Fuel Cell Catalyst Anti-Reverse Electrode Testing Half-Cell System and Testing Evaluation Method

Abstract

This invention discloses a half-cell system and evaluation method for testing the anti-reverse polarity of fuel cell catalysts. The system includes an electrolytic container, an electrode module, a control module, a gas supply module, and a collection module. The electrolytic container stores electrolyte. The electrode module, located inside the electrolytic container, includes a working electrode, a counter electrode, and a reference electrode, with the working electrode, at least a portion of the counter electrode, and at least a portion of the reference electrode immersed in the electrolyte. The control module, located outside the electrolytic container and electrically connected to the electrode module, controls the voltage of the working electrode, counter electrode, and reference electrode. The gas supply module, located outside and connected to the electrolytic container, supplies reactant gases into the electrolytic container. The collection module, located outside and connected to the electrolytic container, collects the gases within the electrolytic container. This invention's half-cell system offers high testing efficiency and accuracy, short testing time, and low cost.

Description

Technical Field

[0001] This invention relates to the field of fuel cell testing technology, and more specifically, to a half-cell system and testing and evaluation method for testing the anti-reaction properties of fuel cell catalysts. Background Technology

[0002] Reverse polarity in fuel cells refers to the phenomenon where, during fuel cell stack operation, insufficient hydrogen supply to the anode causes the cell voltage to drop below zero volts. In this situation, corrosion occurs in the carbon support of the anode catalyst, the catalyst structure collapses, and catalyst (Pt) nanoparticles detach from the support and become ineffective. This also hinders the effective transport of protons in electrocatalysis, causing severe degradation of the membrane electrode catalyst performance and ultimately leading to a decline in cell output performance. Therefore, the proton exchange membrane fuel cell membrane electrode test method (T-CAAMTB12-2020) clearly specifies the evaluation of the membrane electrode's resistance to reverse polarity, which is generally characterized by the shutdown reverse polarity operation time.

[0003] Currently, the testing of membrane electrode assembly (MEA) anti-reverse polarity performance mainly includes the following steps: ① The catalyst is processed into MEAs using processes such as transfer printing and hot pressing, assembled into a single cell, and installed on a proton exchange membrane fuel cell test bench. ② The test uses simulated reverse polarity conditions, i.e., an external constant current source is connected to the cell, the current density is controlled at 0.2 A / cm², and the cell cutoff voltage is set to -1.5 V. During the test, the cell voltage rapidly drops below 0 V, and the potential plateau of carbon corrosion appears at -1.5 to -1.6 V or even higher. At this time, the cathode potential remains at 0.5 to 0.7 V, and the anode potential is 2.0 to 2.3 V vs. RHE. When the cell voltage reaches the cutoff voltage of -1.5 V, the constant current source automatically cuts off the current, the simulated reverse polarity test stops, and the continuous reverse polarity operation time is recorded. The catalyst's anti-reverse polarity performance is evaluated by the length of the reverse polarity operation time.

[0004] However, this testing standard has the following problems: 1) Currently, the testing of anti-reverse polarity mainly relies on fuel cell membrane electrode testing systems. Firstly, the catalyst and anti-reverse polarity catalyst need to be fabricated into membrane electrodes through transfer printing and hot pressing processes, which are complex, time-consuming, and inefficient; 2) The required testing systems and test benches are expensive, and the anti-reverse polarity test is lengthy and inefficient; 3) Many researchers, based on the analysis of the electrode reactions and anti-reverse polarity processes in fuel cells, have found that during continuous operation after shutdown and anti-reverse polarity testing, a hydrolysis plateau occurs at a voltage of 0 to -1.5V. The anti-reverse polarity capability is often judged by the duration of water electrolysis. However, hydrolysis is inevitably accompanied by carbon corrosion, making this evaluation incomplete, unsuitable for evaluating the anti-reverse polarity effect, and inaccurate; 4) During the testing of the anti-reverse polarity membrane electrode catalyst, because a complete (long-term) anti-reverse polarity test of the battery is required, the battery's lifespan is easily shortened after the test, or even failure occurs. This results in the testing of anti-reverse polarity performance at the expense of battery lifespan, significantly increasing testing costs and causing unnecessary economic losses. This problem becomes particularly prominent and obvious when a large number of batteries need to be tested in batches. Summary of the Invention

[0005] The present invention aims to at least partially solve one of the technical problems in the related art.

