

Technical Field

[0001] An electrochemical cell is provided, and a method for generating hydrogen and oxygen from water is introduced. With the electrochemical cell according to the present invention, an electrochemical reaction can be carried out over a long period of time at a temperature of 120°C to 200°C and a pressure of up to 3 MPa (30 bar), even under severe chemical conditions (for example, a KOH mass fraction of up to 35% in the electrolyte). With the method according to the present invention, it is possible to generate hydrogen and oxygen from water at a temperature of 120°C to 200°C and a pressure of up to 3 MPa (30 bar), even under severe chemical conditions (for example, a KOH mass fraction of up to 35% in the electrolyte).

Background Art

[0002] An electrochemical cell for alkaline water electrolysis (AWE) comprises a cathode and an anode separated by a porous separator (or porous membrane). The reaction uses electrical energy and proceeds with respect to equilibrium as H2O→H2+1 / 2O2 as follows.

[0003] The aqueous alkaline liquid electrolyte (for example, an aqueous KOH solution) of the electrochemical cell contains the reactant (H2O) on the one hand and serves as an ionic conduction medium for OH ions on the other hand. In this process, the electrolyte always wets the cathode and the anode and penetrates the separator. The separator creates electrical insulation both with respect to the pure physical contact between the anode and the cathode (to prevent short circuits) and with respect to the electron conduction by the liquid electrolyte (to prevent leakage current). Furthermore, the separator prevents the exchange of the product gases (H2 at the cathode, O2 at the anode), so that an explosive mixture (for example, H2 in O2) does not occur in each compartment of the electrochemical cell. At the same time, the porosity of the separator enables OH - ion conduction due to the penetration of the aqueous alkaline electrolyte.

[0004] The operating temperature of electrochemical cells for alkaline water electrolysis is currently typically 60°C to 90°C, limited by the temperature tolerance of the separator. One option for improving the performance of alkaline water electrolysis is to increase the temperature (and sometimes the pressure) while maintaining the same KOH concentration (mass fraction, e.g., 30% to 35%) of the aqueous electrolyte. In so-called medium-temperature electrolysis, temperatures of 120°C to 200°C and KOH mass fractions up to 35% of the electrolyte have been found at a pressure of 3 MPa (30 bar).

[0005] Non-patent document 1 discloses an electrochemical cell for alkaline water electrolysis that includes a separator having high ionic conductivity and low hydrogen permeability. The separator is made from a Zirfon PERL substrate to which a layer of glutaraldehyde-crosslinked polyvinyl alcohol (PVA) is deposited. The Zirfon PERL substrate is made from zirconium nanoparticles deposited on a planar polyphenylene sulfide substrate (PPS substrate) using a polysulfone binder (PSU binder). The additional deposition of glutaraldehyde-crosslinked PVA significantly reduces the hydrogen permeability of the known Zirfon PERL substrate, thereby improving the operational reliability of the electrochemical cell having this separator. However, the described separator has the disadvantage that, due to its organic components (PSU, PPS, and crosslinked PVA), it is not suitable for the intended medium-temperature electrolysis at temperatures of 120°C to 200°C, pressures up to 30 bar, and KOH mass fractions up to 35% in the electrolyte. This is because the separator is destroyed under these conditions. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] Kim, S. et al. (Journal of Power Sources, 524:231059) [Overview of the project]

[0007] Starting from this, the objective of the present invention was to provide an electrochemical cell (particularly an electrochemical cell for alkaline water electrolysis) that does not have the drawbacks of the prior art. In particular, it is desirable that the electrochemical cell be able to carry out electrochemical reactions for a long period of time at temperatures of 120°C to 200°C and pressures of up to 3 MPa (30 bar), even under harsh chemical conditions (for example, a KOH mass fraction of up to 35% in the electrolyte). Furthermore, it is desirable to introduce a method for producing hydrogen and oxygen from water that can be carried out under these conditions.

[0008] This objective is achieved by an electrochemical cell having the features of claim 1 and a method having the features of claim 16. Dependent claims illustrate advantageous embodiments.

