CN113471494A - Membrane electrode based on molten proton conductor electrolyte membrane and preparation method thereof - Google Patents
Membrane electrode based on molten proton conductor electrolyte membrane and preparation method thereof Download PDFInfo
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/10—Fuel cells with solid electrolytes
- H01M8/1004—Fuel cells with solid electrolytes characterised by membrane-electrode assemblies [MEA]
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/88—Processes of manufacture
- H01M4/8803—Supports for the deposition of the catalytic active composition
- H01M4/8807—Gas diffusion layers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/10—Fuel cells with solid electrolytes
- H01M8/1007—Fuel cells with solid electrolytes with both reactants being gaseous or vaporised
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/10—Fuel cells with solid electrolytes
- H01M8/1016—Fuel cells with solid electrolytes characterised by the electrolyte material
- H01M8/1018—Polymeric electrolyte materials
- H01M8/1041—Polymer electrolyte composites, mixtures or blends
- H01M8/1046—Mixtures of at least one polymer and at least one additive
- H01M8/1048—Ion-conducting additives, e.g. ion-conducting particles, heteropolyacids, metal phosphate or polybenzimidazole with phosphoric acid
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/10—Fuel cells with solid electrolytes
- H01M2008/1095—Fuel cells with polymeric electrolytes
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
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Abstract
The invention provides a membrane electrode based on a molten proton conductor electrolyte membrane and a preparation method thereof; the membrane electrode of the molten proton conductor electrolyte comprises a polymer matrix for supporting a molten proton conductor and a gas diffusion electrode containing phosphoric acid, wherein the phosphoric acid is coated on a catalyst layer of the gas diffusion electrode. Compared with a low-temperature fuel cell, the medium-temperature fuel cell which can work in the temperature range of 100-250 ℃ has the advantages of faster electrode reaction, simplified water management, high CO tolerance and the like. The membrane electrode based on the molten proton conductor electrolyte membrane disclosed by the invention not only greatly improves the output performance of a fuel cell based on the membrane electrode of the molten proton conductor electrolyte membrane, but also has the advantages of simple preparation process and low cost, and is suitable for industrial production.
Description
Technical Field
The invention belongs to the technical field of electrochemistry, and particularly relates to a membrane electrode based on a molten proton conductor electrolyte membrane and a preparation method thereof.
Background
Fuel cells are power generation devices that convert chemical energy directly into electrical energy. The engine is considered to be one of the most promising devices for replacing the internal combustion engine due to the advantages of high efficiency, environmental protection, high flexibility and the like. Medium temperature fuel cells operating at 100-. The intermediate temperature fuel cell overcomes the main technical defects of the traditional low temperature fuel cell and becomes the current research hotspot.
Publication 1(A proton conductor based on molten CsH)5(PO4)2for intermediate-temperature fuel cells, RSC advaves, 2018,8,5225-5(PO4)2) An intermediate-temperature electrolyte membrane and an intermediate-temperature fuel cell assembled by the same; publication 2 (Electrolysis Membranes Based on Molten KH)5(PO4)2for Intermediate Temperature Fuel Cells, FUEL CELLS, 2019,19,280-288), it is reported that PBI is doped with a molten proton conductor (KH)5(PO4)2) An intermediate-temperature electrolyte membrane and an intermediate-temperature fuel cell assembled by the same. In the literature, doped molten proton conductors (CsH)5(PO4)2、KH5(PO4)2) The room temperature is solid and is higher than the melting point, and the solid is transformed into liquid molten mass which has high proton conductivity and becomes a good proton conductor; moreover, since the solid state is below the melting point, the loss is not easy to occur; the PBI doped molten proton conductor electrolyte membrane has good proton conductivity and mechanical strength.
Based on a molten proton conductor (CsH) as shown in publication 1 and Chinese patent CN107331883A (an intermediate temperature proton exchange membrane and a preparation method thereof)5(PO4)2) An electrolyte membrane, which is assembled with a fuel cell membrane electrode using a gas diffusion electrode (a catalyst layer is attached to the gas diffusion layer), and has a peak output power density of not more than 120mW/cm2And 70mW/cm2(ii) a Based on a molten proton conductor (KH), as shown in the publication 25(PO4)2) Electrolyte membrane, fuel cell membrane electrode assembly using gas diffusion electrode, fuel cell peak outputThe output power is lower than 40mW/cm2. In conclusion, the membrane electrode based on the molten proton conductor electrolyte membrane does not exhibit the expected good output performance of the fuel cell, which is also a great obstacle to the industrial application of the technology.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a membrane electrode based on a molten proton conductor electrolyte membrane and a preparation method thereof.
Based on the existing molten proton conductor electrolyte membrane, a proton conduction channel is established on a catalyst layer by coating phosphoric acid on the catalyst layer side of a gas diffusion electrode, and the interface contact between the catalyst layer and the electrolyte membrane is improved, so that the output performance of a fuel cell of the membrane electrode is greatly improved. The problem that the existing membrane electrode based on the molten proton conductor electrolyte membrane does not show correspondingly good output performance of the fuel cell is solved.
The invention can be realized by the following scheme:
in one aspect, the invention relates to a membrane electrode based on a molten proton conductor electrolyte membrane comprising a molten proton conductor-carrying polymer matrix, a gas diffusion electrode containing phosphoric acid coated on a catalytic layer of the gas diffusion electrode.
As an embodiment of the present invention, the polymer matrix is a heat-resistant polymer; the molten proton conductor is MHXO4、MH2X’O4、MH5(X’O4)2Wherein M is Cs, Rb, K or NH4 +X is S or Se, and X' is P or As.
The molten proton conductor according to the present invention has proton conductivity.
As an embodiment of the present invention, the heat resistant polymer is Polybenzimidazole (PBI) or polyvinylidene fluoride (PVDF).
As an embodiment of the present invention, the molten proton conductor is a perphosphate MH5(PO4)2. Selected perphosphate MH according to the invention5(PO4)2Is due to MH5(PO4)2The solid state at room temperature is higher than the melting point and is transformed into liquid state melt, the melt has high proton conductivity, and the solid state below the melting point is not easy to run off; furthermore, the PBI-doped molten proton conductor electrolyte membrane has a low swelling ratio and maintains good mechanical strength, thereby enabling the use of a thinner electrolyte membrane having a lower ohmic resistance and correspondingly higher fuel cell output performance.
