阅读说明：本技术 一种测试质子交换膜质子电导率的装置和方法 (Device and method for testing proton conductivity of proton exchange membrane ) 是由 尹崇山 何春清 刘其城 于 2020-07-07 设计创作，主要内容包括：本发明公开了一种测试质子交换膜质子电导率的装置和方法,包括：夹具、铂片电极、质子交换膜、电化学工作站、温度计、加热台和氮气湿度控制装置；质子交换膜放置在夹具当中,夹具上固定两片铂片电极。质子交换膜两端分别放置在一片铂片电极上,铂片电极接在电化学工作站上,用以测量质子交换膜包括质子电导率在内的电化学性能。氮气湿度控制装置将调解好湿度的氮气输送至夹具内。本发明的优点是：1.同时设定被测薄膜周围的调节温度和湿度,方便测量。2.可测在不同温度湿度条件下的电化学性能。3.可设定的湿度范围大,且调节响应快。4.可设定的温度范围大,只要低于腔室材料的最高耐热温度即可。5.结构简单,不需要额外的设备,成本低,维护简单。(The invention discloses a device and a method for testing proton conductivity of a proton exchange membrane, comprising the following steps: the device comprises a clamp, a platinum sheet electrode, a proton exchange membrane, an electrochemical workstation, a thermometer, a heating table and a nitrogen humidity control device; the proton exchange membrane is placed in a clamp, and two platinum sheet electrodes are fixed on the clamp. Two ends of the proton exchange membrane are respectively arranged on a platinum sheet electrode which is connected on an electrochemical workstation and used for measuring the electrochemical performance of the proton exchange membrane including proton conductivity. And the nitrogen humidity control device conveys the humidity-adjusted nitrogen into the clamp. The invention has the advantages that: 1. meanwhile, the temperature and humidity around the film to be measured are set, so that the measurement is convenient. 2. The electrochemical performance under different temperature and humidity conditions can be measured. 3. The settable humidity range is large, and the adjustment response is fast. 4. The settable temperature range is large as long as it is lower than the maximum heat-resistant temperature of the chamber material. 5. The structure is simple, no extra equipment is needed, the cost is low, and the maintenance is simple.)

1. An apparatus for testing proton conductivity of a proton exchange membrane, comprising: the device comprises a clamp (1), a rubber sealing ring (2), a platinum sheet electrode (3), a proton exchange membrane (4), an electrochemical workstation (5), a computer (6), a hygrometer (7), a heating table (15), a thermometer (16) and a nitrogen humidity control device;

the proton exchange membrane (4) is placed in the clamp (1), a sealing cavity is arranged in the clamp (1), the sealing cavity is sealed by a rubber sealing ring (2) fixed on the clamp (1), and two platinum sheet electrodes (3) are fixed on the clamp (1); two ends of the proton exchange membrane (4) are respectively placed on one platinum sheet electrode (3), and the middle section of the proton exchange membrane (4) is suspended in the central hollow position of the sealed chamber; fixing the clamp (1) by using a fixing clamp or a screw to enable two ends of the proton exchange membrane (4) to be in close contact with the platinum sheet electrode (3), and simultaneously compressing the rubber sealing ring (2) to seal the proton exchange membrane (4) in the clamp (1);

the platinum sheet electrode (3) is connected to the electrochemical workstation (5) and is used for measuring the electrochemical performance of the proton exchange membrane (4) including proton conductivity, and the electrochemical workstation (5) is controlled by a computer to work; wherein the temperature of the proton exchange membrane (4) is controlled by adjusting the power of a heating table (15) at the lower end of the clamp (1);

an air inlet (8) and an air outlet (9) which are communicated with the sealed chamber are arranged on the clamp (1); the thermometer (16) is arranged near the proton exchange membrane (4) to directly measure the temperature around the proton exchange membrane (4), the hygrometer (7) is arranged at the air outlet to measure the humidity near the proton exchange membrane (4), and the air inlet (8) is communicated with the two-way nitrogen control device;

the nitrogen gas humidity control device comprises: the device comprises a pipeline, a nitrogen gas cylinder (10), two valves (11), two gas flow meters (12), a humidifying cylinder (13) and a mixing cylinder (14);

the pipeline of the nitrogen humidity control device is divided into two paths, wherein the connection sequence of one path is sequentially a nitrogen bottle, a valve (11), a gas flowmeter (12), a humidifying bottle (13), a mixing bottle (14) and an air inlet (8);

the other path is connected with a nitrogen cylinder, another valve (11), another gas flowmeter (12), a mixing cylinder (14) and an air inlet (8) in sequence.