[0009] According to the present invention, an electrochemical cell, a) Receptacle for containing liquid electrolyte, b) A membrane assembly, A planar anode layer having an upper surface and a lower surface, A planar protective layer comprising an electrical insulating ceramic material, having pores with a first pore diameter on the upper surface, lower surface, and extending from the upper surface to the lower surface, A film assembly comprising a planar cathode layer having an upper and lower surface. Equipped with, The membrane assembly is in contact with the liquid electrolyte. The membrane assembly is arranged within the receptacle such that the receptacle separates the liquid electrolyte into a first compartment and a second compartment. The membrane assembly separates the first compartment from the second compartment in a way that electrically insulates it and conducts ions. The planar protective layer is positioned on the underside of the planar anode layer, and the upper surface of the planar protective layer is in contact with the underside of the planar anode layer. On the underside of the flat protective layer, i) A cathode layer is provided, and the upper surface of the cathode layer is in contact with the lower surface of a planar protective layer, or ii) A planar substrate is provided, the planar substrate having pores on its top surface, bottom surface, and extending from the top surface to the bottom surface, having a second pore diameter larger than a first pore diameter, the top surface of the planar substrate is in contact with the bottom surface of the planar protective layer, and the cathode layer is provided on the bottom surface of the planar substrate. The membrane assembly does not contain any organic polymers. An electrochemical cell characterized by the above is provided.

[0010] In particular, the term "located" is not necessarily understood to mean "in contact." This means that if one layer is located on another, then at least one further layer may be located between the two layers.

[0011] The electrochemical cell according to the present invention makes it possible to carry out electrochemical reactions over long periods of time at temperatures of 120°C to 200°C and pressures of up to 3 MPa (30 bar), even under harsh chemical conditions (e.g., KOH mass fraction up to 35% in the electrolyte). This characteristic makes it possible to carry out electrochemical reactions (e.g., alkaline water hydrolysis) with higher efficiency and / or higher power density.

[0012] Another advantage is that the membrane assemblies of the electrochemical cell according to the present invention can be manufactured in larger dimensions (e.g., up to 2 m side length) and a larger active surface (e.g., 4 m) compared to polymer-based or ceramic-based membrane assemblies. 2 This can result in an active surface. Therefore, the electrochemical cell according to the present invention makes it possible to further increase the efficiency and / or power density of electrochemical reactions.

[0013] In addition, this offers the advantage of enabling the easy and cost-effective manufacturing of the membrane assemblies of electrochemical cells, and ultimately, the entire electrochemical cell.

[0014] The planar protective layer of the membrane assembly may be deposited on the lower surface of the planar anode layer, the upper surface of the planar cathode layer, and / or the upper surface of the planar substrate by a method selected from the group consisting of atmospheric plasma spraying, slurry-based coating with subsequent binder removal, electrophoretic coating, or gas-based coating. The slurry-based coating process is preferably selected from the group consisting of dip bath coating, slot die coating, lamination, and combinations thereof.

[0015] Furthermore, the planar protective layer of the membrane assembly may have a thickness in the range of 10 - 1000 μm, and the thickness particularly refers to the spread of the protective layer in a direction perpendicular to the upper surface and / or the lower surface of the planar protective layer.

[0016] On the lower surface of the planar substrate of the membrane assembly (described in the second alternative form), a further planar protective layer may be disposed. The further planar protective layer has a first pore diameter extending from the upper surface, the lower surface, and the upper surface to the lower surface. The further planar protective layer contains or consists of an electrically insulating ceramic material. Preferably, the lower surface of the planar substrate is in contact with the upper surface of the protective layer, and the lower surface of the protective layer is in contact with the upper surface of the planar cathode layer.

[0017] The further planar protective layer may be deposited on the lower surface of the planar substrate by a method selected from the group consisting of atmospheric plasma spraying, slurry-based coating with subsequent binder removal, electrophoretic coating, or gas-based coating. The slurry-based coating process is preferably selected from the group consisting of dip bath coating, slot die coating, lamination, and combinations thereof, and / or

[0018] Furthermore, the further planar protective layer may have a thickness in the range of 10 - 1000 μm, and the thickness particularly refers to the spread of the planar protective layer in a direction perpendicular to the upper surface and / or the lower surface of the planar protective layer. <0oooo89>

[0019] The membrane assembly may be assembled by a method selected from the group consisting of pressing, bonding, and combinations thereof. Pressing preferably includes applying a pressure in the range of 50 to 3500 MPa, preferably in the range of 100 to 3000 MPa, and particularly preferably in the range of 150 to 2500 MPa, in a direction perpendicular to the membrane assembly.

