CN102088089A - Preparation method of combined electrode of fuel cell and test device thereof - Google Patents

Abstract

The invention discloses a preparation method and a testing device for a composite electrode of a fuel cell. Its steps are as follows: On the rectangular substrate of carbon paper or thin nickel foam cut into the size of 30mm*50mm, respectively prepare single-wall or multi-wall carbon nanotube films to make composite electrodes. Using graphite rods or graphite plates as anodes and composite electrodes as cathodes, one or more of the metal catalysts Pt, Pd, Mo, Ni, Co, Y, and Sn are sequentially plated on the surface of the composite electrodes. The time is 5s-50s, the temperature in the electroplating process is controlled at 40 degrees, and the catalyst layer is plated on the single-wall or multi-wall carbon nanotube film on the surface of the composite electrode, and the particle size of the metal catalyst is 5nm-5μm. The present invention adopts the single-walled carbon nanotube ultra-thin film prepared by the arc discharge method and the film made by screen printing the multi-walled carbon nanotube prepared by the CVD method. supported metal catalysts.

Description

Preparation method and test device of fuel cell composite electrode

technical field

The invention relates to a preparation method and a testing device for a composite electrode of a fuel cell.

Background technique

The fuel cell has a long history from its invention to the present. In the 1960s, the fuel cell was successfully applied to the Apollo (Appollo) moon landing spacecraft. Since the 1960s, hydrogen-oxygen fuel cells have been widely used in the aerospace field. At the same time, megawatt-level phosphoric acid fuel cells have also been successfully developed. Since the 1980s, various low-power batteries have been applied in various fields such as aerospace, military affairs, and transportation. After entering the 21st century, fuel cell technology has been perfected day by day. The international energy community predicts that fuel cells will be one of the most attractive power generation methods in the 21st century.

Fuel cell power generation is to directly convert the chemical energy of the fuel into electrical energy without combustion and without rotating parts. Theoretically, the energy conversion rate is 100%. Regardless of the size of the device, the actual power generation efficiency can reach 40% to 60%, and direct access to Enterprises, restaurants, hotels, and households realize cogeneration and utilization of heat and power, without power transmission and heat loss, and the overall energy efficiency can reach 80%. The device is an integrated structure, and the capacity can be as small as power supply for mobile phones, as large as the current thermal power generation Compared with the factory, it is very flexible.

The present invention is a research project of using advanced new material single-walled carbon nanotube film in fuel cell compound electrode, which is based on the use of super large surface area, good chemical stability and excellent mechanical properties of single-walled carbon nanotube film . This research is of great significance for the development of new, low-cost, and commercially promising fuel cells.

MEA is the electrochemical heart of proton membrane fuel cell (PEMFC). It is precisely because of its changes that PEMFC presents its vigorous vitality today. The amount of Pt used in early composite electrodes was as high as 10 mg/cm ² , and the utilization rate of Pt was very low. Later, in order to increase the utilization rate of Pt, a Pt/C catalyst was used, but the utilization rate of Pt was still very low. Until the mid-1980s, the Pt loading of PEMFC composite electrodes was still as high as 4mg/cm ² . In the mid-to-late 1980s, Los Alamos National Laboratory (LANL) in the United States proposed a new method, using Nafion proton exchange polymer solution to impregnate Pt/C porous gas diffusion electrode, and then hot pressing it on the proton exchange membrane to form a composite electrode. This method greatly improves the utilization rate of the precious metal Pt, and reduces the platinum loading amount of the composite electrode to 0.4 mg/cm ² . In 1992, LANL improved the method to further reduce the Pt loading of the composite electrode to 0.13 mg/cm ² . In 1995, the Indian Center for Electrochemical Energy Research (CEER) prepared a composite electrode with a Pt loading of 0.1 mg/cm ² by spraying and impregnating, and the performance was good. According to reports, in some single cells tested by LANL, the platinum loading on the composite electrode has dropped to 0.05mg/cm ² . Using the single-walled carbon nanotube film as a carrier will further reduce the amount of noble metal catalyst Pt.

my country's per capita energy resources are poor. At present, the power grid has changed from the main lack of electricity to the main lack of system reserve capacity, peak-shaving capacity, lagging power grid construction, and serious pollution from traditional power generation methods. Research and development of miniaturized fuel cell power generation is of great significance. , The combination of this power generation method with traditional large-scale units and large power grids will bring huge economic benefits to our country.

