CN1195337C - Self-humidifying solid electrolyte composite membrane and manufacturing process thereof - Google Patents

Abstract

The self-humidifying solid electrolyte composite membrane and its preparation process relate to a fuel cell solid electrolyte composite membrane and its preparation. In the invention, the sulfonated resin is used as the base to dope the crystalline hydrate, dissolve it at high temperature and high pressure, and form a film by casting. The composite membrane does not contain precious metals, can carry out the transfer of protons and water, but cannot carry out the transfer of electrons and gases, and has low manufacturing cost; the proton exchange membrane fuel cell can self-humidify and generate electricity without a humidifier, which improves the efficiency of the power generation system. Specific power; and the proton conductivity of the composite membrane is very strong, the electrical conductivity can exceed 0.08S.cm ^-1 , the power density of the fuel cell assembled by it can exceed 2.0W/cm ² ; the battery discharge performance is stable, and the service life can reach tens of thousands Hours; and the invention adopts an original preparation process, so that the film forming area can exceed 1m ² , which is suitable for large-scale production and is conducive to promoting the industrialization of proton exchange membrane fuel cells.

Description

Self-humidifying solid electrolyte composite membrane and its preparation process

technical field

The invention relates to a proton exchange membrane fuel cell self-humidifying solid electrolyte composite membrane and a preparation process thereof, belonging to the field of fuel cell material science and technology.

Background technique

Proton exchange membrane fuel cells are the fifth generation of fuel cells after alkaline fuel cells, phosphoric acid fuel cells, molten carbonate fuel cells and solid oxide fuel cells. Proton exchange membrane fuel cell (PEMFC) has the advantages of high power density, high energy conversion efficiency, low-temperature start-up, and environmental friendliness, and is the most promising power source for zero-emission electric vehicles. Research on PEMFC has become a hot spot in the field of electrochemistry and energy science, and many developed countries are investing huge sums of money in developing this technology.

The proton exchange membrane is the core component of PEMFC, which is very different from the diaphragm used in general chemical power sources, and is an ion conductor. Proton exchange membranes usually use phenolic resin sulfonic acid membranes, polystyrene sulfonic acid membranes, polytrifluorostyrene sulfonic acid membranes and perfluorosulfonic acid membranes, and perfluorosulfonic acid membranes are currently the most Suitable electrolyte for proton exchange membrane fuel cells. Perfluorosulfonic acid membranes include the following types: (1) Nafion series membranes produced by DuPont Corporation of the United States, including Nafion117, Nafion115, Nafion112, Nafion111, etc.; (2) XUS-B204 membranes developed by Dow Chemical Company of the United States; (3) ) Aciplex series membranes and Flemion membranes produced by Asahi Corporation of Japan; (4) C membranes of Chlorine Engineers Corporation of Japan; (5) BAM membranes of Ballard Corporation of Canada, etc.