As an embodiment of the invention, the perphosphate is potassium hydrogen perphosphate (KH)5(PO4)2) Or cesium hydrogen phosphate (CsH)5(PO4)2). Selected perphosphate MH according to the invention5(PO4)2Is cesium hydrogen perphosphate (CsH)5(PO4)2) Or potassium hydrogen perphosphate (KH)5(PO4)2) Is due to CsH5(PO4)2Melting point of about 150 deg.C, KH5(PO4)2The melting point is about 125 ℃, the two are solid at room temperature and higher than the melting point, are transformed into liquid melts, have high proton conductivity, have moderate working temperature, are easy to select a heat-resistant polymer matrix matched with the working temperature, and are difficult to select a proper heat-resistant polymer matrix if the working temperature is too high.
As an embodiment of the invention, the phosphoric acid makes the weight of the gas diffusion electrode increased by 1-20mg/cm2. The invention limits the phosphoric acid to lead the weight of the gas diffusion electrode to be increased by 1-20mg/cm2. Phosphoric acid permeates into a gas diffusion electrode catalyst layer formed by Pt/C and a binder (PTFE and the like), so that a proton transmission channel in the catalyst layer can be effectively improved, the proton transmission resistance in the catalyst layer is reduced, and the electric output performance of the membrane electrode is improved. If the phosphoric acid makes the weight of the gas diffusion electrode increased by less than 1mg/cm2Too little phosphoric acid makes it difficult to establish a sufficient proton conduction channel, so that ohmic resistance increases, resulting in a decrease in output performance of the fuel cell; if the weight of the gas diffusion electrode is increased by more than 20mg/cm2Excessive phosphoric acid, which may cause the excessive phosphoric acid to overflow when the membrane electrode is assembled, lowers the mechanical properties of the membrane, and blocks the gas transmission channel, resulting in a decrease in the output performance of the fuel cell of the membrane electrodeLow.
In a second aspect, the present invention also relates to a method for preparing a membrane electrode based on a molten proton conductor electrolyte membrane, comprising the steps of:
s1, melting the molten proton conductor at a temperature 0-20 ℃ higher than the melting point of the molten proton conductor to obtain a molten mass A;
s2, completely dipping the polymer matrix in the melt A, taking out after full dipping, and treating the residual molten proton conductor on the surface of the membrane to obtain a membrane B;
s3, uniformly coating a phosphoric acid solution on one side of a catalytic layer of the gas diffusion electrode to obtain a gas diffusion electrode C;
and S4, assembling a membrane electrode by using the membrane B and the gas diffusion electrode C.
In the limiting step S1, the melting temperature is 0-20 ℃ higher than the melting point of the molten proton conductor, and if the temperature is too low, the molten proton conductor cannot be completely melted; if the temperature is too high, dehydration reaction may occur in the molten proton conductor, which may affect proton conduction.
In step S2, the temperature of the impregnation is 0 to 20 ℃ higher than the melting point of the molten proton conductor, and the time of the impregnation is 6 to 72 hours. When dipping, the base body is ensured to be completely dipped in the solution, and the thickness of the base body is increased by 30 to 50 percent when the dipping is finished; and taking out the membrane, and cleaning the residual molten proton conductor on the surface to ensure the smoothness of the membrane when the membrane electrode is assembled. The time for the immersion is selected to be 6 to 72 hours in the present invention because the polymer matrix is immersed in the molten proton conductor, the polymer matrix adsorbs the molten mass, the immersion is saturated for a certain time, and the time does not change for more than a while, and therefore, the time is limited to 72 hours in order to ensure the adsorption saturation.
As an embodiment of the present invention, in step S3, the phosphoric acid solution is concentrated phosphoric acid or a combination of concentrated phosphoric acid and other solvents, wherein the other solvents are water, alcohols, benzenes, diethyl ether or acetone.
As an embodiment of the present invention, the volume ratio of the concentrated phosphoric acid to the other solvent is 1: 10-1: 0.1.
the volume ratio of concentrated phosphoric acid to other solvents is limited to 1: 10-1: 0.1, if the volume ratio of other solvents is too small, the phosphoric acid solution is difficult to wet and difficult to permeate into the catalytic layer, so that a proton conduction channel is difficult to establish on the catalytic layer, ohmic resistance is increased, and output performance of the fuel cell is reduced; if the volume ratio of other solvents is too large, the concentration of phosphoric acid in the phosphoric acid solution is too low, and the phosphoric acid solution needs to be repeatedly coated to obtain the required phosphoric acid weight increase, so that the workload is increased, and the phosphoric acid with too low concentration can penetrate through the catalytic layer and excessively infiltrate into the gas diffusion layer, so that the gas transmission is hindered, and the output performance of the fuel cell is reduced.
As an embodiment of the present invention, in step S3, if the phosphoric acid solution is a combination of concentrated phosphoric acid and other solvents, the solvent is removed by drying before step S4;
as an embodiment of the invention, the drying is natural volatilization of the solvent or heating drying.
As an embodiment of the present invention, the phosphoric acid solution is concentrated phosphoric acid or a combination of concentrated phosphoric acid and a lower alcohol, which is methanol, ethanol, n-propanol, isopropanol or butanol.
As one embodiment of the present invention, the phosphoric acid solution is a combination of concentrated phosphoric acid and a low polyhydric alcohol. The phosphoric acid solution is limited to be the combination of concentrated phosphoric acid and low-polyhydric alcohol, because the concentrated phosphoric acid has poor wettability on the catalytic layer and is difficult to permeate into the catalytic layer, and the mixed solution of the alcohol and the concentrated phosphoric acid selected by the invention can improve the wettability on the catalytic layer and help the phosphoric acid to rapidly permeate into the catalytic layer.
As an embodiment of the present invention, in step S3, the coating mode is spray coating or coating.
In a third aspect, the invention also relates to the use of a membrane electrode based on a molten proton conductor electrolyte membrane in a fuel cell.
The PBI doped molten proton conductor electrolyte membrane has higher proton conductivity and great potential in the application of medium-temperature fuel cells, but the membrane electrode is actually assembled and does not have high-level fuel cell output performance. It is known that, in a gas diffusion electrode for an intermediate temperature fuel cell, a catalyst layer is conventionally formed by Pt/C and PTFE powder, and according to a conventional concept (for example, patent publications 1 and 2 and chinese patent CN107331883A), when a membrane electrode is assembled, for a PBI-doped molten proton conductor electrolyte membrane, a proton conductor is melted to form a liquid melt, and the liquid melt diffuses into the catalyst layer, so that a proton conduction channel is established in the catalyst layer. However, the inventors have found that, after the proton conductor is melted, the molten proton conductor is difficult to diffuse into the catalytic layer, and thus it is difficult to establish a proton conduction path in the catalytic layer, resulting in low output performance of the fuel cell. Compared with the prior art, the invention has the following beneficial effects:
(1) the present inventors have made intensive efforts to propose that phosphoric acid is applied to the surface of the catalyst layer of the gas diffusion electrode to establish a proton conduction channel in the catalyst layer in advance. Further, the fuel cell is assembled using the gas diffusion electrode with phosphoric acid, and a greatly improved fuel cell output performance is obtained.