Fuel cells are an energy utilization method that is gradually being perfected. Its investment is constantly decreasing. At present, the foreign commercial price of PEMFC is 10,000 yuan/kW, and the price of PAFC is 21,000/kW. Domestic Fuyuan Company announces that its PEMFC accepts orders at a price of 10,000 yuan/kW. Other fuel cells have no commercial products in China. the

As an advanced new energy source, fuel cells will have great development. Fuel cell vehicles and electric bicycles will gradually enter the market with the rising oil prices; , can effectively inhibit the continuous pollution of the environment and global warming. Fuel cells, like solar cells, are bound to be popular.

Most of the metal catalysts used in fuel cells are noble metals, which causes the cost of fuel cells to be too high. Although fuel cells have many advantages, it is still difficult to promote and utilize them on a large scale. The present invention adopts relatively cheap single metal or binary and ternary metal alloys as much as possible, which can reduce the manufacturing cost of the fuel cell and is beneficial to the mass application of the fuel cell in various fields.

At present, the metal catalysts on the composite electrodes of fuel cells are mostly sprayed, smeared, pasted with glue, etc. As a result, there are many problems such as large consumption of precious metals and uneven distribution. In addition, it is difficult to effectively control the loading of metal catalysts. What is serious is that some of the above-mentioned methods are complicated in technology, and some of the metal catalysts have low efficiency. The invention adopts the electroplating method, can simply, quickly and effectively plate various metal catalysts on the composite electrode, and can control the time and voltage of electroplating, and adopts advanced carbon nanotubes with huge surface area Advanced materials such as thin films, to achieve advanced levels in terms of metal catalyst loading, catalytic efficiency, and composite electrode preparation technology. The self-developed fuel cell test device is used to meet the needs of fuel cell performance testing.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for preparing a composite electrode of a fuel cell and a testing device thereof.

The steps of the preparation method of fuel cell composite electrode are as follows

1) Cut carbon paper or thin nickel foam into several groups of rectangular substrates with a size of 30mm*50mm, use arc discharge method to directly synthesize single-walled carbon nanotubes on the substrate to make composite electrodes, and treat them with alcohol;

Or use the screen printing method to print multi-walled carbon nanotubes on carbon paper or thin nickel foam substrates to make composite electrodes;

2) The composite electrode is electroplated at a DC voltage of 0.5V to 5V, and the electroplating solution is sulfate or nitric acid containing one or more metals among Pt, Pd, Mo, Ni, Co, Y, and Sn as metal catalysts Salt solution, the anode is a graphite rod or graphite plate, the cathode is a composite electrode composed of carbon paper or thin nickel foam substrate and single-wall or multi-wall carbon nanotubes respectively, the plating time is 5s~50s, the temperature control during the electroplating process At 40 degrees, a catalyst layer is plated on the single-wall or multi-wall carbon nanotube film of the composite electrode, and the particle diameter of the metal catalyst is 5nm-5μm.

The sulfate or nitrate catalyst of one or more metals in the Pt, Pd, Mo, Ni, Co, Y, Sn consists of: Pt/Ni, Pt/Ni/Y, Pt/Ni/Co, Pt/Ni/Mo, Pt/Mo/Co, Pt/Ni/Sn, Pd/Ni, Pd/Ni/Mo, Pd/Ni/Y, Pd/Ni/Co, Pd/Mo/Co, Pd/Ni/ Sn.

