CN113871633B - Method for efficiently activating membrane electrode of proton exchange membrane fuel cell in situ - Google Patents

Abstract

The invention discloses a method for efficiently activating a proton exchange membrane fuel cell membrane electrode in situ. Firstly adding materials such as carbon, pore-forming agent and the like into catalyst slurry, then ultrasonically spraying the slurry to two sides of a proton exchange membrane, and attaching gas diffusion layers on the two sides to obtain a membrane electrode. The activation is carried out by the following steps: (1) The membrane electrode is assembled into a single cell, the temperature of the cell is 20-90 ℃, the relative humidity of the anode and the cathode is 20-100%, and the stoichiometric amounts of hydrogen and air are 1.0-4.0 and 1.0-5.0 respectively; (2) The battery voltage is controlled to be 0.8-0.9V, 0.5-0.8V and 0.3-0.5V respectively, and the duration time is 0.5-3 min, 0.5-5 min and 0.5-5 min respectively; (3) circulating the step (2) for 2-8 times. According to the invention, through voltage circulation and adding of carbon, pore-forming agent and other materials, the three-phase interface of the membrane electrode is optimized, the diffusion and transmission of water, gas and electrons are improved, and the activation time of the membrane electrode is shortened. Compared with the traditional activation method, the in-situ activation process is simple, short in time and high in efficiency.

Description

A method for efficient in-situ activation of membrane electrodes of proton exchange membrane fuel cells

technical field

The invention belongs to the technical field of fuel cells, and in particular relates to a method for efficiently in-situ activating a membrane electrode of a proton exchange membrane fuel cell.

Background technique

A fuel cell is a device that converts chemical energy into electrical energy. It needs to be activated after the battery is assembled to achieve the best performance. The traditional activation methods are mainly constant current activation and variable flow forced activation. The activation time takes several hours, and at the same time, the consumption of hydrogen is relatively large, which hinders the commercial development of fuel cells. Therefore, how to improve the activation process of the fuel cell, shorten the activation time, and increase the activation efficiency is one of the important factors influencing the commercialization of the fuel cell.

Contents of the invention

The invention aims to provide a method for rapid activation of membrane electrodes of proton exchange membrane fuel cells with simple operation, which can reduce battery activation time and improve activation efficiency.

The present invention adopts following technical scheme:

A method for activating the membrane electrode of a proton exchange membrane fuel cell with high efficiency in situ. The high and low cycles are used to achieve the purpose of in-situ activation of the membrane electrode of the proton exchange membrane fuel cell.

Further, the membrane electrode is prepared by spraying, and the slurry used for spraying includes: catalyst, solvent and perfluorosulfonic acid resin solution, and the solvent is deionized water and low fat alcohol; optional hydrophilic material, Hydrophobic materials, carbon materials, pore formers and/or anti-reverse catalysts.

Preferably, the catalyst is one or more of Pt/C, PtCo/C, PtNi/C, and PtCoMn/C.

Preferably, the low-fat alcohol is one or more of ethanol, isopropanol, n-propanol and ethylene glycol.

Preferably, the hydrophilic material includes one or more of SiO ₂ , Al ₂ O ₃ , cross-linked polyvinyl alcohol, and silicon-aluminum fiber.

Preferably, the hydrophobic material is one or more of FEP, PTFE, PFA, and PFPE.

Preferably, the pore-forming agent is one or more of oxalic acid, ammonium bicarbonate, ammonium carbonate, and ammonium chloride.

Preferably, the anti-reverse catalyst is one or more of IrO ₂ , PtRu/C, PtIr/C, RuO ₂ , RuO ₂ -IrO ₂ , RuO ₂ -TiO ₂ .

Preferably, the carbon material is one or more of carbon nanotubes, acetylene black, Ketjen black, graphene oxide, graphene, carbon nanohorns, graphite, and activated carbon.

DE2020、IC100、IC154、/>

D79-25BS、/>

D83-24BS中的一种或几种。Preferably, the perfluorosulfonic acid resin solution is

DE2020, IC100, IC154, />

D79-25BS, />

One or more of D83-24BS.

Further, the output voltages are 0.8-0.9V, 0.5-0.8V and 0.3-0.5V, and the duration of each voltage is 0.5min-5min.