[0020] The cathode layer of the membrane assembly may include or consist of a catalyst that catalyzes the reduction of water to hydrogen. The catalyst preferably includes a material selected from the group consisting of metals, metal alloys, and combinations thereof. The material may optionally be selected from the group consisting of nickel, cobalt, molybdenum, manganese, nickel-aluminum, nickel-aluminum-molybdenum, nickel-molybdenum, Raney nickel, and combinations thereof.

[0021] The anode layer of the membrane assembly may include or consist of a catalyst that catalyzes the oxidation of water to oxygen. The catalyst preferably includes a material selected from the group consisting of metals, metal alloys, metal oxides, mixed metal oxides, spinels, perovskites, layered double hydroxides, and combinations thereof. The material may optionally be selected from the group consisting of nickel, cobalt, nickel-aluminum, nickel-aluminum-molybdenum, nickel-molybdenum, Raney nickel, nickel oxide, iridium oxide, and combinations thereof.

[0022] The flat substrate may include or consist of a material selected from the group consisting of metals, metal alloys, and combinations thereof. The material is preferably selected from the group consisting of stainless steel, nickel steel, solid nickel, and combinations and alloys thereof.

[0023] The flat substrate may further include or consist of a structure selected from the group consisting of non-woven fabric, solid foam, expanded metal, mesh, woven fabric, and combinations thereof.

[0024] In addition, the planar substrate may have a thickness in the range of 40 to 1500 μm, preferably in the range of 50 to 1250 μm, and particularly preferably in the range of 60 μm to 1000 μm, where the thickness refers in particular to the spread of the planar substrate in a direction perpendicular to the upper and / or lower surfaces of the planar substrate.

[0025] The pores of the planar substrate may have a second pore diameter in the range of 5 μm to 1250 μm, preferably in the range of 10 μm to 1000 μm, and particularly preferably in the range of 15 μm to 750 μm, where the pore diameter refers to a pore diameter that can be determined by mercury intrusion and / or bubble point measurement.

[0026] The pores of the planar substrate may further have a second pore diameter that decreases from the upper surface of the planar substrate toward the lower surface of the planar substrate, or from the lower surface of the planar substrate toward the upper surface of the planar substrate.

[0027] The electrically insulating ceramic material for the planar protective layer, and optionally, the electrically insulating ceramic material for any further planar protective layer of the film assembly, may include or consist of materials selected from the group consisting of nitride ceramics, carbide ceramics, oxide ceramics, silicate ceramics, cermets, and combinations thereof.

[0028] The electrically insulating ceramic material of the planar protective layer, and optionally further, the electrically insulating ceramic material of the further planar protective layer of the film assembly, may further contain or consist of particles, the particles having a diameter preferably in the range of 0.5 μm to 95 μm, preferably in the range of 5 μm to 70 μm, and particularly preferably in the range of 9 μm to 45 μm, where the particle diameter refers to a measured value of the particle size distribution.

[0029] The pores of the planar protective layer, and optionally, the pores of any further planar protective layer of the film assembly, may have a first pore diameter in the range of 50 nm to 9 μm, where the pore diameter refers to a pore diameter that can be determined by mercury intrusion and / or bubble point measurement.

[0030] The electrical resistance of the planar protective layer, and optionally any further planar protective layers of the film assembly, may be in the range of kΩ to MΩ.

[0031] The ionic resistance of the planar protective layer, and optionally even further planar protective layers of the film assembly, is <0.3~0.8 Ωcm. 2 It may be within that range.

[0032] In addition, the gas permeability of the planar protective layer, and optionally the further planar protective layer of the membrane assembly, is 2-6 L / min·cm at 0.5 MPa (5 bar). 2 It may be within that range.

[0033] Separately, a planar protective layer, and optionally even a further planar protective layer of the film assembly, protects against alkali metal ions, OH - Ions, H + It may be conductive to ions selected from the group consisting of ions and combinations thereof.

[0034] In a preferred embodiment, the film assembly of the electrochemical cell comprises a first conductive current collector layer in contact with the anode layer and a second conductive current collector layer in contact with the cathode layer. The first conductive current collector layer is preferably located on the upper surface of the anode layer, and / or the second conductive current collector layer is preferably located on the lower surface of the cathode layer.