(2) The invention provides a preparation method of a membrane electrode, which has simple process, strong practicability and low cost, and greatly improves the output power density of a fuel cell of the membrane electrode under the condition of hardly increasing the cost.
(3) The membrane electrode based on the molten proton conductor electrolyte membrane prepared by the invention is expected to be widely applied to electrochemical devices such as fuel cells and the like.
Drawings
Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:
FIG. 1 is a schematic view showing a membrane electrode production process of a molten proton conductor electrolyte membrane according to all examples of the present invention;
FIG. 2(a) is the PBI-doped CsH prepared in example 15(PO4)2Scanning electron micrographs of electrolyte membranes; fig. 2(b) is an X-ray scattering spectrum (EDX) diagram of phosphorus (P) element in the electrolyte membrane.
FIG. 3 is the PBI-doped CsH prepared in example 15(PO4)2Electrolyte membrane and PBI doped KH prepared in example 45(PO4)2Mechanical tensile curves of electrolyte membranes, and PBI doped phosphoric acid membranes, PBI membranes as a comparison.
FIG. 4 shows the PBI-based doped CsH prepared in example 1 and comparative example 15(PO4)2The membrane electrode of the electrolyte membrane has a fuel cell output performance curve under the condition of 180 ℃.
FIG. 5 is a graph of the output performance of the fuel cell at different temperatures of 160 ℃ and 220 ℃ of the membrane electrode prepared in example 1.
FIG. 6 is PBI-doped KH prepared in example 45(PO4)2Scanning electron micrographs of the electrolyte membrane.
FIG. 7 is PBI-doped KH prepared in example 45(PO4)2Thermogravimetric curve of electrolyte membrane.
FIG. 8 is PBI-based doped KH prepared in example 45(PO4)2The output performance curve of the fuel cell under the drying condition at 150 ℃ of the membrane electrode of the electrolyte membrane;
wherein 1 is a medium temperature melting proton conductor electrolyte membrane, 2 is a gas diffusion electrode, 2-1 is a gas diffusion layer, 2-2 is a catalyst layer, and 3 is a phosphoric acid coating layer.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments. The following examples, which are set forth to provide a detailed description of the invention and a detailed description of the operation, will help those skilled in the art to further understand the present invention. It should be noted that the scope of the present invention is not limited to the following embodiments, and that several modifications and improvements made on the premise of the idea of the present invention belong to the scope of the present invention.
Fig. 1 is a schematic diagram of a membrane electrode preparation process of a molten proton conductor electrolyte membrane according to all embodiments of the present invention, and the membrane electrode includes, in order from top to bottom, a gas diffusion layer 2-1, a catalyst layer 2-2, a phosphate coating layer 3, an intermediate temperature molten proton conductor electrolyte membrane 1, a phosphate coating layer 3, a catalyst layer 2-2, and a gas diffusion layer 2-1.
Example 1
In this example, the heat-resistant polymer as the matrix was Polybenzimidazole (PBI). The method specifically comprises the following steps:
step 1: adding cesium pentahydrogenphosphate (CsH)5(PO4)2) Melting at 160 ℃ to obtain a molten mass A;
step 2: soaking Polybenzimidazole (PBI) in the melt A at 160 ℃, taking out after 48 hours, and cleaning up cesium potassium phosphate on the surface to obtain a membrane B;
and step 3: and spraying a phosphoric acid solution on the catalytic layer 2-2 side of the gas diffusion electrode, wherein the phosphoric acid solution consists of concentrated phosphoric acid and ethanol, and the volume ratio of the concentrated phosphoric acid to the ethanol is 1: 4;
and 4, step 4: drying and removing ethanol in the phosphoric acid solution on the gas diffusion electrode to obtain a gas diffusion electrode C, and increasing the weight of the gas diffusion electrode by 5mg/cm after drying2；
And 5: and assembling the prepared membrane B and the gas diffusion electrodes C of the upper layer and the lower layer with a membrane electrode.
Example 2
In this example, the heat-resistant polymer as the matrix was Polybenzimidazole (PBI). The method specifically comprises the following steps:
step 1: adding cesium pentahydrogenphosphate (CsH)5(PO4)2) Melting at 160 ℃ to obtain a molten mass A;
step 2: soaking Polybenzimidazole (PBI) in the melt A at 160 ℃, taking out after 48 hours, and cleaning up the cesium pentahydrogen phosphate on the surface to obtain a membrane B;
and step 3: and spraying a phosphoric acid solution on the catalytic layer 2-2 side of the gas diffusion electrode, wherein the phosphoric acid solution consists of concentrated phosphoric acid and ethanol, and the volume ratio of the concentrated phosphoric acid to the ethanol is 1: 4;
and 4, step 4: drying and removing ethanol in the phosphoric acid solution on the gas diffusion electrode to obtain a gas diffusion electrode C, and increasing the weight of the gas diffusion electrode by 1mg/cm after drying2；
And 5: and assembling the prepared membrane B and the gas diffusion electrodes C of the upper layer and the lower layer with a membrane electrode.
Example 3
In this example, the heat-resistant polymer as the matrix was Polybenzimidazole (PBI). The method specifically comprises the following steps:
step 1: adding cesium pentahydrogenphosphate (CsH)5(PO4)2) Melting at 160 ℃ to obtain a molten mass A;
step 2: soaking Polybenzimidazole (PBI) in the melt A at 160 ℃, taking out after 48 hours, and cleaning up the cesium pentahydrogen phosphate on the surface to obtain a membrane B;
and step 3: and spraying a phosphoric acid solution on the catalytic layer 2-2 side of the gas diffusion electrode, wherein the phosphoric acid solution consists of concentrated phosphoric acid and ethanol, and the volume ratio of the concentrated phosphoric acid to the ethanol is 1: 4;
and 4, step 4: drying and removing ethanol in the phosphoric acid solution on the gas diffusion electrode to obtain a gas diffusion electrode C, and increasing the weight of the gas diffusion electrode by 20mg/cm after drying2；
And 5: and assembling the prepared membrane B and the gas diffusion electrodes C of the upper layer and the lower layer with a membrane electrode.
