CN219419092U

CN219419092U - Fuel cell gas diffusion electrode testing device

Info

Publication number: CN219419092U
Application number: CN202220744922.3U
Authority: CN
Inventors: 魏伟; 鄂彬; 李聪; 汪晔
Original assignee: Tabida Technology Suzhou Co ltd
Current assignee: Tabida Technology Suzhou Co ltd
Priority date: 2022-04-01
Filing date: 2022-04-01
Publication date: 2023-07-25
Anticipated expiration: 2032-04-01

Abstract

The utility model relates in particular to a gas diffusion electrode testing device and provides a new ORR testing device to characterize the activity of a catalyst in commercial applications. The device has simple sample preparation and assembly and low operation quality requirement on sample preparation, thereby reducing the influence of electrode quality on test results; compared with the traditional rotary disk method test, the limiting diffusion current is generally smaller, the reactant oxygen of the device is directly contacted with the catalyst, the limitation of solubility of oxygen in water is avoided, the mass transfer polarization is smaller, and the gas diffusion electrode can work under higher current density.

Description

Fuel cell gas diffusion electrode testing device

Technical Field

The utility model belongs to the field of fuel cell testing, and particularly relates to a gas diffusion electrode testing device.

Background

Proton exchange membrane fuel cell (proton exchange membrane fuel cell, PEMFC): the fuel cell is a power generation device which adopts a proton-conductive polymer membrane as electrolyte and directly converts chemical energy existing in fuel into electric energy through electrochemical reaction.

The PEMFC basic structure is mainly a Bipolar plates (BPP) and a membrane electrode (Membrane electrode assembly, MEA), wherein the membrane electrode comprises a cathode, an anode and a polymer electrolyte membrane (Polymer electrolyte membrane, PEM). The cathode and anode in a fuel cell are typically porous structures, commonly referred to as electrodes, and consist of a gas diffusion layer (Gas diffusion layer, GDL) and a Catalytic Layer (CL). When the battery is in operation, reactants enter the catalytic layer through the polar plate and the gas diffusion layer and undergo electrochemical reaction under the action of the electrocatalyst; the anode undergoes oxidation reactions, such as hydrogen oxidation (Hydrogen oxidation reaction, HOR) and methanol oxidation (Methanol oxidation reaction, MOR), and the cathode undergoes reduction reactions, typically oxygen reduction (Oxygen reduction reduction, ORR).

The ORR reaction of the cathode is generally difficult to carry out, so that the polarization of the whole cell is mainly due to the cathode reaction. The polarization of the whole reaction can be effectively reduced by adding the high-efficiency noble metal catalyst, so that ORR performance test is required for comparing the catalytic performance of the catalyst. The most commonly used ORR test method at present is the rotating disk electrode method (RDE) because of the low solubility of oxygen in aqueous solutions, which typically requires the use of rotating disk/ring disk electrodes to overcome mass transfer effects.

There are two fatal disadvantages to rotating disk electrode methods to test the ORR performance of catalysts. First, in the preparation of thin film electrodes, the quality of the thin film has a significant impact on ORR activity, usually requiring a significant amount of time to prepare, and no obvious method to determine the quality of the film before testing. Second, because the complete source of oxygen involved in the ORR reaction and the dissolved oxygen in water greatly limit the mass transfer process of the ORR reaction, the limiting diffusion electricity when tested by the rotating disk methodThe flow can generally reach only 6mA/cm ² Whereas current commercial membrane electrodes generally require a current operating at 2000mA/cm ² The performance of the catalyst tested by the method can not represent the performance of the catalyst when the membrane electrode works truly. Accordingly, the present utility model addresses the deficiencies of the prior art by providing a new ORR test apparatus to characterize the activity of a catalyst in commercial applications.

The technical problems specifically aimed at are as follows: the dissolved oxygen source in water limits ORR mass transfer, making the limiting diffusion current in the test of catalyst performance quite different from commercial membrane electrode conditions.

Disclosure of Invention

The utility model aims to provide a simple fuel cell gas diffusion electrode testing device which has low requirements on sample preparation operation quality and is suitable for a testing device of a commercial membrane electrode working state so as to realize the testing of the diffusion electrode, in particular the performance of a catalyst in the electrode.

The technical scheme of the utility model is as follows:

the utility model provides a fuel cell gas diffusion electrode testing device, which comprises a first end plate, a first current collecting plate, a first polar plate, a gas diffusion electrode, a second polar plate, a second current collecting plate and a second end plate which are sequentially stacked, wherein the first end plate and the second end plate are respectively provided with a feed inlet and a discharge outlet; a flow field is arranged on one side of the first polar plate and one side of the second polar plate, which are close to the gas diffusion electrode; the gas diffusion electrode comprises a first gas diffusion layer, a catalytic layer, a polymer electrolyte membrane and a second gas diffusion layer which are sequentially arranged, wherein the first gas diffusion layer is contacted with the first polar plate, and the second gas diffusion layer is contacted with the second polar plate.