[0035] According to the present invention, the membrane assembly does not contain any organic polymers and does not optionally contain any organic materials.

[0036] The membrane assembly may be stable in an aqueous solution of 35% by weight of KOH based on the total weight of the aqueous solution, preferably without damage, and especially without dissolving.

[0037] Furthermore, the membrane assembly may be stable against a pressure of 3 MPa (30 bar) applied to the upper or lower surface of the membrane, preferably without being damaged by this pressure, and in particular without cracking.

[0038] In addition, the film assembly may be stable at a temperature of 200°C, preferably without damage, and in particular without melting and / or burning.

[0039] The electrochemical cell may further include an inlet for supplying a liquid electrolyte to a first compartment and an outlet for discharging a first fluid from the first compartment.

[0040] In addition, the electrochemical cell may further include an inlet for supplying a liquid electrolyte to a second compartment and an outlet for discharging a second fluid from the second compartment.

[0041] The electrochemical cell may be selected from the group consisting of electrolytic cells, battery cells, fuel cells, and CO2 reduction cells, and the electrochemical cell is particularly preferably a water electrolytic cell, and most particularly preferably an alkaline water electrolytic cell.

[0042] According to the present invention, a method for producing hydrogen and oxygen from water is also provided, a) A step of preparing an electrochemical cell according to the present invention, wherein the liquid electrolyte is an aqueous solution containing 35-40% by weight of KOH based on the total weight of the aqueous solution, b) A step of applying a voltage between the cathode and anode of an electrochemical cell to perform electrolysis. A method including this will be introduced.

[0043] The method according to the present invention makes it possible to produce hydrogen and oxygen from water at temperatures of 120°C to 200°C and pressures up to 30 bar, even under harsh chemical conditions (for example, a KOH mass fraction of up to 35% in the electrolyte).

[0044] In this method, electrolysis is preferably carried out at a pressure in the range of 0.1 to 3 MPa (1 to 30 bar) and / or at a temperature in the range of 120°C to 200°C.

[0045] The subject matter of the present invention will be described in more detail based on the following embodiments, but the subject matter is not limited to the specific embodiments shown herein. [Brief explanation of the drawing]

[0046] [Figure 1] Figure 1 is a schematic diagram of a first film assembly of an electrochemical cell according to the present invention. A planar protective layer 2 having pores 3 with a first pore diameter is located on the lower surface of a planar anode layer 1. A planar cathode layer 4 is located on the lower surface of the planar protective layer 2. A first conductive current collector layer 8 is located on the upper surface of the planar anode layer 1, and a second conductive current collector layer 9 is located on the lower surface of the planar cathode layer 4. [Figure 2] Figure 2 is a schematic diagram of a second film assembly of an electrochemical cell according to the present invention. A planar protective layer 2 having pores 3 with a first pore diameter is located on the underside of a planar anode layer 1. A planar substrate 5 having pores 6 with a second pore diameter is located on the underside of the planar protective layer 2. A further planar protective layer 7 having pores 3 with a first pore diameter is located on the underside of the planar substrate 5. A planar cathode layer 4 is located on the underside of the further planar protective layer 7. The film assembly shown in the figure does not (yet) include a conductive current collector (for example, there is no current collector layer). [Figure 3] Figure 3 is a schematic diagram of a third film assembly of an electrochemical cell according to the present invention. A planar protective layer 2 having pores 3 with a first pore diameter is located on the lower surface of a planar anode layer 1. A planar substrate 5 having pores 6 with a second pore diameter is located on the lower surface of the planar protective layer 2. A further planar protective layer 7 having pores 3 with a first pore diameter is located on the lower surface of the planar substrate 5. A planar cathode layer 4 is located on the lower surface of the further planar protective layer 7. A first conductive current collector layer 8 is located on the upper surface of the planar anode layer 1, and a second conductive current collector layer 9 is located on the lower surface of the planar cathode layer 4. [Modes for carrying out the invention] [Examples]

[0047] Example 1 - First method for preparing a film assembly First, the anode layer is deposited on the underside of the conductive current collector layer. Deposition may be carried out by a method selected from the group consisting of atmospheric plasma spraying (APS), slip-based coating with subsequent binder removal (e.g., immersion bath, slot die and / or lamination), electrophoretic coating, or gas-based coating (e.g., CVD, optionally with subsequent chemical conversion from precursor to target material). The anode layer is preferably deposited to a thickness of at least 5 μm.