The device used to test the performance of fuel cell composite electrodes includes upper electrode fixed metal plate, upper graphite electrode plate, upper composite electrode, proton exchange membrane, lower composite electrode, lower graphite electrode plate, lower electrode fixed metal plate, oxygen intake pipe, oxygen Exhaust pipe, catalyst layer, voltmeter, hydrogen exhaust pipe, hydrogen inlet pipe, bracket, manual control lift valve, thermocouple, temperature-controlled water tank, temperature-controlled heater, hydrogen humidifier outlet pipe, hydrogen humidifier, oxygen humidifier hydrogen flowmeter outlet pipe, hydrogen flowmeter, hydrogen flowmeter inlet pipe, oxygen flowmeter inlet pipe, oxygen flowmeter, oxygen flowmeter outlet pipe, oxygen humidifier inlet pipe, oxygen humidifier outlet pipe, hydrogen humidifier inlet Trachea and gas tank; the lower electrode fixing metal plate, the lower graphite electrode plate, the lower composite electrode, the proton exchange membrane, the upper composite electrode, the upper graphite electrode plate, the upper electrode fixing metal plate, the lower electrode The fixed metal plate is equipped with oxygen intake pipe and oxygen exhaust pipe, the upper electrode fixed metal plate is equipped with hydrogen exhaust pipe and hydrogen gas intake pipe, and the upper electrode fixed metal plate is equipped with a manual control lift valve, placed in a constant temperature control water tank There are hydrogen humidifiers and oxygen humidifiers. There is a temperature-controlled heater under the constant-temperature-controlled water tank. The hydrogen cylinder is connected to the inlet pipe of the hydrogen flowmeter. The outlet pipe of the hydrogen flowmeter is connected to the inlet of the hydrogen humidifier inlet. The inlet of the hydrogen humidifier It is connected to the hydrogen inlet pipe, the oxygen cylinder is connected to the oxygen flowmeter inlet pipe, the oxygen flowmeter outlet pipe is connected to the oxygen humidifier inlet pipe, the oxygen humidifier outlet pipe is connected to the oxygen inlet pipe, and the positive and negative poles of the voltmeter are respectively connected to the lower electrodes. The fixed metal plate is connected to the fixed metal plate of the upper electrode; the upper composite electrode and the lower composite electrode are provided with carbon paper or thinned foamed nickel substrate, and the carbon paper or thinned foamed nickel substrate is provided with a single wall or multiple The walled carbon nanotube film is provided with a catalyst layer on the single-walled or multi-walled carbon nanotube film.

The invention adopts advanced materials and a simple process to prepare hydrogen fuel cell composite electrodes, and studies the use of relatively cheap single metal or multiple metal alloys as catalysts, providing a cost-reducing method for fuel cell production and application. Ultra-thin films of single-walled carbon nanotubes prepared by arc discharge method and multi-walled carbon nanotubes prepared by CVD method are made into films by screen printing. These two films have super large surface area and electrical conductivity, and are suitable for efficient loading of metal catalysts .

Description of drawings

Figure 1(a) is a schematic diagram of the fuel cell testing device;

Figure 1(b) is an outline view of the temperature-controlled water tank of the present invention;

Fig. 1 (c) is the structural representation of hydrogen humidifier and oxygen humidifier of the present invention;

Fig. 1 (d) is the hydrogen flowmeter of the present invention, oxygen flowmeter structural representation;

Fig. 2 is the structural representation of upper electrode graphite electrode plate of the present invention;

Fig. 3 is the structural representation of lower electrode graphite electrode plate of the present invention;

Fig. 4 is an exploded schematic view of the upper composite electrode, the proton exchange membrane and the composite electrode of the present invention.

Detailed ways

The steps of the preparation method of fuel cell composite electrode are as follows

1) Cut carbon paper or thin nickel foam into several groups of rectangular substrates with a size of 30mm*50mm, and use arc discharge method to directly synthesize single-walled carbon nanotubes on the substrate (patent number: ZL 200810059552.4) to make composite electrodes, and treated with alcohol;

Or use the screen printing method to print multi-walled carbon nanotubes on carbon paper or thin nickel foam substrates to make composite electrodes;

2) The composite electrode is electroplated at a DC voltage of 0.5V to 5V, and the electroplating solution is sulfate or nitric acid containing one or more metals among Pt, Pd, Mo, Ni, Co, Y, and Sn as metal catalysts Salt solution, the anode is a graphite rod or graphite plate, the cathode is a composite electrode composed of carbon paper or thin nickel foam substrate and single-wall or multi-wall carbon nanotubes respectively, the plating time is 5s~50s, the temperature during the electroplating process The temperature is controlled at 40 degrees, and a catalyst layer is plated on the single-wall or multi-wall carbon nanotube film of the composite electrode, and the particle size of the metal catalyst is 5nm-5μm.

