Preparation method of nitrogen-repellent membrane electrode material of fuel cell
By preparing the nitrogen-aberaging membrane electrode material of fuel cell, the problem of slow cathode kinetics of fuel cell is solved, and the performance and output capabilities of hydrogen air fuel cells are improved.
Patent Information
- Application Number
- CN202510701394.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-28
- Publication Date
- 2025-09-05
AI Technical Summary
The cathode kinetics of fuel cells are slow, especially in hydrogen air fuel cells. The main reason is that the oxygen content in the air is low, which leads to increased polarization of the cathode catalytic layer and low performance, making it impossible to break through the commercial bottleneck.
Prepare nitrogen-absorbing membrane electrode materials for fuel cell to regulate the catalytic microenvironment, reduce polarization losses and improve reaction kinetics.
The preparation of nitrogen-eating materials is realized, the performance of hydrogen air fuel cells is improved, high power and high current output is shown, and the cathode reaction efficiency is improved.
Smart Images
Figure CN120600839A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of fuel cells, in particular to a method for preparing a nitrogen-phobic membrane electrode material for a fuel cell. Background Art
[0002] Fuel cells are highly efficient and environmentally friendly new energy power generation devices that can directly convert the chemical energy of hydrogen fuel into electrical energy. They can be widely used in energy, automotive, aerospace and other fields. However, the cathode kinetics of fuel cells are slow, especially in hydrogen-air fuel cells. The main reason is that the oxygen content in the air is low, and the main component is nitrogen, which further increases the polarization in the cathode catalyst layer, resulting in low performance and inability to break through the commercial bottleneck. Therefore, developing an efficient cathode catalyst material to improve the fuel cell cathode reaction kinetics, reduce polarization, and achieve further breakthroughs in hydrogen-air fuel cells has important theoretical significance and application value. Summary of the Invention
[0003] The present invention provides a method for preparing a fuel cell nitrogen-phobic membrane electrode material that regulates the catalytic microenvironment, which reduces the polarization loss of the fuel cell cathode and improves the reaction kinetics through the nitrogen-phobicity of the material.
[0004] The implementation path of the present invention is as follows: A method for preparing a nitrogen-phobic membrane electrode for a fuel cell, the specific method steps of which include:
[0005] Step 1 Precursor preparation
[0006] An amino compound, a phenolic compound, and alkaline water are stirred in a mass ratio of 3 to 9:0.6 to 1.8:25 to obtain a mixture A; an aldehyde compound and a template agent are then added in sequence, and stirring is continued. The mixture is then placed into a solution for a solvothermal reaction to obtain the desired precursor;
[0007] Step 2: Heat treatment
[0008] The prepared precursor is immersed in a fuel cell catalyst metal ion solution, continuously stirred, then centrifuged and dried; the obtained material is further subjected to high-temperature treatment, and the heating program starts from room temperature and rises to 350-450 degrees Celsius. After reaching the treatment temperature, it is maintained for 1-3 hours, and then further heated to 600-1000°C, maintained for 2 hours, and cooled to room temperature or naturally cooled to room temperature to obtain the final material.
[0009] Furthermore, the phenolic compound is one or more of phenol, cresol, xylenol, mixed cresols, nonylphenol, aralkylphenol, cardanol, octylphenol or bisphenol A.
[0010] The aldehyde compound is one or more of furfural, acetaldehyde, paraformaldehyde or formaldehyde.
[0011] The amino-containing compound is one or more of dicyandiamide, urea, melamine, and melamine phosphate.
[0012] The template agent is a triblock polymer, a cationic surfactant, an anionic surfactant, a nonionic surfactant, a microemulsion template or a molecular sieve.
[0013] Preferably, the addition ratio of the aldehyde compound to the mixture A is 0.175-0.5 ml / g, and the weight ratio of the added template agent to the mixture A is 0.06-0.18:1.
[0014] Preferably, the stirring temperature of the obtained mixture A is 40-80° C. for 2 hours, and the stirring time after adding the aldehyde compound and the template agent is 24 hours.
[0015] Preferably, the metal ions in the fuel cell catalyst metal ion solution are noble metal ions and / or transition metal ions.
[0016] Preferably, the metal ions in the fuel cell catalyst metal ion solution are one or more of Pt, Pd, Ir, Ru, Rh, Co, Fe, Cu, Au, Sn, Mo, Mn, Ti or Ni ions.
[0017] Preferably, the metal ion concentration of the fuel cell catalyst metal ion solution is 10%-50%.