Further, in the above technical solution, the surface area of the first gas diffusion layer is approximately equal to the area of the catalytic layer, and is smaller than or equal to the area of the second gas diffusion layer.

Further, in the above technical solution, the surface areas of the first gas diffusion layer and the catalytic layer are approximately equal to 1/100 to 1/20 of the surface area of the second gas diffusion layer. To reduce the cost of the catalyst layer, at the same timeThe surface areas of the first gas diffusion layer and the catalytic layer are preferably equal to about 0.2cm to meet current density testing requirements ² And the first gas diffusion layer and the catalytic layer are preferably arranged in a circular shape. The area of the second gas diffusion layer is preferably set to 4cm according to the size of the commercial gas diffusion electrode ² Or 25cm ² And the second gas diffusion layer is preferably arranged in a rectangular shape.

Further, in the above technical solution, the flow field of the first electrode plate is an interdigital flow field, and the area of the interdigital area is approximately equal to the surface area of the first gas diffusion layer. The discontinuous gap in the interdigital region is about 0.1 to 2mm, which allows the gaseous reactants to be forced through the first gas diffusion layer and the catalytic layer, allowing the reaction to proceed more fully.

Further, in the above technical solution, the flow field of the second plate is a serpentine flow field, and the area of the serpentine area is approximately equal to the surface area of the second gas diffusion layer. The serpentine flow allows for more intimate contact of the liquid reactant with the second gas diffusion layer.

Further, in the above technical solution, a heating device is provided on the first end plate and/or the second end plate, and the heating device is a heating rod or a heating sheet.

The utility model also provides a testing method for testing the gas diffusion electrode of the fuel cell by using the device, which comprises the following steps of:

introducing air into the first end plate feed inlet;

introducing dilute acid solution into the feed inlet of the second end plate, and connecting a reference electrode in series in the liquid pipeline, wherein the reference electrode is preferably a standard hydrogen electrode; that is, the catalyst is not in direct contact with the solution during the entire test, H in the solution ⁺ The measurement of the passage through the electrolyte membrane to the catalytic layer, and the ORR reaction with the oxygen in the flow field.

And connecting the fuel cell gas diffusion electrode testing device to an electrochemical workstation, wherein the first current collecting plate is connected with a working electrode clamp, the second current collecting plate is connected with a counter electrode clamp, the series reference electrode is connected with a reference electrode clamp, the electrochemical workstation is set to apply voltage, and corresponding current values are measured.

Further, in the above-described aspect, the stoichiometric ratio of the air flow rate to the first end plate is 1 to 110.

In the above technical scheme, the diluted acid solution is perchloric acid solution, and the concentration of the solution is 0.5-4M.

Further, in the above technical scheme, the steps further include controlling the heating device to enable the temperature of the testing device to be between room temperature and 110 ℃.

Terms such as "about equal to" in connection with a particular distance or dimension herein should be understood not to exclude insignificant deviations from that particular distance or dimension and may include deviations, for example, up to 20%.

The utility model has the advantages that:

1. the test device has simple structure, and expensive vulnerable parts are not required to be used;

2. the sample preparation and the assembly are simple, and the operation quality requirement on the sample preparation is low, so that the influence of the electrode quality on the test result is reduced;

3. less catalytic layer area is used, so that the cost is reduced;

4. compared with the traditional rotary disk method, the limit diffusion current can only reach 6mA/cm ² The oxygen of the reactant of the device directly contacts with the catalyst, the limitation of the solution degree of the oxygen in water is avoided, the mass transfer polarization is smaller, the gas diffusion electrode can work under higher current density, and the performance of the catalyst under a commercial mode is more accurately represented;

5. the concentration of the reactants is kept stable by a non-static introduction mode of the reactants, and the reaction is more sufficient by the design of a flow field;

6. meanwhile, through controlling parameters such as air flow, pressure, perchloric acid solution concentration, temperature and the like, the influence of each parameter on the activity of the catalyst can be studied.

Drawings

Fig. 1 is a schematic sectional view of a testing device for a gas diffusion electrode of a fuel cell according to an embodiment of the present utility model, wherein 101 is a first end plate, 102 is a first current collecting plate, 103 is a first electrode plate, 104 is a gas diffusion electrode, 105 is a second electrode plate, 106 is a second current collecting plate, and 107 is a second end plate.

Fig. 2 is a schematic diagram of a first plate and a flow field according to an embodiment of the present utility model.

Fig. 3 is a schematic diagram of a second plate and a flow field according to an embodiment of the present utility model.

Fig. 4 is a schematic perspective view of a fuel cell gas diffusion electrode testing apparatus according to an embodiment of the present utility model.

FIG. 5 is a current-voltage test curve of an embodiment of the present utility model.

