KR102203753B1 - Electrode for fuel cells and manufacturing method thereof - Google Patents

Abstract

The present invention relates to an electrode for a high temperature polymer electrolyte membrane fuel cell and a method for manufacturing the same, comprising: a first platinum nanoparticle layer on a carbon support; And a second platinum nanoparticle layer formed on the first platinum nanoparticle layer to provide a high-temperature polymer electrolyte membrane fuel cell electrode capable of realizing excellent fuel cell performance, and a method of manufacturing the same.

Description

Electrode for fuel cell and manufacturing method thereof {ELECTRODE FOR FUEL CELLS AND MANUFACTURING METHOD THEREOF}

The present invention relates to an electrode for a high temperature polymer electrolyte membrane fuel cell and a method for manufacturing the same, and relates to an electrode for a high temperature polymer electrolyte membrane fuel cell including a platinum nanoparticle layer capable of improving the performance of the fuel cell, and a method of manufacturing the same.

A polymer electrolyte membrane fuel cell is a power generation device that generates water by using hydrogen at an oxidation electrode and air or oxygen at a reduction electrode as a reactant.

Among polymer electrolyte membrane fuel cells, in particular, high temperature polymer electrolyte membrane fuel cells dramatically increase the resistance to carbon monoxide in hydrogen fuel due to a relatively high driving temperature (120 ℃ to 180 ℃), making it possible to use less purified hydrogen fuel. There is an advantage such as an increase in the reaction speed and an increase in power generation efficiency.

On the other hand, in a high-temperature polymer electrolyte membrane fuel cell, because a moisture-containing Nafion membrane, which is generally used as an electrolyte membrane, cannot be used due to the high driving temperature, a polymer membrane impregnated with phosphoric acid capable of maintaining the conductivity of ions even at high temperatures is used. use.

However, when a polymer membrane impregnated with phosphoric acid is used as an electrolyte membrane, phosphoric acid, which is used as an electrolyte when the fuel cell is driven, flows to the electrode and poisons the surface of the platinum catalyst, thereby reducing the active area of the platinum catalyst. In addition, due to the uneven distribution of phosphoric acid in the electrode layer, the three-phase interface formed by the catalyst, reactant, and electrolyte (phosphoric acid) decreases, thereby inhibiting the catalytic reaction.

Accordingly, there is a need for an electrode capable of improving the performance of a high-temperature polymer electrolyte membrane fuel cell by improving the distribution of phosphoric acid in the electrode layer and allowing a catalytic reaction to occur well.

Patent Publication No. 10-2015-0026326

An object of the present invention is to provide an electrode for a high-temperature polymer electrolyte membrane fuel cell having excellent activity.

However, the problem to be solved by the present invention is not limited to the above-mentioned problems, and other problems that are not mentioned will be clearly understood by those skilled in the art from the following description.

An exemplary embodiment of the present invention is a first platinum nanoparticle layer on a carbon support; And a second platinum nanoparticle layer formed on the first platinum nanoparticle layer, wherein a mass activity ratio of the second platinum nanoparticle layer to the first platinum nanoparticle layer is 5 to 15 times in an air condition. It provides an electrode for a high-temperature polymer electrolyte membrane fuel cell.

Another exemplary embodiment of the present invention includes preparing a plating solution containing a platinum precursor and an electrolyte; Disposing a working electrode, a counter electrode, and a reference electrode including a first platinum nanoparticle layer on a carbon support in the plating solution; And forming a second platinum nanoparticle layer by pulse electrodepositing platinum on the first platinum nanoparticle layer by applying a voltage; a method of manufacturing an electrode for a high-temperature polymer electrolyte membrane fuel cell according to an exemplary embodiment of the present invention comprising: to provide.

A fuel cell including an electrode for a high-temperature polymer electrolyte membrane fuel cell according to an exemplary embodiment of the present invention has excellent performance.

A method of manufacturing an electrode for a high-temperature polymer electrolyte membrane fuel cell according to another exemplary embodiment of the present invention forms an electrode capable of realizing excellent fuel cell performance through a simple process.

