Double-proton conductor layered catalyst layer for high-temperature proton exchange membrane fuel cell

Abstract

The invention discloses a double-proton conductor layered catalyst layer for a high-temperature proton exchange membrane fuel cell. The double-proton conductor layered catalyst layer comprises an outer catalyst layer and an inner catalyst layer, wherein the outer catalyst layer is made of organic phosphonic acid and a platinum-containing catalyst, and the inner catalyst layer is made of a platinum-containing catalyst. The invention further discloses a preparation method and application of the double-proton conductor layered catalyst layer for the high-temperature proton exchange membrane fuel cell and a membrane electrode based on the catalyst layer. Second proton conductor organic phosphonic acid having strong hydrogen bond interaction with a phosphoric acid proton conductor is introduced to the outer side of the adhesive-free double-layer catalyst layer, so that the proton conductivity and phosphoric acid retention capacity of the catalyst layer are greatly improved by utilizing the strong interaction of organic phosphonic acid-phosphoric acid, and the loss rate of the outer proton conductor is reduced; and the voltage attenuation rate of the fuel cell under the steady-state constant-current discharge condition is greatly reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high-temperature proton exchange membrane fuel cell membrane electrode, and particularly relates to a double-proton-conductor layered catalytic layer for high-temperature proton exchange membrane fuel cell. BACKGROUND

[0002] High-temperature proton exchange membrane fuel cell (HT-PEMFC) is a kind of polymer electrolyte membrane fuel cell technology mainly using phosphoric acid doped polymer membrane as proton exchange membrane, and its proton conductor is phosphoric acid. Benefiting from the low volatility and high conductivity of phosphoric acid under high-temperature and low-humidity conditions, HT-PEMFC can be stably operated at 120-200℃, has the advantages of strong resistance to CO and other fuel impurities, the ability to use crude hydrogen fuel, and high system integration, and has important application value in the fields of combined heat and power and emergency backup power supply.

[0003] The catalytic layer is the core part of HT-PEMFC, and the catalyst utilization rate and stability thereof directly determine the performance of the fuel cell. The current HT-PEMFC catalytic layer is mainly composed of porous agglomerates of catalysts such as Pt / C. Benefiting from the porous structure, the phosphoric acid proton conductor in the phosphoric acid doped polymer membrane migrates from the membrane to the catalytic layer under the assembly pressure of the membrane electrode, the microstructure capillary force of the catalytic layer, and the electric migration effect, to construct an electrochemical reaction three-phase interface, and realize the rapid reaction of the reaction gas, protons and electrons. In addition, compared with the traditional catalytic layer containing acid-repellent binders such as polytetrafluoroethylene or acidophilic binders such as polybenzimidazole, the binder-free catalytic layer is more conducive to the distribution of phosphoric acid in the catalytic layer, and therefore has higher activity. However, the liquid migration characteristics of the phosphoric acid small molecules result in a gradient distribution of the phosphoric acid in the binder-free catalytic layer: the phosphoric acid content is too high near the electrolyte membrane side, which easily causes "acid flooding" phenomenon, hinders the oxygen mass transfer and causes concentration polarization; and far from the membrane side, it is difficult to form an effective three-phase interface and a continuous proton channel due to the lack of acid, which causes electrochemical polarization. In addition, the high water solubility of phosphoric acid easily leads to its loss under the water flushing action of the cathode, causing the performance degradation of the membrane electrode. How to realize the stable and balanced distribution of the proton conductor in the catalytic layer has become a key challenge to improve the performance and stability of the binder-free catalytic layer of HT-PEMFC.

[0004] The existing research mainly solves the problem through modification of the proton conductor: ①using organic phosphonic acid groups (such as polyvinyl phosphonic acid or ethylenediamine tetramethylene phosphonic acid) to replace phosphoric acid, which can inhibit migration but has problems such as weak proton self-diffusion ability and low ion exchange capacity, resulting in an electrical conductivity of less than 1 mS / cm under 150℃ water-free conditions; ②doping phosphoric acid in the phosphonic acid polymer matrix to improve the electrical conductivity, but still cannot solve the problem of gradient distribution of phosphoric acid. The above methods are difficult to construct a uniform and continuous hydrogen bond network, resulting in a lack of proton conductor on the outside of the catalytic layer, which causes some catalysts to be unable to participate in the reaction.