[0006] Therefore, this invention proposes a half-cell system for testing the anti-reverse polarity of fuel cell catalysts. This half-cell system has high testing efficiency and accuracy, short testing time, and low cost.

[0007] This invention also proposes a testing and evaluation method for a half-cell system based on the above-mentioned fuel cell catalyst anti-reverse polarity test.

[0008] The fuel cell catalyst anti-reverse electrode test half-cell system of this invention includes:

[0009] An electrolytic container, comprising a box body and a sealing cap, wherein the top of the box body is open, and an opening on the sealing cap is used for assembling an electrode module, and the sealing cap can be sealed and assembled at the top opening of the box body, and the box body is used for storing electrolyte.

[0010] An electrode module is disposed within the electrolytic container. The electrode module includes a working electrode, a counter electrode, and a reference electrode. The electrode module passes through the sealing cap, and the working electrode, at least a portion of the counter electrode, and at least a portion of the reference electrode are immersed in the electrolyte.

[0011] A control module is located on the outside of the electrolytic vessel and is electrically connected to the electrode module. The control module is used to control the voltage of the working electrode, the counter electrode, and the reference electrode.

[0012] A gas supply module is located on the outside of the electrolysis container. The output end of the gas supply module passes through the sealing cover and is connected to the electrolysis container. The gas supply module is used to supply reaction gas into the electrolysis container.

[0013] A collection module is located on the outside of the electrolysis container. The input end of the collection module passes through the sealing cover and is connected to the electrolysis container. The collection module is used to collect the gas inside the electrolysis container.

[0014] The fuel cell catalyst anti-reverse polarity testing half-cell system of this invention has high testing efficiency and accuracy, short testing time, and low cost.

[0015] In some embodiments, the control module includes a working clamp, the working clamp, the counter electrode, and the reference electrode are arranged in parallel, and the working clamp is connected to the working electrode.

[0016] In some embodiments, the control module includes an electrode clamp, and the working electrode is indirectly connected to the working clamp via the electrode clamp;

[0017] And / or, the electrode clip is a platinum sheet electrode clip, a stainless steel electrode clip, a graphite electrode clip, or a glassy carbon electrode clip.

[0018] In some embodiments, the sealing cover is provided with a plurality of mounting holes, and the electrode clamp, the counter electrode, the reference electrode, the gas supply module, and the collection module are respectively mounted to the corresponding mounting holes and extend into the electrolysis container from the mounting holes.

[0019] In some embodiments, the reactant gas is oxygen, nitrogen, or air;

[0020] And / or, the collection module is a gas collection bag, a gas collector, or a gas chromatograph.

[0021] In some embodiments, the electrolyte is perchloric acid, sulfuric acid, or hydrochloric acid;

[0022] And / or, the electrolytic container is made of glass.

[0023] In some embodiments, the counter electrode is a platinum wire, platinum mesh, or platinum sheet;

[0024] And / or, the reference electrode is a saturated calomel electrode or a reversible hydrogen electrode.

[0025] In some embodiments, the working electrode includes an electrode substrate and a catalyst slurry disposed on the surface of the electrode substrate, and the electrode substrate is a titanium mesh, a titanium-plated platinum sheet, a carbon felt, or carbon paper.

[0026] The testing and evaluation method of this invention includes the following steps:

[0027] The electrode substrate and catalyst slurry are determined, and the working electrode is prepared using the electrode substrate and the catalyst slurry;

[0028] Assemble the working electrode, counter electrode, reference electrode, electrolytic capacitor, control module, gas supply module, and collection module to form a half-cell system;

[0029] A gas supply module is used to introduce reactive gas into the electrolysis container to replace the original gas in the electrolysis container;

[0030] The working electrode is activated.

[0031] The gas supply module continuously supplies reaction gas into the electrolysis container, and then the simulated reverse polarity test time is measured by timing current or timing voltage.

[0032] The anti-reverse polarity performance of the catalyst is evaluated and described using the simulated reverse polarity test time.

[0033] In some embodiments, determining the simulated reverse polarity test time includes the following steps:

[0034] Measure the time it takes for the initial current to rapidly decay or the voltage to surge to a smooth plateau.

[0035] Repeat the experiment multiple times and take the average of the time it takes for the current to rapidly decay or the voltage to surge to a smooth plateau. The average value is the simulated reverse polarity test time. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the overall structure of the half-battery system according to an embodiment of the present invention.