1 is a view showing images of the surfaces of an oxide electrode and a reduction electrode of Examples 1 to 5 and Comparative Example 1. FIG.
2 is an image showing a contact angle of an electrode according to an embodiment and a comparative example of the present invention to ultrapure water.
3(a) is a graph showing a Nyquist plot of a membrane electrode assembly according to an embodiment and a comparative example of the present invention measured while injecting hydrogen into an anode and air into a cathode. to be.
3(b) is a graph showing a Nyquist plot of a membrane electrode assembly according to an embodiment and a comparative example of the present invention, measured while injecting hydrogen into an anode and oxygen into a cathode.
4 is a graph showing a cyclic voltammogram of a membrane electrode assembly according to Examples and Comparative Examples of the present invention.
5A is a graph showing a polarization curve of a high-temperature polymer electrolyte membrane fuel cell according to Examples and Comparative Examples of the present invention measured while injecting hydrogen into an anode and air into a cathode.
5B is a graph showing the maximum output of a high-temperature polymer electrolyte membrane fuel cell according to Examples and Comparative Examples of the present invention measured while injecting hydrogen into an anode and air into a cathode.
5C is a graph showing a polarization curve of a high-temperature polymer electrolyte membrane fuel cell according to Examples and Comparative Examples of the present invention measured while injecting hydrogen into an anode and oxygen into a cathode.
5D is a graph showing the maximum output of a high-temperature polymer electrolyte membrane fuel cell according to Examples and Comparative Examples of the present invention measured while injecting hydrogen into an anode and oxygen into a cathode.
6(a) is a graph showing the activity per unit mass of platinum of a high-temperature polymer electrolyte membrane fuel cell according to Examples and Comparative Examples of the present invention measured while injecting hydrogen into an anode and air into a cathode.
6(b) is a graph showing the activity per unit mass of platinum of a high-temperature polymer electrolyte membrane fuel cell according to Examples and Comparative Examples of the present invention measured while injecting hydrogen into an anode and oxygen into a cathode.

When a member is referred to herein as being “on” another member, this includes not only the case where a member is in contact with another member, but also the case where another member exists between the two members.

In the present specification, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components unless otherwise stated.

In the present specification, "mass activity" means the performance of the fuel cell per unit mass of platinum used in the electrode (mW/mg _Pt ).

An exemplary embodiment of the present invention is a first platinum nanoparticle layer on a carbon support; And it provides a high temperature polymer electrolyte membrane fuel cell electrode comprising a second platinum nanoparticle layer formed on the first platinum nanoparticle layer.

According to an exemplary embodiment of the present invention, an activity ratio per mass of the second platinum nanoparticle layer to the first platinum nanoparticle layer is 5 to 15 times in an air condition. Specifically, an activity ratio per mass of the second platinum nanoparticle layer to the first platinum nanoparticle layer may be 5 times to 14.5 times or 10.5 to 14.5 times in air condition. When the activity ratio per mass in the air condition is within the above range, the high-temperature polymer electrolyte membrane fuel cell including the electrode on which the second platinum nanoparticle layer is formed may have excellent performance.

According to an exemplary embodiment of the present invention, an activity ratio per mass of the second platinum nanoparticle layer to the first platinum nanoparticle layer may be 1.5 to 13 times in an oxygen condition. Specifically, an activity ratio per mass of the second platinum nanoparticle layer to the first platinum nanoparticle layer may be 1.8 to 13 times, 1.8 to 3.2 times, or 12.2 to 13 times under oxygen conditions. When the activity ratio per mass in the oxygen condition is within the above range, the high-temperature polymer electrolyte membrane fuel cell including the fuel electrode on which the second platinum nanoparticle layer is formed may have excellent performance.

According to an exemplary embodiment of the present invention, the electrode may be an oxidation electrode or a reduction electrode. Preferably it may be an oxide electrode.

According to an exemplary embodiment of the present invention, the carbon support may be carbon powder, carbon paper, carbon cloth, etc., but is not limited thereto, and carbon generally used in the art. It can be a support.

According to an exemplary embodiment of the present invention, in the first platinum nanoparticle layer, platinum nanoparticles having an average particle size of 2 nm to 6 nm may be uniformly formed on a carbon support. The carbon support on which the first platinum nanoparticle layer is formed may have a total thickness of 80 μm. However, it is not limited thereto.