Detailed Description

While the present utility model is susceptible of embodiment in various embodiments, there is shown in the drawings and will hereinafter be described in detail, a specific embodiment of the utility model, with the understanding that the present disclosure is to be considered an exemplification of the principles of the utility model, and is not intended to limit the utility model to that as illustrated.

As shown in fig. 1, a testing device for a gas diffusion electrode of a fuel cell comprises a first end plate, a first current collecting plate, a first polar plate, a gas diffusion electrode, a second polar plate, a second current collecting plate and a second end plate which are stacked in sequence, wherein both the first end plate and the second end plate are provided with a feed inlet and a discharge outlet. Wherein, one side of the first polar plate and the second polar plate, which is close to the gas diffusion electrode, is provided with a flow field. The gas diffusion electrode comprises a first gas diffusion layer, a catalytic layer, a polymer electrolyte membrane and a second gas diffusion layer which are sequentially arranged, wherein the first gas diffusion layer is contacted with the first polar plate, and the second gas diffusion layer is contacted with the second polar plate.

The surface areas of the first gas diffusion layer and the catalytic layer were 0.2cm ² And is circular in shape. The area of the second gas diffusion layer is 4cm ² And is square in shape.

The flow field of the first polar plate is an interdigital flow field, the interdigital area of which corresponds to the first gas diffusion layer, and the shape and the position are consistent. The discontinuous gap of the interdigital region is about 1mm.

The flow field of the second polar plate is a serpentine flow field, the serpentine area of which corresponds to the second gas diffusion layer, and the shape and the position are consistent.

Two heating rods are respectively arranged on the first end plate and the second end plate.

The testing method for testing the gas diffusion electrode of the fuel cell by using the device comprises the following steps:

first, as shown in fig. 4, a first end plate, a first current collecting plate, a first electrode plate, a gas diffusion electrode, a second electrode plate, a second current collecting plate, and a second end plate are stacked in this order according to positioning holes (not shown), and fastened using screws.

Air was then introduced into the first end plate feed port with an air flow stoichiometric ratio of 110.

Then 4M perchloric acid solution was introduced into the feed inlet of the second end plate at a flow rate of 1ml/min. And a reference electrode is connected in series in the liquid pipeline, and the reference electrode is a standard hydrogen electrode.

The temperature of the heating rod is controlled to make the temperature of the testing device 80 ℃.

And during testing, the fuel cell gas diffusion electrode testing device is connected to an electrochemical workstation, wherein a first current collecting plate is connected with a working electrode clamp, a second current collecting plate is connected with a counter electrode clamp, a series reference electrode is connected with a reference electrode clamp, the electrochemical workstation is set to apply voltage of 0-1.2V, and corresponding current values are measured.

The obtained data were processed to obtain a current-voltage test curve as shown in FIG. 5, from which it was found that the current density was 1800mA/cm at a voltage of 0.6V ² The method comprises the steps of carrying out a first treatment on the surface of the The current density reaches the highest value at the voltage of about 0.2V, which is 2800mA/cm ² Far exceeding 6mA/cm for RDE testing ² Is a limiting diffusion current density of (c). The performance at this time is closer to the performance of the catalyst when the gas diffusion electrode is actually operating.

Claims

1. A fuel cell gas diffusion electrode testing device, characterized in that: the gas diffusion device comprises a first end plate, a first current collecting plate, a first polar plate, a gas diffusion electrode, a second polar plate, a second current collecting plate and a second end plate which are sequentially stacked, wherein the first end plate and the second end plate are respectively provided with a feed inlet and a discharge outlet;

a flow field is arranged on one side of the first polar plate and one side of the second polar plate, which are close to the gas diffusion electrode;

the gas diffusion electrode comprises a first gas diffusion layer, a catalytic layer, a polymer electrolyte membrane and a second gas diffusion layer which are sequentially arranged, wherein the first gas diffusion layer is contacted with the first polar plate, and the second gas diffusion layer is contacted with the second polar plate.

2. A fuel cell gas diffusion electrode testing apparatus according to claim 1, wherein: the first gas diffusion layer has a surface area approximately equal to the catalytic layer area and less than or equal to the second gas diffusion layer.

3. A fuel cell gas diffusion electrode testing apparatus according to claim 2, wherein: the surface areas of the first gas diffusion layer and the catalytic layer are approximately equal to 1/100 to 1/20 of the surface area of the second gas diffusion layer.

4. A fuel cell gas diffusion electrode testing apparatus according to claim 1 or 2, wherein: the flow field of the first polar plate is an interdigital flow field, and the area of the interdigital area is approximately equal to the surface area of the first gas diffusion layer.

5. A fuel cell gas diffusion electrode testing apparatus according to claim 1 or 2, wherein: the flow field of the second polar plate is a serpentine flow field, and the area of the serpentine area is approximately equal to the surface area of the second gas diffusion layer.

6. A fuel cell gas diffusion electrode testing apparatus according to claim 1 or 2, wherein: and the first end plate and/or the second end plate is/are provided with a heating device, and the heating device is a heating rod or a heating sheet.