[0018] Preferably, the solvent thermal reaction time is 24 hours and the reaction temperature is 120°C.
[0019] Preferably, the processing environment atmosphere of the high temperature treatment is an inert gas, including nitrogen or argon; or a reactive gas, including hydrogen or ammonia, or a mixture of an inert gas and a reactive gas.
[0020] Preferably, the gas flow rate of the treatment environment atmosphere is 20 to 50 ml / min.
[0021] Preferably, during the high temperature treatment, the heating rate is 0.5 to 5 degrees Celsius per minute, and the cooling rate is 0.5 to 5 degrees Celsius per minute.
[0022] The invention also discloses a fuel cell nitrogen-phobic membrane electrode material, which is prepared by the above method.
[0023] After the present invention adopts the above technical solution, it has the following main effects:
[0024] (1) In the preparation of the drive body of the present invention, the phenol group preferentially reacts with the aldehyde group under alkaline conditions, while the amino group will also participate in the reaction to carry out copolymerization condensation. Then, by controlling the pH, feed ratio and redox environment, a directional synthesis from a linear soluble polymer to a highly cross-linked network material is achieved. By utilizing the organic site coordination polymerization effect, different templates, different component ratios, different hydrothermal conditions and other optimizations are achieved to achieve different pore structure adjustments and different pore shape controls. The copolymer body achieves from trace metal enrichment (ppb level) to high capacity loading.
[0025] (>10wt%) precise control.
[0026] (2) The present invention utilizes the confinement effect of the proposed pore structure to anchor the catalyst metal, and realizes nitrogen-phobic materials containing different catalyst metals through factors such as different catalyst metals, different calcination temperatures, and different calcination atmospheres.
[0027] (3) The present invention realizes the preparation of nitrogen-repellent materials, exhibits certain nitrogen-repellent properties, effectively improves the performance of hydrogen-air fuel cells, exhibits higher power, and realizes large current output at high potential. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1 These are electron microscope images of the material prepared in Example 1 at different scales.
[0029] Figure 2 1 is a comparison chart of nitrogen and oxygen adsorption test results of the materials prepared in Example 1 and the comparative example.
[0030] Figure 3 1 is a comparison chart of the hydrogen-air fuel cell performance test curves of the membrane electrode in Example 1 and the comparative example.
[0031] Figure 4 This is a graph showing the adsorption test results of nitrogen and oxygen for the material prepared in Example 2.
[0032] Figure 5 This is a performance test curve of the membrane electrode hydrogen-air fuel cell in Example 2.
[0033] Figure 6 This is a graph showing the adsorption test results of nitrogen and oxygen for the material prepared in Example 3.
[0034] Figure 7 This is a performance test curve of the membrane electrode hydrogen-air fuel cell in Example 3. DETAILED DESCRIPTION
[0035] Example 1
[0036] The specific method steps of the nitrogen-phobic material in this embodiment include:
[0037] (1) Precursor preparation
[0038] Melamine, phenol and alkaline water were mixed in the ratio of 3g:0.6g:25g, stirred at 60°C for 2 hours, and then 5ml of formaldehyde and 1.8g of triblock polymer were added in sequence, and stirring was continued for 24 hours. After that, the precursor was configured into a 5% concentration solution and subjected to a 24-hour solvent thermal reaction to obtain the desired precursor. In this example, the temperature of the solvent thermal reaction is exemplarily 120°C, but is not limited to this. The exemplary first stirring and continued stirring times are preferably given here, but are not limited to this. Those skilled in the art can choose the stirring time they feel is necessary.
[0039] (2) Heat treatment
[0040] The prepared precursor was immersed in a 10% Pt ion solution, stirred for 24 hours, and then centrifuged and dried.
[0041] The obtained material was further subjected to high-temperature treatment. The treatment environment atmosphere was nitrogen with a hydrogen content of 5%, the gas flow rate was 50 ml / min, and the heating program started from room temperature and was heated to 350 degrees Celsius at a heating rate of 1 degree Celsius / min. After reaching the treatment temperature, it was maintained for 2 hours, and then further heated to 700°C at a heating rate of 1 degree Celsius / min, maintained for 2 hours, and finally cooled to room temperature at a cooling rate of 5 degrees Celsius / min or naturally cooled to room temperature to obtain the final material, which was stored for use.
