TW202424274A - Porous metal plate material - Google Patents

Abstract

Porous metal plate material and process for producing such a material. The material comprises a perforated metal base plate and an electrodeposited layer with pin-shaped protrusions on at least one side of the perforated base plate made by electrodeposition while conditions are maintained for preferential growth. The perforated metal base plate has a pattern of apertures spaced by material bridges. The apertures include apertures bordered by bridges of varying width.

Description

Perforated metal plate material

The present disclosure relates to porous metal sheet materials, such as sieves, screens or plate electrodes, and to electrodeposition processes for producing such porous metal sheet materials.

Hitherto, such porous plates can be produced, for example, by connecting a conductive perforated substrate, such as a flat sheet or a drum, as a cathode in an electroplating bath containing an electrolyte. During the electroplating process, preferential growth conditions are maintained, i.e. the metal deposit does not grow uniformly in all directions, but grows mainly in the flow direction of the electrolyte stream. The metal plate material has pores of the same size and shape as the perforated base plate, resulting in the desired porosity of the metal plate material. The porous metal plate material can be used, for example, as a filter or screen or a flow-through plate electrode. The porous plate material can be planar or non-planar.

Preferential growth can be achieved, for example, by maintaining an electrolyte flow through the pores of the perforated plate in the desired growth direction, and/or by adding an effective amount of a brightener to the electrolyte, and/or by using a pulsed plating current.

NL1021096 discloses a process using a perforated substrate with slit-shaped through-holes having short material bridges bordering the short sides of the slits and longitudinal material bridges bordering the long sides of the slits. During the electrodeposition process, metal deposition occurs mainly on the short material bridges at the short ends of the slits. This results in pin-shaped protrusions at the short ends of the slits and thus increases the specific surface area (total area m ² /grid area m ² ).

Due to the increased specific surface area, such metal plate materials are particularly suitable as permeable flow-through plate electrodes, for example for water electrolysis. Water electrolysis is a process for producing hydrogen. In alkaline water electrolysis, two electrodes are immersed in a highly concentrated alkaline aqueous solution, such as a potassium hydroxide (KOH) solution. Hydrogen is produced by the reduction of hydrogen cations in the cathode chamber, while oxygen is produced by the oxidation of hydroxide ions in the anode chamber. Since oxidation and reduction occur on the surface of the electrode, the specific surface area of the electrode should preferably be maximized. On the other hand, the generated hydrogen and oxygen should be quickly released and discharged from the electrode surface, and bubbles should be avoided from clogging the pores of the electrode.

Therefore, it is desirable to provide a metal plate material that can be manufactured to have a significantly increased specific surface area.

To this end, the present invention provides a porous metal plate material, comprising a perforated metal base plate and an electro-deposited layer having pin-shaped protrusions on at least one side of the perforated metal base plate, which is made by electro-deposition while maintaining optimal growth conditions. The perforated metal base plate has a pattern of pores separated by material bridges. The pores include pores bordered by bridges of varying widths.

According to the teaching of NL1021095, protrusions grow on material bridges only at the outer ends of slit-shaped pores. It has now been found that protrusions can also be obtained by varying the shortest distance between adjacent pores, for example by varying the width of the material bridges and/or the width of the nodal points, also for non-slit-shaped pores. Patterns can be used together with a high density of bridges, which provides a very efficient way to optimize the specific surface area and porosity of the produced porous plate material.

The bridges may for example each have a fixed width, with some being wider than others. For example, bridges in the length direction of a row of pores may have a greater or lesser width than bridges between pores in an adjacent row. Alternatively, or additionally, the bridges may each have a different width, for example on a side where the pore does not have a straight outline. This may be the case for example with round or star shaped pores, etc.

In a specific embodiment, the ratio R _Bridge of the width Ww of the widest bridge of adjacent pores to the width Wn of the narrowest bridge of adjacent same pores is R>1.0.

The pores may be slit-shaped, but may also be polygonal, such as triangular or rectangular, or circular, oval, elliptical, or star-shaped. Combinations of pores with different profiles and/or sizes may also be used. Therefore, the present disclosure also relates to a porous metal plate material, comprising a perforated metal base plate and an electro-deposited layer having needle-like protrusions on at least one side of the perforated metal base plate, which is made by electro-deposition while maintaining optimal growth conditions, wherein the perforated metal base plate has a pattern of pores separated by material bridges, and wherein the pores are non-slit-shaped, such as triangular or rectangular, or circular, oval, elliptical, or star-shaped. In this regard, the needle-like protrusions are deposition peaks of the electro-deposited material.