[0037] Figure 2 This is a flowchart illustrating the testing and evaluation method according to an embodiment of the present invention.

[0038] Figure 3 These are timing current test curves of embodiments one to four of the present invention.

[0039] Figure 4 This is a timing potential test curve of Embodiment 5 of the present invention.

[0040] Figure 5 This is a timing current test curve of Comparative Example 1 of the present invention.

[0041] Figure 6 This is a timing current test curve of Comparative Example 2 of the present invention.

[0042] Figure 7 This is a test curve of the membrane electrode of Comparative Example 3 of the present invention.

[0043] Figure label:

[0044] Electrolytic container 1; sealing cap 11; box body 12;

[0045] Electrode module 2; Working electrode 21; Counter electrode 22; Reference electrode 23;

[0046] Electrode clip 3;

[0047] Control module 4;

[0048] Gas supply module 5;

[0049] Collection module 6. Detailed Implementation

[0050] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0051] like Figure 1 As shown, the fuel cell catalyst anti-reverse polarity test half-cell system (hereinafter referred to as the half-cell system) of this invention includes an electrolysis container 1, an electrode module 2, a control module 4, a gas supply module 5, and a collection module 6.

[0052] The electrolytic container 1 is generally cylindrical and includes a sealing cap 11 and a housing 12. The top of the housing 12 is open, and the sealing cap 11 is fitted to the open top of the housing 12. The electrolytic container 1 is made of glass, which provides good structural stability and facilitates observation of its internal structure. The housing 12 stores the electrolyte, which can be one of perchloric acid, sulfuric acid, or hydrochloric acid. The electrolytic container 1 provides a relatively sealed environment, facilitating electrochemical reactions within it and preventing air contamination during subsequent collection and monitoring of the product gases.

[0053] like Figure 1As shown, electrode module 2 is installed inside the cavity of electrolytic container 1. Electrode module 2 may include a working electrode 21, a counter electrode 22, and a reference electrode 23. The working electrode 21, counter electrode 22, and reference electrode 23 may be arranged in parallel. The working electrode 21 may be completely immersed in the electrolyte within the electrolytic container 1, and the counter electrode 22 and reference electrode 23 may also be completely immersed in the electrolyte. In some other embodiments, the counter electrode 22 and reference electrode 23 may only be partially immersed in the electrolyte.

[0054] like Figure 1 As shown, the control module 4 can be located above the electrolytic container 1. The wires of the control module 4 can be sealed through the sealing cover 11. The control module 4 can be a voltage control module; for example, it can include a voltage controller, which can be electrically connected to the working electrode 21, the counter electrode 22, and the reference electrode 23. In use, the control module 4 can provide voltage to the working electrode 21, the counter electrode 22, and the reference electrode 23, thereby enabling electrochemical reactions to occur within the electrolytic container 1.

[0055] like Figure 1 As shown, the gas supply module 5 can be an oxygen supply module 5, which can be connected to the left side of the electrolysis container 1. The output end of the gas supply module 5 can be equipped with a connector, which can be sealed and assembled on the sealing cover 11, thereby enabling the gas supply module 5 to communicate with the inner cavity of the electrolysis container 1. In use, the gas supply module 5 can serve as a gas source and can supply reaction gases to the electrolysis container 1. The reaction gases can specifically be oxygen, nitrogen, air, etc., thereby providing reaction conditions for the electrochemical reaction.

[0056] It should be noted that the gas supply module 5 may include a flow controller, which can regulate the gas supply of the gas supply module 5 to meet different test requirements.

[0057] like Figure 1 As shown, the collection module 6 can be connected to the right side of the electrolytic container 1. For example, the input end of the collection module 6 can also be equipped with a connector, which can be sealed and assembled onto the sealing cover 11, thereby allowing the collection module 6 to communicate with the inner cavity of the electrolytic container 1. Specifically, the collection module 6 can be a gas collection bag, a gas collector, a gas chromatograph, etc. The collection module 6 can be used to collect excess reaction gas inside the electrolytic container 1, and can also be used to collect gas generated by the electrolytic container 1 during testing. The gas collected by the collection module 6 can be used for in-situ testing, thereby facilitating understanding of the operating status of the half-cell system.