[0005] Therefore, the core of improving the performance of the HT-PEMFC is to realize the stable and uniform distribution of the proton conductor in the catalyst layer, so as to improve the activity and stability of the binder-free catalyst layer. The bottleneck of the prior art is that the small molecule migration characteristics of phosphoric acid make its distribution easily affected by the dynamic changes of the working conditions, and the immobilized phosphonic acid system is difficult to meet the high conductivity requirement. Therefore, it is urgent to develop a new catalyst layer structure, to realize the balanced distribution of the proton conductor and the construction of the continuous proton transfer channel by strengthening the interaction between phosphoric acid and other proton conductors, so as to effectively expand the three-phase interface and improve the catalyst mass power. This technical breakthrough will fundamentally solve the imbalance of the material transmission in the catalyst layer of the existing HT-PEMFC, and promote the commercialization application process. SUMMARY

[0006] In order to solve the above-mentioned problems of low catalyst utilization rate and poor stability of the high-temperature proton exchange membrane fuel cell, the application provides a binder-free double-proton-conductor layered catalyst layer for high-temperature proton exchange membrane fuel cells and a gas diffusion electrode preparation method and application based on the catalyst layer. By constructing a double-layer catalyst layer containing double-proton-conductor, phosphoric acid and organic phosphonic acid conductor are dispersed in the inner and outer catalyst layers respectively, and the functional characteristics of the two kinds of proton conductors are utilized, so as to solve the problems of low catalyst utilization rate and poor stability caused by the non-uniform distribution of phosphoric acid in the traditional high-temperature proton exchange membrane fuel cell membrane electrode. The application can effectively improve the performance and stability of the high-temperature proton exchange membrane fuel cell.

[0007] In order to achieve the above-mentioned purpose, the technical scheme provided by the application is as follows:

[0008] A high-stability and high-catalyst-utilization-rate double-proton-conductor layered catalyst layer for high-temperature proton exchange membrane fuel cells, comprising an outer catalyst layer and an inner catalyst layer; wherein the inner catalyst layer is a platinum (Pt) catalyst, and the outer catalyst layer is an organic phosphonic acid and a platinum (Pt) catalyst; the platinum (Pt) catalyst is one of Pt / C, PtCo / C, PtFe / C, PtNi / C, PtPb / C, Pt / WO3, Pt / MO3 or Pt / TiO2.

[0009] A double-proton-conductor layered catalyst layer gas diffusion electrode for high-temperature proton exchange membrane fuel cells, comprising the double-proton-conductor layered catalyst layer for high-temperature proton exchange membrane fuel cells as described above, and further comprising a gas diffusion layer, wherein the gas diffusion layer comprises a support layer and a microporous layer; the outer catalyst layer and the inner catalyst layer of the double-proton-conductor layered catalyst layer for high-temperature proton exchange membrane fuel cells are sequentially stacked on the gas diffusion layer with the gas diffusion layer as the bottom layer. Further, the amount of the organic phosphonic acid is 5%-60% of the mass of the platinum (Pt) catalyst, and the loading of the noble metal platinum (Pt) in the double-proton-conductor layered catalyst layer gas diffusion electrode for high-temperature proton exchange membrane fuel cells is 0.05-2 mg / cm2.2 .

[0010] Further, the organic phosphonic acid is at least one of ethylenediaminetetramethylene phosphonic acid (EDTMPA), hydroxyethane diphosphonic acid (HEDP), amino trimethylene phosphonic acid (ATMP), diethylenetriamine pentamethylene phosphonic acid (DTPMPA); preferably ethylenediaminetetramethylene phosphonic acid (EDTMPA).

[0011] The preparation method of the double-proton-conductor layered catalytic layer gas diffusion electrode for high-temperature proton exchange membrane fuel cells as described above comprises the following operation steps:

[0012] (1) Preparation of inner catalytic layer slurry: weigh the platinum (Pt) containing catalyst, mix the platinum (Pt) containing catalyst and the solvent to obtain the inner catalytic layer slurry;

[0013] (2) Preparation of outer catalytic layer slurry: according to the amount of organic phosphonic acid being 5%-60% of the mass of platinum (Pt) containing catalyst, weigh the organic phosphonic acid of the outer catalytic layer, platinum (Pt) containing catalyst, mix the organic phosphonic acid, platinum (Pt) containing catalyst and the solvent to obtain the outer catalytic layer slurry;

[0014] (3) Preparation of double-proton-conductor layered catalytic layer gas diffusion electrode for high-temperature proton exchange membrane fuel cells: coat the outer catalytic layer slurry obtained in step (2) on one side of the microporous layer of the gas diffusion layer, after the outer catalytic layer slurry is slightly dried, continue to coat the inner catalytic layer slurry obtained in step (1), after drying, the original outer layer catalyst slurry layer becomes the outer catalyst layer, and the inner layer catalyst slurry layer becomes the inner catalyst layer, thus obtaining the double-proton-conductor layered catalytic layer gas diffusion electrode for high-temperature proton exchange membrane fuel cells, wherein the noble metal platinum (Pt) loading in the double-proton-conductor layered catalytic layer gas diffusion electrode for high-temperature proton exchange membrane fuel cells is 0.05-2 mg / cm 2 .