Good results are achieved if the ratio R _bridge >1.1, for example >1.4.

The pores are usually arranged in a regular pattern, for example in columns. A high density of needle-like protrusions is obtained if the location of the maximum distance to the nearest pore is offset from the nearest center line of a column containing this pore. In this case, a twin pair of protrusions can be obtained on a single bridge or a protrusion with two peaks.

The pores in the perforated metal substrate may, for example, have a width or diameter of about 5-500 microns. The pores may be aligned, parallel, equidistant, and uniform, but other patterns may also be used.

In the context of the present disclosure, a bridge is a material between two adjacent pores. A pair of pores is considered adjacent if the shortest line between the two pores does not cross the bridge between another pore or another pair of pores that are closer to each other. The width of the bridge at a given point on the bridge is the shortest distance between two adjacent pores at the given point.

The porous metal sheet material can be made, for example, by electrodeposition using a conductive perforated metal substrate as a cathode in an electroplating bath containing an electrolyte, the electrolyte including at least one reduction inhibitor, such as a brightener or a leveling agent, wherein the perforated metal substrate has a pattern of pores separated by material bridges, wherein the flow of the electrolyte is maintained from the upstream side of the porous metal substrate through the pores to the downstream side, wherein the pores include a plurality of pores bordered by bridges of different widths. In this regard, the width is considered to be varying if the width variation exceeds the engineering tolerance or measurement margin.

The width of each bridge may be different and/or the ratio R _bridge of the width Ww of the widest bridge adjacent to a pore to the width Wn of the narrowest bridge adjacent to the same pore may be R>1.0.

The average flow velocity V is defined as the ratio of the volume flow rate to the joint cross sectional flow-through area of all pores, the so-called open area. The average flow velocity V may, for example, be at least 2 cm/s.

If the average flow rate is at least 10 cm/s, a very irregular protrusion structure can be obtained, which has been found to be particularly useful for the production of gas-permeable plate electrodes. Therefore, the present invention also relates to an electroplating process, by using a conductive perforated metal substrate as a cathode in an electroplating bath containing an electrolyte, the electrolyte comprising at least one reduction inhibitor, such as a brightener or a leveling agent, wherein the perforated metal substrate has a pattern of pores separated by material bridges, wherein the flow of the electrolyte is maintained from the upstream side of the porous metal substrate through the pores to the downstream side at an average flow rate of at least 10 cm/s, for example at least 12 cm/s,

Alternatively, or additionally, the positioning of the deposition peaks can also be controlled by changing the width of the bridges connecting the nodes to adjacent materials. Therefore, the present invention also relates to a process for the production of porous metal sheets by electroplating using a conductive perforated metal substrate as a cathode in a plating bath containing an electrolyte, the electrolyte including at least one reduction inhibitor, such as a brightener or a leveling agent, wherein the perforated metal substrate has a pattern of pores separated by material bridges, wherein the flow of the electrolyte is maintained from the upstream side of the porous metal substrate through the pores to the downstream side, wherein the bridges include at least two sets of parallel bridge rows, which are not interrupted by the pores, and one set of rows intersects with another set of rows. This way, different bridge trains cross each other at nodes, where the width of the nodes is at least 1,4 times the width of the bridges themselves, if the width of the bridges is equal.

In certain embodiments, the pattern of pores and bridges may have a rotational symmetry of at least order 3, such as at least 4. The "order of rotational symmetry" refers to the number of times the pattern coincides with itself when rotated 360°. Higher orders or rotational symmetries result in larger nodes.

Reduction inhibitors inhibit the reduction of cations and hinder metal deposition. It has been found that the local geometry of the pores and bridges, for example by changing the shortest distance between adjacent pores, in particular by changing the width of the bridges and/or nodes, can be used to control the variation of the local concentration of the reduction inhibitor along the contour of each pore, resulting in the desired texture and pattern of deposition peaks or protrusions.