Example 4
In this example, the heat-resistant polymer as the matrix was Polybenzimidazole (PBI). The method specifically comprises the following steps:
step 1: mixing potassium pentahydrogen phosphate (KH)5(PO4)2) Melting at 140 ℃ to obtain a molten mass A;
step 2: soaking Polybenzimidazole (PBI) in the melt A at 140 ℃, taking out after 48 hours, and cleaning potassium pentahydrogen phosphate on the surface to obtain a membrane B;
and step 3: and spraying a phosphoric acid solution on the catalytic layer 2-2 side of the gas diffusion electrode, wherein the phosphoric acid solution consists of concentrated phosphoric acid and ethanol, and the volume ratio of the concentrated phosphoric acid to the ethanol is 1: 4;
and 4, step 4: drying and removing ethanol in the phosphoric acid solution on the gas diffusion electrode to obtain a gas diffusion electrode C, and increasing the weight of the gas diffusion electrode by 5mg/cm after drying2；
And 5: and assembling the prepared membrane B and the gas diffusion electrodes C of the upper layer and the lower layer with a membrane electrode.
Example 5
In this example, the heat-resistant polymer as the matrix was Polybenzimidazole (PBI). The method specifically comprises the following steps:
step 1: mixing potassium pentahydrogen phosphate (KH)5(PO4)2) Melting at 140 deg.C higher than its melting point to obtain melt A;
step 2: soaking Polybenzimidazole (PBI) in the melt A at 140 ℃ for 48 hours, taking out the polybenzimidazole, and cleaning potassium pentahydrogen phosphate on the surface to obtain a membrane B;
and step 3: spraying a phosphoric acid solution on the catalytic layer 2-2 side of the gas diffusion electrode, wherein the phosphoric acid solution consists of concentrated phosphoric acid and ethanol, and the mass ratio of the concentrated phosphoric acid: the volume ratio of ethanol is 1: 4;
and 4, step 4: drying and removing ethanol in the phosphoric acid solution on the gas diffusion electrode to obtain a gas diffusion electrode C, and increasing the weight of the gas diffusion electrode by 1mg/cm after drying2；
And 5: and assembling the prepared membrane B and the gas diffusion electrodes C of the upper layer and the lower layer with a membrane electrode.
Example 6
In this example, the heat-resistant polymer as the matrix was Polybenzimidazole (PBI). The method specifically comprises the following steps:
step 1: mixing potassium pentahydrogen phosphate (KH)5(PO4)2) Melting at 140 deg.C higher than its melting point to obtain melt A;
step 2: soaking Polybenzimidazole (PBI) in the melt A at 140 ℃ for 48 hours, taking out the polybenzimidazole, and cleaning potassium pentahydrogen phosphate on the surface to obtain a membrane B;
and step 3: spraying a phosphoric acid solution on the catalytic layer 2-2 side of the gas diffusion electrode, wherein the phosphoric acid solution consists of concentrated phosphoric acid and isopropanol, and the ratio of the concentrated phosphoric acid: the volume ratio of isopropanol is 1: 4;
and 4, step 4: drying and removing isopropanol in the phosphoric acid solution on the gas diffusion electrode to obtain a gas diffusion electrode C, and increasing the weight of the gas diffusion electrode by 20mg/cm after drying2；
And 5: and assembling the prepared membrane B and the gas diffusion electrodes C of the upper layer and the lower layer with a membrane electrode.
Example 7
In this example, the heat-resistant polymer as the matrix was Polybenzimidazole (PBI). The method specifically comprises the following steps:
step 1: adding cesium pentahydrogenphosphate (CsH)5(PO4)2) Melting at 160 ℃ higher than the melting point of the mixture to obtain a molten mass A;
step 2: soaking Polybenzimidazole (PBI) in the melt A at 160 ℃ for 48 hours, taking out the polybenzimidazole, and cleaning the cesium pentahydrogen phosphate on the surface to obtain a membrane B;
and step 3: spraying a phosphoric acid solution with the concentrated phosphoric acid volume fraction of 100% on the catalytic layer 2-2 side of the gas diffusion electrode; drying is not needed, the gas diffusion electrode C is obtained, and the weight of the gas diffusion electrode is increased by 5mg/cm2；
And 4, step 4: and assembling the prepared membrane B and the gas diffusion electrodes C of the upper layer and the lower layer with a membrane electrode.
Example 8
In this example, the heat-resistant polymer as the matrix was Polybenzimidazole (PBI). The method specifically comprises the following steps:
step 1: adding cesium pentahydrogenphosphate (CsH)5(PO4)2) Melting at 160 ℃ higher than the melting point of the mixture to obtain a molten mass A;
step 2: soaking Polybenzimidazole (PBI) in the melt A at 160 ℃ for 48 hours, taking out the polybenzimidazole, and cleaning the cesium pentahydrogen phosphate on the surface to obtain a membrane B;
and step 3: spraying a phosphoric acid solution on the catalytic layer 2-2 side of the gas diffusion electrode, wherein the phosphoric acid solution consists of concentrated phosphoric acid and ethanol, and the mass ratio of the concentrated phosphoric acid: the volume ratio of ethanol is 1: 10;
and 4, step 4: drying and removing ethanol in the phosphoric acid solution on the gas diffusion electrode to obtain a gas diffusion electrode C, and increasing the weight of the gas diffusion electrode by 5mg/cm after drying2；
And 5: and assembling the prepared membrane B and the gas diffusion electrodes C of the upper layer and the lower layer with a membrane electrode.
Example 9
In this example, the heat-resistant polymer as the matrix was Polybenzimidazole (PBI). The method specifically comprises the following steps:
step 1: adding cesium pentahydrogenphosphate (CsH)5(PO4)2) Melting at 160 ℃ higher than the melting point of the mixture to obtain a molten mass A;
step 2: soaking Polybenzimidazole (PBI) in the melt A at 160 ℃ for 48 hours, taking out the polybenzimidazole, and cleaning the cesium pentahydrogen phosphate on the surface to obtain a membrane B;
and step 3: spraying a phosphoric acid solution on the catalytic layer 2-2 side of the gas diffusion electrode, wherein the phosphoric acid solution consists of concentrated phosphoric acid and ethanol, and the mass ratio of the concentrated phosphoric acid: the volume ratio of ethanol is 1: 0.1;
and 4, step 4: drying and removing ethanol in the phosphoric acid solution on the gas diffusion electrode to obtain a gas diffusion electrode C, and increasing the weight of the gas diffusion electrode by 5mg/cm after drying2；
And 5: and assembling the prepared membrane B and the gas diffusion electrodes C of the upper layer and the lower layer at normal temperature to form a membrane electrode.