The steps that the present invention takes are as follows:

Step 1. Preparation of catalyst slurry: 1-100 parts by weight of solvent, 0.1-10 parts by weight of catalyst, 0.1-10 parts by weight of perfluorosulfonic acid resin solution, 0-3 parts by weight of hydrophilic material, 0-10 parts by weight of 3 parts by weight of hydrophobic material, 0-5 parts by weight of pore-forming agent, 0-1 part by weight of anti-reverse catalyst, and 0-5 parts by weight of carbon material are mixed and dispersed evenly, and the solid content of the obtained dispersion is 0.1wt %～15wt%;

Step 2. Preparation of the membrane electrode: uniformly spray the catalyst slurry on both sides of the proton exchange membrane, dry the membrane electrode, and cover the gas diffusion layer to obtain the membrane electrode of the proton exchange membrane fuel cell;

Step 3. Single cell test: Assemble the membrane electrode into a single cell, and test its air tightness, respectively pass air and hydrogen into the cathode and anode, heat the battery to a certain temperature, and adjust the output voltage to 0.8-0.9V, 0.5 ~ 0.8V and 0.3 ~ 0.5V, the duration of each voltage is 0.5min ~ 5min, cycle 2 ~ 8 times.

Preferably, in the step 1; the parts by weight of the pore-forming agent and the carbon material are not 0 at the same time.

Further, in the step 1, the mass ratio of the solvent to the catalyst in the catalyst slurry is (10-100):(0.1-10). The mass ratio of the catalyst to the perfluorosulfonic acid resin solution is (0.1-10): (0.1-6). The mass ratio of the hydrophilic material to the catalyst is (0.01-5): (0.1-10). The mass ratio of the hydrophobic material to the catalyst is (0.01-1): (0.1-10). The mass ratio of the carbon material to the catalyst is (0.01-3): (0.1-10). The mass ratio of the pore-forming agent to the catalyst is (0.01-1): (0.1-10). The mass ratio of the anti-anti-electrode catalyst to the catalyst is (0.01-3): (0.1-10).

Further, in the step 2, the anode Pt loading of the membrane electrode is 0.1 mg/cm ² to 0.5 mg/cm ² , the cathode Pt loading is 0.01 mg/cm ² to 0.3 mg/cm ² , and the drying temperature 30° C. to 90° C., and the thickness of the gas diffusion layer is 100 μm to 350 μm.

Further, in the step 3, the gas leakage rate of the single cell is 0-0.1ml/min, the relative humidity of the anode and cathode is 20%-100%, the stoichiometric ratio of hydrogen is 1.0-4.0, and the stoichiometric ratio of air The ratio is 1.2-4.5, the battery temperature is 20°C-90°C, and the output voltage decreases by 0.2V-0.4V each time.

Further, in the step 1; the parts by weight of the pore-forming agent and the carbon material are not 0 at the same time.

The beneficial effects of the present invention are reflected in:

The invention provides a method for efficient in-situ activation of the membrane electrode of a proton exchange membrane fuel cell. By adding materials such as carbon materials and pore-forming agents to the catalytic layer, and combining the high and low cycles of the output voltage, the impurities and comparatively small impurities in the catalytic layer can be effectively removed. The large porosity improves the efficiency of reactants reaching the active sites of the catalytic layer, so that the fuel cell can reach the optimal working state in a short time. At the same time, the present invention activates by changing the voltage, which can avoid the phenomenon of insufficient hydrogen supply in the sudden loading process of the battery, thereby reducing the possibility of reverse polarity of the battery. The invention has simple process and high activation efficiency, can greatly shorten the activation time of the battery and reduce the production cost.

Description of drawings

Fig. 1, Fig. 2, Fig. 3 are respectively the cross-sectional topography diagrams of the catalytic layer in the embodiment 1, embodiment 2 and embodiment 3 of the present invention.

Fig. 4, Fig. 5 and Fig. 6 are the surface topography diagrams of the catalytic layer in Embodiment 1, Embodiment 2 and Embodiment 3 of the present invention respectively.