[0015] Further, the solvent in step (1) and step (2) is deionized water and anhydrous isopropanol; the coating process in step (3) is one of ultrasonic spraying, blade coating or screen printing; when ultrasonic spraying, blade coating or screen printing is used, the water / alcohol ratio of the above defined solvent (deionized water and anhydrous isopropanol) is the same, but the catalyst solid content is different, wherein the ratio of platinum (Pt) containing catalyst to solvent is about 10% for screen printing and blade coating, and about 1% for spraying.

[0016] The application of the double-proton-conductor layered catalytic layer gas diffusion electrode for high-temperature proton exchange membrane fuel cells as described above as a cathode in the preparation of high-temperature proton exchange membrane fuel cell membrane electrodes.

[0017] A high-temperature proton exchange membrane fuel cell membrane electrode comprises a cathode, a phosphoric acid doped high-temperature proton exchange membrane and an anode arranged in sequence; the cathode is a double-proton conductor layered catalytic layer gas diffusion electrode for the high-temperature proton exchange membrane fuel cell; the inner catalytic layer of the cathode and the anode catalytic layer are both close to the phosphoric acid doped high-temperature proton exchange membrane; and the cathode, the phosphoric acid doped high-temperature proton exchange membrane and the anode are sequentially adhered and then hot-pressed by a hot-pressing method to obtain the high-temperature proton exchange membrane fuel cell membrane electrode.

[0018] Further, the anode is an anode gas diffusion electrode obtained by coating a catalytic layer on one side of a gas diffusion layer microporous layer; and a preparation method of the anode gas diffusion electrode comprises the following operation steps:

[0019] (i) preparing an anode catalytic layer slurry: 40wt% Pt / C catalyst, deionized water and anhydrous isopropanol are weighed according to a mass ratio of 1:15:85, and then ultrasonic dispersion is performed for 1 hour to obtain the anode catalytic layer slurry;

[0020] (ii) preparing the anode gas diffusion electrode: the anode catalytic layer slurry obtained in step (i) is uniformly coated on one side of the anode gas diffusion layer containing the microporous layer by using an ultrasonic spraying method to obtain the anode gas diffusion electrode; and the platinum loading in the anode catalytic layer is 0.5-1.0 mg / cm 2 .

[0021] Further, the phosphoric acid doped high-temperature proton exchange membrane is obtained by immersing an alkaline polymer membrane in phosphoric acid; the mass concentration of the phosphoric acid is 50%-85%, the immersion temperature is 25-160°C, and the immersion time is 2-72h; the alkaline polymer membrane is at least one of a polybenzimidazole membrane, a polyvinylimidazole membrane, a polyvinylpyrrolidone membrane and a polyarylene piperidine membrane; the thickness of the phosphoric acid doped high-temperature proton exchange membrane is 30-200μm, the proton conductivity is 0.01-0.50S / cm, and the mechanical tensile strength is 5-200Mpa.

[0022] The high-temperature proton exchange membrane fuel cell membrane electrode is used for preparing a high-temperature proton exchange membrane fuel cell: the high-temperature proton exchange membrane fuel cell membrane electrode is put into a high-temperature proton exchange membrane fuel cell mold, fuel and oxidant are introduced into the mold, and then the high-temperature proton exchange membrane fuel cell is obtained; during the operation of the high-temperature proton exchange membrane fuel cell, hydrogen is introduced into the anode side, hydrogen oxidation (HOR) occurs in the anode, air or oxygen is introduced into the cathode side, and oxygen reduction (ORR) occurs in the cathode; and the working temperature of the high-temperature proton exchange membrane fuel cell is 120-240°C.

[0023] Compared with the prior art, the high-temperature proton exchange membrane fuel cell membrane electrode has the following beneficial effects:

[0024] (1) The present application is based on the binderless catalytic layer, and a double-layer catalytic layer containing different proton conductors is constructed. The inner layer proton conductor is phosphoric acid, and the outer layer uses organic phosphonic acid as a second proton conductor material. The continuity and uniformity of the proton transfer channel in the binderless double-layer catalytic layer are greatly improved by the synergistic effect between the two, thereby significantly improving the utilization rate of the catalyst. The key technical bottleneck of the existing phosphoric acid doped high-temperature proton exchange membrane fuel cell membrane electrode design is broken through, and it has good application prospect and practical significance.

[0025] (2) The present application introduces a second proton conductor with strong hydrogen bond interaction with the phosphoric acid proton conductor outside the binderless double-layer catalytic layer. The strong interaction between organic phosphonic acid and phosphoric acid greatly improves the proton conductivity and phosphoric acid retention capacity of the catalytic layer, reduces the loss rate of the outer layer proton conductor, and makes the fuel cell discharge voltage decay rate at 0.2 A / cm 2 The voltage decay rate of the discharge at a constant current density is greatly reduced.