The sulfate or nitrate catalyst of one or more metals in the Pt, Pd, Mo, Ni, Co, Y, Sn consists of: Pt/Ni, Pt/Ni/Y, Pt/Ni/Co, Pt/Ni/Mo, Pt/Mo/Co, Pt/Ni/Sn, Pd/Ni, Pd/Ni/Mo, Pd/Ni/Y, Pd/Ni/Co, Pd/Mo/Co, Pd/Ni/ Sn.

As shown in Figure 1, the fuel cell composite electrode testing device includes an upper electrode fixed metal plate 1, an upper graphite electrode plate 2, an upper composite electrode 3, a proton exchange membrane 4 (Nafion117 produced by DuPont, USA), a lower composite electrode 5, and a lower graphite electrode plate. Electrode plate 6, lower electrode fixing metal plate 7, oxygen intake pipe 8, oxygen exhaust pipe 9, catalyst layer 10, voltmeter 11, hydrogen exhaust pipe 12, hydrogen air intake pipe 13, bracket 14, manual control lift valve 15, Thermocouple 16, temperature control water tank 17, temperature control heater 18, hydrogen humidifier outlet pipe 19, hydrogen humidifier 20, oxygen humidifier 21, hydrogen flow meter outlet pipe 22, hydrogen flow meter 23, hydrogen flow meter inlet pipe 24 , oxygen flow meter inlet pipe 25, oxygen flow meter 26, oxygen flow meter outlet pipe 27, oxygen humidifier inlet pipe 28, oxygen humidifier outlet pipe 29, hydrogen humidifier inlet pipe 30, air groove 31; To the top, there are lower electrode fixing metal plate 7, lower graphite electrode plate 6, lower composite electrode 5, proton exchange membrane 4, upper composite electrode 3, upper graphite electrode plate 2, upper electrode fixing metal plate 1, and lower electrode fixing metal plate. An oxygen intake pipe 8 and an oxygen exhaust pipe 9 are arranged on the plate 7, a hydrogen exhaust pipe 12 and a hydrogen air inlet pipe 13 are arranged on the upper electrode fixed metal plate 2, and a manual control lifting valve 15 is arranged above the upper electrode fixed metal plate 1 , a hydrogen humidifier 20 and an oxygen humidifier 21 are placed in the constant temperature control water tank 17, a temperature control heater 18 is arranged under the constant temperature control water tank 17, the hydrogen gas bottle is connected with the inlet pipe 24 of the hydrogen flow meter 23, and the hydrogen flow meter outlet pipe 22 It is connected with the inlet of the hydrogen humidifier inlet pipe 30, the inlet 19 of the hydrogen humidifier 20 is connected with the hydrogen inlet pipe 13, the oxygen cylinder is connected with the inlet pipe 25 of the oxygen flowmeter, and the outlet pipe 27 of the oxygen flowmeter is connected with the inlet pipe 28 of the oxygen humidifier. The outlet pipe 29 of the oxygen humidifier is connected to the oxygen inlet pipe 8, and the positive and negative poles of the voltmeter 11 are respectively connected to the lower electrode fixed metal plate 7 and the upper electrode fixed metal plate 1; A carbon paper or a thinned foamed nickel substrate is provided, a single-wall or multi-walled carbon nanotube film is provided on the carbon paper or a thinned foamed nickel substrate, and a catalyst layer 10 is provided on the single-walled or multi-walled carbon nanotube film.

The implementation is carried out according to the table below. Metal catalysts are plated on single-wall or multi-wall carbon nanotube films of different composite electrodes by means of electroplating, and the electroplating time and DC voltage used for electroplating are changed respectively to form 12 implementations. The samples made under different conditions were assembled into fuel cells respectively, installed on the testing device for testing, and the tested data were screened to form eight examples.