FIG. 7 is a graph showing the variation of the output voltage with time in Embodiment 1 of the present invention. The output voltage of the battery is continuously cycled between low potential and high potential, and it only takes 63 minutes to complete the activation, which is about 74% shorter than the activation time of the existing fuel cell.

FIG. 8 is a graph showing the variation of the output voltage with time in Embodiment 2 of the present invention. The output voltage of the battery is continuously cycled among 0.85V, 0.75V, and 0.45V, and it only takes 60 minutes to complete the activation, which is about 75% shorter than the activation time of the existing fuel cell.

FIG. 9 is a graph showing the variation of the output voltage with time in Embodiment 3 of the present invention. The output voltage of the battery continuously cycles between low potential and high potential, and it takes only 77 minutes to complete the activation, which is about 68% shorter than the activation time of existing fuel cells.

Fig. 10 is a comparison diagram of the polarization curves before and after activation of the single cells of Example 1, Example 2, and Example 3 of the present invention, and the unactivated curves. As can be seen in the figure: the voltage of the activated battery under low current density and high current density has been significantly improved, which shows that the method for activating the membrane electrode of a proton exchange membrane fuel cell proposed by the present invention is useful for short-term activation. Fuel cells have obvious effects.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example 1:

DE2020(固含量25wt％)，所述溶剂为：去离子水、异丙醇、乙醇，所述质子交换膜为科慕NC700。所述气体扩散层为科德宝H24CX483，厚度为250μm。In this example, the proton exchange membrane fuel cell membrane electrode is prepared with the following raw materials: 100 mg of catalyst, 3 mg of carbon material, 140 mg of perfluorosulfonic acid resin solution, 10 g of solvent, 25 cm ² of proton exchange membrane, and 25 cm ² of gas diffusion layer. Wherein, the catalyst is Pt/C (Johnson Matthey, HiSPEC 13100, Pt content is 60wt%), and the carbon material is carbon nanotubes (Wokai, multi-walled carbon nanotubes, pipe diameter 2-10nm, purity ≥ 95 %), the perfluorosulfonic acid resin solution is

DE2020 (solid content 25wt%), the solvent is: deionized water, isopropanol, ethanol, and the proton exchange membrane is Chemours NC700. The gas diffusion layer is Freudenberg H24CX483 with a thickness of 250 μm.

DE2020，3g去离子水、4g异丙醇和3g乙醇，混合后，在室温下分别用细胞破碎机分散20min，超声分散5min，高速剪切分散45min，即获得催化剂分散液，所述催化剂分散液的浓度约为1wt％。Step 1, preparation of catalyst slurry: configure a slurry with a solid content of about 1 wt%, weigh 100 mg of Pt/C catalyst, 3 mg of carbon nanotubes,

DE2020, 3g deionized water, 4g isopropanol and 3g ethanol, after mixing, disperse at room temperature with a cell crusher for 20 minutes, ultrasonic dispersion for 5 minutes, and high-speed shear dispersion for 45 minutes to obtain a catalyst dispersion. The concentration is about 1 wt%.

Step 2. Preparation of membrane electrodes: inject the catalyst slurry into the syringe pump of an ultrasonic sprayer, spray the catalyst onto both sides of the proton exchange membrane, and the anode and cathode platinum loadings are 0.3 mg/cm ² and 0.1 mg/cm ² respectively, Vacuum drying at 80°C, and attaching a gas diffusion layer to the cathode and anode, the membrane electrode can be obtained. Among them, the nozzle height of the ultrasonic spraying machine is 60mm, the liquid feeding rate is 60μl/min, the spraying area is 25cm ² , the vacuum adsorption table temperature of the ultrasonic spraying machine is 90°C, and the vacuum adsorption pressure is 0.1MPa

Step 3, assemble the membrane electrode into a single cell, use 100kPa high-purity nitrogen to detect the air tightness of the cell, and pass air and hydrogen with a relative humidity of 100% into the cathode and anode of the cell respectively, and the cell temperature is 70°C , the air stoichiometric ratio is 1.8, and the hydrogen stoichiometric ratio is 1.5.

Step 4, sequentially adjust the adjusted output voltage of the battery to 0.9V for 1min, 0.7V for 4min and 0.5V for 4min, cycle 7 times, and take 63min to complete the in-situ activation of the membrane electrode of the proton exchange membrane fuel cell.