2. The apparatus for testing proton conductivity of proton exchange membrane according to claim 1, wherein: the humidifying bottle (13) is internally provided with gas refining stones (15).

3. The apparatus for testing proton conductivity of proton exchange membrane according to claim 1, wherein: the clamp (1) comprises the following materials: one of stainless steel, polysulfone plate and teflon.

4. The apparatus for testing proton conductivity of proton exchange membrane according to claim 1, wherein: the method for testing the proton conductivity of the proton exchange membrane by the device comprises the following steps: placing a proton exchange membrane (4) to be tested in a clamp (1), placing two ends of the proton exchange membrane (4) on a platinum sheet electrode, suspending the middle section of a film at the central hollow position of the clamp, fixing the clamp (1) by using a fixing clamp or a screw, enabling two ends of the film to be in close contact with the platinum sheet electrode, simultaneously pressing a rubber sealing ring (2), and sealing the film in the clamp;

then, controlling the humidity around the proton exchange membrane (4) by two paths of nitrogen, wherein one path of nitrogen passes through ionized water in a humidifying bottle (13), the nitrogen enters water, the gas is divided into a large number of small bubbles by a gas refining stone (15), and the contact area of the gas and the water is enlarged to enable the nitrogen to reach the saturated humidity-100% RH; if the temperature is too low, the deionized water needs to be properly heated; the nitrogen gas coming out of the way is called wet nitrogen gas; the other path directly inputs dry nitrogen into a mixing bottle (14), the dry nitrogen and the wet nitrogen are simultaneously introduced into the mixing bottle (14), and the two paths of nitrogen are combined together to be mixed into a bottle of nitrogen with certain humidity; the flow ratio of the two paths of nitrogen is changed through a valve (11), so that the aim of controlling the humidity of the nitrogen in the bottle is fulfilled, and the humidity condition of the tested proton exchange membrane (4) is adjusted; the humidity is measured by a hygrometer (7) arranged at the air outlet.

After the preparation is completed, the internal and external balance is achieved after the proton exchange membrane (4) is stabilized for a certain time under the set temperature and humidity conditions, and then the electrochemical test can be started; testing proton conductivity of the proton exchange membrane (4) using an alternating current impedance mode of the electrochemical workstation (5); applying a perturbation voltage to the material during testing; in the test, a perturbation voltage from 1Hz to 100kHz is applied to the proton exchange membrane (4), then a response electric signal of the proton exchange membrane (4) is read from the platinum sheet electrodes (3) at two ends, and finally an electrochemical alternating current impedance diagram of the proton exchange membrane (4) can be obtained; the ion mobility resistance R can be read from the intersection point of the data point and the real part resistance in the graph; this ion migration resistance is the proton migration resistance for the proton exchange membrane (4); reading the width W and the length L of the proton exchange membrane (4) by using a vernier caliper, measuring the thickness T of the proton exchange membrane (4) by using a micrometer screw, and measuring the proton conductivity sigma of the proton exchange membrane (4) under the conditions of set temperature and humidity by using a formula (1);

after measuring the proton conductivity, changing the humidity by adjusting the nitrogen flow and changing the temperature by adjusting the heating table; after the required humidity and temperature conditions are reached, a new round of electrochemical test can be started after the proton exchange membrane (4) is stabilized for a certain time under the conditions and internal and external balance is achieved.

Technical Field

The invention relates to the technical field of proton exchange membrane conductivity testing, in particular to a device and a method for testing proton conductivity of a proton exchange membrane under different humidity and temperature conditions.

Background

Fuel cells, one of the clean energy sources that is receiving attention today, are devices that directly convert chemical power into electrical energy, and are also considered to be one of the first clean power generation technologies in the 21 st century. The proton exchange membrane is a key component of the proton exchange membrane fuel cell, and is responsible for preventing oxidant gas from directly contacting with fuel gas in the cell and realizing proton exchange. The matrix material constituting the proton exchange membrane determines the overall service performance of the proton exchange membrane to a great extent. In order to improve the practicability of the fuel cell, the proton exchange membrane in the fuel cell needs to be developed towards high performance, long service life and low cost, and the development of a novel proton exchange membrane is also a popular research direction in the world.

