KR20210055269A - Metal Substrate for Electrode and Preparation Method Thereof - Google Patents

Abstract

The present invention relates to a metal substrate for an electrode including a curved unit, a flat unit, and a plurality of polygonal pores, and a method for manufacturing the same. The metal substrate for an electrode of the present invention is energy efficient by improving overvoltage.

Description

Metal Substrate for Electrode and Preparation Method Thereof {Metal Substrate for Electrode and Preparation Method Thereof}

The present invention relates to a metal substrate for an electrode capable of improving overvoltage when used as a substrate for an electrode, and a method of manufacturing the same.

A technology for producing hydroxide, hydrogen and chlorine by electrolyzing inexpensive brine such as seawater is widely known. Such an electrolysis process is commonly referred to as a chlor-alkali process, and it can be said that the performance and reliability of technology have been proven through commercial operation for several decades.

In the electrolysis of such brine, an ion exchange membrane is installed inside the electrolyzer to divide the electrolyzer into a cation chamber and an anion chamber. This is the method being used.

Meanwhile, the electrolysis process of brine is performed through a reaction as shown in the following electrochemical reaction formula.

Oxidation electrode (anode) _{^{reaction: 2Cl - → Cl 2 + 2e}} - (E 0 = +1.36 V)

Reduction electrode (cathode) ^{_{reaction: 2H 2 O + 2e - →}} 2OH - + H 2 (E 0 = -0.83 V)

Total _{^{reaction: 2Cl - + 2H 2 O →}} 2OH - + Cl 2 + H 2 (E 0 = -2.19 V)

The most important factor to be considered when performing electrolysis of brine is the electrolytic potential, which is the theoretically necessary voltage, overvoltage of the oxidation and reduction electrodes, voltage due to the resistance of the ion exchange membrane, and the distance between the oxidation and reduction electrodes. All of the voltage caused by is to be considered. If the electrolytic potential can be reduced, energy required for the operation of the entire process can be reduced to more efficiently produce chlorine gas and hydrogen gas.

Accordingly, various studies are being conducted to reduce the electrolytic potential, and in particular, there is a need for a way to reduce overvoltage by optimizing the structure of a metal substrate used for an electrode.

KR 2011-0094055 A

An object of the present invention is to provide a metal substrate for an electrode capable of improving the overvoltage of an electrode during electrolysis.

In order to solve the above problems, the present invention includes a planar portion and an arcuate curved portion having a plurality of polygonal pores, and the planar portion and the curved portion are disposed at an intersection, and the polygonal pores have an acute angle portion of less than 90°. It provides a metal substrate for the electrode.

In addition, the present invention provides a method of manufacturing a metal substrate for an electrode comprising the step (S1) of processing a polygonal pattern on the surface of the metal substrate by etching or punching, and the step (S2) of stamping multistage molding according to the pattern. do.

When the metal substrate for an electrode of the present invention is applied to an electrode for electrolysis, it is possible to reduce the energy consumed in the electrolysis reaction by reducing the electrolytic potential, so it is energy-efficient.

1 is a simplified operation principle of an electrode for electrolysis to which a metal substrate of the present invention is applied.
2 shows a pore design diagram of Example 1 of the present invention.

Hereinafter, the present invention will be described in more detail.

The terms or words used in the specification and claims should not be construed as being limited to their usual or dictionary meanings, and the inventor may appropriately define the concept of terms in order to describe his own invention in the best way. It should be interpreted as a meaning and concept consistent with the technical idea of the present invention based on the principle that there is.

Metal substrate for electrode

The present invention provides a metal substrate for an electrode comprising a planar portion and an arcuate curved portion having a plurality of polygonal pores, the planar portion and the curved portion are disposed at an intersection, and the polygonal pores have an acute angle portion of less than 90° do.

The metal substrate for an electrode of the present invention includes a curved portion and a flat portion at the same time, and the curved portion and the flat portion may be alternately disposed. The curved portion may have a concave or convex arch shape in a direction perpendicular to the substrate surface.

The metal substrate for an electrode of the present invention has such a curved portion so that the contact with the polymer film can be made uniform, and the contact area can be increased, and the uniform charge transfer can be achieved by improving the surface pressure uniformity in the cell. have.

