EP4347923A1 - Cellule électrolytique pour électrolyse à membrane électrolytique polymère et son procédé de production - Google Patents

Cellule électrolytique pour électrolyse à membrane électrolytique polymère et son procédé de production

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Publication number
EP4347923A1
EP4347923A1 EP22734892.7A EP22734892A EP4347923A1 EP 4347923 A1 EP4347923 A1 EP 4347923A1 EP 22734892 A EP22734892 A EP 22734892A EP 4347923 A1 EP4347923 A1 EP 4347923A1
Authority
EP
European Patent Office
Prior art keywords
layer
cell
anodic
gas diffusion
diffusion layer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP22734892.7A
Other languages
German (de)
English (en)
Inventor
Andre KLINGER
Yashar Musayev
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens Energy Global GmbH and Co KG
Original Assignee
Siemens Energy Global GmbH and Co KG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens Energy Global GmbH and Co KG filed Critical Siemens Energy Global GmbH and Co KG
Publication of EP4347923A1 publication Critical patent/EP4347923A1/fr
Pending legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/02—Hydrogen or oxygen
    • C25B1/04—Hydrogen or oxygen by electrolysis of water
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/02—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/02—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form
    • C25B11/03—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form perforated or foraminous
    • C25B11/031—Porous electrodes
    • C25B11/032—Gas diffusion electrodes
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
    • C25B11/055—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the substrate or carrier material
    • C25B11/057—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the substrate or carrier material consisting of a single element or compound
    • C25B11/061—Metal or alloy
    • C25B11/063—Valve metal, e.g. titanium
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
    • C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
    • C25B11/075—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound
    • C25B11/077—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound the compound being a non-noble metal oxide
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • C25B9/17—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof
    • C25B9/19—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof with diaphragms
    • C25B9/23—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof with diaphragms comprising ion-exchange membranes in or on which electrode material is embedded
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/36—Hydrogen production from non-carbon containing sources, e.g. by water electrolysis

Definitions

  • the invention relates to an electrolytic cell for polymer electrolyte membrane electrolysis, a method for producing such an electrolytic cell, the use of such an electrolytic cell and the use of a catalyst material.
  • Hydrogen can be obtained from deionized water by electrolysis.
  • the electrochemical cell reactions of the hydrogen formation reaction (HER) and oxygen formation reaction (OER) take place.
  • the reactions at the anode and cathode can be defined as follows:
  • PEM electrolysis polymer electrolyte membrane electrolysis
  • the two partial reactions according to equations (I) and (II) are carried out spatially separately from one another in a respective half-cell for OER and HER.
  • the reaction spaces are separated by means of a proton-conducting membrane, the polymer electrolyte membrane (PEM), also known under the term proton exchange membrane.
  • PEM ensures extensive separation of the product gases hydrogen and oxygen, the electrical insulation of the electrodes and the conduction of the hydrogen ions (protons) as positively charged particles.
  • a PEM electrolysis system typically comprises a plurality of PEM electrolysis cells, such as described in EP 3 489 394 A1.
  • a PEM electrolytic cell is described, for example, in EP 2 957 659 A1.
  • the PEM electrolysis cell shown there comprises an electrolyte made of a proton-conducting membrane (proton exchange membrane, PEM), on which the electrodes, a cathode and an anode, are located on both sides.
  • PEM proton-conducting membrane
  • MEA membrane-electrode assembly
  • a gas diffusion layer lies against each of the electrodes.
  • the gas diffusion layers are contacted by so-called bipolar plates.
  • a respective bipolar plate often forms a channel structure at the same time, which is designed for the media transport of the educt and product streams involved.
  • the bipolar plates separate the individual electrolysis cells, which are stacked to form an electrolysis stack with a large number of electrolysis cells.
  • the PEM electrolytic cell is fed with water as a starting material, which is electrochemically broken down at the anode into oxygen product gas and protons H + .
  • the protons H + migrate through the electrolyte membrane towards the cathode. On the cathode side, they recombine to form hydrogen product gas H2.
  • a PEM electrolysis cell is also described in Kumar, S, et al., Hydrogen production by PEM water electrolysis - A review, Materials Science for Energy Technologies, 2 (3) 2019, 442-454. https://doi.org/10.1016/j.mset.2019.03.002.
  • the PEM electrolytic cell consists of two bipolar plates, gas diffusion layers, catalyst layers and the proton-conducting membrane. Due to the formation reaction of the oxygen, there are high oxidative potentials at the anode, which is why high-quality materials with rapid passivation kinetics, e.g. B. Titanium, for example, be used for the Gasdi f fusion layer. This also applies to the choice of material for the anode-side catalyst material. However, even with this, the degradation effects on the anode cannot be completely avoided, but at best delayed.