[0048] To deposit a ceramic protective layer on the underside of the anode layer, a powder made of a non-conductive ceramic material is deposited on the underside of the anode layer. Preferably, the powder is deposited by atmospheric plasma spraying until a pore size in the range of 50 to 5000 nm and a layer thickness in the range of 15 to 250 μm are achieved. The pore size of the ceramic protective layer may be adjusted by the selection of the powder and process-related adjustments of the coating.

[0049] Subsequently, the cathode layer is deposited onto the upper surface of a further conductive current collector layer. Deposition may be carried out by a method selected from the group consisting of atmospheric plasma spraying (APS), slip-based coating with subsequent binder removal (e.g., immersion bath, slot die and / or lamination), electrophoretic coating, or gas-based coating (e.g., CVD, optionally with subsequent chemical conversion from precursor to target material). The cathode layer is preferably deposited to a thickness of at least 5 μm.

[0050] Next, the ceramic protective layer, which has been attached to the lower surface of the anode layer, is attached to the upper surface of the cathode layer to complete the film assembly. This assembly may be carried out by a method selected from the group consisting of pressurization, bonding, and a combination thereof, wherein pressurization preferably involves applying pressure in a direction perpendicular to the film assembly, in the range of 50 to 3500 MPa, preferably in the range of 100 to 3000 MPa, and particularly preferably in the range of 150 to 2500 MPa.

[0051] Next, the fabricated film assembly is annealed at a temperature preferably in the range of 400°C to 700°C for 30 to 300 minutes. The arrangement of the layers in such a film assembly is shown in Figure 1.

[0052] The ceramic protective layer, due to its pore size, ensures not only high ionic conductivity (for example, for hydroxide ions) but also low permeability to hydrogen.

[0053] Example 2 - A second method for fabricating a film assembly First, the cathode layer is deposited onto the upper surface of the conductive current collector layer. Deposition may be carried out by a method selected from the group consisting of atmospheric plasma spraying (APS), slip-based coating with subsequent binder removal (e.g., immersion bath, slot die and / or lamination), electrophoretic coating, or gas-based coating (e.g., CVD, optionally with subsequent chemical conversion from precursor to target material). The cathode layer is preferably deposited to a thickness of at least 5 μm.

[0054] To deposit a ceramic protective layer on the upper surface of the cathode layer, a powder made of a non-conductive ceramic material is deposited on the lower surface of the anode layer. The powder is preferably deposited by atmospheric plasma spraying until a pore size in the range of 50 to 5000 nm and a layer thickness in the range of 15 to 250 μm are achieved. The pore size of the ceramic protective layer may be adjusted by the selection of the powder and process-related adjustments of the coating.

[0055] Subsequently, the anode layer is deposited on the underside of a further conductive current collector layer. Deposition may be carried out by a method selected from the group consisting of atmospheric plasma spraying (APS), slip-based coating with subsequent binder removal (e.g., immersion bath, slot die and / or lamination), electrophoretic coating, or gas-based coating (e.g., CVD, optionally with subsequent chemical conversion from precursor to target material). The anode layer is preferably deposited to a thickness of at least 5 μm.

[0056] Next, the ceramic protective layer, which has been attached to the upper surface of the cathode layer, is attached to the lower surface of the anode layer to complete the film assembly. This assembly may be carried out by a method selected from the group consisting of pressurization, bonding, and a combination thereof, wherein pressurization preferably involves applying pressure in a direction perpendicular to the film assembly in the range of 50 to 3500 MPa, preferably in the range of 100 to 3000 MPa, and particularly preferably in the range of 150 to 2500 MPa.

[0057] Next, the fabricated film assembly is annealed at a temperature preferably in the range of 400°C to 700°C for 30 to 300 minutes. The arrangement of the layers in such a film assembly is shown in Figure 1.

[0058] The ceramic protective layer, due to its pore size, ensures not only high ionic conductivity (for example, for hydroxide ions) but also low permeability to hydrogen.