The conductivity of a proton exchange membrane strongly depends on its water content. When the membrane is in a dry state, the conductivity is almost zero; when the membrane is completely wet, it has good proton conductivity. That is to say, the working performance of the proton exchange membrane fuel cell largely depends on the water content in the membrane. Therefore, in order to ensure the normal power generation of the proton exchange membrane fuel cell, it is necessary to keep the proton exchange membrane in a wet state and perform water management on the fuel cell. The usual method is to humidify the reaction gas to prevent the membrane from drying up, especially to keep the anode side and the inlet end of the proton exchange membrane from losing water, and increase the water content of the proton exchange membrane. Commonly used reactive gas humidifiers include bubble humidifiers, membrane humidifiers, dew point humidifiers, and direct spray humidifiers. However, these humidification devices complicate the entire power generation system, increase system cost, and are not conducive to portable applications. The self-humidification technology without the humidification subsystem is conducive to promoting the industrialization of proton exchange membrane fuel cells. Self-humidification is also called passive humidification, that is, no external water source and heat source are needed to humidify the reaction gas, and the proton exchange membrane fuel cell can also maintain a good degree of humidity and maintain the good proton conductivity of the membrane. Therefore, many scholars have made many self-humidification explorations from the aspects of fuel cell structure, electrodes, and membranes. Japanese scholar Watanabe began to study self-humidification technology in the early 1990s [US Patent number: 5766787, 1998], using platinum and other precious metal particles, SiO ₂ , TiO ₂ and other nano-scale particles to add perfluorosulfonic acid resin The composite membrane is prepared in the solution to realize self-humidification, mainly relying on the _O2 and _H2 permeating from the cathode and anode to chemically catalyze the reaction on the surface of the Pt catalyst in the proton exchange membrane to generate water, which is generated by the electrochemical reaction with the cathode The water and the two together humidify the proton exchange membrane, and the oxide particles in the membrane play a role in retaining water. Another important feature of this method is that it can prevent the reaction gas from penetrating into the counter electrode, which reduces the polarization overpotential of the electrode and can improve the performance of the battery. However, the preparation process of this Pt, Pt/SiO ₂ , Pt/TiO ₂ perfluorosulfonic acid composite membrane is complicated and the cost is high; and the distribution of Pt particles in the composite membrane is uneven, and hot spots will be generated, which will deteriorate the composite membrane; In addition, Pt particles may also make the solid electrolyte conduction, and self-discharge occurs. Recently South Korean Tae-Hyun Yang, Chang-Soo Kin and other scholars have used the three-in-one method of sputtering Pt particles between two electrolyte membranes to realize a self-humidifying composite membrane [Tae-Hyun Yang, Young-Gi Yoon, Chang-Soo Kim, et al..Journal of power Source, 2002, 106:328-332.], the principle is to make the cross-diffused hydrogen and oxygen gas in the membrane react on the Pt catalyst to form a water-wet solid electrolyte. However, this method is costly and increases the internal resistance of the battery. It can be seen that the above self-humidification technologies all focus on using Pt to catalyze the cross-diffusion gas to generate water, but do not use the composite membrane technology that enhances the conductivity of the membrane at low humidity. U.S. Patent [Patent number 6468684, 1999] adopts the method of adding structural adhesive to solid acid to obtain a new type of solid electrolyte. performance or chemical stability. The added structural adhesive is a non-electric conductor or conductor material, and the non-electric conductor material is polymer and glass; and the conductor material is an electronic conductor. In this way, the solid electrolyte made of the electronic conductor material can not only conduct electrons but also Can conduct protons. However, the solid electrolyte is impermeable to water, has low electrical properties, and its preparation process has shortcomings, such as direct thermal compression bonding, which will increase the instability and inhomogeneity of the combination of dopants and polymer substrates. The thickness of the composite film is difficult to reach the ultra-thin level.

Contents of the invention

The purpose of the present invention is to provide a novel self-humidifying solid electrolyte composite membrane and its preparation process for proton exchange membrane fuel cells. The solid electrolyte composite membrane has low production cost, does not contain noble metals, and does not generate hot spots when the battery generates electricity. There is also no self-discharge phenomenon, and can effectively enhance its conductivity under low humidity.

The present invention is achieved through the following technical scheme: a self-humidifying solid electrolyte composite membrane, characterized in that: the composite membrane uses sulfonated resin as the base doped with crystalline hydrate, and is prepared according to the following steps:

(1) crushing the doped crystal hydrate liquid flow into nanoparticles with a size between 5 and 100 nm;

(2) Dissolving one or more of the sulfonated resin and anhydrous alcohol solvent in an autoclave with a pressure of 0.5-8MPa and a temperature of 200-650°C under the protection of an inert gas to prepare A solution;

(3) Dissolving one or more of the crystalline hydrate and anhydrous alcohol solvents in an autoclave with a pressure of 0.5-8 MPa and a temperature of 110-300 °C under the protection of an inert gas to prepare a solution B;

(4) Take the B solution and A solution, mix them according to the mass percentage of crystalline hydrate and sulfonated resin at 0.5-30%, and mix them uniformly at a pressure of 0.5-8MPa and a temperature of 200-650°C to obtain a uniform mixed solution;

(5) cooling the homogeneously mixed solution in step (4) to 150-580°C under normal pressure, and forming a film by casting method;

(6) After drying at room temperature, heat treatment is carried out at a temperature of 80-550° C. and an inert environment.

The sulfonated resin described in the present invention adopts the perfluorosulfonic acid polymer of following formula (I) or the sulfonated polymer or PBI [poly(2,2-m-( One or more of phenylene)-5,5-dibenzimidazole)] resins.