Example 10
In this example, the heat-resistant polymer as the matrix was Polybenzimidazole (PBI). The method specifically comprises the following steps:
step 1: mixing potassium pentahydrogen phosphate (KH)5(PO4)2) Melting at 130 deg.C higher than its melting point to obtain melt A;
step 2: soaking Polybenzimidazole (PBI) in the melt A at 130 ℃ for 72 hours, taking out the polybenzimidazole, and cleaning potassium pentahydrogen phosphate on the surface to obtain a membrane B;
and step 3: spraying a phosphoric acid solution on the catalytic layer 2-2 side of the gas diffusion electrode, wherein the phosphoric acid solution consists of concentrated phosphoric acid and n-propanol, and the ratio of the concentrated phosphoric acid: volume ratio of n-propanol is 1: 4;
and 4, step 4: drying and removing n-propanol in the phosphoric acid solution on the gas diffusion electrode to obtain a gas diffusion electrode C, and increasing the weight of the gas diffusion electrode by 5mg/cm after drying2；
And 5: and assembling the prepared membrane B and the gas diffusion electrodes C of the upper layer and the lower layer with a membrane electrode.
Example 11
In this example, the heat-resistant polymer as the matrix was Polybenzimidazole (PBI). The method specifically comprises the following steps:
step 1: adding cesium pentahydrogenphosphate (CsH)5(PO4)2) Melting at 170 deg.C higher than its melting point to obtain melt A;
step 2: soaking Polybenzimidazole (PBI) in the melt A at 170 ℃ for 6 hours, taking out the polybenzimidazole, and cleaning the cesium pentahydrogen phosphate on the surface to obtain a membrane B;
and step 3: spraying a phosphoric acid solution on the catalytic layer 2-2 side of the gas diffusion electrode, wherein the phosphoric acid solution consists of concentrated phosphoric acid and ethanol, and the mass ratio of the concentrated phosphoric acid: the volume ratio of methanol is 1: 4;
and 4, step 4: drying and removing methanol in the phosphoric acid solution on the gas diffusion electrode to obtain a gas diffusion electrode C, and increasing the weight of the gas diffusion electrode by 5mg/cm after drying2；
And 5: and assembling the prepared membrane B and the gas diffusion electrodes C of the upper layer and the lower layer with a membrane electrode.
Example 12
In this example, the heat-resistant polymer as the matrix was polyvinylidene fluoride (PVDF). The method specifically comprises the following steps:
step 1: mixing potassium pentahydrogen phosphate (KH)5(PO4)2) Melting at 140 deg.C higher than its melting point to obtain melt A;
step 2: soaking polyvinylidene fluoride (PVDF) in the melt A at 140 ℃ for 24 hours, taking out the PVDF, and cleaning potassium pentahydrogen phosphate on the surface to obtain a membrane B;
and step 3: spraying a phosphoric acid solution on the catalytic layer 2-2 side of the gas diffusion electrode, wherein the phosphoric acid solution consists of concentrated phosphoric acid and acetone, and the mass ratio of the concentrated phosphoric acid: the volume ratio of acetone is 1: 4;
and 4, step 4: drying and removing acetone in the phosphoric acid solution on the gas diffusion electrode to obtain a gas diffusion electrode C, and increasing the weight of the gas diffusion electrode by 5mg/cm after drying2；
And 5: and assembling the prepared membrane B and the gas diffusion electrodes C of the upper layer and the lower layer with a membrane electrode.
Comparative example 1
In this example, the heat-resistant polymer as the matrix was Polybenzimidazole (PBI). The method specifically comprises the following steps:
step 1: mixing potassium pentahydrogenphosphate (CsH)5(PO4)2) Melting at 160 ℃ higher than the melting point of the mixture to obtain a molten mass A;
step 2: soaking Polybenzimidazole (PBI) in the melt A at 160 ℃ for 48 hours, taking out the polybenzimidazole, and cleaning potassium pentahydrogen phosphate on the surface to obtain a membrane B;
and step 3: no phosphoric acid solution is sprayed on the catalyst layer 2-2 of the gas diffusion electrode;
and 4, step 4: and (3) assembling the membrane B prepared in the steps 1 and 2 and the gas diffusion electrodes C on the upper layer and the lower layer to form a membrane electrode.
The comparative example differs from example 1 only in that the catalytic layer of the gas diffusion electrode is not sprayed with a phosphoric acid solution.
Comparative example 2
In this example, the heat-resistant polymer as the matrix was Polybenzimidazole (PBI). The method specifically comprises the following steps:
step 1: adding cesium pentahydrogenphosphate (CsH)5(PO4)2) Melting at 160 ℃ to obtain a molten mass A;
step 2: soaking Polybenzimidazole (PBI) in the melt A at 160 ℃, taking out after 48 hours, and cleaning potassium pentahydrogen phosphate on the surface to obtain a membrane B;
and step 3: and spraying a phosphoric acid solution on the catalytic layer 2-2 side of the gas diffusion electrode, wherein the phosphoric acid solution consists of concentrated phosphoric acid and ethanol, and the volume ratio of the concentrated phosphoric acid to the ethanol is 1: 4;
and 4, step 4: drying and removing ethanol in the phosphoric acid solution on the gas diffusion electrode to obtain a gas diffusion electrode C, and increasing the weight of the gas diffusion electrode by 0.3mg/cm after drying2；
And 5: and assembling the prepared membrane B and the gas diffusion electrodes C of the upper layer and the lower layer with a membrane electrode.
Comparative example 3
In this example, the heat-resistant polymer as the matrix was Polybenzimidazole (PBI). The method specifically comprises the following steps:
step 1: adding cesium pentahydrogenphosphate (CsH)5(PO4)2) Melting at 160 ℃ to obtain a molten mass A;
step 2: soaking Polybenzimidazole (PBI) in the melt A at 160 ℃, taking out after 48 hours, and cleaning potassium pentahydrogen phosphate on the surface to obtain a membrane B;
and step 3: and spraying a phosphoric acid solution on the catalytic layer 2-2 side of the gas diffusion electrode, wherein the phosphoric acid solution consists of concentrated phosphoric acid and ethanol, and the volume ratio of the concentrated phosphoric acid to the ethanol is 1: 4;
and 4, step 4: drying and removing ethanol in the phosphoric acid solution on the gas diffusion electrode to obtain a gas diffusion electrode C, and increasing the weight of the gas diffusion electrode by 25mg/cm after drying2；
And 5: and assembling the prepared membrane B and the gas diffusion electrodes C of the upper layer and the lower layer with a membrane electrode.
Comparative example 4
In this example, the heat-resistant polymer as the matrix was Polybenzimidazole (PBI). The method specifically comprises the following steps:
step 1: mixing potassium pentahydrogen phosphate (KH)5(PO4)2) Melting at 140 deg.C higher than its melting point to obtain melt A;
step 2: soaking Polybenzimidazole (PBI) in the melt A at 140 ℃ for 48 hours, taking out the polybenzimidazole, and cleaning potassium pentahydrogen phosphate on the surface to obtain a membrane B;
and step 3: no phosphoric acid solution is sprayed on the catalyst layer 2-2 of the gas diffusion electrode;
and 4, step 4: and assembling the prepared membrane B and the gas diffusion electrodes C of the upper layer and the lower layer with a membrane electrode.