  • the cathodic potential is less oxidative, so that the gas diffusion layers can be made of stainless steel there.
  • these corrode due to the acidic environment of the PEM electrolysis. This corrosion process is called acid corrosion.
  • the presence of elemental oxygen is not necessary here, since this is provided solely by the dissociation of the surrounding water.
  • the metal ions at the interface of the metal surface are oxidized by the hydroxide anion to form the respective hydroxide salt. This leads to degradation of the cell, which manifests itself in an increased internal resistance and in foreign ions entering the PEM.
  • EP 2 770 564 A1 discloses a membrane electrode assembly (MEA) which has a barrier layer.
  • the barrier layer is arranged over the entire area between a catalyst layer and a gas diffusion layer, the barrier layer being an electrically conductive ceramic material, u. a iridium oxide in the IrCh and I ⁇ Os, and a non-ionomeric polymer binder.
  • the barrier layer has a layer thickness of up to 0.1 to 100 ⁇ m with a correspondingly high use of material and associated material costs, especially for the expensive iridium. As a result, a larger quantity and concentration of catalytically active species are kept available and degradation is delayed or delayed as a result. stretched .
  • the object of the invention is to provide an electrolytic cell with which the above-mentioned problems can be reduced or, if possible, avoided entirely, with improvements being able to be achieved in terms of less material use and a current distribution that is as homogeneous as possible.
  • a further object of the invention is to specify a method for producing such an electrolytic cell.
  • a first aspect of the invention relates to an electrolytic cell for polymer electrolyte membrane electrolysis with a cathodic half-cell and with an anodic half-cell, the cathodic half-cell and the anodic half-cell being separated from one another by a polymer-electrolyte membrane.
  • the anodic half-cell has a gas diffusion layer made of a fine-meshed metallic carrier material and an anodic catalyst layer applied to the polymer electrolyte membrane, into which an anodic catalyst material is introduced.
  • the anodic catalyst layer is arranged adjacent to the gas diffusion layer, with a thin protective layer (14) being applied locally to the fine-meshed carrier material in the area of the contact points between the gas diffusion layer and the adjacent anodic catalyst layer, and with the protective layer (14 ) iridium and / or iridium oxide , so that the entry of anodic catalyst material ( 18 ) into the gas diffusion layer ( 9b ) is inhibited .
  • the polymer electrolyte membrane can, for example, consist of a tetrafluoroethylene-based polymer sulfonated side groups may be formed.
  • the cathodic half-cell forms the reaction space in which the cathode reaction (s), z. B. run according to equation (II).
  • the anodic half-cell forms the reaction space in which the anode reaction (s), z. B. run according to equation (I).
  • the invention is based on the finding that in an electrolytic cell, in particular on the side of the anodic half-cell, only inadequate approaches to avoiding or reducing technical problems and limitations due to degradation effects and inhomogeneous current distribution have been proposed that do not address the cause.
  • two disadvantageous effects can be observed in the electrolysis of water in an electrolytic cell, which are largely avoided or even overcome with the invention:
  • the fine-meshed carrier material is preferably uniform or regular lattice, for example made of expanded metal, designed so that a multiplicity of contact points with the protective layer extend regularly and in the form of a lattice over the facing surfaces of the gas diffusion layer and the anodic catalyst layer. Due to the regular contact points, local contact surfaces are formed with a corresponding grid regularity, which promote good and particularly uniform contacting for an improvement in the current distribution. In this case, a particularly small amount of material is used in the form of expensive iridium and/or iridium oxide.
  • the invention thus counteracts both problems with a gas diffusion layer which is advantageously designed as a diffusion barrier against the entry of anodic catalyst material and acts accordingly.
  • the gradual degradation during operation and thus the loss of anodic catalyst material is avoided by inhibiting the entry of catalyst material into the gas diffusion layer.
  • the catalytic activity is retained and the gas diffusion layer is at the same time protected against degradation and can fulfill its function in an electrolyzer.
  • the formation of the gas diffusion layer with an advantageous effect as a diffusion barrier serves to prevent the movements of atoms and molecules between the adjacent materials in the anodic half-cell, here the inhibition of the entry of anodic catalyst material and the base material of the gas diffusion electrode.
  • the diffusion processes with the invention are particularly effective and permanently prevented, which would otherwise lead to contamination or over time. undesired chemical reactions, as in the well-known concepts .
  • one Barrier created against the entry of anodic catalyst material in the gas diffusion layer is particularly effective and permanently prevented, which would otherwise lead to contamination or over time.
  • one Barrier created against the entry of anodic catalyst material in the gas diffusion layer.