[0059] Example 3 - A third method for preparing a film assembly First, a porous, flat surface (metal substrate) is degreased in ethanol or another alcohol, and then treated with sandblasting to increase the bonding strength of the surface to be coated. The particle size of the sand must be larger than the pore size of the substrate.

[0060] Subsequently, a ceramic protective layer is applied to the top and bottom surfaces of a planar substrate. For this purpose, a powder made of a non-conductive ceramic material is applied to both sides of a porous metal substrate. The powder is preferably applied by atmospheric plasma spraying until a pore size in the range of 50 to 5000 nm and a layer thickness in the range of 15 to 250 μm are achieved. The pore size of the ceramic protective layer may be adjusted by the selection of the powder and process-related adjustments of the coating.

[0061] A ceramic protective layer deposited on a porous metal substrate electrically insulates the porous metal substrate and, due to its pore size, ensures not only high ionic conductivity (for example, hydroxide ions) but also low permeability to hydrogen.

[0062] Subsequently, the anode layer is deposited onto the upper surface of the planar substrate (more precisely, onto the ceramic protective layer deposited thereon), and the cathode layer is deposited onto the lower surface of the planar substrate (more precisely, onto the ceramic protective layer deposited thereon). Deposition may be carried out by a method selected from the group consisting of atmospheric plasma spraying (APS), slip-based coating with subsequent binder removal (e.g., immersion bath, slot die and / or lamination), electrophoretic coating, or gas-based coating (e.g., CVD, optionally with subsequent chemical conversion from precursor to target material). The anode and cathode layers are preferably each deposited to a thickness of at least 5 μm.

[0063] Next, the fabricated film assembly is annealed for 30 to 300 minutes at a temperature preferably in the range of 400°C to 700°C.

[0064] Thus, a film assembly without any conductive current collectors is fabricated. The arrangement of layers in such a film assembly is shown in Figure 2.

[0065] As an alternative to this procedure, the anode layer is pre-deposited onto the underside of the conductive current collector layer, and the cathode layer is deposited onto the upper surface of a further conductive current collector layer. Deposition may be carried out by a method selected from the group consisting of atmospheric plasma spraying (APS), slip-based coating with subsequent binder removal (e.g., immersion bath, slot die and / or lamination), electrophoretic coating, or gas-based coating (e.g., CVD, optionally with subsequent chemical conversion from precursor to target material). The anode and cathode layers are preferably each deposited to a thickness of at least 5 μm.

[0066] Next, the anode layer (with a conductive current collector layer) is deposited onto the upper surface of a planar substrate (more precisely, onto the ceramic protective layer deposited thereon), and the cathode layer (with an additional conductive current collector layer) is deposited onto the lower surface of a planar substrate (more precisely, onto the ceramic protective layer deposited thereon). This assembly may be carried out by a method selected from the group consisting of pressurization, bonding, and combinations thereof, wherein pressurization preferably involves applying pressure in a direction perpendicular to the film assembly, in the range of 50 to 3500 MPa, preferably in the range of 100 to 3000 MPa, and particularly preferably in the range of 150 to 2500 MPa.

[0067] Next, the fabricated film assembly is annealed for 30 to 300 minutes at a temperature preferably in the range of 400°C to 700°C.

[0068] In this alternative configuration, a film assembly is fabricated that already contains two conductive current collectors. The layer arrangement in such a film assembly is shown in Figure 3. [Explanation of Symbols]

[0069] 1. Planar anode layer 2. Planar protective layer 3. Pores having a first pore diameter 4 Planar cathode layers 5. Planar substrate 6. Pores having a second pore diameter 7. Further planar protective layer 8. First conductive current collector layer 9. Second conductive current collector layer

Claims

1. It is an electrochemical cell, a) Receptacle for containing liquid electrolytes, b) A membrane assembly, A planar anode layer having an upper surface and a lower surface, A planar protective layer comprising an electrical insulating ceramic material, having an upper surface, a lower surface, and pores having a first pore diameter extending from the upper surface to the lower surface, A film assembly comprising a planar cathode layer having an upper and lower surface. Equipped with, The membrane assembly is in contact with the liquid electrolyte. The membrane assembly is arranged such that the receptacle separates the liquid electrolyte into a first compartment and a second compartment. The film assembly is electrically insulated from the second compartment and separated in a manner that allows ions to be conducted between them. The protective layer of the plane is positioned on the lower surface of the anode layer of the plane, and the upper surface of the protective layer of the plane is in contact with the lower surface of the anode layer of the plane. On the lower surface of the aforementioned protective layer of the plane, i. The cathode layer is arranged such that the upper surface of the cathode layer is in contact with the lower surface of the planar protective layer, or ii. A planar substrate is provided, the planar substrate having an upper surface, a lower surface, and pores having a second pore diameter larger than the first pore diameter extending from the upper surface to the lower surface, the upper surface of the planar substrate is in contact with the lower surface of the planar protective layer, and the cathode layer is provided on the lower surface of the planar substrate. The aforementioned membrane assembly does not contain any organic polymers. An electrochemical cell characterized by the following features.