[0042] Figure 1 This is an electron microscope image of the nitrogen-repellent material prepared in this example. As can be seen from part a of the figure, the phenol group in phenol preferentially reacts with the aldehyde group of formaldehyde under alkaline conditions, while the amino group in melamine will also participate in the reaction to undergo copolymerization and condensation. By controlling the pH, feed ratio and redox environment in this example, a directional synthesis from a linear soluble polymer to a highly cross-linked network material is achieved. The material in the figure shows a distinct porous microstructure. By utilizing the organic site coordination polymerization effect and the template agent, under the optimized component ratio (quinone / phenol ratio) and hydrothermal conditions in this example, pore structure adjustment and different pore shape regulation are achieved. As shown in part b of the figure, Pt ions exist in the form of nanoparticles at the end of the porous structure. It can be seen that the nitrogen-repellent material prepared in this example has achieved an improvement from trace metal enrichment (ppb level) to high capacity loading (>10wt%).
[0043] It is worth noting that while phenol, melamine, and formaldehyde are used in this example, the present invention is not limited thereto. Other phenolic compounds, amino compounds, and aldehyde compounds can also be used for copolymerization. Templates other than triblock polymers are also suitable for the present invention, including but not limited to cationic surfactants, anionic surfactants, nonionic surfactants, microemulsion templates, or molecular sieves. In addition to the aforementioned Pt ions, other catalytic noble metal ions and / or transition metal ions are also suitable for use in the present invention.
[0044] Finally, in this example, Pt ions exist in the porous structure in the form of nanoparticles, which also alleviates the problem of sulfonate poisoning of Pt sites during membrane electrode preparation.
[0045] (3) Nitrogen repellency test
[0046] The prepared materials were tested for nitrogen and oxygen adsorption using a gas adsorption instrument.
[0047] (4) Fuel cell testing
[0048] The fuel cell test was carried out on the membrane electrode based on the material prepared in this example using a fuel cell test system (Scribner 850e). The effective active area of the membrane electrode was fixed at 5 cm 2 The fuel cell's flow field plate uses a single serpentine graphite flow field plate, and the cell assembly is performed with a torque of 4.5 N·m. Membrane electrode polarization curves were obtained at a cell temperature of 80°C and a back pressure of 0.2 MPa. The anode hydrogen flow rate was set at 0.2 L / min, the cathode air flow rate was set at 0.5 L / min, and the relative humidity of the reactant gases was controlled at 100%.
[0049] Comparative Example 1
[0050] (1) Commercial platinum carbon membrane electrode.
[0051] (2) Nitrogen repellency test is the same as above.
[0052] (3) Fuel cell test is the same as above.
[0053] The material prepared in this example showed good nitrogen-repellent properties, such as Figure 2 As shown in Figure 2, the prepared nitrogen-phobic material has lower nitrogen adsorption, and the nitrogen adsorption capacity is only 1.5 cm when the nitrogen pressure reaches 1 Bar. 3 / g, much lower than the comparison material 14cm 3 / g nitrogen adsorption capacity; on the other hand, in the oxygen adsorption test, the material prepared in this example showed higher oxygen adsorption. With the increase of pressure, the oxygen adsorption of the material prepared in this example can reach up to 7.23cm 3 / g, while the comparison material only reached 0.797cm3 / g.
[0054] like Figure 3 As shown in Figure 2, the prepared membrane electrode outputs a higher current (J / A.cm) at a high potential (E / V) -3 ), showing better performance. This shows that the polarization loss of the fuel cell cathode can be significantly reduced and its reaction kinetics can be improved through the nitrogen-repellent property of the material.
[0055] Example 2
[0056] A method for preparing a nitrogen-phobic material, the specific method steps comprising:
[0057] (1) Precursor preparation
[0058] Melamine, phenol, and alkaline water were mixed in a ratio of 3 g:1.8 g:25 g, stirred at 40° C. for 2 hours, and then 15 ml of formaldehyde and 5.4 g of triblock polymer were added in sequence. Stirring was continued for 24 hours, and then a 20% solution was prepared and subjected to a 24-hour solvothermal reaction to obtain the desired precursor. In this example, the solvothermal reaction temperature is preferably 120° C., but is not limited thereto. In the embodiments of the present invention, solvothermal reactions at different temperatures are allowed.
[0059] (2) Heat treatment
[0060] The prepared precursor was immersed in a 50% Pt ion solution, stirred for 24 hours, then centrifuged and dried. The obtained material was further subjected to high-temperature treatment in a treatment environment atmosphere of nitrogen with a hydrogen content of 5%, a gas flow rate of 50 ml / min, and a heating program starting from room temperature and increasing the temperature to 400 degrees Celsius at a heating rate of 1 degree Celsius / minute. After reaching the treatment temperature, it was maintained for 2 hours, then further heated to 1000°C and maintained for 2 hours. Finally, it was cooled to room temperature at a cooling rate of 5 degrees Celsius / minute or naturally cooled to room temperature to obtain the final material and stored for use.