According to an exemplary embodiment of the present invention, the nanoparticles included in the first platinum nanoparticle layer may be platinum nanoparticles or platinum alloy nanoparticles. The platinum alloy nanoparticles may be, for example, platinum-nickel alloy nanoparticles.

According to an exemplary embodiment of the present invention, the second platinum nanoparticle layer may include platinum nanoparticles having an average particle size of 10 nm to 50 nm. Specifically, the nanoparticles included in the second platinum nanoparticle layer may have an average particle size of 10nm to 30nm, 10nm to 20nm, 20nm to 30nm, 30nm to 50nm, 30nm to 40nm, or 40nm to 50nm. When the average particle size of the platinum nanoparticles of the second platinum nanoparticle layer is within the above range, the active surface area of the electrode including the same may be increased, the surface hydrophilicity may be increased, and thus the distribution of phosphoric acid in the electrode layer is uniform. It can be done. In conclusion, the fuel cell including the electrode including the platinum nanoparticles of the second platinum nanoparticle layer may implement excellent performance.

According to an exemplary embodiment of the present invention, the electrode may include a second platinum nanoparticle layer in which uniform platinum nanoparticles are formed on the first platinum nanoparticle layer. As the uniform platinum nanoparticles are additionally formed on the first platinum nanoparticle layer, the active surface area of the platinum catalyst included in the electrode may increase, thereby increasing the activity of the electrode.

According to an exemplary embodiment of the present invention, the contact angle of the electrode to water may be 60° to 120°. Specifically, the contact angle of the electrode with water, for example, ultrapure water, may be 60° to 80°, 60° to 75°, 70° to 120°, 75° to 120°, or 70° to 80°. The contact angle of an electrode having a platinum nanoparticle layer on a generally used carbon support with water is 130° to 140°. The electrode according to an exemplary embodiment of the present invention further includes a second platinum nanoparticle layer on the first platinum nanoparticle layer on a carbon support, thereby increasing the hydrophilicity of the electrode surface. When the contact angle of the electrode is within the above range, the three-phase interface in the electrode can be increased by uniformly distributing phosphoric acid in the first and second platinum nanoparticle layers of the electrode due to the increase in hydrophilicity of the electrode surface, including the electrode. It is possible to implement a reduction in resistance of the membrane electrode assembly.

Another exemplary embodiment of the present invention includes preparing a plating solution containing a platinum precursor and an electrolyte; Disposing a working electrode, a counter electrode, and a reference electrode including a first platinum nanoparticle layer on a carbon support in the plating solution; And forming a second platinum nanoparticle layer by pulse electrodepositing platinum on the first platinum nanoparticle layer by applying a voltage; a method of manufacturing an electrode for a high-temperature polymer electrolyte membrane fuel cell according to an exemplary embodiment of the present invention comprising: to provide.

According to an exemplary embodiment of the present invention, the plating solution may be prepared by adding the platinum precursor and the electrolyte to distilled water, stirring, and purging with nitrogen gas. The stirring may be performed by adding a magnetic bar to the solution and using a magnetic stirrer, but is not limited thereto. When the plating solution is purged with the nitrogen gas, gases dissolved in the plating solution may be removed to prevent the presence of impurities. The step of preparing the plating solution may be performed under conditions of room temperature and pressure.

According to an exemplary embodiment of the present invention, the platinum precursor is potassium tetrachloroplatinate (K ₂ PtCl ₄ ), chloroplatinic acid hydrate (Chloroplatinic acid hydrate, H ₂ PtCl ₆ xH ₂ O), for example, chloroplatinic acid. Hexahydrate (Chloroplatinic acid hexahydrate, H ₂ PtCl ₆ 6H ₂ O), platinum chloride, such as platinum (II) (PtCl ₂ ) or platinum chloride (IV) (PtCl ₄ ), platinum acetylaceto Nate (Platinum acetylacetonate, Pt(C ₅ H ₇ O ₂ ) ₂ )), platinum bromide, such as platinum (II) bromide (PtBr ₂ ) or platinum bromide (IV) (PtBr ₄ ), and platinum diaminedichloride ( Platinum diamine dichloride, Pt(NH ₃ ) ₂ Cl ₂ ) It may be one or more selected from. Specifically, the platinum precursor may be potassium tetrachloroplatinate.