[0058] It should be noted that the sealing cap 11 and the housing 12 of the electrolysis container 1 facilitate the addition of electrolyte and the assembly and replacement of the electrode module 2. Furthermore, the control module 4, gas supply module 5, and collection module 6 are all connected to and integrated with the sealing cap 11. When the sealing cap 11 and housing 12 are disassembled, the housing 12 remains relatively independent, avoiding interference. This facilitates the addition of electrolyte to the housing 12, simplifies the operation, and ensures the sealing performance of the housing 11 itself.

[0059] The fuel cell catalyst anti-reverse electrode testing half-cell system of this invention simplifies the testing process, eliminating the need to fabricate the catalyst and anti-reverse electrode through transfer and hot pressing processes before testing. It also avoids the problems of long testing time and high battery failure rate when using a fuel cell testing system as a platform for batch evaluation of a large number of batteries in related technologies. The system has higher testing efficiency, avoids shortened battery life or even failure, and reduces testing costs.

[0060] In some embodiments, the control module 4 includes a working clamp, a counter electrode, and a reference electrode arranged in parallel. For example, the working clamp, counter electrode, and reference electrode can all be electrically connected to the voltage controller of the control module 4 via wires. In use, the working electrode 21 can be clamped and fixed and electrically connected using the working clamp. This facilitates the installation and fixing of the control module 4 and the working electrode 21, and also facilitates disassembly and replacement, providing convenience for multiple tests.

[0061] In some embodiments, such as Figure 1 As shown, the control module 4 includes an electrode clamp 3, which can clamp and fix the working electrode 21, and the working clamp can clamp and fix the electrode clamp 3. The working electrode 21 and the working clamp can be electrically connected through the electrode clamp 3.

[0062] Optionally, the electrode clip 3 can be a platinum sheet electrode clip, a stainless steel electrode clip, a graphite electrode clip, or a glassy carbon electrode clip.

[0063] In some embodiments, the sealing cover 11 may have multiple mounting holes. Some mounting holes may be located on the top side of the sealing cover 11. The electrode clip 3, counter electrode 22, reference electrode 23, etc., can be mounted one-to-one to the mounting holes on the top side of the sealing cover 11 and extend into the electrolytic container 1 through the corresponding mounting holes. The left side of the sealing cover 11 may also have mounting holes, where the connector of the gas supply module 5 can be mounted and connected to the electrolytic container 1. The right side of the sealing cover 11 may also have mounting holes, where the connector of the collection module 6 can be mounted and connected to the electrolytic container 1. This facilitates the assembly of the electrode module 2, the electrolytic container 1, the gas supply module 5, the control module 4, and the collection module 6.

[0064] It should be noted that the assembly of electrode module 2, gas supply module 5, control module 4, and collection module 6 at their respective assembly holes must be airtight, so as to provide a relatively sealed reaction space for the electrochemical reaction inside the electrolysis container 1.

[0065] In some embodiments, the counter electrode 22 may be a platinum wire, platinum mesh, or platinum sheet, and the reference electrode 23 may be a saturated calomel electrode or a reversible hydrogen electrode.

[0066] In some embodiments, the working electrode 21 includes an electrode substrate and a catalyst slurry disposed on the surface of the electrode substrate, and the electrode substrate is a titanium mesh, a titanium-plated platinum sheet, a carbon felt, or carbon paper. For example, considering cost, the electrode substrate can be carbon paper, with a thickness of 0.08 mm to 1.50 mm and a bulk density of 0.10-1.80 g / cm³. 3 Furthermore, the carbon paper should possess a highly graphite crystal structure. The catalyst slurry can be Pt / C-1, Pt / C-2, Pt / C-3, etc., and the catalyst slurry can be arranged on the surface of the electrode substrate by drop addition.

[0067] During the reverse electrode test, the potential plateau of carbon corrosion appears at -1.5 to -1.6V or even higher. At this time, the cathode potential remains at 0.5 to 0.7V, and the anode potential is 2.0 to 2.3V vs. RHE. The titanium or carbon-based electrodes meet the requirements for use as catalyst support electrodes due to their good conductivity.

[0068] Optionally, the catalyst slurry may also contain deionized water, isopropanol, and ionomer solution, wherein the ionomer solution may specifically be a perfluorosulfonic acid type polymer solution.

[0069] The testing and evaluation methods of embodiments of the present invention are described below.