[0061] (3) Nitrogen repellency test
[0062] The material was tested for nitrogen and oxygen adsorption using a gas adsorption instrument.
[0063] (4) Fuel cell testing
[0064] The fuel cell test system (Scribner 850e) was used to test the membrane electrode. The effective active area of the membrane electrode was fixed at 5 cm 2The fuel cell's flow field plate uses a single serpentine graphite flow field plate, and the cell assembly is performed with a torque of 4.5 N·m. Membrane electrode polarization curves were obtained at a cell temperature of 80°C and a back pressure of 0.2 MPa. The anode hydrogen flow rate was set at 0.2 L / min, the cathode air flow rate was set at 0.5 L / min, and the relative humidity of the reactant gases was controlled at 100%.
[0065] like Figure 4 As shown in the figure, the material prepared in this example also exhibits good nitrogen-repellent properties. On the other hand, in the oxygen adsorption test, the material prepared in this example exhibits higher oxygen adsorption. Figure 5 As shown in the figure, the membrane electrode prepared in this example also outputs a higher current (J / A.cm) at a high potential (E / V). -3 ), showing better performance.
[0066] Example 3
[0067] A method for preparing a nitrogen-phobic material, the specific method steps comprising:
[0068] (1) Precursor preparation
[0069] Prepare precursor raw materials such as melamine, phenol, alkaline water, formaldehyde and triblock polymer in a mass ratio of 9:0.6:25:12:5.4. First, mix melamine, phenol and alkaline water, then formaldehyde and triblock polymer in sequence, continue stirring for 24 hours, and then prepare a 5% concentration solution for 24 hours of solvothermal reaction.
[0070] (2) Heat treatment
[0071] The prepared precursor was immersed in a 10% Pt ion and 10% Co ion solution, stirred for 24 hours, then centrifuged and dried. The resulting material was further subjected to high-temperature treatment in a nitrogen atmosphere with a 5% hydrogen content, a gas flow rate of 50 ml / min, and a heating program starting from room temperature and increasing the temperature to 450 degrees Celsius at a heating rate of 1 degree Celsius / minute. After reaching the treatment temperature, it was maintained for 2 hours, then further heated to 600 degrees Celsius and maintained for 2 hours. Finally, it was cooled to room temperature at a cooling rate of 5 degrees Celsius / minute or naturally cooled to room temperature to obtain the final material and stored for future use.
[0072] (3) Nitrogen repellency test
[0073] The material was tested for nitrogen and oxygen adsorption using a gas adsorption instrument.
[0074] (4) Fuel cell testing
[0075] The fuel cell test system (Scribner 850e) was used to test the membrane electrode. The effective active area of the membrane electrode was fixed at 5 cm2 The fuel cell's flow field plate uses a single serpentine graphite flow field plate, and the cell assembly is performed with a torque of 4.5 N·m. Membrane electrode polarization curves were obtained at a cell temperature of 80°C and a back pressure of 0.2 MPa. The anode hydrogen flow rate was set at 0.2 L / min, the cathode air flow rate was set at 0.5 L / min, and the relative humidity of the reactant gases was controlled at 100%.
[0076] like Figure 6 As shown in the figure, the material prepared in this example also exhibits good nitrogen-repellent properties. On the other hand, in the oxygen adsorption test, the material prepared in this example exhibits higher oxygen adsorption. Figure 7 As shown, the membrane electrode prepared in this example also outputs a higher current (J / A.cm-3) at a high potential (E / V), showing better performance.
[0077] It is worth noting that, in addition to phenol, other phenolic compounds may also be used in the preparation of the precursor of the present invention, specifically one or more of phenol, cresol, xylenol, mixed cresols, nonylphenol, aralkylphenol, cardanol, octylphenol or bisphenol A.
[0078] In the preparation of the precursor of the present invention, in addition to melamine, an amino compound may also be used, specifically one or more of dicyandiamide, urea, phosphoric acid or melamine.
[0079] In the preparation of the precursor of the present invention, in addition to formaldehyde, other aldehyde compounds may also be used, specifically one or more of furfural, acetaldehyde, paraformaldehyde or formaldehyde.