According to an exemplary embodiment of the present invention, the platinum precursor may be included in the plating solution at a concentration of 0.1mM to 100mM. Specifically, the concentration of the platinum precursor may be 0.1mM to 50mM, 0.1mM to 30mM, 0.1mM to 10mM, 1mM to 10mM, 1mM to 5mM, 1mM to 3mM or 3mM to 5mM. When the concentration of the platinum precursor is within the above range, the size and amount of platinum nanoparticles included in the second platinum nanoparticle layer can be adjusted, and a high-temperature polymer electrolyte membrane fuel including a fuel electrode on which the second platinum nanoparticle layer is formed The battery can be excellent in performance.

According to an exemplary embodiment of the present invention, the electrolyte is one selected from sodium chloride (NaCl), potassium chloride (KCl), potassium hydroxide (KOH), sodium hydroxide (NaOH), sulfuric acid (H ₂ SO ₄ ) and hydrochloric acid (HCl) It can be more than that. When the electrolyte is used, it is possible to facilitate electrodeposition of the second platinum nanoparticle layer on the first platinum nanoparticle layer.

According to an exemplary embodiment of the present invention, a three-electrode system may be used when the platinum is pulse electrodeposited. Accordingly, a working electrode, a counter electrode, and a reference electrode can be disposed in the plating solution.

According to an exemplary embodiment of the present invention, the working electrode may be a carbon paper coated with a platinum to platinum alloy electrode layer, a carbon cloth coated with a platinum to platinum alloy electrode layer, or the like. In addition, the electrode layer may be formed on the carbon powder in the form of round particles of platinum or platinum alloy. However, it is not limited thereto. The commercially available working electrode may be, for example, BASF Celtec ^® Gas Diffusion Electrode.

According to an exemplary embodiment of the present invention, the counter electrode may be one selected from a platinum wire, a platinum plate, a platinum mesh, a graphite rod, and a glassy carbon.

According to an exemplary embodiment of the present invention, the reference electrode may be a saturated calomel electrode. However, it is not limited thereto.

According to an exemplary embodiment of the present invention, when a voltage is applied to the three-electrode system, platinum ions present in the plating solution are reduced at the working electrode, and platinum is electrodeposited on the working electrode to form a second platinum nanoparticle layer.

According to an exemplary embodiment of the present invention, in the pulse electrodeposition, the voltage is applied from 0.3V to 0.5V for 1 second to 3 seconds, -1.0V to -0.8V for 5 seconds to 15 seconds and 0.3V based on the saturated calomel electrode. 2 to 4 seconds are sequentially applied at 0.5V to one cycle. Specifically, the one cycle may be to apply a voltage at 0.4V for 2 seconds, -0.9V for 10 seconds, and 0.4V for 3 seconds based on the saturated calomel electrode. When the voltage is applied as described above, uniform platinum nanoparticles may be formed. Accordingly, the active surface area of the platinum catalyst included in the electrode may increase. In addition, phosphoric acid is evenly distributed in the electrode layer due to the increase in surface hydrophilicity, and a uniform three-phase interface can be formed.

According to an exemplary embodiment of the present invention, the pulse electrodeposition may mean electrodeposition by applying a voltage by repeating the one cycle 50 to 500 times. Specifically, the pulse electrodeposition may be electrodeposition by applying a voltage by repeating the one cycle 50 to 300 times, 50 to 100 times, or 100 to 300 times. When the second platinum nanoparticle layer is electrodeposited by applying a voltage by repeating the above one cycle a number of times within the above range, platinum is uniformly formed, so that the active surface area of the platinum catalyst included in the electrode may increase. In addition, phosphoric acid is evenly distributed in the electrode layer due to the increase in surface hydrophilicity, and a uniform three-phase interface can be formed. Accordingly, the high-temperature polymer electrolyte membrane fuel cell including the electrode on which the second platinum nanoparticle layer is formed may have excellent performance.

According to an exemplary embodiment of the present invention, the step of forming the second platinum nanoparticle layer may be performed under conditions of room temperature and pressure.

Another embodiment of the present invention is an oxide electrode; Reduction electrode; And it provides a high-temperature polymer electrolyte membrane fuel cell comprising an electrolyte membrane positioned between the anode and the cathode, the anode, or the anode and the cathode are electrodes according to an exemplary embodiment of the present invention.