[0070] like Figure 2 As shown, the test evaluation method of this invention may include the following steps:

[0071] S1: Determine the electrode substrate and catalyst slurry, and prepare the working electrode 21 using the electrode substrate and catalyst slurry. Specifically, the electrode substrate can be carbon paper. During processing, the carbon paper can be cut and packaged to have an effective working area of ​​0.1 cm². 2 up to 5cm 2 The electrode is then prepared by weighing an appropriate amount of catalyst to form a catalyst slurry. This slurry is dispersed on a carbon paper electrode, and can be added dropwise to cover the carbon paper. The catalyst slurry can then be dried. The loading of the catalyst slurry on the electrode substrate can be 10–1000 μg / cm³. 2 Finally, the carbon paper covering the catalyst slurry can be fixed to the electrode clamp 3 to form the working electrode 21.

[0072] S2: Assemble the working electrode 21, counter electrode 22, reference electrode 23, electrolytic container 1, control module 4, gas supply module 5, and collection module 6 to form a half-cell system. For example, the working electrode 21, reference electrode 23, counter electrode 22, and electrolyte can be first loaded into the electrolytic container 1 to form a half-cell, and then the half-cell can be assembled with the gas supply module 5, control module 4, and collection module 6 to form a half-cell system.

[0073] S3: The gas supply module 5 is used to introduce a reaction gas into the electrolysis container 1 to replace the original gas in the electrolysis container 1. For example, the reaction gas can be high-purity oxygen. The gas supply module 5 can introduce the gas into the electrolysis container 1 for 10 to 50 minutes, thereby completely replacing the original gas in the electrolysis container 1, providing reaction conditions for the subsequent electrochemical reaction, and also enhancing the accuracy of the test.

[0074] S4: Activate the working electrode 21. For example, the activation treatment can be cyclic voltammetry (CV) activation treatment. That is, under given activation conditions, by controlling the voltage at a specific rate, the voltage is repeatedly scanned over time in a triangular waveform, causing the catalyst (catalyst slurry) on the working electrode 21 to alternately undergo reduction and oxidation reactions until the voltage curves coincide. It should be noted that cyclic voltammetry activation involves performing cyclic voltammetry tests, where the potential is selected as -0.05 to 1.5V vs. RHE, the scan rate is 20 to 200 mV / s, and the number of cycles is 50 to 500.

[0075] S5: The gas supply module 5 continuously supplies reaction gas into the electrolysis container 1, and then the simulated reverse polarity test time is measured by timing current or timing voltage.

[0076] For example, before the test, oxygen can be continuously introduced into the electrolysis container 1 through the gas supply module 5. After a preset time, the reverse polarity test can be simulated through the half-cell system. The test data is collected during the test phase, including the time t at which the first change point of the current is obtained (which can be regarded as the simulated reverse polarity test time).

[0077] It should be noted that the above-mentioned simulated reverse polarity test includes, but is not limited to, timing current and timing voltage. Preferably, timing current can be used for the test, that is, the current change can be recorded over a certain test time under a fixed voltage. The fixed voltage can be 1.5–3.0V vs. RHE, preferably 1.7–2.5V vs. RHE. The test time can be 10–10000s, preferably 1000–4000s.

[0078] In some other possible implementations, voltage changes can be recorded over a certain test period under a fixed current.

[0079] S6: The anti-reverse polarity performance of the catalyst is evaluated and described using simulated reverse polarity test time.

[0080] Specifically, the anti-reverse polarity performance of the catalyst can be described based on the simulated reverse polarity test time. This description may include: the longer the simulated reverse polarity test time, the longer the water electrolysis platform lasts during the reverse polarity process, the lower the degree of carbon corrosion, and the better the anti-reverse polarity performance of the catalyst.

[0081] The testing and evaluation method of this invention can more accurately, rapidly, and conveniently reflect the chemical processes of the catalyst in fuel cells, thereby obtaining more accurate anti-reverse polarity performance data and having an anti-reverse polarity time consistent with single-cell testing. Furthermore, the half-cell testing and evaluation method of this invention can also be used to evaluate the anti-reverse polarity performance of a large number of fuel cell anti-reverse polarity catalysts at a lower cost.

[0082] In some embodiments, determining the simulated reverse polarity test time further includes the following steps:

[0083] S51: Measure the duration of current decay or voltage increase corresponding to the transition point from a rapid decay of the initial current or a voltage surge to a smooth plateau. For example, when using a timing current method for testing, the decay time is the time taken from the start of the test to the lowest point of the first change in current. When using a timing voltage method for testing, the decay time is the time taken from the start of the test to the highest point of the first change in voltage increase.