The comparative example differs from example 4 only in that the catalytic layer of the gas diffusion electrode is not sprayed with a phosphoric acid solution.
Comparative example 5
The comparative example is different from example 4 only in that, in step 4, the gas diffusion electrode C is obtained after drying and removing ethanol in the phosphoric acid solution on the gas diffusion electrode, and the weight of the gas diffusion electrode is increased by 0.3mg/cm after drying2。
Comparative example 6
The comparative example is different from example 4 only in that, in step 4, the gas diffusion electrode C is obtained after drying and removing ethanol in the phosphoric acid solution on the gas diffusion electrode, and the weight of the gas diffusion electrode is increased by 25mg/cm after drying2。
Comparative example 7
The present comparative example differs from example 1 only in that: in step 3, spraying a phosphoric acid solution on the catalyst layer 2-2 side of the gas diffusion electrode, wherein the phosphoric acid solution consists of concentrated phosphoric acid and ethanol, and the mass ratio of the concentrated phosphoric acid: the volume ratio of ethanol is 1: 14.
examples Performance testing
A photograph of a cross section of the molten proton conductor electrolyte membrane used for preparing the membrane electrode was obtained using a field emission scanning electron microscope (JSM-7800F).
Using an electronic universal tester to test the mechanical properties of the prepared sample, wherein the size of the test sample is 10mm multiplied by 60mm (width multiplied by length); the test conditions were room temperature, 5cm/min of tensile speed, and 5cm of distance between tensile chucks.
Thermogravimetric analysis is carried out on the electrolyte membrane by using a synchronous thermal analyzer (STA449), the test gas atmosphere is air, the flow is 40ml/min, the temperature rise speed is 10 ℃/min, and the test temperature range is 30-900 ℃.
Testing the performance of the single battery: for comparison, the gas diffusion electrodes used in the examples and comparative examples were each manufactured using a gas diffusion electrode (HT140E) commercially available from Advent corporation, and the active area was 5cm2The membrane electrode of (1) respectively introducing hydrogen and oxygen into the anode and cathode of the single cell, wherein the gas flow rates of the hydrogen and the oxygen are both 0.4L/min, the cathode side of the cell can be humidified by using a peristaltic pump, the humidity range is 0-30% RH, and the performance test of the fuel cell is carried outThe temperature range is 150-220 ℃.
The composition ratios and properties of the molten proton conductor electrolyte membranes prepared in the respective examples and comparative examples, and the properties of the fuel cells assembled using the electrolytes are summarized in table 1.
FIG. 2(a) shows the PBI-doped CsH prepared in example 15(PO4)2Fig. 2(b) is an X-ray scattering spectrum (EDX) diagram of a phosphorus (P) element in the electrolyte membrane. The significance of FIG. 2: indicating molten proton conductor CsH5(PO4)2Fully and uniformly filled into the PBI film because the phosphorus element in the film can only come from CsH5(PO4)2PBI itself contains no phosphorus element.
FIG. 3 is the PBI-doped CsH prepared in example 15(PO4)2Electrolyte membrane and PBI doped KH prepared in example 45(PO4)2Mechanical tensile curves of electrolyte membranes, and PBI doped phosphoric acid membranes, PBI membranes as a comparison. Fig. 3 compares the mechanical properties of PBI-doped molten proton conductor electrolyte membranes and PBI-doped phosphoric acid electrolyte membranes. PBI doped phosphoric acid membrane is a conventional commercial high temperature proton exchange membrane. As shown in FIG. 3, the tensile strength of the pure PBI film was 97MPa, and the PBI-doped CsH prepared in example 1 was used5(PO4)2Electrolyte membrane 84MPa, PBI doped KH prepared in example 45(PO4)2The electrolyte membrane is 58Mpa, and the PBI doped phosphoric acid membrane is only 13 Mpa. It is clear that the tensile strength of PBI-doped phosphoric acid membranes is much lower than that of PBI-doped molten proton conductors (CsH)5(PO4)2、KH5(PO4)2) An electrolyte membrane. Because the PBI is doped with a molten proton conductor (CsH)5(PO4)2、KH5(PO4)2) The electrolyte membrane has good mechanical properties, so thinner PBI-doped molten proton conductor (CsH) can be selected5(PO4)2、KH5(PO4)2) The electrolyte membrane prepares a membrane electrode, thereby reducing ohmic resistance from the electrolyte membrane and correspondingly improving the output performance of the fuel cell.
FIG. 4 shows the PBI-based doped CsH prepared in example 1 and comparative example 15(PO4)2The membrane electrode of the electrolyte membrane has a fuel cell output performance curve under the condition of 180 ℃. FIG. 4 and Table 1 compare example 1 (5 mg/cm on the catalytic layer of the gas diffusion electrode)2Phosphoric acid) and comparative example 1 (no phosphoric acid on the catalytic layer of the gas diffusion electrode), as shown in fig. 4, the peak power densities of example 1 and comparative example 1 were 476mW/cm, respectively2And 62mW/cm2It was shown that the output performance of the fuel cell of example 1 was significantly higher than that of comparative example 1. Similarly, Table 1 compares example 4 (5 mg/cm on the catalytic layer of the gas diffusion electrode)2Phosphoric acid) with comparative example 4 (no phosphoric acid on the catalytic layer of the gas diffusion electrode) based on PBI doped KH5(PO4)2The fuel cell output performance of the membrane electrode of the electrolyte membrane also shows that the fuel cell output performance of example 4 is significantly higher than that of comparative example 4. The above results indicate that the application of phosphoric acid on the catalytic layer of the gas diffusion electrode has a critical effect on the fuel cell performance. This is because, for the gas diffusion electrode of an intermediate-temperature fuel cell, the catalytic layer thereof is conventionally composed of Pt/C and a binder (PTFE or the like), without a proton conductor. Phosphoric acid is coated on the catalyst layer, and permeates into the catalyst layer formed by Pt/C and a binder (PTFE and the like), so that a proton transmission channel can be established in the catalyst layer, the proton transmission resistance in the catalyst layer is reduced, and the output performance of the fuel cell of the membrane electrode is obviously improved; in contrast, in comparative example 1, the catalytic layer of the gas diffusion electrode was not supported with phosphoric acid, resulting in difficulty in establishing a proton conduction channel in the catalytic layer of the gas diffusion electrode composed of Pt/C and a binder, and poor contact of the interface between the electrolyte membrane and the catalytic layer, resulting in large interface resistance, resulting in low output performance of the fuel cell.