According to an exemplary embodiment of the present invention, the high-temperature polymer electrolyte membrane fuel cell includes compression plates, current collectors, bipolar plates, gas diffusion layers, membrane electrode assemblies, gas diffusion layers, positive plates, and houses. The whole and compression plates may be sequentially stacked.

According to an exemplary embodiment of the present invention, the membrane electrode assembly may be one in which the oxide electrode according to the present invention, the electrolyte membrane, and the reduction electrode according to the present invention are sequentially bonded. The membrane electrode assembly may be an anode, or both an anode and a cathode may be electrodes according to an embodiment of the present invention. The electrolyte membrane may be a polymer layer impregnated with phosphoric acid. The commercialized electrolyte membrane may be, for example, a BASF Celtec ^® membrane impregnated with phosphoric acid.

According to an exemplary embodiment of the present invention, a membrane electrode assembly can be manufactured by bonding an electrolyte membrane between an anode and a cathode, which are electrodes manufactured by forming a second platinum nanoparticle layer on the first platinum nanoparticle layer of the working electrode. have. Before bonding the oxide electrode and the reduction electrode to the electrolyte membrane, the electrolyte membrane may be dried in a high-temperature dryer. Drying the electrolyte membrane may be drying for 30 minutes to 2 hours at a temperature of 100 ℃ to 150 ℃.

According to an exemplary embodiment of the present invention, a high temperature polymer electrolyte membrane fuel cell may be manufactured by bonding the membrane electrode assembly with a flow path using a Teflon gasket and a polyimide gasket.

Hereinafter, examples will be described in detail to illustrate the present invention in detail. However, the embodiments according to the present invention may be modified in various other forms, and the scope of the present invention is not construed as being limited to the embodiments described below. The embodiments of the present specification are provided to more completely describe the present invention to those of ordinary skill in the art.

Example One

Using platinum pulse electrodeposition Oxide electrode Produce

Prepare an aqueous solution containing 3mM K ₂ PtCl ₄ (Alfa Aesar, 43946) as a platinum precursor and 0.5M NaCl (Daejung, 7548-4100) as an electrolyte, and purged with nitrogen gas for 30 minutes or longer to remove dissolved gases in the aqueous solution. Thus, a plating solution was prepared. Wherein in the plating solution, to form a first platinum nanoparticle layer BASF Celtec ^® Gas Diffusion Electrode, a platinum wire as a counter electrode, reference electrode and three-electrode system by placing a saturated calomel electrode as a working electrode comprising a.

Applying voltage to the three-electrode system sequentially for 2 seconds at 0.4V, 10 seconds at -0.9V, and 3 seconds at 0.4V based on the saturated calomel electrode as one cycle, and repeating the above one cycle 50 times By applying, platinum was electrodeposited on the first platinum nanoparticle layer of the BASF Celtec ^® commercial oxide electrode to prepare an oxide electrode having a second platinum nanoparticle layer formed thereon.

All steps were carried out at room temperature and pressure.

Manufacture of Membrane Electrode Assembly

A commercial BASF Celtec ^® membrane impregnated with phosphoric acid was dried in a dryer at 120° C. for 1 hour to prepare an electrolyte membrane.

The platinum pulse electrodeposition and the oxidizing electrode, bonding the electrolyte membrane and BASF Celtec ^® commercial reduction electrode was prepared using a membrane-electrode assembly manufacturing. Each electrode had an area of 1 cm ² .

Manufacture of high temperature polymer electrolyte membrane fuel cell

A high-temperature polymer electrolyte membrane fuel cell was manufactured by bonding the membrane electrode assembly with a flow path with a torque of 50 N·m using a 340 μm Teflon gasket and a 25 μm polyimide gasket.

Example 2

When manufacturing an anode using platinum pulse electrodeposition, a membrane electrode assembly and a polymer electrolyte membrane fuel cell were manufactured in the same manner as in Example 1, except that the anode was manufactured by applying a voltage by repeating the above one cycle 100 times. .

Example 3

When manufacturing an anode using platinum pulse electrodeposition, a membrane electrode assembly and a polymer electrolyte membrane fuel cell were manufactured in the same manner as in Example 1, except that the anode was manufactured by applying a voltage by repeating the above one cycle 300 times. .