Suitable reduction inhibitors include brighteners and leveling agents. During the electrodeposition process, such compounds are more easily reduced than metal cations, so they inhibit metal deposition. Specific examples include carrier brighteners (e.g., paratoluene sulfonamide, benzene sulphonic acid) at a concentration of about 0.75-23 g/l, leveling agents, second-class brighteners (e.g., allyl sulfonic acid, formaldehyde chloral hydrate), and auxiliary brighteners, such as sodium allyl sulfonate, pyridinium propyl sulfonate, for example, at a concentration of 0.075-3.8 g/l. Alternatively, or additionally, inorganic brighteners such as cobalt or zinc may be used in a concentration of 0.075-3.8 g/l. Specific examples of suitable brighteners include, for example, 1-(2-hydroxy-3-sulfopropyl)-pyridinium betaine, 1-(3-sulfopropyl)-pyridinium betaine (PPS), propionitrile, hydroxy propionitril (HPN), 2-butyn-1,4-diol, 1,4 butyndiol, 3-butyn-1-ol, 3-pentyn-1-ol, 1-(3-sulfopropyl), 2-vinylpyridinium betaine ... betaine, thio ureum, fumaronitrile, propargyl alcohol, amino-acetonitril-hydrogen chloride, diallyl amine, 2-propyn-1-ol, chinoxaline, 3-amino propionitril fumarate, 1,4-butyndiol diethoxylaat, ethylene cyanohydrine, 1-(2-hydroxy-3-sulfopropyl) pyridine and 4-benzyl-1-(3-sulfopropyl)-pyridinium betaine).

Generally speaking, higher concentrations of reduction inhibitors result in larger protrusions. Suitable concentrations are, for example, 250 mg/l or more. During the electrodeposition process, the reduction inhibitor is consumed. The average concentration of the reduction inhibitor in the electrolyte can be maintained at a constant level, for example by an in-line system for measurement and dosing.

This process is particularly useful for the production of porous materials based on, for example, nickel or copper. Suitable electrolytes include nickel sulfamide, nickel sulfate or nickel chloride baths, for example at a concentration of 50-800 g/l, preferably 300-450 g/l.

During the electrodeposition process, the current through the through-hole metal substrate may be maintained at, for example, about 5-20 A/dm ² . Other parameters, such as pH and temperature, may be maintained at levels commonly used in electrodeposition, such as a pH below 6 and a temperature above 50° C.

Good results are obtained if the perforated metal base used as starting material is made of nickel or a nickel alloy. Other conductive materials such as steel, copper or brass can also be used.

The perforated metal substrate used as a starting material for the disclosed process may be, for example, in the form of a plate or a rotating drum, such that the electro-deposition process can be configured as a continuous roll-to-roll process. The perforated metal substrate may be produced, for example, by electro-deposition.

The porous metal sheet material produced can be flat, plane plate or sheet. Alternatively, it can be formed as a cylinder or have any other suitable configuration. The porous metal sheet material can have any desired thickness. If it is used as an electrode, it can, for example, have a thickness of up to 5 mm (including the height of the needle-like protrusions), such as at least about 0.01 mm, such as 0.8-1.3 mm, such as up to 1 mm.

The needle-like protrusions can extend from one side or from both sides. To obtain protrusions on both sides of the perforated metal substrate, the flow direction of the electrolyte can be reversed during the process.

If desired, the needle-like protrusions may all have substantially the same length or may be of different lengths. The needle-like protrusions may, for example, have a length of up to 1000 μm. The needle-like protrusions may, for example, have a maximum diameter of 120-180 μm. The core-to-core distance between adjacent needle-like protrusions may, for example, be about 150-300 μm.

The resulting effective surface area of the porous metal plate may for example be at least 4 times, for example at least 6 times, the total surface area (width times height) of the perforated metal base plate. Optionally, the specific surface area of the porous metal plate may be further increased, for example by a surface area enhancing coating. Examples of such surface area enhancing coatings, in particular for alkaline electrolysis, are disclosed in WO 2010/063695 and EP 3 159 433 A1. In the paper "Alkaline membrane water electrolysis using non-precious metal catalysts" by Kraglund, M. R., & Christensen, E. (2017) (Department of Energy Conversion and Storage, Technical University of Denmark), electrodes with a Raney nickel coating for increasing the specific surface area are disclosed.