The crystal hydrate used in the present invention adopts M.nH ₂ O, wherein M is an inorganic compound. For example, crystalline hydrates are H ₃ PW ₁₂ O ₄₀ nH ₂ O, H ₃ PMo ₁₂ O ₄₀ nH ₂ O, H ₄ SiW ₁₂ O ₄₀ nH ₂ O, H _1+x Zr _{2 Six} P _3-x O ₁₂ nH ₂ O, H _1+x Y _x Zr _2-x (PO ₄ ) ₃ nH ₂ O, H _x Zr _1+x Nb _1-x (PO ₄ )3 nH ₂ O, H _1.28 Zn Any of _0.36 SO ₄ ·nH ₂ O, H _1.6 Mg _0.2 SO ₄ ·nH ₂ O, H _1.72 Mg _0.14 SO ₄ ·nH ₂ O, ZrHPO ₄ ·nH ₂ O or CaHPO ₄ ·nH ₂ O.

The present invention also provides a preparation process of a self-humidifying solid electrolyte composite membrane, which is prepared according to the following steps:

(1) Break the doped crystalline hydrate flow into nanoparticles with a size of 5-100nm under the dynamic load of 100Mpa-600MPa by nano-crushing method;

(2) One or more of the sulfonated resin and anhydrous alcohol solvent are dissolved in an autoclave with a pressure of 0.5-8 MPa and a temperature of 200-650 ° C under the protection of an inert gas to prepare a solution;

(3) Dissolving one or more of the crystalline hydrate and anhydrous alcohol solvents in an autoclave with a pressure of 0.5-8 MPa and a temperature of 110-300 °C under the protection of an inert gas to prepare a solution B;

(4) Take the B solution and A solution, mix them according to the mass percentage of crystalline hydrate and sulfonated resin at 0.5-30%, and mix them at a pressure of 0.5-8MPa and a temperature of 200-650°C, and process them under ultrasonic polymerization. It can be uniformly mixed under the action of dispersion to obtain a uniform mixed solution;

(5) The homogeneously mixed solution in step (4) is cooled to 150-580° C. under normal pressure, and film is formed by casting method;

(6) After drying at room temperature, heat treatment is carried out at a temperature of 80 to 550°C and in an inert environment;

(7) The proton exchange membrane is placed in 1.0-10.0vol% _H2O2 aqueous solution and _boiled for 30-120 minutes to remove organic impurities. After taking it out, wash it with deionized water, and then place it in 0.1-1.0M dilute sulfuric acid solution Boil in medium for 30-240 minutes to remove inorganic metal ions, take it out and wash it with deionized water to prepare a self-humidifying solid electrolyte composite membrane.

The self-humidifying solid electrolyte composite membrane provided by the present invention has the following advantages and outstanding effects: the composite membrane does not contain precious metals, can carry out the transfer of protons and water, cannot carry out the transfer of electrons and gases, and has low manufacturing cost; it can make protons The exchange membrane fuel cell can self-humidify and generate electricity without a humidifier, which improves the specific power of the power generation system; it can operate at high temperature (over 100°C), which enhances the ability of CO poisoning and electrochemical reaction kinetics; at low temperature (0 below ℃) can also generate electricity normally. Moreover, the proton conduction ability of the composite membrane is very strong, the electrical conductivity can exceed 0.08S.cm ^-1 , and the power density of the fuel cell assembled by it can exceed 2.0W/cm ² ; the discharge performance of the battery is stable, and the service life can reach tens of thousands of hours; and The invention adopts an original preparation process: high temperature, high pressure dissolution and casting method to form a film, so that the film forming area can exceed 1m ² , which is suitable for large-scale production and is conducive to promoting the industrialization of proton exchange membrane fuel cells.

Description of drawings

Fig. 1 is an outline view of the self-humidifying solid electrolyte composite membrane provided by the present invention.

Fig. 2 is a graph showing the voltage-current characteristics of a battery using the self-humidifying solid electrolyte composite membrane provided by the present invention.

Fig. 3 is the stability performance curve of the self-humidifying solid electrolyte composite membrane battery provided by the present invention.