FIG. 5 is a graph of the output performance of the fuel cell at different temperatures of 160 ℃ and 220 ℃ of the membrane electrode prepared in example 1. It can be observed that at all temperatures, the open circuit voltage is kept above 1.0V, the maximum value of the open circuit voltage can reach 1.04V, and the high open circuit voltage benefits from the low swelling ratio, high compactness, and low hydrogen permeability of the PBI-doped molten proton conductor electrolyte membrane. Fig. 5 shows that as the temperature increases, the peak power density increases with increasing temperature in the temperature interval 160 ℃ -200 ℃, which is due to the increased conductivity of the molten proton conductor and the increased kinetic activity of the cathode. But continuing to raise the temperature to 220 c, the peak power density decreases, which may be attributed to the increase in ohmic resistance caused by dehydration of the molten proton conductor.
The amount of phosphoric acid on the catalytic layer has a large impact on fuel cell performance. For doping CsH based on PBI5(PO4)2Membrane electrode of electrolyte membrane, as shown in table 1, the membrane electrodes of examples 1, 2, 3 had higher peak power density of the fuel cell as compared with comparative examples 2, 3; for PBI based doping KH5(PO4)2The membrane electrodes of the electrolyte membranes, as shown in table 1, had higher peak power densities of the fuel cells as compared with the membrane electrodes of comparative examples 5, 6. Thus, as in examples 1, 2 and 3, and examples 4, 5 and 6, phosphoric acid (1-15 mg/cm) was sprayed on the catalytic layer of the gas diffusion electrode2) Phosphoric acid permeates into the catalyst layer formed by Pt/C and a binder (PTFE and the like), so that a proton transmission channel in the catalyst layer can be effectively improved, the proton transmission resistance in the catalyst layer is reduced, and the electric output performance of the membrane electrode is improved. However, as in comparative examples 2 and 5, too little phosphoric acid (0.3 mg/cm)2) It is difficult to establish a sufficient proton conduction channel, so that ohmic resistance increases, resulting in a decrease in output performance of the fuel cell; in contrast, as in comparative examples 3 and 6, excess phosphoric acid (25 mg/cm)2) This may lead to overflow of excess phosphoric acid when the membrane electrode is assembled, lowering the mechanical properties of the membrane, and blocking the gas transmission channel, resulting in a decrease in the output performance of the fuel cell.
FIG. 6 is PBI-doped KH prepared in example 45(PO4)2Scanning Electron micrograph of electrolyte Membrane, as shown in FIG. 6, after immersion of molten proton conductor for 48 hours, Polybenzimidazole (PBI) matrix has distributed therein a large amount of KH5(PO4)2Proton conductor, which makes the membrane possess certain proton conductivity.
FIG. 7 is PBI-doped KH prepared in example 45(PO4)2Thermogravimetric curve of electrolyte membrane. It can be seen that the TGA curve for PBI membrane experiences a sharp weight loss at 450-650 deg.C, while KH5(PO4)2The weight is relatively stable in a high-temperature state, and the weight loss caused by only a small amount of hydrolysis is realized, so that the high-temperature-resistant polyester resin has certain thermal stability. PBI doped KH5(PO4)2The electrolyte membrane basically keeps a stable state in weight in a temperature region of 150-200 ℃, and has good thermal stability.
The membrane electrode according to example 4 was assembled with a single cell of a fuel cell and the test temperature was 150 ℃. FIG. 8 is PBI-based doped KH prepared in example 45(PO4)2The membrane electrode of the electrolyte membrane has a fuel cell output performance curve under the drying condition at 150 ℃. As shown in FIG. 8, the Open Circuit Voltage (OCV) reached 0.98V and the peak power density was about 400mW/cm2And exhibits good fuel cell output performance. And the output power curve in fig. 8 is the result of the non-humidified working condition, if the testing condition is changed to cathode humidification of 10% -30% RH, or the testing temperature is properly increased, the performance is better.
As in example 1 (volume ratio of concentrated phosphoric acid: ethanol 1: 4) examples 8 (volume ratio of concentrated phosphoric acid: ethanol 1: 0.1) and 9 (volume ratio of concentrated phosphoric acid: ethanol 1: 10), the present invention defines the volume ratio of concentrated phosphoric acid to other solvents as 1: 10-1: 0.1, the prepared membrane electrode obtains good output performance of the fuel cell. If the volume ratio of the other solvent is too small, as in example 7 (the volume ratio of concentrated phosphoric acid to ethanol is 1: 0), the phosphoric acid solution is difficult to wet and penetrate into the catalytic layer compared to example 1, and thus it is difficult to establish a proton conduction channel in the catalytic layer, so that the ohmic resistance increases, and the output performance of the fuel cell decreases; if the volume ratio of other solvents is too large, as in comparative example 7 (volume ratio of concentrated phosphoric acid to ethanol is 1: 14), the phosphoric acid concentration in the phosphoric acid solution is too low, and repeated coating is required to obtain the required phosphoric acid weight gain, so that the workload is increased, and phosphoric acid with too low concentration passes through the catalytic layer, excessively infiltrates into the gas diffusion layer, hinders gas transmission, and reduces the output performance of the fuel cell.
Example 10 Polybenzimidazole (PBI) was immersed in a molten proton conductor (KH) at 130 deg.C5(PO4)2) After 72 hours, the membrane was immersed at a lower temperature and for a longer time than in example 4, and the molten proton conductor was allowed to sufficiently diffuse into the PBI matrix, thereby obtaining an electrolyte membrane sufficiently filled with the molten proton conductor. Example 11 Polybenzimidazole (PBI) was immersed in a 170 ℃ molten proton conductor (CsH)5(PO4)2) After 6 hours, the membrane was immersed at a higher temperature and for a shorter time than in example 1, and the molten proton conductor was allowed to sufficiently diffuse into the PBI matrix, thereby obtaining an electrolyte membrane sufficiently filled with the molten proton conductor.
Example 12 differs from example 4 only in that the membrane electrode obtained good fuel cell output performance with PVDF as the polymer matrix, as shown in table 1.