In the metal substrate for an electrode of the present invention, it is preferable that a plurality of polygonal pores are formed on a curved portion. Since gas is generated at a portion where the polymer membrane and the electrode contact during the electrolysis process, it is preferable that pores are formed on the curved surface in contact with the polymer membrane. On the other hand, since the flat portion is in contact with the substrate layer, when pores are formed on the flat portion, the electrical resistance of the electrode may be rather increased.

Polygonal pores of the metal substrate for an electrode of the present invention may have an acute angle of less than 90°. The acute angle portion is suitable for inducing the growth and release of gas.

It is preferable that the plurality of polygonal pores have a trapezoidal shape or a parallelogram shape. When the pores have a trapezoidal shape or a parallelogram shape, an acute angle portion and an obtuse angle portion may exist at the same time in each pore. When the pores are trapezoidal or parallelogram, the angle of the acute angle may be 30 to 80 degrees, preferably 40 to 75 degrees, and more preferably 50 to 70 degrees. If the angle of the acute angle is too small, pore formation in the manufacturing process may not be easy, and if the angle of the acute angle is too large and approaches 90 degrees, it may not be easy to discharge gas through the acute angle.

The metal substrate for an electrode of the present invention can be elastically deformed to a thickness of 50 to 100%, preferably 55 to 100% of the thickness of the substrate when bound to a cell. The metal substrate of the present invention can be elastically deformed after manufacture to adjust porosity and thickness, and can have a desired degree of flexibility and stiffness. In addition, when the degree of elastic deformation increases, the contact area between the curved portion and the polymer film increases, so that overvoltage may be improved. However, if the degree of elastic deformation is too large, there may be a disadvantage that the release of the lag is not easy.

The metal substrate for an electrode of the present invention may have a porosity of 0.3 to 0.7, preferably 0.35 to 0.65, and more preferably 0.4 to 0.6. The porosity is defined as the ratio of the pore area to the sum of the substrate area and the pore area, and if the porosity is lower than this, the number of pores and the total area are insufficient, so that gas growth and release through the pores may not be easy. If the porosity is higher than this, the mechanical strength of the substrate may be lowered, so that the durability of the electrode may be lowered, and the contact area may also decrease, thereby increasing the overvoltage.

The metal substrate for an electrode of the present invention may have a thickness of less than 1 mm, preferably 0.7 mm or less, and more preferably 0.1 to 0.5 mm. If the thickness of the electrode metal substrate is too thick, processing including formation of pores may be difficult, and if it is too thin, the mechanical strength of the substrate may be weak. In addition, when the thickness of the metal substrate for an electrode is outside the above-described range, the flexibility is poor, the adhesion to the polymer film is deteriorated, and accordingly, the overvoltage may increase.

When the metal substrate for an electrode of the present invention has a desirable range of porosity and thickness, it is possible to optimize the size and fraction of gas bubbles generated in the electrolysis process and electrode capture properties, and the problem of increasing contact resistance due to increased porosity is solved. Can be.

In the metal substrate for an electrode of the present invention, the metal may be selected from the group consisting of nickel, titanium, tantalum, niobium, zirconium, hafnium, molybdenum, tungsten, stainless steel, and alloys thereof, particularly preferably nickel. Do.

Method of manufacturing metal substrate for electrode

The present invention provides a method of manufacturing a metal substrate for an electrode comprising the step (S1) of processing a polygonal pattern on the surface of the metal substrate by etching or punching, and the step of performing multi-stage stamping (S2) according to the pattern.

In the method of manufacturing a metal substrate for an electrode of the present invention, step S1 is a step of forming pores by patterning the shape of the pores on the surface of the substrate in advance, and may be performed through etching or punching.

In the method of manufacturing a metal substrate for an electrode of the present invention, step S2 is a step of forming a metal substrate having pores formed through multi-stage stamping, in which a curved portion of the metal substrate is formed.

In the method of manufacturing a metal substrate for an electrode of the present invention, the polygon is as described in relation to the metal substrate for an electrode.

Hereinafter, examples and experimental examples will be described in more detail in order to specifically describe the present invention, but the present invention is not limited by these examples and experimental examples. The embodiments according to the present invention may be modified in various different forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. The embodiments of the present invention are provided to more completely describe the present invention to those of ordinary skill in the art.