[0026] (3) The preparation method of the present application is simple, which is conducive to large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 A is a structural schematic diagram of the double-proton conductor layered catalytic layer gas diffusion electrode for high-temperature proton exchange membrane fuel cell prepared by the present application; Figure 1 B is a distribution schematic diagram of two kinds of proton conductors, Figure 1 The right side of B is an organic phosphonic acid, Figure 1 The left side of B is phosphoric acid; wherein, 1 - support layer, 2 - microporous layer, 3 - outer catalytic layer, 4 - inner catalytic layer; 1 and 2 are gas diffusion layers.

[0028] Figure 2 Polarization characteristic curves of high-temperature proton exchange membrane fuel cell membrane electrodes prepared by different organic phosphonic acids as second proton conductors.

[0029] Figure 3 The platinum utilization rate of high-temperature proton exchange membrane fuel cell membrane electrodes prepared by different organic phosphonic acids as second proton conductors.

[0030] Figure 4 Impedance diagram of high-temperature proton exchange membrane fuel cell membrane electrodes prepared by different organic phosphonic acids as second proton conductors.

[0031] Figure 5 Discharge stability of high-temperature proton exchange membrane fuel cell membrane electrodes prepared by different organic phosphonic acids as second proton conductors. DETAILED DESCRIPTION

[0032] The specific embodiments will be described in detail below with reference to the drawings, but it should be understood that the scope of the present application is not limited to the specific embodiments. The raw materials and reagents used in the examples are commercially available unless otherwise specified.

[0033] The gas diffusion layer was purchased from Beijing Haideliz New Technology Co., Ltd. The gas diffusion layer has a support layer and a microporous layer. The support layer is carbon fiber, and the microporous layer is carbon layer. The platinum (Pt) catalysts 40wt% PtNi / C and 40wt% Pt / C were purchased from Beijing Haideliz New Technology Co., Ltd. The high-temperature proton exchange membrane fuel cell mold was purchased from Beijing Haideliz New Technology Co., Ltd.

[0034] Example 1

[0035] A method for preparing a high-stability and high-catalyst-utilization-rate double-proton-conductor layered catalytic layer gas diffusion electrode for high-temperature proton exchange membrane fuel cells, the operation steps are as follows:

[0036] (1) Preparation of inner catalytic layer slurry: according to the mass ratio of 40wt% PtNi / C catalyst: deionized water: anhydrous isopropanol = 1:15:85, 40wt% PtNi / C catalyst, deionized water and anhydrous isopropanol were weighed, then the weighed 40wt% PtNi / C catalyst, deionized water and anhydrous isopropanol were ultrasonically dispersed for 1 hour, and the inner catalytic layer slurry was obtained after uniform dispersion.

[0037] (2) Preparation of outer catalytic layer slurry: according to the mass ratio of 40wt% PtNi / C: organic phosphonic acid: deionized water: anhydrous isopropanol = 1:0.2:15:85, 40wt% PtNi / C catalyst, ethylenediaminetetramethylene phosphonic acid (EDTMPA), deionized water and anhydrous isopropanol were weighed, then the weighed 40wt% PtNi / C catalyst, ethylenediaminetetramethylene phosphonic acid (EDTMPA), deionized water and anhydrous isopropanol were ultrasonically dispersed for 1 hour, and the outer catalytic layer slurry was obtained after 48 hours of ball milling.

[0038] (3) Preparation of a double-proton-conductor layered catalytic layer gas diffusion electrode for high-temperature proton exchange membrane fuel cells: ultrasonic spraying of the outer catalytic layer slurry obtained in step (2) on one side of the microporous layer of the gas diffusion layer, after the outer catalytic layer slurry is slightly dry, ultrasonic spraying of the inner catalytic layer slurry obtained in step (1) on the slightly dry outer catalytic layer, ensuring that the platinum loading is 0.8 mg / cm 2 , to obtain a double-proton-conductor layered catalytic layer gas diffusion electrode for high-temperature proton exchange membrane fuel cells prepared with organic phosphonic acid as the second proton. See Figure 1 , the double-proton-conductor layered catalytic layer gas diffusion electrode (cathode) for high-temperature proton exchange membrane fuel cells with high stability and high catalyst utilization rate is composed of a gas diffusion layer, an outer catalytic layer and an inner catalytic layer.

[0039] Example 2

[0040] In step (2), "ethylenediaminetetramethylene phosphonic acid (EDTMPA)" is replaced by "hydroxyethylidene diphosphonic acid (HEDP)", and the rest of the operations are the same as those in step of Example 1, to obtain a double-proton conductor layered catalytic layer gas diffusion electrode for high-temperature proton exchange membrane fuel cells prepared by using an organic phosphonic acid as a second proton.