Example 1:

Test with experimental scheme 1, promptly take carbon paper/single-walled carbon nanotube film as composite electrode, plate Ni/Pd on it, electroplating time: the time of plating metal Ni is 10 seconds, the time of plating metal Pd is 50 seconds. The electroplating temperature was controlled at 40°C, the DC voltage selected for electroplating was 0.5V, and the measured open circuit voltage of the fuel cell was 0.78V.

Example 2:

Experimental scheme 3 was used to test, that is, carbon paper/single-walled carbon nanotube film was used as a composite electrode, and Pd/Ni/Sn was plated on it, and the electroplating time: the time for plating metal Pd was 50 seconds, and the time for plating metal Ni was 50 seconds. The time is 10 seconds, and the time for metal Sn plating is 5 seconds. The electroplating temperature was controlled at 40°C, the DC voltage selected for electroplating was 5V, and the measured open circuit voltage of the fuel cell was 0.81V.

Example 3:

Test with experimental scheme 4, namely take carbon paper/multi-walled carbon nanotube thin film as composite electrode, plate Ni/Pd on it, electroplating time: the time of plating metal Ni is 10 seconds, the time of plating metal Pd is 50 seconds. The electroplating temperature was controlled at 40°C, the DC voltage selected for electroplating was 0.5V, and the measured open circuit voltage of the fuel cell was 0.71V. the

Example 4:

Test with experimental scheme 6, that is, use carbon paper/multi-walled carbon nanotube film as composite electrode, plate Pd/Ni/Sn on it, electroplating time: the time of plating metal Ni is 10 seconds, the time of plating metal Pd The time is 50 seconds, and the time for metal Sn plating is 5 seconds. The electroplating temperature was controlled at 40°C, the DC voltage selected for electroplating was 5V, and the measured open circuit voltage of the fuel cell was 0.67V. the

Example 5:

Test with experimental scheme 7, promptly take foam nickel/single-walled carbon nanotube thin film as composite electrode, plate Ni/Pd on it, electroplating time: the time of plating metal Ni is 10 seconds, the time of plating metal Pd is 10 seconds 50 seconds. The electroplating temperature was controlled at 40°C, the DC voltage selected for electroplating was 1V, and the measured open circuit voltage of the fuel cell was 0.56V.

Embodiment 6:

Test with experimental scheme 9, that is, use nickel foam/single-walled carbon nanotube film as a composite electrode, and plate Pd/Ni/Sn on it, and the electroplating time: the time for plating metal Pd is 50 seconds, and the time for plating metal Ni is 50 seconds. The time is 10 seconds, and the time for metal Sn plating is 5 seconds. The electroplating temperature was controlled at 40°C, the DC voltage selected for electroplating was 4V, and the measured open circuit voltage of the fuel cell was 0.61V.

Embodiment 7:

Test with experimental scheme 10, promptly take foam nickel/multi-walled carbon nanotube thin film as composite electrode, plate Ni/Pd on it, electroplating time: the time of plating metal Ni is 10 seconds, the time of plating metal Pd is 50 seconds. The electroplating temperature was controlled at 40°C, the DC voltage selected for electroplating was 0.5V, and the measured open circuit voltage of the fuel cell was 0.71V. the

Embodiment 8:

Experimental scheme 12 is used for testing, that is, nickel foam/multi-walled carbon nanotube film is used as a composite electrode, and Pd/Ni/Sn is plated on it, and the electroplating time: the time for plating metal Ni is 10 seconds, and the time for plating metal Pd is 10 seconds. The time is 50 seconds, and the time for metal Sn plating is 5 seconds. The electroplating temperature was controlled at 40°C, the DC voltage selected for electroplating was 5V, and the measured open circuit voltage of the fuel cell was 0.63V.