The important properties of the proton exchange membrane mainly include proton conductivity, gas and water molecule blocking rate, physical and chemical stability, mechanical strength and the like. Among them, proton conductivity is its core property. However, the proton conductivity of the proton exchange membrane is unstable, and is affected by the external environment and is very sensitive to the change of the external temperature and humidity conditions. Therefore, proton conductivity test of proton exchange membranes under different temperature and humidity conditions is extremely important. Proton conductivity can be tested by the ac impedance mode of the electrochemical workstation. The principle of testing electrochemical ac impedance is by applying a perturbation voltage (low intensity sine wave) to the material. The material generates an electrochemical response signal due to the application of the perturbation voltage. By analyzing electrochemical response signals generated by different perturbation voltages, an equivalent circuit in the material can be calculated. And finally, various dynamic processes and principles of the material including proton conductivity are calculated by combining the geometrical shape of the material. Besides direct measurement of the alternating current impedance, the electrochemical hydrogen pump test can also obtain the proton conductivity of the proton exchange membrane. This test is based on the redox reaction of hydrogen, forcing hydrogen to lose electrons at the positive electrode by pressurizing the fuel cell system externally, converting the hydrogen into hydrogen ions, which migrate from across the proton exchange membrane to the negative electrode, and then obtaining two electrons at the negative electrode to be converted back into hydrogen. And then directly testing the voltage and the current to calculate the migration resistance of the protons in the proton exchange membrane. Similar testing methods also include testing of single fuel cells, which requires a large-scale tester to directly simulate the operating conditions of the fuel cell to measure the proton conductivity of the proton exchange membrane. The results obtained by the different test methods are slightly different, but are essentially the measured proton migration resistance. Based on these common testing methods, the proton conductivity of the proton exchange membrane under different conditions can be well tested by artificially controlling the external environment (temperature and humidity) of the proton exchange membrane. The obtained results have important guiding significance for the development of novel fuel cells. Temperature control during testing is relatively simple and can be achieved by using a heating device and a temperature sensor. The humidity control method can be realized by a constant humidity box, a dehumidifier, a brine concentration humidity control method, a lime wet absorption method and the like.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a device and a method for testing the proton conductivity of a proton exchange membrane, which solve the defects in the prior art.

In order to realize the purpose, the technical scheme adopted by the invention is as follows:

an apparatus for testing proton conductivity of a proton exchange membrane, comprising: the device comprises a clamp 1, a rubber sealing ring 2, a platinum sheet electrode 3, a proton exchange membrane 4, an electrochemical workstation 5, a computer 6, a hygrometer 7, a heating table 15, a thermometer 16 and a nitrogen humidity control device;

proton exchange membrane 4 is placed in anchor clamps 1, is equipped with sealed cavity in anchor clamps 1, and sealed cavity is sealed by fixed rubber seal 2 on anchor clamps 1, fixes two platinum sheet electrodes 3 on anchor clamps 1. Two ends of the proton exchange membrane 4 are respectively arranged on one platinum sheet electrode 3, and the middle section of the proton exchange membrane 4 is suspended in the central hollow position of the sealed chamber. The fixture 1 is fixed by using a fixing clamp or a screw, so that two ends of the proton exchange membrane 4 are in close contact with the platinum sheet electrode 3, and meanwhile, the rubber sealing ring 2 is compressed, so that the proton exchange membrane 4 is sealed in the fixture 1.

The platinum sheet electrode 3 is connected on the electrochemical workstation 5 and is used for measuring the electrochemical properties of the proton exchange membrane 4 including the proton conductivity, and the computer controls the electrochemical workstation 5 to work. Wherein the temperature of the proton exchange membrane 4 is controlled by adjusting the power of the heating table 15 at the lower end of the clamp 1.

An air inlet 8 and an air outlet 9 which are communicated with the sealed chamber are arranged on the clamp 1; the hygrometer 7 is arranged at the air outlet 9 and used for measuring the humidity condition near the membrane, the thermometer 16 is arranged in the sealed cavity and used for directly measuring the temperature near the proton exchange membrane 4, and the air inlet 8 is communicated with the two-way nitrogen control device;

the nitrogen gas humidity control device comprises: a pipeline, a nitrogen gas cylinder 10, two valves 11, two gas flow meters 12, a humidifying cylinder 13 and a mixing cylinder 14;

the pipeline of the nitrogen humidity control device is divided into two paths, wherein the connection sequence of one path is sequentially a nitrogen bottle, a valve 11, a gas flowmeter 12, a humidifying bottle 13, a mixing bottle 14 and an air inlet 8;

the other path is connected with a nitrogen cylinder, another valve 11, another gas flowmeter 12, a mixing cylinder 14 and an air inlet 8 in sequence.