  • the diffusion barrier acts at the same time to protect the electrically conductive gas diffusion layer from oxidation and thus disadvantageous losses in electrical conductivity, as a result of which the local contacts are significantly improved.
  • the gas diffusion layer can continue to fulfill its task for electrical transport and for material transport.
  • the current density over the effective cell area of the electrolytic cell becomes more homogeneous, which is an advantage.
  • the gas diffusion layer therefore has a thin protective layer that is only applied locally and into which a diffusion-inhibiting layer material is introduced.
  • a layer can be understood to mean a flat structure whose dimensions in the layer plane, length and width, are significantly greater than the dimension in the third dimension, the layer thickness.
  • the gas diffusion layer which is formed from a base body made of a base material, to which the diffusion-inhibiting protective layer is locally applied over a large area at the contact points.
  • the base body with the base material forms a first layer
  • the diffusion-inhibiting protective layer forms a second layer of the gas diffusion layer.
  • the fine-meshed carrier material is therefore designed in the form of a grid, so that the contact points with the protective layer extend regularly over the mutually facing surfaces of the gas diffusion layer and the anodic catalyst layer.
  • the anodic catalyst material is introduced into an anodic catalyst layer.
  • anodic catalyst layer which is introduced into a corresponding catalyst layer provided specifically for this purpose.
  • the catalyst layer can be arranged adjacent, preferably immediately adjacent, ie in direct contact, to the gas diffusion layer, with the anodic catalyst layer and the protective layer being in contact.
  • the anodic catalyst layer is therefore preferably arranged directly adjacent to the protective layer, so that a planar contact is brought about.
  • planar dif fusion-inhibiting protective layer and the anodic catalyst layer can directly adjoin one another, forming boundary surfaces arranged parallel to the respective layer planes, e.g. B. be arranged directly on top of each other. An entry of anodic catalyst material from the anodic catalyst layer into the gas diffusion layer is prevented or at least largely avoided by the diffusion-inhibiting protective layer.
  • the anodic catalyst layer is adjacent, preferably directly adjacent, i.e. in direct contact, to the polymer electrolyte membrane.
  • the polymer-electrolyte membrane which is also flat, and the anodic catalyst layer can directly adjoin one another, forming an interface that is parallel to the plane of the layer, e.g. B. be arranged directly on top of each other.
  • the diffusion-inhibiting protective layer of the gas diffusion layer is also arranged adjacent to the anodic catalyst layer, the result is an arrangement in which the anodic catalyst layer adjoins the diffusion-inhibiting protective layer on one side and the polymer-electrolyte membrane on the opposite side.
  • the anodic half cell of the electrolytic cell can have a gas diffusion layer.
  • the gas diffusion layer can be arranged adjacent, preferably directly adjacent, to the anodic catalyst layer.
  • the gas diffusion layer of the electrolytic cell is used to transport the gaseous reaction products of the catalytic reaction(s) away from the catalyst material(s) and to make electrical contact. It can therefore also be referred to as a current collector layer or gas diffusion electrode.
  • the invention achieves a particularly homogeneous current density distribution, so that local current peaks are avoided during operation.
  • the catalytic activity of the anodic catalyst layer is stable over the long term, since degradation of the anodic half-cell is inhibited by avoiding the entry of anodic catalyst material into the gas diffusion layer.
  • the gas diffusion layer of the anodic half-cell has a porous material to ensure adequate gas permeability.
  • the gas diffusion layer can, for example It can be made from titanium as the base material with a porous base body, such as a titanium-based expanded metal or wire mesh, and be provided with the diffusion-inhibiting protective layer. As a result, the useful life or The service life of the gas di f fusion layer can be increased, the adverse degradation effects described are reduced.
  • the protective layer has a layer thickness of approximately 50 nm to 200 nm, in particular approximately 80 nm to 120 nm. Even small layer thicknesses of only around 100 nm are sufficient to set the diffusion-inhibiting effect. Compared to typical layer thicknesses of a catalyst layer, only very small amounts of layer material for the protective layer are required to form this diffusion barrier. A small layer thickness is of economic advantage since only a small amount of material is required for the protective layer.
  • a catalytically active layer material is introduced into the protective layer.
  • a catalytic effect can be achieved at the same time in addition to the effect as a diffusion barrier with respect to the anodic catalyst material.
  • the targeted introduction of catalyst material into the protective layer causes saturation with catalyst material at the interface between the gas diffusion layer and the anodic catalyst layer. This saturation inhibits further entry of anodic catalyst material into the gas diffusion layer, and the kinetics of further entry of anodic catalyst material are practically prevented.