The porous metal sheet material can be used, for example, as a screen, filter or mesh, or as a catalyst, as a textured roller, or as a flow-through plate electrode, such as an anode or cathode in an electrolysis cell or a fuel cell. Such electrodes are particularly useful in cells for the electrolysis of water, more particularly as cathodes in alkaline electrolysis.

An electrode that can be used in an electrolytic cell includes: - an electrolyte reservoir; - a membrane or separator that separates the electrolyte reservoir into an oxygen production section and a hydrogen production section; - a gas diffusion anode on a first surface of the separator in an oxygen evolution reaction (OER) section; - a gas diffusion cathode on a second surface of the separator in a hydrogen evolution reaction (HER) section; wherein the gas diffusion cathode and/or anode is an electrode according to the present disclosure.

Very good results are obtained when the needle-like protrusions of the gas diffusion cathode are pointed towards the separator. This leads to higher current density at lower voltage. In the zero-gap configuration, the tip of the needle-like protrusion can, for example, abut the separator.

The electrode can be made of, for example, a non-noble metal or an alloy thereof. Alloys showing high catalytic activity in the hydrogen evolution reaction (HER) include low-d-electron metals (hypo-d-electronic metals), such as nickel or iron, and high-d-electron elements (hyper-d-electronic elements), such as alloys of molybdenum, tungsten, titanium, niobia or rhodium. Very good results have been achieved with nickel. Among the non-noble metals, nickel is one of the most stable metals in strong alkaline solutions and is also a good catalyst for the formation of hydrogen and oxygen. Nickel alloys can also be used. For example, it has been found that iron-nickel alloys, for example including up to about 10% iron, are particularly suitable as anodes. Nickel alloys comprising vanadium, molybdenum and/or manganese have been found to be particularly suitable for use as cathodes.

The above aspects will be further explained below with more details and benefits with reference to the accompanying drawings which illustrate various embodiments by way of example.

Embodiment 1

As shown in FIG. 1A , a through-hole metal substrate 1 having a pattern of holes 2 and bridges 3 is provided. The through-hole metal substrate is made of electro-deposited nickel.

The aperture 2 is a slit with rounded edges, having a length of 0.44 mm and a width of 0.22 mm.

The bridges 3 between the outer ends of the oval slits have varying widths. The pores 2 are arranged in a line along the central axis L1. The position P of the maximum distance to the nearest pore 2 is offset from the central line L1 at the wider node. The pores 2 of each line are staggered with the pores 2 of the adjacent line. The material bridges 3 include three sets of parallel bridge rows R1, R2, R3, which are not interrupted by pores.

The perforated metal substrate 1 is activated and rinsed using a Wood's nickel strike bath. The perforated metal substrate is then placed in an electrolyte bath of a nickel sulfamide solution as a flow-through cathode, the nickel sulfamide solution including more than 250 mg/l of 1-(3-sulfopropyl)-pyridinium betaine as a reduction inhibitor. The deposition is carried out at 13A/ ^dm2 /17Ah/ ^dm2 . The electrolyte flow is maintained through the perforated metal plate at an average flow rate of 7cm/s. The pH is less than 5. The temperature is greater than 50°C.

The resulting texture is shown in Fig. 1B. The protrusions 4 mainly grow at positions P and bend back to the outer ends of the corresponding pores to form lip-shaped edges.

Embodiment 2

As shown in FIG. 2A , a perforated metal base plate 1A having a pattern of apertures 2A and bridges 3A is provided. Apertures 2A are quite similar to apertures 2 in FIG. 1A , except that the straight longitudinal sides are slightly longer. The ratio R _bridge between the shortest width Ww between the longitudinal sides and the shortest width Wn between the outer ends is R _bridge = 1.1.

The through-hole metal substrate 1A is made of electro-deposited nickel.

The perforated metal substrate 1A is activated and rinsed using a Wood nickel impact bath. The perforated metal substrate 1A is then placed in an electrolyte bath of a nickel sulfamide solution as a flow-through cathode, the nickel sulfamide solution including more than 250 mg/l of 1-(3-sulfopropyl)-pyridinium betaine as a reduction inhibitor. The deposition is carried out at 13A/ ^dm2 /17Ah/ ^dm2 . The electrolyte flow is maintained at an average flow rate of 7cm/s through the perforated metal plate. The pH is less than 5. The temperature is higher than 50°C.