Detailed ways

The self-humidifying solid electrolyte composite membrane provided by the invention is a kind of solid electrolyte for PEMFC, and the conductivity of the composite membrane depends on the conductivity of the matrix material polymer and the dopant material and the interaction between them; in order to strengthen the solid Electrolyte moisture retention and conductivity at low humidity, the invention adopts the method of doping crystalline hydrate in the sulfonated resin matrix with proton conduction function to make a composite membrane, which has better conductivity. The sulfonated resin used in the present invention refers to a sulfonated polymer, including the above-mentioned perfluorosulfonic acid polymer containing the structural formula (I), the sulfonated polymer containing the aromatic ring structure shown in the structural formula (II), sulfonated PBI [poly(2,2-m-(phenylene)-5,5-bisbenzimidazole)] polymer. The sulfonation referred to here refers to the introduction of groups with S elements on some C atoms of the polymer molecular structure, and the groups containing S elements refer to sulfonate groups (-SO ₃ H) and their metal ions Chemical groups such as (-SO ₃ M, M represents a metal ion), sulfonyl group (SO ₂ X, X represents a non-metal element).

In the perfluorosulfonic acid polymer in formula (I), x, y, m, n are different degrees of polymerization, such as Nafion, Dow film. The X of the aromatic ring structure polymer in the formula (II) represents: X≠aliphatic CH groups (Aliphatic CH groups); X=-S-: polyphenylene sulfide (Polyphenylene sulfide); X=-O-: Polyphenylene oxide; X=-SO ₂ -: Polysulfone; X=-NHCO-: Polyamides; X=-COO-: Polyesters; X=- CO-: Polyketones.

The general formula of the doped crystalline hydrate is: M.nH ₂ O, where M is an inorganic compound. Typical representatives of crystalline hydrates are: H ₃ PW ₁₂ O ₄₀ nH ₂ O, H ₃ PMo ₁₂ O ₄₀ nH ₂ O, H ₄ SiW ₁₂ O ₄₀ nH ₂ O, H _1+x Zr _{2 Six} P _{3 -x} O ₁₂ nH ₂ O, H _1+x Y _x Zr _2-x (PO ₄ ) ₃ nH ₂ O, H _x Zr _1+x Nb _1-x (PO ₄ ) ₃ nH ₂ O,H _1.28 Zn _0.36 SO ₄ ·nH ₂ O, H _1.6 Mg _0.2 SO ₄ ·nH ₂ O, H _1.72 Mg _0.14 SO ₄ ·nH ₂ O, ZrHPO ₄ ·nH ₂ O, CaHPO ₄ ·nH ₂ O.

The above crystalline hydrates have strong hydrophilic properties and proton conductivity. Crystalline hydrate molecules can not only strongly attract bonded electron pairs, but also have lone electron pairs, and the negative charge is very concentrated, making this type of compound have the ability to transfer protons. Water molecules are polar molecules. When water molecules are combined around these crystalline hydrate molecules, the dipoles of water molecules will attract each other with protons, so hydration will occur and hydrogen bonds will be formed, which is very beneficial to the protons. transmission. Therefore, the crystalline hydrate with a certain number of coordinated water molecules can enhance the water content of the proton exchange membrane at low humidity and improve the proton transfer capacity.

The manufacturing method of the composite membrane greatly affects its performance. The present invention specifically adopts the following method to prepare: the crystalline hydrate can be prepared by chemical reaction methods such as sol-gel, and can also be purchased from the market at a low price. The dopant needs to be pulverized and purified before doping, and the nano-crushing method can be used to break the doped crystal hydrate liquid flow into particles with a size of 5-100nm under the dynamic load of 100MPa-600MPa. Use anhydrous alcohol solvent to dissolve under the protection of inert gas (such as N ₂ , Ar ₂ ) or under vacuum. The temperature should not be too high, so as not to decompose and damage the polymer, generally between 200-650°C. Then dissolve one or more of the crystalline hydrate and anhydrous alcohol solvents in an autoclave with a pressure of 0.5-8MPa and a temperature of 110-300°C; the doping ratio of the two is a key parameter, and the crystalline hydrate Do not do too much, otherwise the mechanical strength of the composite membrane will be deteriorated and easily broken. Generally, the mass ratio of crystalline hydrate to sulfonated resin is between 0.5% and 30%. The smaller the crystalline hydrate particles, the better the distribution. Ultrasonic energy-gathering dispersion is a more effective means of dispersion. Due to the unusual activity of nanoparticles, the interaction between individuals is also very strong, often causing several particles to aggregate together to form larger (cluster) particles. Therefore, the composite film dispersion technology is very important. In the preparation process of the present invention, the ultrasonic energy-gathering dispersion technology is used to make the dopant disperse evenly. Forming by extension method, the film thickness can be controlled in the range of 10-300μm, and then dried and sliced. Finally, it needs to be treated with hydrogen peroxide and sulfuric acid to remove impurities and strengthen the proton conductivity of the composite membrane.