  • anodic catalyst material is introduced as the catalytic layer material. Due to the similarity of the choice of material, adjustment problems are avoided. In particular, a catalytic effect is long-term stable with a simultaneous effective effect Action against migration by diffusion of anodic catalyst material from the anodic catalyst layer into the gas diffusion layer. The anodic catalyst layer does not degrade. In addition, passivation is already effected by the catalytic layer material in the protective layer, and an oxidative attack on the base material of the gas diffusion layer is therefore prevented.
  • the mechanism of action specifically exploited here by this advantageous embodiment is such that by applying a dense protective layer to the anode-side base material of the gas diffusion layer, a less conductive oxide layer of oxygen and the base material can no longer form, since it is necessary for the passivation of the base material required oxygen is no longer available.
  • the role of the passive layer is now performed by the catalytic layer material.
  • the in the anodic catalyst layer or. Electrons released at the active center of the anodic catalyst can be transferred via the protective layer into the bulk material without increased resistance. As a result, the local contacts are significantly improved and the current density over the cell area becomes more homogeneous.
  • the anodic half-cell has iridium and/or iridium oxide or mixtures thereof as the anodic catalyst material. Due to the high oxidation and solution stability, iridium or Iridium oxide is particularly advantageous as a catalytically active species when choosing the anode-side catalyst material.
  • the anodic half-cell preferably has a gas diffusion layer formed from titanium as the base material.
  • a gas diffusion layer formed from titanium as the base material.
  • the term “grid” refers to a fine-meshed network.
  • the carrier materials mentioned are characterized by high corrosion resistance.
  • the terms "grid” and “fabric” describe a directional structure, the term “fleece” a non-directional structure .
  • the diffusion-inhibiting and catalytically active layer material made of iridium or Iridium oxide are applied.
  • the layer material can be provided with the largest possible surface area, so that the catalytic effect and the passivation effect can be improved with the same amount of layer material, with very little material being required due to the low layer thicknesses of about 100 nm for the protective layer.
  • the anodic half-cell preferably has a gas diffusion layer formed from titanium as the base material and made from a fine-meshed carrier material. This can be expanded metal with a large number of corresponding, regularly arranged elevations at the contact points, so that regular contact surfaces are formed, which are locally provided with a thin protective layer of iridium and/or iridium oxide.
  • the gas diffusion layer is usually made of a material on the surface of which a passivation layer forms quickly, as is the case with titanium. Due to the protective layer, however, in the present case the passivation is not effected by the titanium itself but by the iridium, which is very advantageous.
  • the iridium in the protective layer acts as a catalyst and diffusion barrier.
  • the gas diffusion layer is designed to be electrically conductive and porous for fluid transport and current distribution.
  • a channel structure can be arranged adjacent, preferably directly adjacent, to the gas diffusion layer.
  • the channel structure is used to collect and discharge the gaseous reaction product of the electrolysis in the anodic half-cell, ie z.
  • the channel structure can be designed as a bipolar plate, for example. Bipolar plates allow several electrolytic cells to be stacked to form an electrolytic cell module by electrically conductively connecting the anode of one electrolytic cell to the cathode of an adjacent electrolytic cell. In addition, the bipolar plate enables gas separation between adjacent electrolytic cells.
  • a further aspect of the invention relates to a method for producing an electrolytic cell for polymer electrolyte membrane electrolysis.
  • the method comprises: providing a polymer electrolyte membrane, forming a cathodic half-cell adjacent to the polymer electrolyte membrane and forming an anodic half-cell adjacent to the polymer electrolyte membrane, the cathodic half-cell and the anodic half-cell being arranged separately from one another by means of the polymer electrolyte membrane and a gas diffusion layer made of a fine-mesh Support material is arranged in the anodic half-cell, an anodic catalyst layer being applied to the polymer electrolyte membrane, into which an anodic catalyst material is introduced, the anodic catalyst layer being adjacent to the Gasdi f fusion layer is arranged, and wherein a thin protective layer is applied to the fine-mesh support material locally in the area of the contact points between the Gasdi f fusion layer and the adjacent anodic catalyst layer, which has iridium and/
  • One of the electrolytic cells described above for polymer electrolyte membrane electrolysis can be produced by means of the method. Accordingly, reference is made to the above explanations and advantages of these electrolytic cells.
  • a diffusion-inhibiting layer material is also introduced into the gas diffusion layer in order to prevent rapid degradation of the anodic catalyst material.
  • anodic catalyst material is introduced into an anodic catalyst layer.
  • a carrier material can also be used to produce the anodic catalyst layer, to which the anodic catalyst material is applied as catalytically active species in a coating process.
  • the anodic catalyst layer is arranged adjacent to the protective layer.
  • the immediately adjacent arrangement of the anodic catalyst layer and the protective layer of the gas diffusion layer is preferred, so that these form a common interface.