[0084] S52: Repeat the experiment multiple times and average the time taken for the current to rapidly decay or the voltage to surge to a plateau. This average value is the simulated reverse electrode test time. For example, at least 2 to 10 catalyst electrode preparations and tests can be performed with the same catalyst loading on the electrode substrate. The decay time of each test is recorded, and the average of the multiple decay times is calculated. This eliminates errors and ensures the accuracy of the test.

[0085] In some embodiments, the present invention can also perform subsequent screening and classification of anti-reverse polarity catalysts and their products based on the above-described testing and evaluation methods. This screening and classification method may include the following steps:

[0086] A1: Using the above-mentioned half-cell test and evaluation method for anti-reverse catalysts for fuel cells, benchmark data corresponding to the simulated anti-reverse performance of at least one benchmark anti-reverse catalyst in a half-cell can be obtained. The benchmark data may include the benchmark data time t1.

[0087] A2: The anti-reverse electrode catalyst for the fuel cell to be screened is subjected to half-cell test, and the detection data corresponding to the anti-reverse electrode catalyst for the fuel cell to be screened is obtained according to the above half-cell test evaluation method. The detection data may include the detection data time t2.

[0088] A3: Based on the comparison results of the corresponding data in the benchmark data and the test data, for example, by comparing the test data time t2 and the benchmark data time t1, if the fit or difference between the test data time t2 and the benchmark data time t1 meets the requirements, the fuel cell anti-reverse electrode catalyst corresponding to the test data that meets the requirements can be used as the screening object or classified.

[0089] The following describes several specific embodiments of the present invention and several comparative test and evaluation methods.

[0090] Example 1

[0091] In Embodiment 1, the process can be broadly divided into two stages: a preparation stage and a testing stage. The preparation stage may include steps 1 and 2, while the testing stage may include steps 3 to 6.

[0092] Step 1: The catalyst electrode can be prepared first. Carbon paper with a thickness of 0.19 mm and a bulk density of 0.44 g / cm³ can be used for preparation. 3 Carbon paper can be cut to a size with an effective working area of ​​1 cm². 2 The well-dispersed Pt / C-1 catalyst slurry (containing 50 wt% Pt, with low-graphitic carbon support, i.e., carbon paper) was dropwise added onto carbon paper and dried for later use. The catalyst slurry loading on the carbon paper could be 200 μg / cm³. 2 .

[0093] Step 2: After the catalyst electrode is prepared, the half-cell can be assembled. During assembly, the catalyst electrode to be tested can be fixed with glassy carbon electrode clamp 3 and used as the working electrode 21. The reference electrode 23 can be saturated calomel, and the counter electrode 22 can be a Pt (platinum) mesh. The working electrode 21, reference electrode 23, and counter electrode 22 form a three-electrode system. The electrolysis container 1 can be filled with a 0.1 mol / L perchloric acid solution as the electrolyte. Then, oxygen can be introduced into the electrolysis container 1 through the gas supply module 5. The amount introduced can be controlled at 100 mL / min, and the introduction time can be 20 min, so that the oxygen in the electrolyte can be saturated.

[0094] Step 3: During the test, oxygen can be continuously supplied into the electrolysis container 1 using the gas supply module 5.

[0095] Step 4: Before conducting the test, the catalyst electrode to be tested can be activated by cyclic voltammetry (CV), where the potential can be selected as 0.05 to 1.2 V vs. RHE, the scan rate is 50 mV / s, and 100 cycles can be performed.

[0096] Step 5: After the catalyst electrode is activated, it can be tested by chronoamperometry. The fixed voltage can be 2.3V vs. RHE, and the test time can be selected as 4000s. Under the same Pt / C-1 catalyst slurry loading, the catalyst electrode can be prepared and tested at least 4 times.

[0097] Step 6: After the test is completed, the data can be processed. Specifically, the time corresponding to the initial current decay to the first lowest point can be selected, and the average value of the four test times can be taken. The average value is the simulated reverse polarity resistance time.

[0098] Example 2

[0099] The catalyst slurry in Example 1 can be replaced with Pt / C-2 with the same Pt ​​loading (50%), and the low-graphitic-density carbon support can be replaced with medium-graphitic-density carbon. Other conditions remain unchanged, and a half-cell test is performed. Since the testing procedure is the same as in Example 1, it will not be repeated here.