[0080] Under alkaline conditions, the phenolic groups in phenolic compounds preferentially react with the aldehyde groups in phenolic compounds, while the amino groups in amino compounds also participate in the reaction, resulting in copolymerization and condensation. By manipulating the topology and redox state (quinone / phenol ratio) of the copolymer, precise control from trace metal enrichment (ppb level) to high capacity loading (>10wt%) can be achieved.
[0081] In addition to the aforementioned Pt and Co ions, in other embodiments of the present invention, the metal ions in the fuel cell catalyst metal ion solution may also be other precious metal ions and / or transition metal ions, specifically, one or more of Pt, Pd, Ir, Ru, Rh, Co, Fe or Ni ions, which can be used as the catalyst metal ions required for this method.
[0082] In other embodiments of the present invention, the high-temperature treatment environment atmosphere is an inert gas, including nitrogen or argon; a reactive gas, including hydrogen or ammonia; or a mixture of an inert gas and a reactive gas. Furthermore, the gas flow rate of the high-temperature treatment environment atmosphere can be selected between 20 and 50 ml / min.
[0083] In the high temperature treatment of other embodiments of the present invention, the heating rate is selected between 0.5 and 5 degrees Celsius per minute, the cooling rate is selected between 0.5 and 5 degrees Celsius per minute, and the holding time after reaching the treatment temperature can be selected between 1 and 3 hours.
[0084] The above is only an embodiment of the present invention, and the common knowledge such as the specific technical solutions and / or characteristics in the solution are not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several variations and improvements can be made, which should also be regarded as the scope of protection of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by the present invention shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.
Claims
1. A method for preparing a nitrogen-phobic membrane electrode material for a fuel cell, characterized in that: include: Step 1: Precursor preparation: An amino compound, a phenolic compound, and alkaline water are stirred in a mass ratio of 3 to 9:0.6 to 1.8:25 to obtain a mixture A; an aldehyde compound and a template agent are then added in sequence, and stirring is continued. The mixture is then placed into a solution for a solvothermal reaction to obtain the desired precursor; Step 2 Heat treatment: The prepared precursor is immersed in a fuel cell catalyst metal ion solution, continuously stirred, then centrifuged and dried; the obtained material is further subjected to high-temperature treatment, and the heating program starts from room temperature and rises to 350-450 degrees Celsius. After reaching the treatment temperature, it is maintained for 1-3 hours, and then further heated to 600-1000°C, maintained for 2 hours, and cooled to room temperature or naturally cooled to room temperature to obtain the final material.
2. The method according to claim 1, characterized in that The phenolic compound is one or more of phenol, cresol, xylenol, mixed cresols, nonylphenol, aralkylphenol, cardanol, octylphenol or bisphenol A.
3. The method according to claim 1, characterized in that The aldehyde compound is one or more of furfural, acetaldehyde, paraformaldehyde or formaldehyde.
4. The method according to claim 1, wherein The amino-containing compound is one or more of dicyandiamide, urea, melamine, and melamine phosphate.
5. The method according to claim 1, characterized in that The template agent is a triblock polymer, a cationic surfactant, an anionic surfactant, a nonionic surfactant, a microemulsion template or a molecular sieve.
6. The method according to claim 5, characterized in that The added ratio of formaldehyde to mixture A is 0.175-0.5 ml / g, and the weight ratio of the added template agent to mixture A is 0.06-0.18:
1.
7. The method according to claim 6, characterized in that The obtained mixture A is stirred at a temperature of 40-80°C for 2 hours, and the stirring time after adding formaldehyde and template agent is 24 hours; The solvent thermal reaction time is 24 hours, and the reaction temperature is 120°C.
8. The method according to claim 1, characterized in that The metal ions in the fuel cell catalyst metal ion solution are noble metal ions and / or transition metal ions; The metal ions in the fuel cell catalyst metal ion solution are one or more of Pt, Pd, Ir, Ru, Rh, Co, Fe or Ni ions; The metal ion concentration of the fuel cell catalyst metal ion solution is 10%-50%.
9. The method according to claim 1, characterized in that The processing environment atmosphere of the high temperature treatment is an inert gas, including nitrogen or argon; or a reactive gas, including hydrogen or ammonia, or a mixture of an inert gas and a reactive gas; During the high temperature treatment, the heating rate is 0.5 to 5 degrees Celsius per minute, and the cooling rate is 0.5 to 5 degrees Celsius per minute.
10. A fuel cell nitrogen-phobic membrane electrode material, characterized in that: The material is prepared by the method according to any one of claims 1 to 9.