Example 4

When manufacturing an anode using platinum pulse electrodeposition, a membrane electrode assembly and a polymer electrolyte membrane fuel cell were manufactured in the same manner as in Example 1, except that the anode was manufactured by applying a voltage by repeating the above one cycle 500 times. .

Example 5

When manufacturing an anode using platinum pulse electrodeposition, the anode was manufactured by applying voltage by repeating the above one cycle 100 times, and platinum on the BASF Celtec ^® commercial cathode instead of the BASF Celtec ^® commercial cathode as the cathode. A membrane electrode assembly and a polymer electrolyte membrane fuel cell were manufactured in the same manner as in Example 1, except that the cathode prepared by pulse electrodeposition was used.

The method of platinum pulse electrodeposition on the BASF Celtec ^® commercial cathode electrode was carried out in the same manner as the method of platinum pulse electrodeposition to prepare an oxide electrode in Example 1.

Comparative example One

A membrane electrode assembly and a polymer electrolyte membrane fuel cell were manufactured in the same manner as in Example 1, except that a BASF Celtec ^® commercial anode was used as the anode, not manufactured by using the platinum pulse plating.

Experimental example 1-FE- on the electrode surface SEM Image measurement

In order to confirm the size and shape of the platinum nanoparticles of the oxide and reduction electrodes of Examples 1 to 5 and Comparative Example 1, an image of the surface was measured with FE-SEM (SIGMA, Carl Zeiss).

1 is a view showing images of the surfaces of an oxide electrode and a reduction electrode of Examples 1 to 5 and Comparative Example 1. FIG. Table 1 shows the sizes of platinum nanoparticles included in the second platinum nanoparticle layer formed on the first platinum nanoparticle layer identified from the FE-SEM image.

In the case of the oxide electrode of Examples 1 to 5 and the reduction electrode of Example 5, it can be seen that platinum nanoparticles are uniformly electrodeposited on the first platinum nanoparticle layer to form a second platinum nanoparticle layer. The reason that the size of the platinum particles formed on the cathode of Example 5 is larger than the size of the platinum particles formed on the oxide electrodes of Examples 1 to 5 is that the platinum-nickel alloy nanoparticles present in the first platinum nanoparticle layer of the commercial cathode This is because heavy nickel can cause a substitution electrodeposition reaction with the platinum precursor in the pulse electrodeposition process.

Experimental example 2-of the electrode Contact angle Measure

The contact angles of the oxide and reduction electrodes of Examples 1 to 5 and Comparative Example 1 for ultrapure water were measured by FM40Mk2 EasyDrop (KRUSS GmbH Germany).

Images showing the contact angles of the oxide and reduction electrodes of Examples 1 to 5 and Comparative Example 1 with respect to ultrapure water are shown in FIG. 2 and the contact angles are shown in Table 1 below.

Experimental example 3-Evaluation of resistance of membrane electrode assemblies according to electrochemical impedance analysis (EIS)

Example 2, while injecting hydrogen into the anode and air or oxygen into the cathode, measuring the impedance with an electrochemical impedance spectroscopy (Autolab PGSTAT302N, Metrohm Corp.) at a constant voltage of 0.75 V with an amplitude of 5 mV in the range of 10 kHz to 0.01 Hz. The resistance of the membrane electrode assembly according to Example 5 and Comparative Example 1 was evaluated.

Figure 3(a) shows the Nyquist plot graphs of the membrane electrode assemblies according to Examples 2, 5, and 1, measured while injecting hydrogen into the anode and air into the cathode, and Fig. 3(b) shows Nyquist plot graphs of the membrane electrode assemblies according to Examples 2, 5, and 1, measured while oxygen is injected into the cathode. In addition, the evaluated resistance is shown in Table 1 below.

Experimental example 4 -Evaluation of electrochemical active surface area of membrane electrode assembly

Using an electrochemical measuring instrument (Autolab PGSTAT302N, Metrohm) by cyclic voltammetry, injecting hydrogen into the anode at 0.1 L/min and nitrogen into the cathode at 0.3 L/min, while the working electrode with the cathode as the counter electrode. The anode was connected to the and reference electrode, and the electrochemically active surface area of the membrane electrode assembly was evaluated by measuring the current generated while changing the voltage at a rate of 200 mV/s in the voltage range of 0.05V to 1.2V.