Further, a gas reducing stone 15 is provided in the humidifying bottle 13.

Further, the material of the clamp 1 can be stainless steel, polysulfone plate, Teflon and other rigid high temperature resistant materials;

the invention also discloses a method for testing the proton conductivity of the proton exchange membrane, which comprises the following steps: the proton exchange membrane 4 to be measured is placed in a clamp 1, two ends of the proton exchange membrane 4 are placed on platinum sheet electrodes, the middle section of the membrane is suspended in the central hollow position of the clamp, the clamp 1 is fixed by using a fixing clamp or a screw, two ends of the membrane are in close contact with the platinum sheet electrodes, the rubber sealing ring 2 is compressed, and the membrane is sealed in the clamp.

Then, the humidity around the proton exchange membrane 4 is controlled by two paths of nitrogen, one path of nitrogen passes through ionized water in a humidifying bottle 13, the gas is divided into a large number of small bubbles by gas refining stones 15 after the nitrogen enters the water, the contact area of the gas and the water is enlarged, and the nitrogen reaches the saturated humidity (100% RH) as much as possible. If the temperature is too low, the deionized water can be properly heated. This outgoing nitrogen is referred to as humid nitrogen. And the other path of nitrogen gas directly inputs dry nitrogen gas into the mixing bottle 14, the dry nitrogen gas and the wet nitrogen gas are simultaneously introduced into the mixing bottle 14, and the two paths of nitrogen gas are combined together to be mixed into a bottle of nitrogen gas with certain humidity. The flow ratio of the two paths of nitrogen is changed through the valve 11, so that the purpose of controlling the humidity of the nitrogen in the bottle is achieved, and the humidity condition of the detected proton exchange membrane 4 is adjusted.

After the preparation is completed, the internal and external balance is achieved after the proton exchange membrane 4 is stabilized for a certain time under the set temperature and humidity conditions, and then the electrochemical test can be started. Testing proton conductivity of the proton exchange membrane 4 the alternating current impedance mode of the electrochemical workstation 5 was used. A perturbation voltage (low intensity sine wave of 10 mV) was applied to the material during the test. In the test, a perturbation voltage from 1Hz to 100kHz is applied to the proton exchange membrane 4, then the response electric signals of the proton exchange membrane 4 are read from the platinum sheet electrodes 3 at the two ends, and finally an electrochemical alternating current impedance diagram of the proton exchange membrane 4 can be obtained. The ion mobility resistance R can be read from the intersection of the data point and the real resistance in the graph. This ion mobility resistance is the proton mobility resistance for the proton exchange membrane 4. The width W and the length L of the proton exchange membrane 4 are read by using a vernier caliper, the thickness T of the proton exchange membrane 4 is measured by using a micrometer caliper, and the proton conductivity sigma of the proton exchange membrane 4 under the conditions of set temperature and humidity can be measured by using a formula (1).

After measuring the proton conductivity, the humidity was changed by adjusting the nitrogen flow and the temperature was changed by adjusting the heating stage. After the required humidity and temperature conditions are reached, a new round of electrochemical test can be started after the proton exchange membrane 4 is stabilized for a certain time under the conditions and internal and external balance is achieved.

Compared with the prior art, the invention has the advantages that:

1. meanwhile, the temperature and humidity around the film to be measured are set, so that the measurement is convenient.

2. The electrochemical performance of the proton exchange membrane under different temperature and humidity conditions can be tested.

3. The settable humidity range is large (-1% RH to-100% RH) and the regulation response is fast.

4. The settable temperature range is large as long as it is lower than the maximum heat-resistant temperature of the chamber material.

5. The structure is simple, no extra equipment is needed, the cost is low, and the maintenance is simple.

Drawings

FIG. 1 is a schematic structural diagram of an apparatus for testing proton conductivity of a proton exchange membrane according to the present invention;

FIG. 2 is a schematic diagram of the nitrogen humidity control device of the present invention;

FIG. 3 is a Nyquist plot of a pure Nafion film measured at 25% RH humidity and 25 ℃ in example 1 of the present invention;

FIG. 4 is a Nyquist plot of a pure Nafion film measured at 50% RH humidity and 25 ℃ in example 2 of the present invention;

FIG. 5 is a Nyquist plot of a pure Nafion film measured at 99% RH humidity and 40 ℃ in example 3 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail below with reference to the accompanying drawings by way of examples.