The resulting texture is shown in FIG. 2B . The protrusion 4A grows mainly above position P. The bridge at the rounded end has two such protrusions, which merge at the bottom due to the short distance. This results in twin peak protrusions.

Embodiment 3

As shown in FIG. 3A , a perforated metal base plate 1B having a pattern of apertures 2B and bridges 3B is provided. The apertures 2B are diamond-shaped and have a length of 0.31 mm and a width of 0.23 mm. The material bridges 3 comprise three parallel rows R1b, R2b, R3b of bridges 3 which are not interrupted by the apertures 2B.

The bridges 3B at the outer points of the diamond-shaped aperture 2B have a width of 0,11 mm. The bridges 3B between the lateral sides of the aperture have a width of 0,18 mm.

Therefore, the ratio R _bridge of the width Ww of the widest bridge to the width of the narrowest bridge of adjacent pores is R _bridge = 1.7. The pores 2B are arranged in a line along the central axis L2. The pores 2B of each line are arranged in a staggered manner, offset from the pores 2B of the adjacent line.

The perforated metal substrate 1B was activated and rinsed using a Wood nickel impact bath. The perforated metal substrate 1B was then placed in an electrolyte bath of a nickel sulfamide solution as a flow-through cathode, the nickel sulfamide solution comprising more than 250 mg/l of 1-(3-sulfopropyl)-pyridinium betaine as a reduction inhibitor. The deposition was carried out at 13 A/dm ² /17 Ah/dm ^2. The electrolyte flow was maintained through the perforated metal plate at an average flow rate of 4,3 cm/s.

The resulting texture is shown in Figure 3B. Protrusions 4B grow primarily at the nodes between three adjacent pores and fuse at the bottom, especially in the wider bridges.

Embodiment 4

As shown in FIG. 4A , a perforated metal base plate 1C having a pattern of pores 2C and bridges 3C is provided. The pores 2C are diamond-shaped and have a length of 0.21 mm and a width of 0.11 mm. The material bridges 3C comprise three parallel rows of bridges 3C R1c, R2c, R3c, which are not interrupted by the pores 2C.

The bridges 3C at the outer points of the diamond-shaped apertures have a width of 0,11 mm, which is equal to the width Ww of the bridges 3C between the lateral sides of the aperture, so the ratio _Rbridge = 1. The apertures 2C are arranged in a line along the central axis L3. The apertures 2C of each line are offset from the apertures of the adjacent line.

The perforated metal substrate 1C is activated and rinsed using a Wood nickel impact bath. The perforated metal substrate 1C is then placed in an electrolyte bath of a nickel sulfamide solution as a flow-through cathode, the nickel sulfamide solution comprising more than 250 mg/l of 1-(3-sulfopropyl)-pyridinium betaine as a reduction inhibitor. The deposition is carried out at 13 A/dm ² /17 Ah/dm ^2. The electrolyte flow is maintained through the perforated metal plate 1C at an average flow rate of 4,7 cm/s.

The resulting texture is shown in Figure 4B. Protrusions 4C mainly grow on the nodes between three adjacent pores.

Embodiment 5

As shown in Fig. 5A, a perforated metal base plate 1D having a pattern of holes 2D and bridges 3D is provided. The holes 2D are slit-shaped and have a length of 0.44 mm and a width of 0.03 mm.

The bridges 3D at the outer points of the aperture 2D have a width of 0,19 mm. The bridges 3D between the lateral sides of the aperture 2D have a width of 0,13 mm.

Therefore, the ratio R _bridge of the width Ww of the widest bridge to the width of the narrowest bridge of adjacent pores 2D is R _bridge =1.5. The pores 2D are arranged in a line along the central axis L4. The pores 2D of each line are arranged in a staggered manner, offset from the pores 2D of the adjacent line.

The through-hole metal substrate 1D is made of electro-deposited nickel.

The perforated metal substrate 1D was activated and rinsed using a Wood's nickel impact bath. The perforated metal substrate 1D was then placed in an electrolyte bath of a nickel sulfamide solution as a flow-through cathode, the nickel sulfamide solution including more than 250 mg/l of 1-(3-sulfopropyl)-pyridinium betaine as a reduction inhibitor. The deposition was carried out at 13A/ ^dm2 /17Ah/ ^dm2 . The electrolyte flow was maintained at an average flow rate of 10cm/s through the perforated metal plate 1D.