Example

A nickel plate substrate (manufacturer: Nilaco, product name: NI-313323) was prepared, and after processing a pattern as shown in FIG. 2 on the prepared titanium substrate, multi-stage stamping was formed. The processed and molded substrate had a porosity of 0.6 and a thickness of 0.35 mm. Before forming the coating layer on the metal substrate, the substrate surface was sandblasted with aluminum oxide (White alumina, F120) at 0.8 kgf/cm2, and then put in 50% by weight H2SO4 aqueous solution heated to 90°C and treated for 3 minutes. Then, the metal substrate of Example 1 was prepared by washing with distilled water.

A coating composition was first prepared in order to perform coating on a metal substrate. As a solvent for the coating composition, a mixture of 1.5 ml of isopropyl alcohol and 1.5 ml of 2-butoxyethanol was used. 300 mg of ruthenium (III chloride, 127 mg of cerium (III nitrate hexahydrate _{), and platinum chloride (PtCl 4} ) was added so that the molar ratio to the ruthenium (III chloride) was 0.1, and then 1.5 at 50°C. After that, urea was further added so that the molar ratio to ruthenium (III chloride) was 0.31, and then further stirred for 18 hours at 50° C. The coating solution was brushed on the pretreated nickel substrate. Then, it was put in a convection drying oven and dried for 10 minutes at 180° C. After that, it was placed in an electric heating furnace at 500° C. for further heat treatment for 10 minutes, and the coating, drying and heat treatment processes were repeated eight more times, and finally Final heat treatment at 500° C. for 1 hour to prepare an electrode for electrolysis.

Comparative example

An existing nickel metal net substrate (manufacturer: Nilaco, product name: NI-318040) was used, and an electrode was manufactured through the same procedure as in Example 1.

The porosity, the shape of the pores, and the thickness of the substrate of the above-described Examples and Comparative Examples are summarized in Table 1 below.

Porosity Pore shape Thickness(mm) Example 0.60 Trapezoid/parallelogram 0.35 Comparative example 0.61 Mesh structure (40mesh) 0.30

Experimental Example 1. Voltage measurement

In order to confirm the performance of the prepared electrode, a voltage measurement experiment was performed in Chlor-Alkali Electrolysis. A 30.7% NaOH aqueous solution was used as the cathode electrolyte, and 350 g/L NaCl aqueous solution was used as the anode electrolyte, and the flow rates were set to 15 ml/min, respectively. The cell temperature was maintained at 90° C., and the voltage was measured under the condition of a ^{current density of 0.62 A/cm 2.} When configuring the cell, the electrode of the example was elastically deformed and the thickness was compressed to 0.20 mm.

Each electrode area used in the experiment was 5*5 cm ² , and the electrodes of Example 1 and Comparative Example 1 were used as the cathode, and Asahi-Kasei's commercial DSA (Dimensionally Stable Anode) was used as the anode, and the separator. Asahi-Kasei's commercial Aciplex F6808 was used.

electrode Example Comparative example Voltage(mV) 3.105 3.131

From Table 2, it was confirmed that the electrode of the example of the present invention exhibits a lower overvoltage than the electrode of the comparative example, from which the electrode of the present invention was made of an expanded titanium substrate that was generally used (Comparative Example). It was confirmed that it is more energy efficient than that.

Claims (8)

Flat part; And an arcuate curved surface portion having a plurality of polygonal pores,
The flat portion and the curved portion are arranged at an intersection
The polygonal pores are metal substrates for electrodes having an acute angle of less than 90˚.
The method of claim 1,
The metal substrate for an electrode is capable of elastic deformation up to a thickness of 80 to 120% of the thickness of the substrate.
The method of claim 1,
The polygon is a metal substrate for an electrode that has a trapezoidal shape or a parallelogram shape having an acute angle portion.
The method of claim 3,
The angle of the acute angle portion is 30 to 80 ° for the electrode metal substrate.
The method of claim 1,
The metal substrate for the electrode will have a porosity of 0.3 to 0.7.
The method of claim 1,
The thickness of the substrate is a metal substrate for an electrode that is less than 1mm.
Processing a polygonal pattern on the surface of the metal substrate through etching or punching (S1); And
Method of manufacturing a metal substrate for an electrode comprising a; step of stamping multi-stage molding according to the pattern (S2).
The method of claim 7,
The polygon is a method of manufacturing a metal substrate for an electrode that has a trapezoidal shape or a parallelogram shape having an acute angle portion.

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