[0041] Example 3

[0042] In step (2), "ethylenediaminetetramethylene phosphonic acid (EDTMPA)" is replaced by "aminotri(methylene) phosphonic acid (ATMP)", and the rest of the operations are the same as those in step of Example 1, to obtain a double-proton conductor layered catalytic layer gas diffusion electrode for high-temperature proton exchange membrane fuel cells prepared by using an organic phosphonic acid as a second proton.

[0043] Example 4

[0044] A method for preparing a double-proton conductor layered catalytic layer gas diffusion electrode for high-temperature proton exchange membrane fuel cells with high stability and high catalyst utilization rate, the operation steps are as follows:

[0045] (1) Preparation of inner catalytic layer slurry: according to the mass ratio of 40wt% PtNi / C catalyst: deionized water: anhydrous isopropanol = 10:15:85, 40wt% PtNi / C catalyst, deionized water and anhydrous isopropanol are weighed, and then the weighed 40wt% PtNi / C catalyst, deionized water and anhydrous isopropanol are ultrasonically dispersed for 1 hour. After uniform dispersion, ball milling is carried out for 48 hours to obtain the inner catalytic layer slurry.

[0046] (2) Preparation of outer catalytic layer slurry: according to the mass ratio of 40wt% PtNi / C: organic phosphonic acid: deionized water: anhydrous isopropanol = 10:2:15:85, 40wt% PtNi / C catalyst, diethylene triamine penta methylene phosphonic acid (DTPMPA), deionized water and anhydrous isopropanol are weighed, and then the weighed 40wt% PtNi / C catalyst, diethylene triamine penta methylene phosphonic acid (DTPMPA), deionized water and anhydrous isopropanol are ultrasonically dispersed for 1 hour. After uniform dispersion, ball milling is carried out for 48 hours to obtain the outer catalytic layer slurry.

[0047] (3) Preparation of double-proton conductor layered catalytic layer gas diffusion electrode for high-temperature proton exchange membrane fuel cells: the outer catalytic layer slurry obtained in step (2) is screen printed on the microporous layer side of the gas diffusion layer, and then the inner catalytic layer slurry obtained in step (1) is screen printed on the slightly dried outer catalytic layer, to ensure that the platinum loading is 0.8 mg / cm 2 , to obtain a double-proton conductor layered catalytic layer gas diffusion electrode for high-temperature proton exchange membrane fuel cells prepared by using an organic phosphonic acid as a second proton.

[0048] Comparative Example 1

[0049] A method for preparing a gas diffusion electrode for high temperature proton exchange membrane fuel cell without second proton conductor organic phosphonic acid, without step (2) of preparing the outer catalytic layer, the remaining operations are the same as step of Example 1, to obtain a gas diffusion electrode for high temperature proton exchange membrane fuel cell without second proton conductor organic phosphonic acid, the operation steps are as follows:

[0050] (1) Preparation of inner catalytic layer slurry: according to the mass ratio of 40wt% PtNi / C catalyst: deionized water: anhydrous isopropanol = 1:15:85, 40wt% PtNi / C catalyst, deionized water and anhydrous isopropanol are weighed, then the weighed 40wt% PtNi / C catalyst, deionized water and anhydrous isopropanol are ultrasonically dispersed for 1 hour, and after uniform dispersion, the inner catalytic layer slurry is obtained.

[0051] (2) Ultrasonic spraying of the inner catalytic layer slurry obtained in step (1) on the microporous layer side of the gas diffusion layer, ensuring that the platinum loading is 0.8 mg / cm 2 , to obtain a gas diffusion electrode for high temperature proton exchange membrane fuel cell without second proton conductor organic phosphonic acid.

[0052] Comparative Example 2

[0053] In step (2), replace "ethylenediaminetetramethylene phosphonic acid (EDTMPA)" with "phosphoric acid (PA)", and the remaining operations are the same as step of Example 1, to obtain a gas diffusion electrode for high temperature proton exchange membrane fuel cell supplemented with a single phosphoric acid proton conductor away from the membrane side in the catalytic layer.

[0054] Example 5

[0055] A method for preparing an anode gas diffusion electrode for high temperature proton exchange membrane fuel cell, the operation steps are as follows:

[0056] (i) Preparation of anode catalytic layer slurry: according to the mass ratio of 40wt% Pt / C catalyst: deionized water: anhydrous isopropanol = 1:15:85, 40wt% Pt / C catalyst, deionized water and anhydrous isopropanol are weighed, then the weighed 40wt% Pt / C catalyst, deionized water and anhydrous isopropanol are ultrasonically dispersed for 1 hour, and after uniform dispersion, the anode catalytic layer slurry is obtained;

[0057] (ii) Preparation of anode gas diffusion electrode: the anode catalytic layer slurry obtained in step (i) is uniformly coated on the side containing the microporous layer of the anode gas diffusion layer by ultrasonic spraying, to obtain an anode gas diffusion electrode for high temperature proton exchange membrane fuel cell. The platinum loading in the anode catalytic layer is 0.8 mg / cm 2 .