[0100] Example 3

[0101] The catalyst slurry in Example 1 can be replaced with Pt / C-3 with the same Pt ​​loading (50%), and the low-graphitic-density carbon support can be replaced with high-graphitic-density carbon. Other conditions remain unchanged, and a half-cell test is performed. Since the test procedure is the same as in Example 1, it will not be repeated here.

[0102] Example 4

[0103] An appropriate amount of IrO2 can be added to the Pt / C-1 catalyst slurry in Example 1, wherein the mass ratio of Pt / C-1 to IrO2 can be 10:2. Other conditions remain unchanged, and a half-cell test is performed. Since the test procedure is the same as in Example 1, it will not be repeated here.

[0104] Example 5

[0105] The half-cell test in Example 4 can be performed after the catalyst electrode is activated, using a chronovoltammetric method, where the fixed current can be 0.01A and the test time can be selected as 4000s. Other conditions remain unchanged.

[0106] Comparative Example 1

[0107] The loading of the catalyst slurry in Example 1 on carbon paper can be reduced to 20 μg / cm³. 2With other conditions remaining unchanged, a half-cell test was conducted. Since the testing process is the same as in Example 1, it will not be repeated here.

[0108] Comparative Example 2

[0109] The catalyst loading on carbon paper in Example 4 can be increased to 300 μg / cm³. 2 With other conditions remaining unchanged, a half-cell test was conducted. Since the testing process is the same as in Example 1, it will not be repeated here.

[0110] Comparative Example 3

[0111] The catalyst slurry Pt / C-1 and IrO2 in Example 3 can be used to make membrane electrodes through transfer and hot pressing processes, and then they can be assembled into single cells. Unlike Example 1, the assembled single cells can be installed on a proton exchange membrane fuel cell test bench for reverse electrode testing.

[0112] The test information curves of Examples 1 to 4 above can correspond to Figure 3 The test information in Example 5 corresponds to Figure 4 The test information curves of Comparative Examples 1 to 3 can respectively correspond to Figures 5 to 7 Furthermore, the information from Examples 1 to 5 and Comparative Examples 1 to 3 can also be summarized in Table 1 below.

[0113] Table 1 Information on each embodiment and comparative example

[0114]

[0115] By comparing and analyzing Examples 1, 2 and 3, when the Pt / C loading on the carbon paper is the same, the higher the degree of graphitization of the carbon support, the longer the time t (simulated reverse polarity test time), indicating that the higher the degree of graphitization of the carbon support in the catalyst, the better its anti-reverse polarity performance.

[0116] By comparing and analyzing Examples 1 and 4, it was found that adding an appropriate amount of IrO2 to the Pt / C-1 catalyst significantly increased the time, indicating that the addition of IrO2 effectively increased the simulated anti-reverse polarization time, demonstrating that IrO2 has a good anti-reverse polarization effect, which is consistent with the anti-reverse polarization test results using a membrane electrode.

[0117] By comparing and analyzing Examples 4 and 5, the same catalyst was tested using either chronocurrent or chronopotential, and the simulated anti-reverse polarization time of the catalyst was basically the same. This indicates that the two test methods can be used to evaluate the anti-reverse polarization effect of the catalyst equally.

[0118] By comparing and analyzing Example 1, Comparative Example 1, and Comparative Example 2, the catalyst loading on carbon paper was investigated. When the catalyst loading was too low (20 μg / cm³), the catalyst loading was significantly reduced. 2When the catalyst loading is too high (300 ug / cm³), the morphology of the simulated anti-reverse electrode test curve is consistent with that of the carbon paper test curve, making it impossible to clearly distinguish the current change range caused by catalyst corrosion, which will lead to a large error in the data analysis. 2 When the catalyst loading is too high, the simulated anti-reverse electrode test time is too long, resulting in reduced test efficiency. Therefore, the optimal loading range should be controlled between 60 and 250 μg / cm³. 2 .

[0119] By comparing and analyzing Example 4 and Comparative Example 3, the catalysts Pt / C-1 and IrO2 were fabricated into membrane electrodes using transfer and hot pressing processes, and assembled into single cells. These cells were then installed on a proton exchange membrane fuel cell test bench for single-cell reverse polarity testing. The results showed that the catalyst's reverse polarity resistance time in the single-cell test was 2220s, which is consistent with the reverse polarity resistance time in the half-cell system test (1635s). This indicates that the half-cell test method in this invention can quickly and reliably evaluate the reverse polarity resistance performance of catalysts used in fuel cells.