Example 1

Example of Composite Membrane Prepared by Sulfonated PBI [Poly(2,2-m-(Phenylene)-5,5-Bibenzimidazole)] Resin and H ₃ PW ₁₂ O ₄₀ ·nH ₂ O Crystalline Hydrate The details are as follows:

Using a compound high-shear crushing and dispersing machine, the crystalline hydrate H ₃ PW ₁₂ O ₄₀ ·nH ₂ O powder is broken into 100 nanometer-sized particles by liquid flow at 600 MPa for future use. Adopt sulfonated PBI dry resin as the substrate material of composite membrane, use alcohol mixture (5vol% methanol, 50vol% ethanol, 45vol% propanol) as the solvent of sulfonated PBI dry resin, add in autoclave under argon protection Press to 8MPa, and heat to 530°C for dissolution to obtain a sulfonated PBI solution for future use. Put H ₃ PW ₁₂ O ₄₀ ·nH ₂ O crystalline hydrate and absolute ethanol into an autoclave, pressurize to 8 MPa, and heat to 110° C. to dissolve to obtain a dopant solution. According to the sulfonated PBI dry resin: _{H 3} PW ₁₂ O ₄₀ nH ₂ O = 100:30 (mass ratio) ingredients, to obtain a composite membrane solution, pressurized to 8MPa in the autoclave, and heated to 530 ° C to dissolve, and Under the action of a 600W ultrasonic energy-concentrating disperser, until the mixture is uniform. Then the composite film mixture was cooled to 480° C., and cast into a film, and the film thickness was controlled at 50 microns. Finally, dry the composite membrane at 430°C. After the drying is completed, cut the composite membrane into a certain size, boil it with 1vol% hydrogen peroxide solution for 2 hours, wash it with distilled water, and then boil it with 0.1M dilute sulfuric acid. After 4 hours, boiling and washing with distilled water, the H ₃ PW ₁₂ O ₄₀ ·nH ₂ O composite membrane/sulfonated PBI composite membrane was prepared.

Example 2

An example of preparing a composite membrane with sulfonated polyphenylene sulfone (PS) resin and ZrHPO ₄ ·nH ₂ O crystalline hydrate is detailed as follows:

The crystalline hydrate ZrHPO ₄ ·nH ₂ O powder is crushed into 50 nanometer sized particles under 400 MPa by using a compound high-shear crushing and dispersing machine. Use sulfonated polyphenylene sulfone dry resin as the base material of the composite membrane, use absolute ethanol as the solvent of sulfonated polyphenylene sulfone dry resin, pressurize to 0.5MPa in the autoclave under the protection of nitrogen, and heat Dissolve at 650°C to obtain a sulfonated polyphenylene sulfone solution for future use. ZrHPO ₄ ·nH ₂ O crystalline hydrate and anhydrous pentanol were placed in an autoclave, pressurized to 1 MPa, and heated to 300°C for dissolution to obtain a dopant solution. According to sulfonated polyphenylene sulfone dry resin: ZrHPO ₄ nH ₂ O = 100:1 (mass ratio) ingredients, to obtain a composite membrane solution, pressurized to 1MPa in the autoclave, and heated to 650 ° C to dissolve, and Under the action of a 500W ultrasonic energy-concentrating disperser, until the mixture is uniform. Then the composite film mixture was cooled to 580° C., and cast into a film, and the film thickness was controlled at 50 microns. Finally, dry the composite membrane at 550°C, cut into composite membranes of a certain size after drying, and boil them with 10vol% hydrogen peroxide solution for half an hour, then wash them with distilled water, and then boil them with 1M dilute sulfuric acid for half an hour. After boiling and washing with distilled water, the ZrHPO ₄ ·nH ₂ O/sulfonated polyphenylene sulfone composite membrane was prepared.