[0058] Example 6

[0059] Preparation of high temperature proton exchange membrane PBI / H3PO4 composite membrane (phosphoric acid doped high temperature proton exchange membrane): polybenzimidazole (PBI) membrane from Beijing Haideliz New Technology Co., Ltd. was used, the thickness of the membrane was 30-200 μm, and the mechanical tensile strength was 5-200 Mpa. PBI / H3PO4 composite membrane was prepared by impregnation method. First, the PBI proton exchange membrane was cut into the desired size, and then the cut membrane was soaked in 85wt% phosphoric acid at 40°C for 12 hours. The excess phosphoric acid on the surface of the PBI membrane was absorbed with filter paper, and then weighed quickly to obtain a PBI proton exchange membrane with a phosphoric acid doping amount of 230%, a thickness of 80 microns, and a proton conductivity of 0.01-0.50 S / cm, i.e. a high temperature proton exchange membrane PBI / H3PO4 composite membrane.

[0060] Example 7

[0061] The double-proton-conductor layered catalytic layer gas diffusion electrode for high temperature proton exchange membrane fuel cell prepared from the high temperature proton exchange membrane prepared in Example 1, Example 2, and Example 3, and the gas diffusion electrode for high temperature proton exchange membrane fuel cell prepared from Comparative Example 1 and Comparative Example 2 were used as cathodes, the anode gas diffusion electrode for high temperature proton exchange membrane fuel cell prepared in Example 5 was used as an anode, and the phosphoric acid doped high temperature proton exchange membrane PBI / H3PO4 composite membrane prepared in Example 6 was used as a proton exchange membrane. The cathode, the proton exchange membrane, and the anode were stacked in the order of “first place the anode, then place the proton exchange membrane, and finally place the cathode”, and then placed in a hot press to be hot-pressed at 160°C under a pressure of 900 kg for 10 minutes. After cooling to room temperature, the press-fitted product with an effective area of 45 cm 2 membrane electrode was obtained. Five different high temperature proton exchange membrane fuel cell membrane electrodes were obtained, and the phosphoric acid proton conductor accounted for 5-60% of the volume fraction of the inner catalytic layer in the obtained high temperature proton exchange membrane fuel cell membrane electrode.

[0062] Example 8

[0063] The five different high temperature proton exchange membrane fuel cell membrane electrodes obtained in Example 7 were placed in a high temperature proton exchange membrane fuel cell mold, and then ventilated to obtain a high temperature proton exchange membrane fuel cell. During the operation of the high temperature proton exchange membrane fuel cell, hydrogen was introduced into the anode side, and the HOR reaction occurred in the anode. Air or oxygen was introduced into the cathode side, and the ORR reaction occurred in the cathode. The working temperature was 120-240°C.

[0064] Performance detection

[0065] With reference to T / ZHFCA 1014.3-2024, polarization curve tests were conducted on the membrane electrode of the high-temperature proton exchange membrane fuel cell obtained above. The specific operating conditions were: a single cell operating temperature of 160°C, pure hydrogen feed for the anode, atmospheric pressure air feed for the cathode, and a cathode / anode feed ratio of 1.25 / 2.5 times the stoichiometric ratio, respectively.

[0066] The impedance test of the membrane electrode of the high-temperature proton exchange membrane fuel cell obtained above was carried out according to T / ZHFCA 1014.3-2024. The specific operating conditions are as follows: the single cell operating temperature is 160°C, the anode is fed with pure hydrogen, the cathode is fed with atmospheric pressure air, the cathode / anode feeds are 1.25 / 2.5 times the stoichiometric ratio, and the discharge current density is 0.5 Acm -2 .

[0067] The operating stability test of the high-temperature proton exchange membrane fuel cell membrane electrode obtained above was carried out according to T / ZHFCA 1014.3-2024. The specific operating conditions are: the single cell operating temperature is 160°C, the anode is fed with pure hydrogen, the cathode is fed with atmospheric pressure air, the cathode / anode feeds are 1.25 / 2.5 times the stoichiometric ratio, and the discharge current density is 0.2A cm -2 .