  • the protective layer is deposited by means of plasma vapor deposition, plasma-assisted chemical vapor deposition (PACVD), atomic layer deposition or Pulsed Laser Deposition (PLD) applied locally in the area of the contact points on the fine-meshed carrier material.
  • the carrier material is provided by a base material of the gas diffusion layer, in particular titanium. This is appropriately designed for use as part of the anodic half-cell for electrical contacting and homogeneous current conduction as well as for fluid transport in the shape.
  • plasma-assisted chemical vapor deposition (PACVD) can be used particularly advantageously for a gas diffusion layer with a fine-meshed structure, for example titanium metal grids or nonwovens, of the gas diffusion layers
  • the desired effect of protecting the gas diffusion layer against degradation effects and uniform electrical contacting and homogeneous current density distribution can be achieved even with the formation of a very thin layer thickness for the protective layer.
  • the use of material and the selected coating process are very favorable from an economic point of view due to the local lattice-like application to the elevations in a thin layer with layer thicknesses in the nanometer range.
  • a full-area coating of the contact surface between the gas diffusion layer and the catalyst layer is not necessary.
  • application by means of chemical vapor deposition can be preferred for porous structures and carrier materials, while application by means of physical vapor deposition can be preferred for non-porous structures.
  • both chemical vapor deposition and, in particular, physical vapor deposition advantageously enable the production of very thin layers with a layer thickness in the range from a few nanometers to a few micrometers.
  • material for the diffusion-inhibiting layer material preferably iridium
  • the term "apply on” does not necessarily refer to a specific spatial arrangement in the sense of "above”. Rather, it should only be expressed that the layers mentioned are arranged adjacent to one another.
  • the sequence of the process steps can also be reversed or changed, ie the formation of the anodic half-cell can alternatively be based on the gas diffusion layer or the channel structure.
  • one of the middle layers, e.g. B. the gas diffusion layer or the anodic catalyst layer can be selected as a starting point, on both sides, the respective adjacent layers are applied.
  • the structure of the cathodic half-cell can be done in an analogous manner, i. H. a catalytic layer for catalyzing the cathode reaction, e.g. B. according to equation (II), then a gas diffusion layer and then optionally a channel structure, z. B. in the form of a bipolar plate applied.
  • the materials used for this can preferably be adapted to the conditions prevailing in the cathodic half-cell, e.g. B. with regard to the requirements for their corrosion resistance.
  • a further aspect of the invention relates to the use of an electrolytic cell for the electrolytic generation of hydrogen.
  • Another aspect of the invention relates to the use of a catalyst material as a diffusion-inhibiting layer material rial in a gas diffusion layer of an anodic half-cell of an electrolytic cell.
  • the catalyst material can be, for example, the anodic catalyst material described above, so that reference is made to the relevant explanations and advantages.
  • the material of choice is preferably iridium and/or iridium oxide.
  • a specifically and locally introduced or Iridium content applied to the carrier material in the protective layer of the gas diffusion electrode inhibits the entry and thus loss of further catalyst material from the anodic catalyst layer into the gas diffusion layer.
  • Iridium as a catalyst material is therefore a particularly advantageous use as a diffusion-inhibiting layer material and at the same time promotes a homogeneous current distribution.
  • iridium and/or iridium oxide as diffusion-inhibiting layer material is particularly preferable, and only applied locally in the area of the contact points between a gas diffusion layer formed from a fine-meshed carrier material and an adjacent anodic catalyst layer of an anodic half-cell of an electrolytic cell.
  • a large number of local contact points are formed, for example, by the flat elevations and surfaces of an expanded metal structure or similar open-pored metal structures with elevations protruding from the surface, which form a respective contact area.
  • Fig. 1 shows a schematic representation of an electrolytic cell for polymer electrolyte membrane electrolysis according to the prior art
  • Fig. 2 shows a schematic representation of an exemplary electrolysis cell
  • Fig. 3 shows an anodic half-cell with a section of the exemplary gas diffusion layer in a schematic representation
  • Fig. 4 shows a flowchart of an exemplary method according to the invention.
  • the electrolytic cell 1 shows an electrolytic cell 1 for polymer electrolyte membrane electrolysis according to the prior art in a schematic representation.
  • the electrolytic cell 1 is used for the electrolytic generation of hydrogen.
  • the electrolytic cell 1 has a polymer electrolyte membrane 4 .
  • the cathodic half cell 2 of the electrolytic cell 1 is arranged on one side of the polymer electrolyte membrane 4, on the left in the illustration according to FIG. 1, and the anodic half cell is on the other side of the polymer electrolyte membrane 4, on the right in the illustration according to FIG 3 of the electrolytic cell 1 arranged.