Example 3

An example of preparing a composite membrane with sulfonated polyphenoxy resin (PPO) resin and H _1.28 Zn _0.36 SO ₄ ·nH ₂ O crystalline hydrate is as follows:

Use a compound high-shear crushing and dispersing machine to crush the crystalline hydrate H _1.28 Zn _0.36 SO ₄ ·nH ₂ O powder under 300 MPa into 10 nanometer-sized particles for use. Adopt sulfonated polyphenoxy resin as the base material of composite membrane, use alcohol mixture (45vol% methanol, 35vol% amyl alcohol, 20vol% octanol) as the solvent of sulfonated polyphenoxy resin, under argon protection Pressurize to 4MPa in the autoclave, and heat to 200°C for dissolution to obtain a sulfonated polyphenoxy resin solution for future use. Put H _1.28 Zn _0.36 SO ₄ ·nH ₂ O crystalline hydrate and absolute ethanol into an autoclave, pressurize to 0.5 MPa, and heat to 200° C. to dissolve to obtain a dopant solution. Mixing according to sulfonated polyphenoxy resin: H _1.28 Zn _0.36 SO ₄ nH ₂ O = 100:0.5 (mass ratio) to obtain a composite membrane solution, pressurize to 0.5MPa in an autoclave, and heat to 200°C for Dissolve, and under the action of a 500W ultrasonic energy-concentrating disperser, until the mixture is uniform. Then the composite film mixture was cooled to 150° C., and cast into a film, and the film thickness was controlled at 50 microns. Finally, the composite membrane was dried at 80°C, and after the drying was completed, the composite membrane was cut into a certain size, boiled with 4vol% hydrogen peroxide solution for 3 hours, washed with distilled water, and then boiled with 1M dilute sulfuric acid for 2 hours. H _1.28 Zn _0.36 SO ₄ ·nH ₂ O composite membrane/sulfonated polyphenoxy resin was obtained after boiling and washing with distilled water.

Example 4

An example of preparing a composite membrane with sulfonated polysulfone resin (PSF) and H ₃ PMo ₁₂ O ₄₀ ·nH ₂ O crystalline hydrate is as follows:

Using a compound high-shear crushing and dispersing machine, the crystalline hydrate H ₃ PMo ₁₂ O ₄₀ ·nH ₂ O powder is crushed into 15 nanometer-sized particles under a pressure of 450 MPa. Use sulfonated polysulfone dry resin as the base material of the composite membrane, use absolute ethanol as the solvent of polysulfone dry resin, pressurize to 1.5MPa in the autoclave under the protection of nitrogen, and heat to 550°C to dissolve to obtain sulfonation The polysulfone solution was used for later use. Put H ₃ PMo ₁₂ O ₄₀ ·nH ₂ O crystalline hydrate and anhydrous pentanol into an autoclave, pressurize to 1 MPa, and heat to 250° C. to dissolve to obtain a dopant solution. According to sulfonated polysulfone dry resin: H ₃ PMo ₁₂ O ₄₀ nH ₂ O = 100:1 (mass ratio) ingredients, to obtain a composite membrane solution, pressurized to 1MPa in the autoclave, and heated to 450 ° C to dissolve, And under the action of a 500W ultrasonic energy-concentrating disperser, until the mixture is uniform. Then the composite film mixture was cooled to 520° C., and cast into a film, and the film thickness was controlled at 50 microns. Finally, dry the composite membrane at 160°C. After the drying is completed, cut the composite membrane into a certain size, and boil it with 10vol% hydrogen peroxide solution for half an hour, then wash it with distilled water, and then boil it with 1M dilute sulfuric acid for half an hour. H ₃ PMo ₁₂ O ₄₀ ·nH ₂ O/sulfonated polysulfone resin composite membrane was prepared after boiling and washing with distilled water.

Example 5

The details of the example of preparing composite membranes with Nafion perfluorosulfonic acid resin and crystalline hydrate CaHPO ₄ ·nH ₂ O are as follows:

The crystalline hydrate CaHPO ₄ ·nH ₂ O powder is crushed into 5nm-sized particles under 100 MPa by using a compound high-shear crushing and dispersing machine. Adopt perfluorosulfonic acid dry resin as the base material of composite membrane, use alcohol mixture (10vol% methanol, 30vol% ethanol, 60vol% isopropanol) as the solvent of perfluorosulfonic acid dry resin, under the protection of argon under high pressure Pressurize the kettle to 3.5MPa, and heat to 280°C for dissolution to obtain a sulfonic acid resin solution for future use. The crystalline hydrate CaHPO ₄ ·nH ₂ O and alcohol mixture (10vol% methanol, 90vol% ethanol) was placed in an autoclave, pressurized to 2.5MPa, and heated to 150°C for dissolution to obtain a dopant solution. Perfluorosulfonic acid dry resin: CaHPO ₄ ·nH ₂ O = 100:3 (mass ratio) ingredients, to obtain a composite membrane solution, pressurized to 3.5MPa in the autoclave, and heated to 280 ° C to dissolve, and in 400W Under the action of an ultrasonic energy-concentrating disperser until the mixture is uniform. Then the composite film mixture was cooled to 170° C., and a film was formed by casting method, and the film thickness was controlled at 50 microns. Finally, dry the composite membrane at 135°C, cut into composite membranes of a certain size after drying, and boil them with 3wt% hydrogen peroxide solution for 1 hour, then wash them with distilled water, and then boil them with 0.3M dilute sulfuric acid. After 1 hour, boil and wash with distilled water for later use. Figure 1 shows the morphology of the prepared CaHPO ₄ ·nH ₂ O/perfluorosulfonic acid resin composite film, and the surface distribution is relatively uniform. It is translucent (PFSA is colorless and transparent), the tensile modulus is 290MPa, and its mechanical properties are equivalent to those of Dupont's Nafion112 film.

The above composite membrane was made into a membrane electrode and assembled into a PEMFC for self-humidification performance evaluation. First, the carbon paper (Toray Co., Japan) used as the base of the gas diffusion layer was ultrasonically cleaned for 30 minutes, dried at room temperature, and treated at a high temperature of 340° C. for 30 minutes. Using a certain proportion of water and ethanol as a solvent, mix activated carbon (Vulcan XC-72, 150 mesh) with polytetrafluoroethylene PTFE (Dupont, USA) emulsion, and vibrate with ultrasonic waves. After mixing evenly, the mixture is evenly leveled on the surface of the treated carbon paper, and sintered at a high temperature of 340° C. to form a gas diffusion layer, which is used as the base of the electrode catalytic layer. Then add a certain amount of Pt/C (20%, Johnson-Matthey Company), Nafion (10%, U.S. Dupont Company) and double distilled water into the beaker, place in the ultrasonic cleaning tank, after fully mixing, form the catalytic layer ink-like The substance is evenly sprayed on the substrate of the electrode catalytic layer, dried in vacuum at 90°C, and then heat-treated at 120°C for 30 minutes under the protection of argon. Finally, the surface of the catalytic layer was specially treated to prepare a hydrophilic thin-layer hydrogen electrode with a Pt loading of 0.4 mg/cm ² .

The MEAs were assembled into single cells with an active area of ⁵ cm. The fuel gas is dry hydrogen, which is fed directly at 1.5 times the stoichiometric amount without humidification, and the oxidizing gas is dry oxygen, which is directly fed at 2 times the stoichiometric amount without humidification; the internal pressure of the battery is controlled at 0.3 MPa, and the battery operating temperature is 70 ℃. After the battery was activated for 5 hours, the self-humidification performance of the battery was evaluated under steady-state operation. The volt-ampere characteristics of the battery are shown in Figure 2, and the discharge stability under constant voltage is shown in Figure 3.

The performance of the battery assembled with the composite membrane manufactured by the present invention is very excellent, and the maximum power density exceeds 2.0W/cm ² in the self-humidification mode; the performance of the battery is stable, and the performance has no attenuation during the working period of 200 hours , with a slight upward trend.

Claims (3)

1. one kind from the humidification electrolyte compound film for solid, it is characterized in that: described composite membrane is that to adopt with the sulfate resin be that substrate doping crystalline hydrate is prepared from, and its preparation process is as follows:

(1) the crystalline hydrate liquid stream that mixes being broken into particle size is between 5～100nm; Described crystalline hydrate is H ₃PW ₁₂O ₄₀NH ₂O, H ₃PMo ₁₂O ₄₀NH ₂O, H ₄SiW ₁₂O ₄₀NH ₂O, H _1+xZr ₂Si _xP _3-xO ₁₂NH ₂O, H _1+xY _xZr _2-x(PO ₄) ₃NH ₂O, H _xZr _1+xNb _1-x(PO ₄) ₃NH ₂O, H _1.28Zn _0.36SO ₄NH ₂O, H _1.6Mg _0.2SO ₄NH ₂O, H _1.72Mg _0.14SO ₄NH ₂O, ZrHPO ₄NH ₂O or CaHPO ₄NH ₂Among the O any;