The activation parameters set in Table 1 Embodiment 1

Figure 1 and Figure 4 are respectively the cross-section and surface morphology of the catalytic layer of the membrane electrode prepared in Example 1 of the present invention. The thickness of the cathode of the catalytic layer is 9 μm, the thickness of the anode is 3 μm, and the surface of the catalytic layer is smooth without cracks.

FIG. 7 is a graph showing the variation of the output voltage with time in Embodiment 1 of the present invention. The output voltage of the battery is continuously cycled between low potential and high potential, and it only takes 63 minutes to complete the activation. Compared with the activation time of the existing fuel cell (the activation time of the existing fuel cell is the national standard GB/T 20042.5-2009, 6.6 The activation time ≥ 4h) in single cell activation is shortened by about 74%.

Example 2:

DE2020(固含量25wt％)，所述溶剂为：去离子水、正丙醇、乙醇。所述质子交换膜为科慕NC700。所述气体扩散层为科德宝H24CX483，厚度为250μm。In this embodiment, the membrane electrode of the proton exchange membrane fuel cell is prepared with the following raw materials: 100 mg of catalyst, 5 mg of carbon material, 160 mg of perfluorosulfonic acid resin solution, 10 g of solvent, and 25 cm ² of proton exchange membrane. Wherein, the catalyst is Pt/C (Pt content is 60wt%, Johnson Matthey, HiSPEC 13100), the carbon material is carbon black (Cabot, Vulcan XC-72), and the perfluorosulfonic acid resin solution is

DE2020 (solid content 25wt%), the solvent is: deionized water, n-propanol, ethanol. The proton exchange membrane is Chemours NC700. The gas diffusion layer is Freudenberg H24CX483 with a thickness of 250 μm.

DE2020，2g去离子水、4g正丙醇和4g乙醇，混合后，在室温下分别用细胞破碎机分散20min，超声分散5min，高速剪切分散45min，即获得催化剂分散液，所述催化剂分散液的浓度约为1wt％。Step 1, preparation of catalyst slurry: configure a slurry with a solid content of about 1 wt%, weigh 100 mg of Pt/C catalyst, 5 mg of carbon black,

DE2020, 2g deionized water, 4g n-propanol and 4g ethanol, after mixing, disperse at room temperature with a cell crusher for 20min, ultrasonic dispersion for 5min, and high-speed shear dispersion for 45min to obtain a catalyst dispersion. The concentration is about 1 wt%.

Step 2. Preparation of membrane electrodes: inject the catalyst slurry into the syringe pump of an ultrasonic sprayer, spray the catalyst onto both sides of the proton exchange membrane, and the anode and cathode platinum loadings are 0.3 mg/cm ² and 0.1 mg/cm ² respectively, Vacuum drying at 80°C, and attaching a gas diffusion layer to the cathode and anode, the membrane electrode can be obtained. Among them, the nozzle height of the ultrasonic spraying machine is 60mm, the liquid feeding rate is 65μl/min, the spraying area is 25cm ² , the vacuum adsorption table temperature of the ultrasonic spraying machine is 80°C, and the vacuum adsorption pressure is 0.1MPa

Step 3, assemble the membrane electrode into a single cell, use 100kPa high-purity nitrogen to detect the air tightness of the cell, and pass air and hydrogen with a relative humidity of 100% into the cathode and anode of the cell respectively, and the cell temperature is 75°C , the air stoichiometric ratio is 2.5, and the hydrogen stoichiometric ratio is 2.0.

Step 4, sequentially adjust the adjusted output voltage of the battery to 0.85V for 1min, 0.75V for 4min and 0.45V for 5min, cycle 6 times, and take 60min to complete the in-situ activation of the membrane electrode of the proton exchange membrane fuel cell.

The activation parameter that table 2 embodiment 2 is set

Figure 2 and Figure 5 are respectively the cross-section and surface topography of the catalytic layer of the membrane electrode prepared in Example 2 of the present invention. The thickness of the cathode of the catalytic layer is 8 μm, the thickness of the anode is 3 μm, and the surface of the catalytic layer is smooth without cracks.