TABLE 1
In conclusion, the adoption of the embodiment of the invention can effectively improve the output performance of the fuel cell of the membrane electrode based on the molten proton conductor electrolyte membrane. According to the membrane electrode based on the molten proton conductor electrolyte membrane, disclosed by the invention, the proton conduction of the catalyst layer and the interface contact between the catalyst layer and the electrolyte membrane are improved by a simple process, so that the performance of the membrane electrode is greatly improved, and the membrane electrode is suitable for industrial production; meanwhile, the cheap raw materials are beneficial to keeping low preparation cost of the membrane electrode, and the membrane electrode is expected to be widely applied to the field of medium-temperature fuel cells and the related field needing medium-temperature proton conduction electrolyte membranes. In particular, the invention is based on PBI-doped fused proton conductors (CsH)5(PO4)2) The membrane electrode of the medium-temperature electrolyte membrane has the capability of matching the operating temperature (200-300 ℃) of the methanol reformer when the operating temperature of the fuel cell is 160-220 ℃. Compared with high-pressure hydrogen storage, methanol is used as fuel, the reformer is utilized to generate hydrogen in situ through the reforming reaction of water and methanol, and the method has the advantages of convenient storage and transportation of fuel, safety and reliabilityAnd high energy density. Moreover, compared with other hydrocarbon fuels (ethanol, propanol, methane and the like), the reforming temperature of the methanol is the lowest, and the energy consumption is low. The hydrogen production of the methanol reformer is endothermic reaction, the power generation of the fuel cell is exothermic reaction, and the methanol reformer and the fuel cell operate on the same temperature platform, so that the waste heat generated by the power generation of the fuel cell can be supplied to the reformer and the temperature of the reformer can be maintained, thereby reducing the heat loss, improving the system efficiency, being convenient for the compact structure design and reducing the size and the weight of the system.
The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes or modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention. The embodiments and features of the embodiments of the present application may be combined with each other arbitrarily without conflict.
Claims (10)
1. A membrane electrode based on a molten proton conductor electrolyte membrane, characterized in that the membrane electrode comprises a polymer matrix carrying a molten proton conductor, a gas diffusion electrode containing phosphoric acid, and the phosphoric acid is coated on a catalyst layer of the gas diffusion electrode.
2. The molten proton conductor electrolyte membrane-based membrane electrode assembly according to claim 1, wherein the polymer matrix is a heat-resistant polymer;
the molten proton conductor is MHXO4、MH2X’O4、MH5(X’O4)2Wherein M is Cs, Rb, K or NH4 +X is S or Se, and X' is P or As.
3. The membrane electrode assembly according to claim 2, wherein the molten proton conductor is a perphosphate MH5(PO4)2。
4. According to the claimsClaim 1 said membrane electrode based on a molten proton conductor electrolyte membrane, characterized in that said phosphoric acid increases the gas diffusion electrode weight by 1-20mg/cm2。
5. A production method of a molten proton conductor electrolyte membrane-based membrane electrode according to any one of claims 1 to 4, characterized by comprising the steps of:
s1, melting the molten proton conductor at a temperature 0-20 ℃ higher than the melting point of the molten proton conductor to obtain a molten mass A;
s2, completely dipping the polymer matrix in the melt A, taking out after full dipping, and treating the residual molten proton conductor on the surface of the membrane to obtain a membrane B;
s3, uniformly coating a phosphoric acid solution on one side of a catalytic layer of the gas diffusion electrode to obtain a gas diffusion electrode C;
and S4, assembling a membrane electrode by using the membrane B and the gas diffusion electrode C.
6. The method of manufacturing a membrane electrode assembly based on a molten proton conductor electrolyte membrane according to claim 5, wherein the dipping temperature is 0 to 20 ℃ higher than the melting point of the molten proton conductor and the dipping time is 6 to 72 hours in step S2.
7. The method of manufacturing a membrane electrode assembly based on a molten proton conductor electrolyte membrane according to claim 5, wherein the phosphoric acid solution is concentrated phosphoric acid or a combination of concentrated phosphoric acid and other solvents in step S3, wherein the other solvents are water, alcohols, benzenes, ethers, or acetone.
8. The method of producing a molten proton conductor electrolyte membrane-electrode assembly according to claim 7, wherein the volume ratio of the concentrated phosphoric acid to the other solvent is 1: 10-1: 0.1.
9. the method of manufacturing a membrane electrode assembly based on a molten proton conductor electrolyte membrane according to claim 5, wherein in step S3, if the phosphoric acid solution is a combination of concentrated phosphoric acid and other solvents, the solvent is removed by drying before step S4.
10. Use of a membrane electrode based on a molten proton conductor electrolyte membrane according to claim 1 in a fuel cell.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010245019A (en) * | 2008-09-30 | 2010-10-28 | Dainippon Printing Co Ltd | Catalyst layer for fuel cell, gas diffusion electrode for fuel cell, membrane-electrode assembly for fuel cell, fuel cell, and catalyst layer for fuel cell with film base material |
| CN105742649A (en) * | 2014-12-11 | 2016-07-06 | 中国科学院大连化学物理研究所 | High-temperature proton exchange membrane fuel cell membrane electrode and preparation method thereof |
| CN107240705A (en) * | 2017-05-10 | 2017-10-10 | 上海交通大学 | A kind of middle temperature melting proton conductor dielectric film and its production and use |
| CN107331883A (en) * | 2017-05-10 | 2017-11-07 | 上海交通大学 | A kind of middle temperature proton exchange film and preparation method thereof |
| CN108110286A (en) * | 2016-11-25 | 2018-06-01 | 中国科学院大连化学物理研究所 | The preparation method of one proton conductive oxide electrolytic thin-membrane |
| CN108306031A (en) * | 2018-01-10 | 2018-07-20 | 江苏乾景新能源产业技术研究院有限公司 | A method of enhancing high temperature membrane fuel cell catalyst layer proton conductivity |
-
2021
- 2021-06-30 CN CN202110739963.3A patent/CN113471494A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010245019A (en) * | 2008-09-30 | 2010-10-28 | Dainippon Printing Co Ltd | Catalyst layer for fuel cell, gas diffusion electrode for fuel cell, membrane-electrode assembly for fuel cell, fuel cell, and catalyst layer for fuel cell with film base material |
| CN105742649A (en) * | 2014-12-11 | 2016-07-06 | 中国科学院大连化学物理研究所 | High-temperature proton exchange membrane fuel cell membrane electrode and preparation method thereof |
| CN108110286A (en) * | 2016-11-25 | 2018-06-01 | 中国科学院大连化学物理研究所 | The preparation method of one proton conductive oxide electrolytic thin-membrane |
| CN107240705A (en) * | 2017-05-10 | 2017-10-10 | 上海交通大学 | A kind of middle temperature melting proton conductor dielectric film and its production and use |
| CN107331883A (en) * | 2017-05-10 | 2017-11-07 | 上海交通大学 | A kind of middle temperature proton exchange film and preparation method thereof |
| CN108306031A (en) * | 2018-01-10 | 2018-07-20 | 江苏乾景新能源产业技术研究院有限公司 | A method of enhancing high temperature membrane fuel cell catalyst layer proton conductivity |
Non-Patent Citations (1)
| Title |
|---|
| 郭瑞华, 冶金工业出版社 * |
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