A cyclic voltammogram graph of the membrane electrode assemblies according to Examples 2, 5 and Comparative Example 1 measured according to the cyclic voltammetry method is shown in FIG. 4. In addition, the electrochemically active surface area is shown in Table 1 below.

Experimental example 5-High-temperature polymer electrolyte membrane fuel cell performance evaluation

After purging the high-temperature polymer electrolyte membrane fuel cells according to Examples 1 to 5 and Comparative Example 1 with nitrogen at 150° C. for 20 minutes, hydrogen was injected at 150° C. to the oxidation electrode at 0.1 L/min, and air to the reduction electrode. Alternatively, oxygen was injected at 0.3 L/min.

The high-temperature polymer electrolyte membrane fuel from the polarization curve of the fuel cell obtained by increasing the current by 20 mA/cm ² for 1 minute after driving the unit cell at a voltage fixed at 0.6 V for 3 hours to activate the membrane electrode assembly. The performance of the fuel cell was evaluated by checking the maximum output of the cell.

A graph showing the polarization curve and maximum output of the high-temperature polymer electrolyte membrane fuel cells according to Examples 1 to 5 and Comparative Example 1 measured while injecting hydrogen into the anode and air or oxygen into the cathode is shown in FIG. 5. In addition, the maximum output is shown in Table 1.

Experimental example 6-Evaluation of activity per unit mass of platinum

Using an inductively coupled plasma mass spectrometer (ICP-MS, NexION300, PerkinElmer), the total mass of platinum formed on the electrode was calculated, and the output of the high-temperature polymer electrolyte membrane fuel cell obtained in Experimental Example 5 was divided by the mass of platinum, and the platinum unit The activity per mass was determined.

A graph showing the activity per unit mass of platinum of the high-temperature polymer electrolyte membrane fuel cells according to Examples 1 to 3, 5 and Comparative Example 1 measured while injecting hydrogen into the oxidation electrode and air or oxygen into the reduction electrode is shown. It is shown in 6. In addition, the activity per unit mass of platinum is shown in Table 1.

Contact angle (°) Resistance (Ω) Electrochemically active surface area
(m ² /g) Output
(mW/cm ² ) Active per unit mass of platinum (mW/mg _pt ) Oxide electrode Reduction pole In case of injecting air into the cathode When oxygen is injected into the cathode In case of injecting air into the cathode When oxygen is injected into the cathode In case of injecting air into the cathode When oxygen is injected into the cathode Example 1 118.6 141.5 - - - 446.3 698.0 259.5 405.8 Example 2 79.5 141.5 0.392 0.417 5.49 473.3 748.3 276.5 437.1 Example 3 73.6 141.5 - - - 443.0 598.0 250.4 338.0 Example 4 63.8 141.5 - - - 415.0 557.5 - - Example 5 79.5 112.0 0.788 0.877 1.63 445.5 645.6 252.3 365.6 Comparative Example 1 137.6 141.5 0.867 0.896 1.60 319.6 532.5 192.9 321.4

It can be seen that the hydrophilicity of the electrode surface increases from the respective contact angle values of the anodes of Examples 1 to 5 and the cathode of Example 5 including the second platinum nanoparticle layer, and accordingly, the phosphoric acid behavior in the electrode layer is changed. Occurs, and the three-phase interface increases due to the uniform distribution of phosphoric acid. Accordingly, it can be seen that the resistance of the membrane electrode assembly including the oxide electrode and the reduction electrode decreases, and the performance of the fuel cell can be increased.

In addition, by including the second platinum nanoparticle layer in the electrode through platinum electroplating, the electrochemically active surface area of the membrane electrode assembly including the electrode is increased, and such an increase in the active surface area is a high temperature polymer electrolyte including the membrane electrode assembly. It can be seen that it contributes to the increase in the performance of the membrane fuel cell. That is, it can be seen that the maximum output of the high-temperature polymer electrolyte membrane fuel cell and the activity per unit mass of platinum are all superior to that of Comparative Example 1 which does not include an electrode according to an exemplary embodiment of the present invention.

