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EP-4285427-B1 - ELECTROCHEMICAL CELL, AND METHOD OF FORMING A PLURALITY OF INTERCONNECTED LAYERS FOR AN ELECTROCHEMICAL CELL

EP4285427B1EP 4285427 B1EP4285427 B1EP 4285427B1EP-4285427-B1

Inventors

  • EAGLESHAM, DAVID
  • GOBRON, Danielle
  • TRIVEDI, JIGISH
  • SAJJAD, SYED DAWAR

Dates

Publication Date
20260506
Application Date
20220126

Claims (15)

  1. An electrochemical cell (300) comprising: a first electrode (302); a membrane (306); and a plurality of interconnecting layers (308) positioned between the first electrode and the membrane (306), wherein the plurality of interconnecting layers (308) comprise a local interconnecting layer (311) positioned adjacent to the membrane (306) and a global interconnecting layer (313) positioned adjacent to the first electrode (302), wherein the global interconnecting layer (313) provides flow field channels for fluid flow in and out of the electrochemical cell (300), characterised in that patterned lines or segments of the global interconnecting layer (313) have a diameter or width as measured along a plane of the global interconnecting layer (313) that is greater than a diameter or width of patterned lines or line segments of the local interconnecting layer (311) as measured along a plane of the local interconnecting layer (311), and in that the plurality of interconnecting layers (308) provides a vertical conduction in a direction extending along an axis running between the first electrode (302) and the membrane (306).
  2. The cell of claim 1, wherein the local interconnecting layer (311) of the plurality of interconnecting layers (308) comprises an oxidation-resistant metal, and wherein the oxidation-resistant metal comprises Pt, Au, Ti, Cr, Si, Zr, Y, Nb, Al, or a combination thereof.
  3. The cell of claim 1 or 2, wherein the local interconnecting layer (311) of the plurality of interconnecting layers (308) comprises a substrate that is coated with an oxidation-resistant composition.
  4. The cell of claim 3, wherein the oxidation-resistant composition is Pt, Nb, a conducting oxide, a ternary layered carbide or nitride compound, or a combination thereof, wherein the conducting oxide is W- or Nb-doped TiO 2 , SnO 2 , or AZO, and wherein the ternary layered carbide or nitride compound is TiAlN, Ti 2 AlC, TiSiC, or any MAX phase material having a formula of M n+1 AX n , where n = 1-3, M is an early transition metal, A is an A group element, and X is nitrogen or carbon.
  5. The cell of any of the preceding claims, wherein the local interconnecting layer (311) of the plurality of interconnecting layers (308) comprises a conducting polymer or an oxygen-stable conducting organic composition or an oxidation-resistant metal, and wherein the conducting polymer is poly(3,4-ethlenedioxythiophene) (PEDOT), poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), polyaniline (PANI), polypyrrole (PPy), or a derivative thereof.
  6. The cell of any of the preceding claims, wherein the patterned lines of the local interconnecting layer (311) extend in a same direction, wherein the diameter or the width of the patterned lines is in a range of 1-50 microns, and wherein the local interconnecting layer (311) comprises openings between adjacent segments of material in a range of 5-100 microns as measured along the plane of the local interconnecting layer.
  7. The cell of any of the preceding claims, wherein the local interconnecting layer (311) comprises a mesh or web pattern of material having openings in the local interconnecting layer between connected segments of the material, wherein the diameter or the width of the segments of the material is in a range of 1-50 microns, and wherein the local interconnecting layer (311) comprises openings between adjacent segments of the material in a range of 5-100 microns as measured along the plane of the local interconnecting layer (311).
  8. The cell of any of the preceding claims, wherein the patterned lines or the line segments of the local interconnecting layer (311) extend in a first direction, and wherein the patterned lines or the line segments of the global interconnecting layer (313) extend in a second direction different from the first direction.
  9. The cell of any of the preceding claims, wherein the diameters or the widths of the patterned lines or the line segments of the global interconnecting layer (313) are in a range of 0.1-10 mm as measured along a plane of the global interconnecting layer, and wherein the global interconnecting layer (313) comprises openings between adjacent lines of material in a range of 0.1-10 mm as measured along the plane of the local interconnecting layer (311).
  10. The cell of any of the preceding claims, wherein the global interconnecting layer (313) of the plurality of interconnecting layers (308) comprises a single metallic structure having a plurality of fins extending in a direction of the axis running between the first electrode (302) and the membrane (306), and wherein the fins provide the flow field channels for the cell.
  11. The cell of any of the preceding claims, wherein the plurality of interconnecting layers (308) further comprises a mid-level interconnecting layer (312) positioned between the local interconnecting layer (311) and the global interconnecting layer (313).
  12. The cell of claim 11, wherein each of the local interconnecting layer (311), the mid-level interconnecting layer (312), and the global interconnecting layer (313) comprises patterned lines of material, wherein the patterned lines of the global interconnecting layer (313) have a diameter or width as measured along a plane of the global interconnecting layer (313) that is greater than a diameter or width of the patterned lines of the mid-level interconnecting layer (312) as measured along a plane of the mid-level interconnecting layer (312), and wherein the diameter or width of the mid-level interconnecting layer (312) is greater than a diameter or width of the patterned lines of the local interconnecting layer (311) as measured along a plane of the local interconnecting layer (311).
  13. The cell of claim 12, wherein the patterned lines of the mid-level interconnecting layer (312) have diameters or widths in a range of 10 microns to 5 mm as measured along a plane of the mid-level interconnecting layer (312), and wherein the global interconnecting layer (313) comprises openings between adjacent lines of the material in a range of 50 microns to 5 mm as measured along the plane of the mid-level interconnecting layer (312).
  14. The cell of any of the preceding claims, wherein the cell (300) is configured to operate with 200 mV or less of pure resistive loss when operating at a current density of at least 3 Amps/cm 2 .
  15. A method of forming a plurality of interconnected layers for an electrochemical cell (300), the method comprising: providing a plurality of interconnecting layers (308); characterised in that : the interconnecting layers (308) comprise a local interconnecting layer (311), at least one mid-level interconnecting layer (312), and a global interconnecting layer (313); the method being further characterised by the following steps: positioning the at least one mid-level interconnecting layer (312) on a surface of the global interconnecting layer (313); positioning the local interconnecting layer (311) on a surface of a mid-level interconnecting layer (312) of the at least one mid-level interconnecting layer (312) such that the at least one mid-level interconnecting layer (312) is positioned between the local interconnecting layer (311) and the global interconnecting layer (313); covering at least one surface of the local interconnecting layer (311) with a mask layer; applying a coating to the plurality of interconnecting layers (308), wherein the coating covers surfaces of the at least one mid-level interconnecting layer (312) and the global connecting layer (313) with the mask layer preventing the local interconnecting layer (311) from being coated; and removing the mask layer from the local interconnecting layer (311).