The resulting texture is shown in Figure 5B. The protrusions 4D grow primarily on the wider bridges between the outer ends of the pores 2D in a very regular pattern.

Embodiment 6

As shown in Fig. 6A, a perforated metal base plate 1E is provided with a pattern of holes 2E and bridges 3E. The holes 2E are triangles with three equal sides of 0.07 mm.

Each triangular pore 2E is surrounded by four triangular pores 2E of the same size but pointing in opposite directions, resulting in different widths of the bridge 3E. The material bridge 3E includes three parallel rows of bridges 3E R1e, R2e, and R3e, which are not interrupted by pores 2E.

The perforated metal substrate 1E is made of electrodeposited nickel.

The perforated metal substrate 1E was activated and rinsed using a Wood nickel impact bath. The perforated metal substrate 1E was then placed in an electrolyte bath of a nickel sulfamide solution as a flow-through cathode, the nickel sulfamide solution including more than 250 mg/l of 1-(3-sulfopropyl)-pyridinium betaine as a reduction inhibitor. The deposition was carried out at 13A/ ^dm2 /17Ah/ ^dm2 . The electrolyte flow was maintained at an average flow rate of 17cm/s through the perforated metal plate 1E.

The resulting texture is shown in Fig. 6B. The protrusions 4E mainly grow between the tips of the triangular pores 2E.

Embodiment 7

As shown in Fig. 7A, a perforated metal base plate 1F is provided with a pattern of holes 2F and bridges 3F. The holes 2F are circular with a diameter of 0.06 mm.

The shortest distance between adjacent pores is 0,10 mm.

Each circular pore 2F is surrounded by six circular pores 2F of the same size at equal distances, resulting in different widths of bridges 3F. The material bridge 3F includes three parallel rows of bridges 3F R1f, R2f, R3f, which are not interrupted by pores 2E. Therefore, the three rows of bridges 3F cross each other at each node. The pattern of pores 2F and bridges 3F have rotational symmetry of at least order 6.

The perforated metal substrate 1F is made of electrodeposited nickel.

The perforated metal substrate 1F is activated and rinsed using a Wood nickel impact bath. The perforated metal substrate 1F is then placed in an electrolyte bath of a nickel sulfamide solution as a flow-through cathode, the nickel sulfamide solution comprising more than 250 mg/l of 1-(3-sulfopropyl)-pyridinium betaine as a reduction inhibitor. The deposition is carried out at 13A/ ^dm2 /17Ah/ ^dm2 . The electrolyte flow is maintained through the perforated metal plate 1F at an average flow rate of 10,6cm/s.

The resulting texture is shown in Figure 7B. Protrusions 4F mainly grow on the nodes between three adjacent circular pores.

Embodiment 8

As shown in Fig. 8A, a perforated metal base plate 1G is provided with a pattern of holes 2G and bridges 3G. The holes 2G are star-shaped with a maximum width of 0.14 mm.

Each star-shaped pore 2G is surrounded by six pores 2G of the same shape and size, resulting in different widths of the bridges 3G. The material bridge 3G comprises three parallel rows R1g, R2g, R3g of bridges 3G which are not interrupted by pores 2G.

The through-hole metal substrate 1G is made of electro-deposited nickel.

The perforated metal substrate 1G was activated and rinsed using a Wood nickel impact bath. The perforated metal substrate 1G was then placed in an electrolyte bath of a nickel sulfamide solution as a flow-through cathode, the nickel sulfamide solution comprising more than 250 mg/l of 1-(3-sulfopropyl)-pyridinium betaine as a reduction inhibitor. The deposition was carried out at 13A/ ^dm2 /17Ah/ ^dm2 . The electrolyte flow was maintained through the perforated metal plate 1G at an average flow rate of 9,3cm/s.

The resulting texture is shown in Figure 8B. Protrusions 4G grow in an irregular pattern.

Embodiment 9

As shown in Fig. 8A, a perforated metal base plate 1H having a pattern of holes 2H and bridges 3H is provided. The holes 2H are square with a maximum width of 0.14 mm.