2. The aforementioned protective layer of the plane is i. The lower surface of the planar anode layer, the upper surface of the planar cathode layer and / or the upper surface of the planar substrate are coated by a method selected from the group consisting of atmospheric plasma spraying, slurry-based coating with subsequent binder removal, electrophoretic coating, or gas-based coating, wherein the slurry-based coating is preferably selected from the group consisting of immersion bath coating, slot die coating, lamination, and / or a combination thereof, ii. Having a thickness in the range of 10 to 1000 μm, the thickness in particular refers to the spread of the protective layer in a direction perpendicular to the upper and / or lower surfaces of the planar protective layer. The electrochemical cell according to claim 1, characterized in that

3. An electrochemical cell according to claim 1 or 2, wherein a further planar protective layer is disposed on the lower surface of the planar substrate, the further planar protective layer has an upper surface, a lower surface, and pores having a first pore diameter extending from the upper surface to the lower surface, the further planar protective layer contains or consists of an electrically insulating ceramic material, preferably the lower surface of the planar substrate is in contact with the upper surface of the protective layer, and the lower surface of the protective layer is in contact with the upper surface of the planar cathode layer.

4. The aforementioned further planar protective layer is i. The lower surface of the planar substrate is coated by a method selected from the group consisting of atmospheric plasma spraying, slurry-based coating with subsequent binder removal, electrophoretic coating, or gas-based coating, wherein the slurry-based coating is preferably selected from the group consisting of immersion bath coating, slot die coating, lamination, and / or a combination thereof, ii. Having a thickness in the range of 10 to 1000 μm, wherein the thickness refers in particular to the spread of the planar protective layer in a direction perpendicular to the upper and / or lower surfaces of the planar protective layer. The electrochemical cell according to claim 3, characterized in that

5. The electrochemical cell according to any one of claims 1 to 4, wherein the membrane assembly is assembled by a method selected from the group consisting of pressurization, bonding, and combinations thereof, the pressurization preferably includes pressurizing in a direction perpendicular to the membrane assembly at a pressure in the range of 50 to 3500 MPa, preferably in the range of 100 to 3000 MPa, and particularly preferably in the range of 150 to 2500 MPa.

6. The electrochemical cell according to any one of claims 1 to 5, wherein the cathode layer contains or comprises a catalyst that catalyzes the reduction of water to hydrogen, the catalyst preferably comprises a material selected from the group consisting of metals, metal alloys and combinations thereof, and the material is optionally selected from the group consisting of nickel, cobalt, molybdenum, manganese, nickel-aluminum, nickel-aluminum-molybdenum, nickel-molybdenum, Raney nickel and combinations thereof.

7. The electrochemical cell according to any one of claims 1 to 6, wherein the anode layer contains or comprises a catalyst that catalyzes the oxidation of water to oxygen, and the catalyst preferably comprises a material selected from the group consisting of metals, metal alloys, metal oxides, mixed metal oxides, spinel, perovskite, layered double hydroxides and combinations thereof, and the material is optionally selected from the group consisting of nickel, cobalt, nickel-aluminum, nickel-aluminum-molybdenum, nickel-molybdenum, Raney nickel, nickel oxide, iridium oxide and combinations thereof.