[0120] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0121] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0122] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0123] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0124] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0125] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A test and evaluation method for a half-cell system based on the anti-reverse polarity test of a fuel cell catalyst, characterized in that, The fuel cell catalyst anti-reverse polarity test half-cell system includes: An electrolytic container, comprising a box body and a sealing cap, wherein the top of the box body is open, and an opening on the sealing cap is used for assembling an electrode module, and the sealing cap can be sealed and assembled at the top opening of the box body, and the box body is used for storing electrolyte. An electrode module is disposed within the electrolytic container. The electrode module includes a working electrode, a counter electrode, and a reference electrode. The electrode module passes through the sealing cap. The working electrode, at least a portion of the counter electrode, and at least a portion of the reference electrode are immersed in the electrolyte. The working electrode includes an electrode substrate and a catalyst slurry disposed on the surface of the electrode substrate. The electrode substrate is a titanium mesh, a titanium-plated platinum sheet, a carbon felt, or carbon paper. A control module is located on the outside of the electrolytic vessel and is electrically connected to the electrode module. The control module is used to control the voltage of the working electrode, the counter electrode, and the reference electrode. A gas supply module is located on the outside of the electrolysis container. The output end of the gas supply module passes through the sealing cover and is connected to the electrolysis container. The gas supply module is used to supply reaction gas into the electrolysis container. A collection module is provided on the outside of the electrolysis container. The input end of the collection module passes through the sealing cover and communicates with the electrolysis container. The collection module is used to collect the gas inside the electrolysis container. The test evaluation method includes the following steps: The electrode substrate and catalyst slurry are determined, and the working electrode is prepared using the electrode substrate and the catalyst slurry; Assemble the working electrode, counter electrode, reference electrode, electrolytic capacitor, control module, gas supply module, and collection module to form a half-cell system; A gas supply module is used to introduce reactive gas into the electrolysis container to replace the original gas in the electrolysis container; The working electrode is activated. The gas supply module continuously supplies reaction gas into the electrolysis container, and then the simulated reverse polarity test time is measured by timing current or timing voltage. The anti-reverse polarity performance of the catalyst is evaluated and described using the simulated reverse polarity test time. The determination of the simulated reverse polarity test time includes the following steps: Measure the time it takes for the initial current to rapidly decay or the voltage to surge to a smooth plateau. Repeat the experiment multiple times and take the average of the time it takes for the current to rapidly decay or the voltage to surge to a smooth plateau. The average value is the simulated reverse polarity test time.

2. The test and evaluation method for a half-cell system based on the anti-reverse polarity test of a fuel cell catalyst according to claim 1, characterized in that, The control module includes a working clamp, the working clamp, the counter electrode and the reference electrode are arranged in parallel, and the working clamp is connected to the working electrode.

3. The test and evaluation method for a half-cell system based on the anti-reverse polarity test of a fuel cell catalyst according to claim 2, characterized in that, The control module includes an electrode clamp, and the working electrode is indirectly connected to the working clamp via the electrode clamp; And / or, the electrode clip is a platinum sheet electrode clip, a stainless steel electrode clip, a graphite electrode clip, or a glassy carbon electrode clip.

4. The test and evaluation method for a half-cell system based on the anti-reverse polarity test of a fuel cell catalyst according to claim 3, characterized in that, The sealing cover is provided with multiple assembly holes. The electrode clamp, the counter electrode, the reference electrode, the gas supply module, and the collection module are respectively assembled to the corresponding assembly holes and extend into the electrolysis container through the assembly holes.

5. The test and evaluation method for a half-cell system based on fuel cell catalyst anti-reverse polarity testing according to claim 1, characterized in that, The reacting gas is oxygen, nitrogen, or air; And / or, the collection module is a gas collection bag, a gas collector, or a gas chromatograph.

6. The test and evaluation method for a half-cell system based on the anti-reverse polarity test of a fuel cell catalyst according to claim 1, characterized in that, The electrolyte is perchloric acid, sulfuric acid, or hydrochloric acid; And / or, the electrolytic container is made of glass.

7. The test and evaluation method for a half-cell system based on the anti-reverse polarity test of a fuel cell catalyst according to claim 1, characterized in that, The counter electrode is a platinum wire, platinum mesh, or platinum sheet; And / or, the reference electrode is a saturated calomel electrode or a reversible hydrogen electrode.

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