Each square pore 2H is surrounded by eight pores 2H of the same shape and size. The material bridges 3H comprise two parallel rows R1h, R2h of bridges 3H, which are not interrupted by pores 2H. The bridges 3H of the first row are at right angles to the bridges 3H of the second row, resulting in a node 5H having a width 1.4 times that of the adjacent material bridges 3H. The pattern of pores 2H and bridges 3H has a rotational symmetry of at least 4th order.

The perforated metal base plate 1H is made of electro-deposited nickel.

The perforated metal substrate 1H was activated and rinsed using a Wood's nickel impact bath. The perforated metal substrate 1H was then placed in an electrolyte bath of a nickel sulfamide solution as a flow-through cathode, the nickel sulfamide solution including more than 250 mg/l of 1-(3-sulfopropyl)-pyridinium betaine as a reduction inhibitor. Deposition took place at 13A/dm ² /17Ah/dm ² . The electrolyte flow was maintained through the perforated metal plate at an average flow rate of 9,3 cm/s.

The resulting texture is shown in Figure 9B. The protrusions 4H grow in a very regular pattern.

FIG. 10 shows an electrolytic cell 21 for alkaline electrolysis of water to produce oxygen and hydrogen. The electrolytic cell 21 includes an electrolyte reservoir 22 filled with an alkaline electrolyte. A membrane or separator 23 separates the electrolyte reservoir 22 into an oxygen evolution reaction (OER) section 24 and a hydrogen evolution reaction (HER) section 25. A gas diffusion anode 26 is mounted to a first surface of the separator 23 in the OER section 24. A gas diffusion cathode 27 is mounted to the opposite surface of the separator 23 in the HER section 25.

The gas diffusion cathode 27 is a porous metal plate as shown in FIG. 1B or FIG. 2B and has needle-like protrusions 29. The needle-like protrusions 29 extend in the direction of the separator 23. In the zero-gap configuration of FIG. 3, the needle-like protrusions 29 abut the separator 23. The gas diffusion anode 26 can be, for example, a conventional mesh electrode.

The electrolytic cells 21 are bordered by bipolar plates 28 which conduct current from or to other cells in the stack (not shown).

1, 1A, 1B, 1C, 1D, 1E, 1F, 1G: Perforated metal base plate 2, 2A, 2B, 2C, 2D, 2E, 2F, 2G: Pores 3, 3A, 3B, 3C, 3D, 3E, 3F, 3G: Bridges 4, 4A, 4B, 4C, 4D, 4E, 4F, 4G: Protrusions 5H: Node 21: Electrolytic cell 22: Electrolyte storage 23: Separator 24: OER section 25: HER section 26: Gas diffusion anode 27: Gas diffusion cathode 28: Bipolar plate 29: Needle protrusions L1: Center axis/center line L2, L3, L4: Center axis R1, R1b, R1c, R1e, R1f, R1g, R1h, R2, R2b, R2c, R2c, R2e, R2f, R2g, R2h, R3, R3b, R3c, R3e, R3f, R3g: row Rbridge: ratio P: position V: average flow rate Ww, Wn: width

FIG. 1A: The above view shows an exemplary embodiment of a perforated substrate used in the process of the present invention; FIG. 1B: Shows a detailed photograph of a porous metal plate produced using the substrate of FIG. 1A; FIG. 2A: The above view shows a second exemplary embodiment of the perforated substrate. FIG. 2B: A detailed photograph of a porous metal plate produced using the substrate of FIG. 2A is shown; FIG. 3A: The above view shows the third exemplary embodiment of the perforated substrate; FIG. 3B: A detailed photograph of a porous metal plate produced using the substrate of FIG. 3A is shown; FIG. 4A: The above view shows the fourth exemplary embodiment of the perforated substrate; FIG. 4B: A detailed photograph of a porous metal plate produced using the substrate of FIG. 4A is shown; FIG. 5A: The above view shows the fifth exemplary embodiment of the perforated substrate; FIG. 5B: A detailed photograph of a porous metal plate produced using the substrate of FIG. 5A is shown; FIG. 6A: The above view shows the sixth exemplary embodiment of the perforated substrate; FIG. 6B: A detailed photograph of a porous metal plate produced using the substrate of FIG. 6A is shown; FIG. 7A: The above view shows the seventh exemplary embodiment of the perforated substrate; FIG. 7B: A detailed photograph of a porous metal plate produced using the substrate of FIG. 7A is shown; FIG. 8A: The above view shows the eighth exemplary embodiment of the perforated substrate; FIG. 8B: A detailed photograph of a porous metal plate produced using the substrate of FIG. 8A is shown; FIG. 9A: The above view shows the ninth exemplary embodiment of the perforated substrate; FIG. 9B: A detailed photograph of a porous metal plate produced using the substrate of FIG. 9A is shown; FIG. 10: An electrolytic cell having an electrode according to the present invention is shown.