When comparing the activity per mass by the first platinum nanoparticle layer and the activity per mass by the second platinum nanoparticle layer, the maximum output is 319.6 mW/cm when the total amount of platinum used in both electrodes of Comparative Example 1 is 1.657 mg under air conditions. ² shows an activity per mass of 192.9 mW/mg _Pt , whereas in Example 2, the amount of platinum plated on the second platinum nanoparticle layer was about 0.055 mg, and the total amount of the first platinum nanoparticle layer and the second platinum nanoparticle layer When the platinum content is 1.712mg, the maximum output is 473.3mW/cm ² , and thus the activity per mass of 276.5mW/mg _Pt is shown. In this case, the activity per mass of platinum added to the increase in performance due to the formation of the second platinum nanoparticle layer is 2794.5mW/mg _{Pt, which} is approximately 15 times higher than the activity per mass of the first platinum nanoparticle layer. Seems to represent. This phenomenon is not simply due to the high catalytic activity of the second platinum nanoparticle layer, but also the activity of the first platinum nanoparticle layer due to the change of the phosphoric acid behavior in the first platinum nanoparticle layer through platinum electroplating, and the expansion of the three-phase interface. Because it increased.

Therefore, the membrane electrode assembly including the electrode according to the exemplary embodiment of the present invention has low resistance and excellent electrochemical activity, and the high-temperature polymer electrolyte membrane fuel cell including the membrane electrode assembly has a high maximum output and a platinum per unit mass. Since the activity is excellent, it can be seen that the electrode improves the performance of the high-temperature polymer electrolyte membrane fuel cell.

Claims (10)

A first platinum nanoparticle layer on a carbon support; And
Including a second platinum nanoparticle layer formed on the first platinum nanoparticle layer,
The mass activity ratio of the second platinum nanoparticle layer to the first platinum nanoparticle layer is 5 to 15 times in air condition,
The contact angle with water is 70° to 120°,
The second platinum nanoparticle layer is an electrode for a high temperature polymer electrolyte membrane fuel cell comprising platinum nanoparticles having an average particle size of 10 nm to 50 nm. The method of claim 1,
An electrode for a high temperature polymer electrolyte membrane fuel cell in which an activity ratio per mass of the second platinum nanoparticle layer to the first platinum nanoparticle layer is 1.5 to 13 times in an oxygen condition. delete delete Preparing a plating solution containing a platinum precursor and an electrolyte;
Disposing a working electrode, a counter electrode, and a reference electrode including a first platinum nanoparticle layer on a carbon support in the plating solution; And
The electrode for a high-temperature polymer electrolyte membrane fuel cell according to any one of claims 1 and 2 comprising a step of forming a second platinum nanoparticle layer by pulse electrodepositing platinum on the first platinum nanoparticle layer by applying a voltage Method of manufacturing. The method of claim 5,
The platinum precursor is potassium tetrachloroplatinate (K ₂ PtCl ₄ ), chloroplatinic acid hydrate (H ₂ PtCl ₆ xH ₂ O), platinum chloride (Platinum chloride), platinum acetylacetonate (Platinum acetylacetonate, Pt(C ₅ H ₇ O ₂ ) ₂ )), platinum bromide and platinum diamine dichloride (Platinum diamine dichloride, Pt(NH ₃ ) ₂ Cl ₂ ) A method of manufacturing an electrode for a high-temperature polymer electrolyte membrane fuel cell, which is one or more selected from. The method of claim 5,
The platinum precursor is a method of manufacturing an electrode for a high-temperature polymer electrolyte membrane fuel cell contained in the plating solution at a concentration of 0.1mM to 100mM. The method of claim 5,
The electrolyte is one or more selected from sodium chloride (NaCl), potassium chloride (KCl), potassium hydroxide (KOH), sodium hydroxide (NaOH), sulfuric acid (H ₂ SO ₄ ), and hydrochloric acid (HCl). Manufacturing method. The method of claim 5,
The counter electrode is one selected from a platinum wire, a platinum plate, a platinum mesh, a graphite rod, and a glassy carbon. A method of manufacturing an electrode for a high-temperature polymer electrolyte membrane fuel cell. Oxide electrode; Reduction electrode; And an electrolyte membrane positioned between the oxidation electrode and the reduction electrode,
The high temperature polymer electrolyte membrane fuel cell wherein the oxide electrode, or the oxide electrode and the reduction electrode is an electrode according to any one of claims 1 and 2.

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