(2) making sulfate resin and absolute alcohol kind solvent is that 0.5～8MPa, temperature are to dissolve in 200～650 ℃ the autoclave in pressure under inert gas shielding, makes A solution; Described sulfate resin adopts as shown in the formula the perfluorinated sulfonic acid polymer of I or sulfonated polymer that contains aromatic ring structure or the sulfonation PBI polymer of formula II;

The X of aromatic ring structure polymer representative among the formula II: X ≠ aliphat C-H group; X=-S-: polyphenylene sulfides; X=-O-: polyphenylene oxide; X=-SO ₂-: polysulfones; X=-NHCO-: polyamide; X=-COO-: polyester; X=-CO-: polyketone;

(3) with described crystalline hydrate and absolute alcohol kind solvent being that 0.5～8MPa, temperature are to dissolve in 110～300 ℃ the autoclave in pressure under the inert gas shielding, make B solution;

(4) getting described B solution and A solution, is 0.5～30% batching by crystalline hydrate and sulfate resin mass percent, and is that 0.5～8MPa, temperature are 200～650 ℃ and mix down evenly at pressure; Make homogeneous mixture solotion;

(5) solution that mixes in the step (4) is cooled to 150～580 ℃ under normal pressure, adopts the The tape casting film forming;

(6) at room temperature after the drying, place under 80～550 ℃ of temperature and inert environments under heat-treat.

2. one kind according to claim 1 from the preparation technology of humidification electrolyte compound film for solid, and this technology prepares as follows:

(1) adopting the nanometer crush method under 100MPa～600MPa dynamic load amount the crystalline hydrate liquid stream that mixes to be broken into particle size is 0.005～0.1 μ m; Described crystalline hydrate is H ₃PW ₁₂O ₄₀NH ₂O, H ₃PMo ₁₂O ₄₀NH ₂O, H ₄SiW ₁₂O ₄₀NH ₂O, H _1+xZr ₂Si _xP _3-xO ₁₂NH ₂O, H _1+xY _xZr _2-x(PO ₄) ₃NH ₂O, H _xZr _1+xNb _1-x(PO ₄) ₃NH ₂O, H _1.28Zn _0.36SO ₄NH ₂O, H _1.6Mg _0.2SO ₄NH ₂O, H _1.72Mg _0.14SO ₄NH ₂O, ZrHPO ₄NH ₂O or CaHPO ₄NH ₂Among the O any;

(2) making sulfate resin and absolute alcohol kind solvent is that 0.5～8MPa, temperature are to dissolve in 200～650 ℃ the autoclave in pressure under inert gas shielding, makes A solution; Described sulfate resin adopts as shown in the formula the perfluorinated sulfonic acid polymer of I or sulfonated polymer that contains aromatic ring structure or the sulfonation PBI polymer of formula II;

The X of aromatic ring structure polymer representative among the formula II: X ≠ aliphat C-H group; X=-S-: polyphenylene sulfides; X=-O-: polyphenylene oxide; X=-SO ₂-: polysulfones; X=-NHCO-: polyamide; X=-COO-: polyester; X=-CO-: polyketone;

(3) with crystalline hydrate and absolute alcohol kind solvent being that 0.5～8MPa, temperature are to dissolve in 110～300 ℃ the autoclave in pressure under the inert gas shielding, make B solution;

(4) get described B solution and A solution, by crystalline hydrate and sulfate resin mass percent is 0.5～30% batching, and be that 0.5～8MPa, temperature are 200～650 ℃ and mix down at pressure, and under ultrasonic wave cumulative peptizaiton, evenly mix, make homogeneous mixture solotion;

(5) solution that mixes in the step (4) is cooled to 150～580 ℃ under normal pressure, adopts the The tape casting film forming;

(6) at room temperature after the drying, place under 80～550 ℃ of temperature and inert environments under heat-treat;

(7) proton exchange membrane is placed the H of 1.0～10.0vol% ₂O ₂Boiled in the aqueous solution 30～120 minutes, and removed organic impurities, take out the back and use washed with de-ionized water, place the dilution heat of sulfuric acid of 0.1～1.0M to boil again 30～240 minutes,, take out the back and clean up with deionized water to remove inorganic metal ion.

3. according to the described preparation technology from the humidification electrolyte compound film for solid of claim 2, it is characterized in that: the absolute alcohol kind solvent described in the step (2) is to contain the following absolute alcohol solvent of 8 C atoms; Absolute alcohol kind solvent described in the step (3) adopts and contains the following absolute alcohol solvent of 5 C atoms.