[0068] Test results see Figure 2 、 Figure 3 、 Figure 4 and Figure 5 : Comparative Example 1 is a cathode structure with a single catalytic layer composed of PtNi / C; Comparative Example 2 is a cathode structure with a single catalytic layer in which phosphoric acid is added to the outside on the basis of Comparative Example 1; Example 2 is a cathode structure with a double catalytic layer composed of hydroxyethylidene diphosphonic acid (cathode outer catalytic layer) and PtNi / C (cathode inner catalytic layer), Example 3 is a cathode structure with a double catalytic layer composed of aminotrimethylenephosphonic acid (cathode outer catalytic layer) and PtNi / C (cathode inner catalytic layer), and Example 1 is a cathode structure with a double catalytic layer composed of ethylenediaminetetramethylenephosphonic acid (cathode outer catalytic layer) and PtNi / C (cathode inner catalytic layer).

[0069] Under these conditions, it can be seen that the performance of the membrane electrode corresponding to the catalytic layer of EDTMPA as the second proton conductor is relatively high, and the corresponding current density at 0.6 V can reach 873.72 mA cm -2 , the peak power density can reach 1.14W cm -2 , and the unit mass utilization rate of Pt can reach 1.42W g -1 .

[0070] Depend on Figure 5The battery discharge stability diagram shows that the cell performance of Example 1, Example 2 and Example 3 corresponding to the catalyst layer of the second proton conductor with organic phosphonic acid still maintains above 0.7V after 1750h of stability test, and Figure 4 The impedance spectrum shows that the cathode charge transfer resistance changes little. This is mainly due to the organic phosphonic acid contained in the cathode outer catalyst layer, which acts as a second proton conductor. Due to its strong interaction with phosphoric acid, the number of three-phase interfaces in the catalyst layer away from the membrane increases, the proton transfer channel becomes more continuous, and the fuel cell stability and catalyst utilization rate are greatly improved.

[0071] Comparative Example 1 without the second proton conductor has the worst performance, with a current density of only 534 mA cm at 0.6 V. -2 , the peak power density can reach 635.6W cm -2 , the unit mass utilization rate of Pt is only 0.99W g -1 Similarly, the performance of Comparative Example 2, which added phosphoric acid to the side of the catalyst layer away from the membrane, was poor, with a corresponding current density of 610 mA cm at 0.6 V. -2 , the peak power density can reach 743W cm -2 , the unit mass utilization rate of Pt is only 1.17 W g -1 .

[0072] Depend on Figure 5 The cell discharge stability graph shows that the cell potential of the membrane electrode assembly in Comparative Example 2, which uses phosphoric acid supplementation on the side of the catalyst layer away from the membrane, drops below 0.6V after only 500 hours, while the cell potential of Comparative Example 1 drops below 0.6V after only 400 hours. This is primarily due to the severe lack of an external proton conductor in Comparative Example 1, and the fact that the interaction between phosphoric acid and other phosphoric acids is much weaker than the interaction between phosphoric acid and the organic phosphonic acid, resulting in a free state of phosphoric acid. The catalyst layer has a poor ability to retain phosphoric acid, leading to rapid loss. Furthermore, the external proton transfer pathway is easily interrupted, resulting in low catalyst utilization on the side away from the membrane, resulting in poor membrane electrode assembly performance.

[0073] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many variations and modifications are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and modifications. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A dual proton conductor layered catalyst layer for a high-temperature proton exchange membrane fuel cell, characterized in that: It comprises an outer catalytic layer and an inner catalytic layer; wherein, the inner catalytic layer is a platinum-containing catalyst, and the outer catalytic layer is an organic phosphonic acid and a platinum-containing catalyst; the platinum-containing catalyst is one of Pt / C, PtCo / C, PtFe / C, PtNi / C, PtPb / C, Pt / WO3, Pt / MO3 or Pt / TiO2.

2. A dual-proton conductor layered catalytic layer gas diffusion electrode for a high-temperature proton exchange membrane fuel cell, characterized in that: It comprises the dual proton conductor layered catalytic layer for a high-temperature proton exchange membrane fuel cell as claimed in claim 1, and also comprises a gas diffusion layer, wherein the gas diffusion layer includes a support layer and a microporous layer; with the gas diffusion layer as the bottom layer, the outer catalytic layer and the inner catalytic layer of the dual proton conductor layered catalytic layer for a high-temperature proton exchange membrane fuel cell are stacked in sequence on the gas diffusion layer.

3. The dual proton conductor layered catalytic layer gas diffusion electrode for a high-temperature proton exchange membrane fuel cell according to claim 2, characterized in that: The amount of the organic phosphonic acid is 5%-60% of the mass of the platinum (Pt) catalyst, and the platinum loading in the dual proton conductor layered catalytic layer for the high-temperature proton exchange membrane fuel cell is 0.05-2 mg / cm 2 ; The organic phosphonic acid is at least one of ethylenediaminetetramethylenephosphonic acid, hydroxyethylidene diphosphonic acid, aminotrimethylenephosphonic acid, and diethylenetriaminepentamethylenephosphonic acid; preferably ethylenediaminetetramethylenephosphonic acid.