As shown in fig. 1, an apparatus for testing proton conductivity of a proton exchange membrane comprises: the device comprises a clamp 1, a rubber sealing ring 2, a platinum sheet electrode 3, a proton exchange membrane 4, an electrochemical workstation 5, a computer 6, a hygrometer 7 and a thermometer 16;

firstly, a proton exchange membrane 4 to be tested is placed in a specially-made clamp 1, the material of the clamp 1 can be stainless steel, polysulfone plate, Teflon and other rigid high-temperature resistant materials, and a rubber sealing ring 2 and a platinum sheet electrode 3 are fixed on the clamp 1. Two ends of the proton exchange membrane 4 are arranged on the platinum sheet electrode 3, and the middle section of the proton exchange membrane 4 is suspended in the central hollow position of the clamp 1. The fixture 1 is fixed by using a fixing clamp or a screw, so that two ends of the proton exchange membrane 4 are in close contact with the platinum sheet electrode 3, and meanwhile, the rubber sealing ring 2 is compressed, so that the proton exchange membrane 4 is sealed in the fixture 1. The platinum sheet electrode 3 is connected on the electrochemical workstation 5 and is used for measuring the electrochemical performance of the proton exchange membrane 4 including proton conductivity.

The humidity around the proton exchange membrane 4 is then controlled by two nitrogen paths, as shown in figure 2. One of the ways is completely dry pure nitrogen (humidity near 0% RH). The other path of nitrogen firstly passes through the deionized water, the nitrogen enters the water, the gas is divided into a large number of small bubbles through the gas refining stone, the contact area of the gas and the water is enlarged, and the nitrogen reaches the saturated humidity (100% RH) as much as possible. If the temperature is too low, the deionized water can be properly heated. This outgoing nitrogen is referred to as humid nitrogen. Dry nitrogen and wet nitrogen are simultaneously introduced into a glass bottle, and the two paths of nitrogen are combined together to form a bottle of nitrogen with certain humidity. The purpose of controlling the humidity of the nitrogen in the bottle can be achieved by adjusting the flow valve and changing the flow ratio of the two paths of nitrogen. Experimental results show that the humidity of the nitrogen in the bottle can be varied freely from-1% RH to-100% RH. This method is used to adjust the humidity conditions of the tested proton exchange membrane 4. Nitrogen with a certain humidity enters from the holes in the upper half part of the clamp 1 and exits from the holes in the lower half part of the clamp 1, as shown in figure 1. The nitrogen gas is introduced into a plastic chamber with a volume of about 100mL, and a hygrometer is arranged in the chamber, and the reading of the hygrometer is the instant humidity near the proton exchange membrane 4 in the clamp 1.

The temperature of the proton exchange membrane 4 is controlled by adjusting the power of the heating stage at the lower end of the fixture 1, and the temperature around the proton exchange membrane 4 is directly measured by using a temperature sensor arranged near the proton exchange membrane 4 in the fixture 1, as shown in fig. 1 and 2. Before each measurement, the humidity was set by adjusting the nitrogen flow and the temperature was set by adjusting the heating stage.

After the preparation is completed, the internal and external balance is achieved after the proton exchange membrane 4 is stabilized for a certain time under the set temperature and humidity conditions, and then the electrochemical test can be started. Testing proton conductivity of the proton exchange membrane 4 the alternating current impedance mode of the electrochemical workstation 5 was used. In the test, a perturbation voltage (a low intensity sine wave of 10 mV) is applied to the material, and the application of the perturbation voltage can cause the material to generate an electrochemical response signal. In the test, a perturbation voltage from 1Hz to 100kHz is applied to the proton exchange membrane 4, then the response electric signals of the proton exchange membrane 4 are read from the platinum sheet electrodes 3 at the two ends, and finally an electrochemical alternating current impedance diagram of the proton exchange membrane 4 can be obtained. The ion mobility resistance R can be read from the intersection of the data point and the real resistance in the graph. This ion mobility resistance is the proton mobility resistance for the proton exchange membrane 4. The width W and the length L of the proton exchange membrane 4 are read by a vernier caliper, the thickness T of the proton exchange membrane 4 is measured by a micrometer caliper, and the proton conductivity σ of the proton exchange membrane 4 under the conditions of the set temperature and the set humidity can be measured by the following formula (1).

After measuring the proton conductivity, the humidity was changed by adjusting the nitrogen flow and the temperature was changed by adjusting the heating stage. After the required humidity and temperature conditions are reached, a new round of electrochemical test can be started after the proton exchange membrane 4 is stabilized for a certain time under the conditions and internal and external balance is achieved.