8. The aforementioned planar substrate is i. A material selected from the group consisting of metals, metal alloys and combinations thereof, wherein the material is preferably selected from the group consisting of stainless steel, nickel steel, solid nickel and combinations and alloys thereof, and / or ii. A structure comprising or consisting of a structure selected from the group consisting of nonwoven fabrics, solid foams, expanded metals, meshes, woven fabrics and combinations thereof, and / or iii. Having a thickness in the range of 40 to 1500 μm, preferably in the range of 50 to 1250 μm, and particularly preferably in the range of 60 μm to 1000 μm, wherein the thickness refers in particular to the spread of the planar substrate in a direction perpendicular to the upper and / or lower surfaces of the planar substrate. An electrochemical cell according to any one of claims 1 to 7, characterized in that

9. The pores in the planar substrate are i. Having a second pore diameter in the range of 5 μm to 1250 μm, preferably in the range of 10 μm to 1000 μm, and particularly preferably in the range of 15 μm to 750 μm, wherein the pore diameter refers to a pore diameter that can be determined by mercury intrusion and / or bubble point measurement, and / or ii. Having a second pore diameter that decreases from the upper surface of the planar substrate toward the lower surface of the planar substrate, or from the lower surface of the planar substrate toward the upper surface of the planar substrate. An electrochemical cell according to any one of claims 1 to 8, characterized in that

10. The electrically insulating ceramic material of the planar protective layer, and optionally further, the electrically insulating ceramic material of any additional planar protective layer of the film assembly, i. A material selected from the group consisting of nitride ceramics, carbide ceramics, oxide ceramics, silicate ceramics, cermets and combinations thereof, or comprising such a material; and / or ii. Containing or consisting of particles, the particles preferably having a diameter in the range of 0.5 μm to 95 μm, preferably in the range of 5 μm to 70 μm, and particularly preferably in the range of 9 μm to 45 μm, where the particle diameter refers to the measured value of the particle diameter distribution. An electrochemical cell according to any one of claims 1 to 9, characterized in that

11. The electrochemical cell according to any one of claims 1 to 10, characterized in that the pores of the planar protective layer, and optionally further, the pores of the further planar protective layer of the film assembly, have a first pore diameter in the range of 50 nm to 9 μm, wherein the pore diameter refers to a pore diameter that can be determined by mercury intrusion and / or bubble point measurement.

12. The aforementioned planar protective layer, and optionally further, any additional planar protective layer of the film assembly, i. Having an electrical resistance in the range of kΩ to MΩ, and / or ii. <0.3~0.8Ωcm ２ It has an ionic resistance in the range of, and / or, iii. 2-6 L / min·cm at 0.5 MPa (5 bar) ２ It has a gas permeability in the range of and / or iv. Alkali metal ions, OH － Ion, H ＋ It is conductive to ions selected from the group consisting of ions and combinations thereof. An electrochemical cell according to any one of claims 1 to 11, characterized in that

13. The aforementioned film assembly does not contain any organic material and / or, i. Stable in an aqueous solution of 35% by weight of KOH based on the total weight of the aqueous solution, preferably undamaged, especially insoluble, and / or ii. The film is stable against a pressure of 3 MPa (30 bar) on the upper or lower surface, preferably undamaged by the said pressure, in particular without cracking, and / or iii. It is stable at a temperature of 200°C, preferably undamaged, and especially does not melt and / or burn. An electrochemical cell according to any one of claims 1 to 12, characterized in that

14. The electrochemical cell further, i. comprising an inlet for supplying a liquid electrolyte to the first compartment and an outlet for discharging the first fluid from the first compartment, ii. The apparatus comprises an inlet for supplying a liquid electrolyte to the second compartment and an outlet for discharging the second fluid from the second compartment. An electrochemical cell according to any one of claims 1 to 13, characterized in that

15. The electrochemical cell includes an electrolytic cell, a battery cell, a fuel cell, and CO2. ２ An electrochemical cell according to any one of claims 1 to 14, characterized in that it is selected from the group consisting of reduction cells, and the electrochemical cell is particularly preferably a water electrolytic cell, and most particularly preferably an alkaline water electrolytic cell.

16. A method for producing hydrogen and oxygen from water, a) A step of preparing an electrochemical cell according to any one of claims 1 to 15, wherein the liquid electrolyte is an aqueous solution containing 35 to 40% by weight of KOH based on the total weight of the aqueous solution, b) The process includes the step of applying a voltage between the cathode and anode of the electrochemical cell to perform electrolysis, A method for performing the electrolysis described above, preferably at a pressure in the range of 0.1 to 3 MPa (1 to 30 bar) and / or at a temperature in the range of 120°C to 200°C.

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