4. The method for preparing a dual proton conductor layered catalytic layer gas diffusion electrode for a high-temperature proton exchange membrane fuel cell according to claim 2, characterized in that: The following steps are included: (1) Preparing an inner catalytic layer slurry: weighing a platinum (Pt) catalyst, mixing the platinum (Pt) catalyst and a solvent to obtain an inner catalytic layer slurry; (2) preparing an outer catalytic layer slurry: weighing the organic phosphonic acid and the platinum (Pt) catalyst of the outer catalytic layer according to the amount of the organic phosphonic acid being 5% to 60% of the mass of the platinum (Pt) catalyst, and mixing the organic phosphonic acid, the platinum (Pt) catalyst and the solvent to obtain an outer catalytic layer slurry; (3) Preparation of a dual-proton conductor layered catalytic layer gas diffusion electrode for a high-temperature proton exchange membrane fuel cell: coating the outer catalytic layer slurry obtained in step (2) on one side of the microporous layer of the gas diffusion layer; after the outer catalytic layer slurry is dried, coating the inner catalytic layer slurry obtained in step (1) to obtain a dual-proton conductor layered catalytic layer gas diffusion electrode for a high-temperature proton exchange membrane fuel cell, wherein the platinum loading in the gas diffusion electrode is 0.05-2 mg / cm 2 .

5. The method for preparing a dual-proton conductor layered catalytic layer gas diffusion electrode for a high-temperature proton exchange membrane fuel cell according to claim 4, characterized in that: The solvents in step (1) and step (2) are deionized water and anhydrous isopropyl alcohol; the coating process in step (3) is one of ultrasonic spraying, scraping or screen printing.

6. Use of the dual-proton conductor layered catalytic layer gas diffusion electrode for a high-temperature proton exchange membrane fuel cell as described in any one of claims 2 to 4 or the dual-proton conductor layered catalytic layer gas diffusion electrode for a high-temperature proton exchange membrane fuel cell prepared according to claim 5 as a cathode in the preparation of a membrane electrode for a high-temperature proton exchange membrane fuel cell.

7. The use according to claim 6, characterized in that: A high-temperature proton exchange membrane fuel cell membrane electrode is prepared by sequentially arranging a cathode, a phosphoric acid-doped high-temperature proton exchange membrane, and an anode. The cathode is a dual-proton conductor layered catalytic layer gas diffusion electrode for a high-temperature proton exchange membrane fuel cell according to any one of claims 1 to 3, or a dual-proton conductor layered catalytic layer gas diffusion electrode for a high-temperature proton exchange membrane fuel cell prepared according to claim 4. The inner catalytic layer of the cathode and the catalytic layer of the anode are both in close contact with the phosphoric acid-doped high-temperature proton exchange membrane. The cathode, the phosphoric acid-doped high-temperature proton exchange membrane, and the anode are sequentially bonded and then hot-pressed to obtain the product.

8. The application according to claim 7, characterized in that: The anode is an anode gas diffusion electrode, which is obtained by coating a catalytic layer on one side of a microporous layer of a gas diffusion layer. The preparation method of the anode gas diffusion electrode comprises the following steps: (i) Preparing an anode catalyst layer slurry: Weighing 40 wt % Pt / C catalyst, water, and isopropanol in a mass ratio of 40 wt % Pt / C catalyst: water: isopropanol = 1:15:85, ultrasonically dispersing the 40 wt % Pt / C catalyst, water, and isopropanol for 1 hour until uniformly dispersed to obtain an anode catalyst layer slurry; (ii) Preparation of an anode gas diffusion electrode: The anode catalyst layer slurry obtained in step (i) is uniformly coated on the side of the anode gas diffusion layer containing the microporous layer by ultrasonic spraying to obtain an anode gas diffusion electrode; the platinum loading in the anode catalyst layer is 0.5-1.0 mg / cm 2 .

9. The use according to claim 7, characterized in that: The phosphoric acid-doped high-temperature proton exchange membrane is obtained by soaking an alkaline polymer membrane in phosphoric acid; the mass concentration of the phosphoric acid is 50%-85%, the soaking temperature is 25-160°C, and the soaking time is 2-72 hours; the alkaline polymer membrane is at least one of a polybenzimidazole membrane, a polyvinyl imidazole membrane, a polyvinyl pyrrolidone membrane, and a polyarylene piperidine membrane; the phosphoric acid-doped high-temperature proton exchange membrane has a thickness of 30-200 μm, a proton conductivity of 0.01-0.50 S / cm, and a mechanical tensile strength of 5-200 MPa.

10. Use of the high-temperature proton exchange membrane fuel cell membrane electrode according to claim 7 in the preparation of a high-temperature proton exchange membrane fuel cell.

Images