FIG. 8 is a graph showing the variation of the output voltage with time in Embodiment 2 of the present invention. The output voltage of the battery continuously cycles between 0.85V, 0.75V, and 0.45V, and it only takes 60 minutes to complete the activation. Compared with the activation time of existing fuel cells (the existing activation time refers to the national standard GB/T 20042.5 -2009, 6.6 The activation time of single cell activation (≥4h) was shortened by about 75%.

Example 3:

D79-25BS(固含量为25wt％)，所述溶剂为：去离子水、异丙醇，所述质子交换膜为科慕NC700。所述气体扩散层为科德宝H24CX483，厚度为250μm。In this example, the proton exchange membrane fuel cell membrane electrode is prepared with the following raw materials: 100 mg of catalyst, 10 mg of pore forming agent, 112 mg of perfluorosulfonic acid resin solution, 10 g of solvent, and 25 cm ² of proton exchange membrane. Wherein, the catalyzer is Pt/C (JohnsonMatthey, HiSPEC 13100, Pt content is 60wt%) and IrO ₂ (Shanghai Jiping), the pore forming agent is ammonium carbonate, and the perfluorosulfonic acid resin solution is

D79-25BS (solid content is 25wt%), the solvent is: deionized water, isopropanol, and the proton exchange membrane is Chemours NC700. The gas diffusion layer is Freudenberg H24CX483 with a thickness of 250 μm.

D79-25BS、25mgIrO₂，1g去离子水和9g异丙醇，混合后，在室温下分别用细胞破碎机分散20min，超声分散5min，高速剪切分散45min，即获得催化剂分散液。Step 1, preparation of catalyst slurry: configure a slurry with a solid content of about 1wt%, weigh 100mg of Pt/C catalyst, 10mg of ammonium carbonate,

After mixing D79-25BS, 25mg IrO ₂ , 1g deionized water and 9g isopropanol, disperse at room temperature with a cell crusher for 20 minutes, ultrasonic dispersion for 5 minutes, and high-speed shear dispersion for 45 minutes to obtain a catalyst dispersion.

Step 2. Preparation of membrane electrodes: inject the catalyst slurry into the syringe pump of an ultrasonic sprayer, spray the catalyst onto both sides of the proton exchange membrane, and the anode and cathode platinum loadings are 0.3 mg/cm ² and 0.5 mg/cm ² respectively, Vacuum drying at 80°C, and attaching a gas diffusion layer to the cathode and anode, the membrane electrode can be obtained. Among them, the nozzle height of the ultrasonic spraying machine is 60 mm, the liquid feeding rate is 125 μl/min, the spraying area is 25 cm ² , the vacuum adsorption table temperature of the ultrasonic spraying machine is 90° C., and the vacuum adsorption pressure is 0.1 MPa.

Step 3, assemble the membrane electrode into a single cell, use 100kPa high-purity nitrogen to detect the air tightness of the cell, and pass air and hydrogen with a relative humidity of 100% into the cathode and anode of the cell respectively, and the cell temperature is 80°C , the air stoichiometric ratio is 2.0, and the hydrogen stoichiometric ratio is 1.8.

Step 4, sequentially adjust the adjusted output voltage of the battery to 0.85V for 2min, 0.65V for 4min and 0.5V for 5min, cycle 7 times, and take 77min to complete the in-situ activation of the membrane electrode of the proton exchange membrane fuel cell.

The activation parameters set by the embodiment 3 of table 3

Fig. 3 and Fig. 6 are respectively the cross-section and surface morphology of the membrane electrode catalytic layer prepared in Example 3 of the present invention. The thickness of the cathode of the catalytic layer is 9 μm, and the thickness of the anode is 3 μm. down the hole.

FIG. 9 is a graph showing the variation of the output voltage with time in Embodiment 3 of the present invention. The output voltage of the battery continuously cycles between low potential and high potential, and it takes only 77 minutes to complete the activation, which is about 68% shorter than the activation time of existing fuel cells.

Fig. 10 is a comparison diagram of the polarization curves before and after activation of the single cells of Example 1, Example 2, and Example 3 of the present invention, and the unactivated curves. As can be seen in the figure: the voltage of the activated battery under low current density and high current density has been significantly improved, which shows that the method for activating the membrane electrode of a proton exchange membrane fuel cell proposed by the present invention is useful for short-term activation. Fuel cells have obvious effects.