  • the anodic half cell 3 comprises an anodic catalyst layer 12 arranged directly adjacent to the polymer electrolyte membrane 4, a gas diffusion layer 9b arranged directly adjacent to the anodic catalyst layer 12 and a channel structure 11b arranged directly adjacent to the gas diffusion layer 9b.
  • the anodic catalyst layer 12 includes an anodic catalyst material 18 and catalyzes the anode reaction according to Equation (I).
  • the anodic catalyst material 18 is iridium or Iridium oxide is chosen as the catalytically active species incorporated into the anodic catalyst layer. iridium or . Iridium oxide has a high oxidation and solution stability and is therefore well suited as an anodic catalyst material.
  • the gas diffusion layer 9b is made of a material on the surface of which a passivation layer is quickly formed, e.g. B. made of titanium . Titanium dioxide, which has a lower conductivity than titanium, is formed as a result of the passivation of the titanium.
  • the channel structure 11b is designed as a bipolar plate, so that a stacking of several electrolytic cells 1 is made possible.
  • the cathodic half cell 2 comprises a cathodic catalyst layer 8 with a cathodic catalyst material 6 which is arranged directly adjacent to the polymer electrolyte membrane 4 .
  • the cathodic catalyst material 6 is designed to catalyze a reduction of hydrogen ions, in particular according to equation (II) to form molecular hydrogen.
  • a gas diffusion layer 9a is also arranged on the cathodic catalyst layer 8 .
  • the gas diffusion layer 9a of the cathodic half-cell 2 is made of high-grade steel.
  • a channel structure 11a is also arranged directly adjacent to the gas diffusion layer 9a, which, analogously to the anodic half-cell 3, is designed as a bipolar plate.
  • a disadvantage of this electrolytic cell 1 known from the prior art, as explained at the outset, is generally the susceptibility to corrosion of the materials. Significant degradation effects, which adversely affect the service life of the electrolytic cell 1, are particularly evident in the anodic half-cell 3.
  • the gas diffusion layer 9b be formed in the anodic half-cell 3 in such a way that the disadvantageous and continuous entry of the anodic catalyst material 18 into the gas diffusion layer 9b during operation is inhibited or, at best, even prevented.
  • the Gasdi f- Fusion layer 9b has a protective layer 14 into which a diffusion-inhibiting layer material 16 is introduced.
  • Such an advantageously modified and further developed electrolytic cell 1 is shown schematically as an example in FIG.
  • the cathodic half-cell 2 of the exemplary embodiment of an electrolytic cell 1 shown in FIG. 2 is constructed analogously to the electrolytic cell according to FIG. 1, so that reference can be made to the relevant statements.
  • the anodic half-cell 3 has, also analogously to the electrolytic cell according to FIG. 1, a gas diffusion layer 9b and a channel structure 11b.
  • an anodic catalyst layer 12 with an anodic catalyst material 14 is arranged directly adjacent to the polymer electrolyte membrane 4, the anodic catalyst material 14 for catalyzing oxygen (OER), in particular according to equation (I) to form molecular oxygen, which is formed by the Channel structure 11b is derived from the anodic half-cell 3 and processed.
  • the gas diffusion layer 9b also has a protective layer 14 into which the diffusion-inhibiting layer material 16 is introduced.
  • the layer material 16 is in this case designed as iridium and/or iridium oxide or a mixture thereof, with the layer material 16 being introduced accordingly into the gas diffusion layer 9b.
  • the carrier material 10 also forms the base body of the gas diffusion layer 9b, to which the layer material 16 containing iridium or based on iridium is applied by means of a suitable coating method.
  • the anodic catalyst material 18 is introduced into the anodic catalyst layer 12, which is immediately adjacent to the protective layer 14 of the gas diffusion layer 9b on one side. borders . On the other side, the anodic catalyst layer 12 is directly adjacent to the polymer electrolyte membrane 4 .
  • the diffusion-inhibiting protective layer 14 of the gas diffusion layer 9b is designed as an iridium coating on the carrier material 10, titanium in the example, and has a very small layer thickness of only about 100 nm.
  • the protective layer 14 on the titanium base body which is in the form of iridium, also takes on the passivation task and also leads to a more homogeneous current density distribution over the cell surface of the anodic half-cell 3 due to uniform and long-term stable electrical contacting.
  • a passivation layer is provided by the thin protective layer 14 made of iridium and/or iridium oxide without any significant increase in the electrical resistance. The electrons can be transferred via the protective layer 14 into the titanium bulk material of the gas diffusion layer 9b.
  • FIG. 3 shows an anodic half-cell 3 with a section of the exemplary gas diffusion layer 9b in a schematic and enlarged representation.
  • Titanium is used as the carrier material 10, which can be designed, for example, as a layer of plug metal or a spiral mesh or formed from other porous and at the same time mechanically stable structures. So are e.g. B. fleeces are also possible, which are arranged in layers or layers on a wire mesh, metal foam or a sintered metal disk.