Claims (3)

1. A preparation method for a fuel cell composite electrode, characterized in that its steps are as follows 1) Cut carbon paper or thin nickel foam into several groups of rectangular substrates with a size of 30mm*50mm, use arc discharge method to directly synthesize single-walled carbon nanotubes on the substrate to make composite electrodes, and treat them with alcohol; Or use the screen printing method to print multi-walled carbon nanotubes on the substrate to make composite electrodes; 2) The composite electrode is electroplated at a DC voltage of 0.5V to 5V, and the electroplating solution is sulfate or nitric acid containing one or more metals among Pt, Pd, Mo, Ni, Co, Y, and Sn as metal catalysts Salt solution, the anode is a graphite rod or graphite plate, the cathode is a composite electrode composed of carbon paper or thin nickel foam substrate and single-wall or multi-wall carbon nanotubes respectively, the plating time is 5s~50s, the temperature control during the electroplating process At 40 degrees, a catalyst layer is plated on the single-wall or multi-wall carbon nanotube film of the composite electrode, and the particle diameter of the metal catalyst is 5nm-5μm. 2. the preparation method of a kind of fuel cell composite electrode according to claim 1 is characterized in that the sulfate or nitrate of one or more metals in described Pt, Pd, Mo, Ni, Co, Y The composition of the catalyst layer formed after plating is: Pt/Ni, Pt/Ni/Y, Pt/Ni/Co, Pt/Ni/Mo, Pt/Mo/Co, Pt/Ni/Sn, Pd/Ni, Pd/ Ni/Mo, Pd/Ni/Y, Pd/Ni/Co, Pd/Mo/Co, Pd/Ni/Sn. 3. A fuel cell composite electrode testing device, characterized in that it includes an upper electrode fixed metal plate (1), an upper graphite electrode plate (2), an upper composite electrode (3), a proton exchange membrane (4), and a lower composite electrode ( 5), lower graphite electrode plate (6), lower electrode fixing metal plate (7), oxygen inlet pipe (8), oxygen exhaust pipe (9), catalyst layer (10), voltmeter (11), hydrogen exhaust Pipe (12), hydrogen inlet pipe (13), bracket (14), manual control lift valve (15), thermocouple (16), temperature-controlled water tank (17), temperature-controlled heater (18), hydrogen humidifier outlet Gas pipe (19), hydrogen humidifier (20), oxygen humidifier (21), hydrogen flow meter outlet pipe (22), hydrogen flow meter (23), hydrogen flow meter inlet pipe (24), oxygen flow meter inlet pipe ( 25), oxygen flow meter (26), oxygen flow meter outlet pipe (27), oxygen humidifier inlet pipe (28), oxygen humidifier outlet pipe (29), hydrogen humidifier inlet pipe (30), air tank (31 ); the lower electrode fixing metal plate (7), the lower graphite electrode plate (6), the lower composite electrode (5), the proton exchange membrane (4), and the upper composite electrode (3) are sequentially arranged in the bracket (14) from bottom to top ), the upper graphite electrode plate (2), the upper electrode fixing metal plate (1), the lower electrode fixing metal plate (7) is equipped with an oxygen intake pipe (8), an oxygen exhaust pipe (9), and the upper electrode fixing metal plate (2) There is a hydrogen exhaust pipe (12) and a hydrogen inlet pipe (13) on the top, a manual control lift valve (15) is provided above the upper electrode fixing metal plate (1), and hydrogen gas is placed in the constant temperature control water tank (17) A humidifier (20) and an oxygen humidifier (21), a temperature-controlled heater (18) is provided under the constant-temperature-controlled water tank (17), the hydrogen cylinder is connected to the intake pipe (24) of the hydrogen flowmeter (23), and the hydrogen flowmeter The outlet pipe (22) is connected to the inlet of the hydrogen humidifier inlet pipe (30), the inlet of the hydrogen humidifier (19) is connected to the hydrogen inlet pipe (13), the oxygen cylinder is connected to the oxygen flow meter inlet pipe (25), and the oxygen flow meter The outlet pipe (27) is connected to the oxygen humidifier inlet pipe (28), the oxygen humidifier outlet pipe (29) is connected to the oxygen inlet pipe (8), and the positive and negative poles of the voltmeter (11) are respectively connected to the lower electrode fixed metal plate ( 7) Connected to the upper electrode fixed metal plate (1), the upper composite electrode (3) and the lower composite electrode (5) are provided with carbon paper or thinned foamed nickel substrate, carbon paper or thinned foamed nickel A single-wall or multi-wall carbon nanotube film is arranged on the substrate, and a catalyst layer (10) is arranged on the single-wall or multi-wall carbon nanotube film.

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