without

2: Porosity

3: Bridge

L1: Center axis/center line

R1: Column

R2: Column

R3: Column

P: Position

Claims (12)

A porous metal plate material, comprising a perforated metal base plate and an electro-deposition layer having a plurality of pin-shaped protrusions on at least one side of the perforated metal base plate, is produced by electro-deposition while maintaining preferential growth conditions, wherein the perforated metal base plate has a pattern of a plurality of apertures separated by a plurality of material bridges, wherein the apertures include a plurality of apertures bordered by a plurality of bridges of varying widths. A porous metal plate material as claimed in claim 1, wherein the ratio R _bridge of the width Ww of the widest bridge adjacent to a pore to the width Wn of the narrowest bridge adjacent to the same pore is less than 1. A porous metal plate material as claimed in claim 1, wherein the pores comprise a plurality of pores bordered by at least one bridge having a different width. A porous metal plate material as claimed in any of the preceding claims, wherein the pores comprise a plurality of pores having a polygonal shape, such as a triangle or a rectangle, or a circular, an oval, an elliptical, a star or a slit-shaped profile, wherein the ratio R _aperture of the slit-shaped profile, such as the maximum width Wl to the minimum width Ws, is less than 6. A porous metal plate material as claimed in any of the preceding claims, wherein the location of the maximum distance to the nearest pore is offset from the nearest center line of a row containing the nearest pore. A porous metal plate material as claimed in any of the preceding claims, wherein the perforated metal base plate comprises an electro-deposited plate. The porous metal plate material of any of the preceding claims is made by maintaining an average flow rate of the electrolyte at least 10 cm/s during electrodeposition. A use of a porous metal sheet material as claimed in any of the preceding claims, wherein the porous metal sheet material is used as a screen, a flow-through catalyst, a textured roller or an electrode, for example, in an electrolysis cell or a fuel cell. A method for manufacturing a porous metal sheet material, by performing electroplating in an electroplating bath containing an electrolyte using a conductive perforated metal substrate as a cathode, the electrolyte including at least one reduction inhibitor, such as a brightener or a leveling agent, wherein the perforated metal substrate has a pattern of a plurality of pores separated by a plurality of material bridges, wherein the flow of the electrolyte is maintained from an upstream side of the porous metal substrate through the pores to a downstream side, wherein the pores include a plurality of pores bordered by a plurality of bridges of varying widths. A manufacturing method as claimed in claim 9, wherein the average flow rate of the electrolyte is maintained at at least 2 cm/s, for example at least 10 cm/s during electrodeposition. A method for manufacturing a porous metal sheet material, by electroplating using a conductive perforated metal substrate as a cathode in an electroplating bath containing an electrolyte, the electrolyte including at least one reduction inhibitor, such as a brightener or a leveling agent, wherein the perforated metal substrate has a pattern of a plurality of pores separated by a plurality of material bridges, wherein the flow of the electrolyte is maintained from an upstream side of the porous metal substrate through the pores to a downstream side, wherein the bridges include at least two sets of parallel bridge rows, the rows are not interrupted by the pores, and the rows of one set intersect with the rows of another set. A method for manufacturing a porous metal sheet material, by electroplating using a conductive perforated metal substrate as a cathode in an electroplating bath containing an electrolyte, the electrolyte including at least one reduction inhibitor, such as a brightener or a leveling agent, wherein the perforated metal substrate has a pattern of a plurality of pores separated by a plurality of material bridges, wherein the flow of the electrolyte is maintained from an upstream side of the porous metal substrate through the pores to a downstream side, wherein the pattern of the pores has at least 3rd order rotational symmetry with the bridges.