  • the gas diffusion layer 9b ensures optimal distribution of the water and the removal of the product gases.
  • the present gas di f fusion layer 9b also serves as a current distributor for the anodic Half cell 3 .
  • the gas diffusion layer 9b is formed from an electrically conductive, porous material, here for example titanium, which is introduced into the gas diffusion layer 9b in a corresponding structure and arrangement.
  • the gas diffusion layer 9b in the exemplary embodiment shown compensates for component tolerances, in particular those of the adjacent channel structure 11b, since the porosity and the choice of material provide a certain spring elasticity with respect to mechanical forces.
  • a thin protective layer 14 made of iridium is applied as a layer material 16 to the titanium-based carrier material 10 , which is designed in the form of a grid in the detailed section of the anodic half-cell 3 in FIG. 3 .
  • the protective layer 14 is directly adjacent to the anodic catalyst layer 12, which also contains iridium.
  • FIG. 3 shows a region between the anodic catalyst layer 12 and the gas diffusion layer 9b in somewhat more detail. Only in the area of the contact points between the gas diffusion layer 9b and the adjacent anodic catalyst layer 12 is a thin protective layer 10 additionally applied locally and selectively to the carrier material 10 of the gas diffusion layer 9b, which has iridium and/or iridium oxide.
  • This protective layer 14 acts both as a diffusion barrier against entry of anodic catalyst material 18 from the catalyst layer 12 and also as a passivation layer for gas diffusion layer 9b. Due to the advantageous choice of material, iridium and/or iridium oxide, the protective layer 14 also acts at the same time as a catalytically active layer for a reserve of material.
  • the fine-meshed carrier material (10) is in the form of a lattice as a uniform lattice, for example made of expanded metal, so that a large number of contact points with the protective layer (14) are regular and latticed over the facing surfaces of the gas diffusion layer (9b) and the anodic catalyst layer ( 12 ) extend .
  • the regular contact points form local contact surfaces that ensure good and even contact to improve the current Facilitate distribution - with a low material input of iridium and/or iridium oxide. Only the contact surfaces are coated and provided with the protective layer (14).
  • step S1 shows a simplified flow chart of an exemplary method 100 for producing an electrolytic cell 1, for example the electrolytic cell 1 shown in FIG. 2.
  • a polymer electrolyte membrane 4 is provided in step S1.
  • step S2 a cathodic half-cell 2 adjoining the polymer-electrolyte membrane 4 is formed.
  • the cathodic catalyst layer 12, the gas diffusion layer 9a and the channel structure 11a can be arranged one on top of the other, e.g. B. are deposited on each other.
  • Step S3 generally has further partial steps S4 to S7, ie the anodic half-cell 2 is formed in the exemplary embodiment by means of steps S4 to S7. These sub-steps are adapted to the respective manufacturing process with regard to the order. Individual steps can also be carried out at the same time or in reverse order:
  • a protective layer 14 with a diffusion-inhibiting layer material 16 is first introduced into the gas diffusion layer 9b.
  • the protective layer 14 by means of suitable coating methods, such as plasma vapor deposition (PVD), plasma assisted chemical vapor deposition (PACVD), atomic layer deposition (ALD) or pulsed laser deposition ( PLD) formed on the titanium-based carrier material (10).
  • PVD plasma vapor deposition
  • PVD plasma assisted chemical vapor deposition
  • ALD atomic layer deposition
  • PLD pulsed laser deposition
  • the plasma-assisted chemical vapor deposition (PACVD) process can be used particularly advantageously for the requirements of a gas diffusion layer with a fine-meshed structure, for example titanium metal grid or titanium expanded metal or fleece, which is sometimes arranged in several gas diffusion layers.
  • the thin protective layer (14) made of iridium and/or iridium oxide is only applied locally to the fine-mesh support material (10) made of titanium in the area of the contact points between the gas diffusion layer (9b) and the adjoining anodic catalyst layer (12), as in the in 3 shown enlarged section and described in detail.
  • the protective layer (14) of iridium and/or iridium oxide prevents anodic catalyst material (18) from entering the gas diffusion layer (9b), so that degradation effects are inhibited.
  • the layer thickness is already monitored in the method in a step S5 during the coating process until the desired layer thickness of typically only about 100 nm and less is reached.
  • the anodic catalyst layer 12 is placed immediately adjacent to the protective layer 14 so that these layers are adjacent to each other. As a result, a common interface or contact surface between the anodic catalyst layer 12 and the protective layer 14 is formed.
  • the gas diffusion layer 9b having the protective layer 14 is therefore applied to the anodic catalyst layer 7 before a channel structure 11b in the form of a bipolar plate is applied to the gas diffusion layer 9b in step S7.