Parts not described in detail in the present invention belong to the known techniques of those skilled in the art. The above-mentioned embodiments are only descriptions of the preferred implementations of the present invention, and the preferred embodiments do not exhaustively describe all the details, nor limit the invention to the described specific implementations. Without departing from the design spirit of the present invention, various modifications and improvements to the technical solution of the present invention by those skilled in the art shall fall within the scope of protection determined by the claims of the present invention.

Claims (1)

1. A method for efficient in-situ activation of the membrane electrode of a proton exchange membrane fuel cell, characterized in that: the in-situ activation method is to assemble the membrane electrode into a single cell, and detect its air tightness, then feed hydrogen and air and The output voltage of the battery is cycled up and down to achieve the purpose of in-situ activation of the membrane electrode of the proton exchange membrane fuel cell; The membrane electrode is prepared by spraying, and the slurry used for spraying includes: Catalyst, solvent and perfluorosulfonic acid resin solution, described solvent is deionized water and low-fat alcohol; Hydrophilic materials, hydrophobic materials, carbon materials, pore formers and anti-reverse catalysts; The catalyst is one or more of Pt/C, PtCo/C, PtNi/C, PtCoMn/C; Described low-fat alcohol is one or more in ethanol, isopropanol, n-propanol, ethylene glycol; The hydrophilic material includes one or more of SiO ₂ , Al ₂ O ₃ , cross-linked polyvinyl alcohol, and silicon-aluminum fiber; The hydrophobic material is one or more of FEP, PTFE, PFA, PFPE; The pore-forming agent is one or more of oxalic acid, ammonium bicarbonate, ammonium carbonate, ammonium chloride; The anti-reverse catalyst is one or more of IrO ₂ , PtRu/C, PtIr/C, RuO ₂ , RuO ₂ -IrO ₂ , RuO ₂ -TiO ₂ ; The carbon material is one or more of carbon nanotubes, acetylene black, Ketjen black, graphene oxide, graphene, carbon nanohorns, graphite, and activated carbon; The perfluorosulfonic acid resin solution is one or more of Nafion®DE2020, IC100, IC154, Aquivion®D79-25BS, Aquivion®D83-24BS; The output voltages are 0.8-0.9V, 0.5-0.8V and 0.3-0.5V, and the duration of each voltage is 0.5min-5min; The method comprises the steps of: Step 1. Preparation of catalyst slurry: 10 to 100 parts by weight of solvent, 0.1 to 10 parts by weight of catalyst, 0.1 to 6 parts by weight of perfluorosulfonic acid resin solution, 0.01 to 3 parts by weight of hydrophilic material, 0.01 to 10 parts by weight of 1 part by weight of hydrophobic material, 0.01-1 part by weight of pore-forming agent, 0.01-3 parts by weight of anti-reverse catalyst, and 0.01-3 parts by weight of carbon material are uniformly mixed and dispersed, and the solid content of the obtained dispersion is 0.1 wt%. ~15wt%; Step 2, preparation of the membrane electrode: uniformly spray the catalyst slurry on both sides of the proton exchange membrane, dry the membrane electrode, and cover the gas diffusion layer to obtain the membrane electrode assembly; Step 3. Single cell test: Assemble the membrane electrode into a single cell, and test its air tightness, respectively pass air and hydrogen into the cathode and anode, heat the battery, and adjust the output voltage to 0.8-0.9V, 0.5-0.8 V and 0.3 ~ 0.5V, the duration of each voltage is 0.5min ~ 5min, cycle 2 ~ 8 times; the anode Pt loading of the membrane electrode is 0.1mg/cm ² ~ 0.5mg/cm ² , the cathode Pt loading The amount is 0.01mg/cm ² ~0.3mg/cm ² , the drying temperature is 30℃~90℃, and the thickness of the gas diffusion layer is 100μm~350μm; The gas leakage rate of the single cell is 0-0.1ml/min, the relative humidity of the anode and cathode is 20%-100%, the battery temperature is 20°C-90°C, and the output voltage decreases by 0.1V-0.4V each time .

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