Description

This application claims the benefit of U.S. Provisional Patent Application No. 63/141,738, filed January 26, 2021. FIELD The present invention relates to electrochemical or electrolysis cells and components thereof. More specifically, the following disclosure relates to an electrochemical cell, and to a method of forming a plurality of interconnected layers for an electrochemical cell (see claims 1 and 15), e.g. low electrical impedance cells having interconnecting layers. BACKGROUND An electrochemical or electrolysis cell or system uses electrical energy to drive a chemical reaction. For example, within a water splitting electrolysis reaction within the electrolysis cell, water is split to form hydrogen and oxygen. The products may be used as energy sources for later use. In recent years, improvements in operational efficiency have made electrolyzer systems competitive market solutions for energy storage, generation, and/or transport. For example, the cost of generation may be below $10 per kilogram of hydrogen in some cases. Increases in efficiency and/or improvements in operation will continue to drive installation of electrolyzer systems. For example, various challenges are present with operation at the membrane of an electrolysis cell. These challenges are not well described within the literature and are not fully appreciated in the field. For example, at the interface, a 4- or 5-fold junction is required at which a catalyst (e.g., IrOx catalyst) is supplied with water and electricity. Additionally, at the interface, protons and gas are needed to be removed. In other words, an electrolysis cell requires a 5-way interface between catalyst, water, electrical conductor, proton transport, and bubble formation/gas transport. However, this need for multiple interfaces is not fully appreciated in the literature and as a result the requirement is not well incorporated into existing state-of-the-art PEM systems. The current best-in-class commercial PEM electrolyzers do not have interfaces designed to optimize the transport and fluxes outlined above. The central PEM/catalyst/water/gas interface is accomplished by randomly coating a catalyst and PEM material (ionomer) onto one or both of a Proton Exchange Membrane (PEM) layer plus a porous gas diffusion layer (GDL) that permits liquids and gases to flow through the holes while the solid material conducts electricity. The PEM layer and the GDL are then joined with the hope that the desired multi-way junctions are present. This is especially problematic for the anode GDL. The anode side is traditionally the rate-limiting reaction, owing to slower catalyst kinetics and the requirement for larger overpotential. Moreover, because the anode GDL sits in an oxidizing acidic environment, it is typically made of platinum-coated titanium. Titanium is a poor conductor, and the platinum is very expensive. Therefore, there is a desire to improve the interface to improve electrical conductivity and increase the density of "5-way junctions" and reduce costs, while maintaining fluid flow and bubble/gas removal. Electrical conductivity is the most crucial problem in that the impedance is far too high within the current state of the art. For example, as disclosed in Papakonstaniou et al., Applied Energy 280 (2020) 115911, more than 50% of the system losses come from "CLs+contacts" plus "hardware." These losses not only drive energy loss in the system but create enormous heat loads in the system and thermal management problems at the system level. While the existing state-of-the-art designs are adequate for historical applications of PEM electrolysis (e.g., making oxygen on submarines) they are inadequate for the anticipated future applications (e.g., making hydrogen for fertilizer manufacturing or hydrogen to reduce iron ore in steel production). The document WO 2020/020467 A1 (describing the preamble of claims 1 and 15) relates to a porous transport layer for an electrochemical cell consisting of a mixture of metal powder and binder. The document JP 2012 094438 A describes a fuel cell power generation system having a diffusion layer with a pore-shaped communication hole. The document DE 10 2018 105 115 A1 relates to an electrolyzer having a carrier element layer formed as a mesh structure. The document US 2007/0298267 A1 discloses an electrically conductive element for an electrochemical cell having an enhanced protection for an underlying metal substrate. Therefore, there remains a desire to improve the interface to minimize impedance losses arising from electrical transport and proton transport, while maintaining maximum access for flowing liquid and egress for produced gases. SUMMARY The invention is defined in the independent claims. The dependent claims describe embodiments of the invention. In one embodiment, an electrochemical cell is defined in claim 1, the cell includes an electrode, a membrane, and the plurality of interconnecting layers positioned between the electrode