  • the cathodic half-cell 2 can also be formed starting from the channel structure 11a. D. H .
  • the channel structure 11a can be chosen, to which first the gas diffusion layer 9a, then the cathodic catalyst layer 8 and finally the polymer-electrolyte membrane 4 is applied.
  • a corresponding procedure is possible for the anodic half cell 3 . Consequently, the layers and structures of the electrolytic cell 1 can alternatively also be built up starting from the channel structure 11a of the cathodic half-cell 2 or starting from the channel structure 11b of the anodic half-cell 3 .
  • the term "and/or" when used in a set of two or more items means that each of the listed items can be used alone, or any combination of two or more of the listed items can be used.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)

Abstract

L'invention concerne une cellule électrolytique (1) pour électrolyse à membrane électrolytique polymère avec une demi-cellule de cathode (2) et une demi-cellule d'anode (3), la demi-cellule de cathode (2) et la demi-cellule d'anode (3) étant séparées l'une de l'autre au moyen d'une membrane électrolytique polymère (4). La demi-cellule anodique (3) présente une couche de diffusion de gaz (9b). La couche de diffusion de gaz (9b) est constituée d'un matériau de support métallique à mailles fines (10). Une couche de catalyseur anodique (12) avec un matériau catalyseur anodique (18) est appliquée sur la membrane électrolytique polymère (4). La couche de catalyseur anodique (12) est agencée de manière adjacente à la couche de diffusion de gaz (9b), une couche de protection mince (14) étant appliquée dans chaque cas localement et sélectivement sur le matériau de support à mailles fines (10) dans la zone des points de contact entre la couche de diffusion de gaz (9b) et la couche de catalyseur anodique (12) adjacente. La couche de protection mince (14) comprend de l'iridium et/ou de l'oxyde d'iridium de sorte que l'entrée du matériau catalyseur anodique (18) dans la couche de diffusion de gaz (9b) est inhibée. L'invention concerne également un procédé (100) de production d'une cellule électrolytique (1) pour l'électrolyse à membrane électrolytique polymère.
EP22734892.7A 2021-08-06 2022-06-08 Cellule électrolytique pour électrolyse à membrane électrolytique polymère et son procédé de production Pending EP4347923A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP21190122.8A EP4130341A1 (fr) 2021-08-06 2021-08-06 Cellule d'électrolyse destinée à l'électrolyse à membrane électrolytique polymère et son procédé de fabrication
PCT/EP2022/065490 WO2023011781A1 (fr) 2021-08-06 2022-06-08 Cellule électrolytique pour électrolyse à membrane électrolytique polymère et son procédé de production

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EP4347923A1 true EP4347923A1 (fr) 2024-04-10

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EP21190122.8A Withdrawn EP4130341A1 (fr) 2021-08-06 2021-08-06 Cellule d'électrolyse destinée à l'électrolyse à membrane électrolytique polymère et son procédé de fabrication
EP22734892.7A Pending EP4347923A1 (fr) 2021-08-06 2022-06-08 Cellule électrolytique pour électrolyse à membrane électrolytique polymère et son procédé de production

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EP21190122.8A Withdrawn EP4130341A1 (fr) 2021-08-06 2021-08-06 Cellule d'électrolyse destinée à l'électrolyse à membrane électrolytique polymère et son procédé de fabrication

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EP (2) EP4130341A1 (fr)
CN (1) CN117795131A (fr)
AU (1) AU2022321803A1 (fr)
CA (1) CA3228183A1 (fr)
WO (1) WO2023011781A1 (fr)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2770564B1 (fr) * 2013-02-21 2019-04-10 Greenerity GmbH Couche barrière de protection contre la corrosion dans des dispositifs électrochimiques
PT2957659T (pt) 2014-06-16 2019-05-31 Siemens Ag Camada de difusão de gás, célula eletrolítica pem com uma camada de difusão de gás desta natureza assim como eletrolisador
EP3489394B1 (fr) 2017-11-24 2020-08-19 Siemens Aktiengesellschaft Électrolyseur pour électrolyse pem à basse pression
CN111139497B (zh) * 2020-01-22 2022-11-29 同济大学 一种固体聚合物电解质电解槽用膜电极组件及制备方法
EP3859049A1 (fr) * 2020-01-30 2021-08-04 Siemens Aktiengesellschaft Électrode à diffusion de gaz pour un système électrochimique de dissociation de l'eau

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EP4130341A1 (fr) 2023-02-08
CA3228183A1 (fr) 2023-02-09
WO2023011781A1 (fr) 2023-02-09
AU2022321803A1 (en) 2024-01-25

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