CN104470852B - The mixed-metal oxides of fluorinated ion-exchange polymer are used for as scavenger - Google Patents

Abstract

A kind of mixed oxide of Si and at least one metal M, the mixed oxide include inorganic group-SO₃H.The mixed oxide is added in the fluorinated polymer containing sulfonic acid functional group and increases these fluorinated polymers when being used for fuel cells applications to the stability of free radical cracking.

Description

The mixed-metal oxides of fluorinated ion-exchange polymer are used for as scavenger

This application claims the priority of the European application EP12175923.7 submitted on July 11st, 2012, for all Purpose entire contents of this application is incorporated herein by reference.

Technical field

The present invention relates to can be improved the ion exchange fluorinated polymer films for fuel cells applications to free radical cracking Tolerance mixed-metal oxides.The invention further relates to include the mixed oxide and ion exchange fluorinated polymer Composition and by its obtain amberplex.

Background technique

Fluorinated polymer comprising azochlorosulfonate acid ion cation exchange groups, due to its ionic conduction characteristic, in manufacture for electricity It has found and is widely applied in the dielectric film of chemical devices such as electrolytic cell and fuel cell.Notably example is for example Proton exchange membrane (PEM) fuel cell, uses hydrogen as fuel and uses oxygen or air as oxidant.

In typical PEM fuel cell, hydrogen is introduced in anode part, and hydrogen reacts and separates there At multiple protons and multiple electronics.These protons are transmitted to cathode portion by the film, while electron stream being allowed to flow through one External circuit is to the cathode portion to provide electric power.Oxygen is introduced in cathode portion and reacts with these protons and electronics To form water and heat.

The film requires excellent ionic conductivity, vapor barrier properties (mixing to avoid hydrogen with the direct of oxygen), machinery strong Degree and the chemistry under cell operating conditions, electrochemistry and thermal stability.Specifically, the long-time stability of film are a keys Requirement: the lifetime goal of available fuel cell application is operation up to 40,000 hour, and operation 20,000 hour is automobile combustion Expect the requirement of battery applications.

Both peroxyl radical (^■OH,^■OOH) (it is generated in fuel cell operation) is to proton exchange membrane One of erosion the reason of being frequently described as membrane degradation.The free radical cracking of film causes the drop of the service life of fuel cell It is low.Generally, it is considered that form hydrogen peroxide due to penetrating through reacting between the hydrogen of the film and oxygen among other mechanism.It crosses Then hydrogen oxide is decomposed to form peroxy and hydroperoxy radical, see, for example, SCHLICK, S.'s et al. uses ESR method Degradation fuel cell membranes: ex situ and experiment in situ, polymer Preprint (Degradation of fuel cell Membranes using ESR methods:ex situ and in situ experiments.Polymer Preprints.), 2009, volume 50, the 2nd phase, the 745-746 pages.The direct formation of free radical is also considered as possible.

Several trials have been carried out to reduce the free radical cracking of fluorination proton exchange membrane, such as by will suitable gold The salt or oxide of category are combined into the film.Increased using the salt of different metal (including rare earth metal, Al and Mn) in fuel The stability of amberplex used in battery is except other things in 1702378 A of EP (BDF IP Holdings L. L. C. (BDF IP HOLDINGS LTD)) 1662595 A of 20.09.2006 and EP (Japanese Toyota center Co., Ltd., research institute (TOYOTA CHUO KENKYUSHO)) it has been disclosed in 31.05.2006.

20070213209 A of US (E.I.Du Pont Company (EI DU PONT DE NEMOURS)) 13.09.2007 is disclosed and is used for The compound of hydrogen peroxide in decomposition fuel cell membrane-electrode assembly, these compounds include it is a kind of come self-alumina, two Silica, titanium dioxide, zirconium oxide, manganese dioxide, Y₂O₃、Fe₂O₃, FeO, tin oxide, copper oxide, nickel oxide, tungsten oxide, oxygen Change the metal oxide in the group of germanium, cerium oxide；It is steady in group of the one kind selected from metal ion and metalloid ion (such as boron) Determine agent；And at least one catalyst different from the group of the stabilizer and selected from cerium and ruthenium.It is draped over one's shoulders in US20070213209 The compound of dew is prepared on the metal oxide being modified in advance by stabilizer by Catalyst Adsorption.Catalyst granules because This is not combined into may thus penetrate into the lattice of the metal oxide and in fuel cell operation the film and subsequent It is oozed out from the film.

The MnO2/SiO2-SO3H nanocomposite of doctor Zhao et al. is used for proton exchange as hydrogen peroxide scavenger The durability of film improves, membrane science magazine (ZHAO, D., et al.MnO2/SiO2-SO3H nanocomposite as hydrogen peroxide scavenger for durability improvement in proton exchange Membranes.J.Membrane Science), volume 2010,346, the 143-151 pages disclose have be grafted on its surface On organic sulfonic acid group nanometer mixing MnO₂/SiO₂Oxide.These compounds are by nanometer MnO₂Surface on Precipitate SiO₂Then make SiO₂Surface hydroxyl react and prepares with suitable organic sulfonated reagent (such as ring sulphonic acid ester).In Zhao etc. The mixing MnO that people discloses₂/SiO₂In oxide, MnO₂Only with SiO₂Physical bond, this may result in fuel cell operation Mn (IV) is reduced to Mn (II) also, considers the higher solubility of Mn (II) species in the process, leads to the subsequent of them Removal.

GILL, C.S. et al., the magnetic nanoparticle catalyst of the silicon dioxide coating of sulfonic acid functional are catalyzed magazine (Sulfonic acid-functionalized silica-coated magnetic nanoparticle Catalysts.J.Catalysis), volume 2007,251, the 145-152 pages discloses including being grafted to silicon dioxide coating The organic/inorganic catalyst of the hydridization of organic sulfonic acid on magnetic nanoparticle carrier.

In two kinds of systems described above, the part of organic hydride is by-SO₃H group is fixed to SiO₂On surface.This Presence of the organic moiety hydrogenated a bit in inorganic oxide be considered as so that the system is unsuitable for using in a fuel cell, Because it may provide the additional source of free radical generation or free radical cracking in film under fuel cell high oxidation service condition.

Summary of the invention

Have now found that the fluorination containing sulfonic acid functional group, which is added, in certain mixed oxides of Si and at least one metal M gathers It closes in object and improves proton exchange membrane prepared therefrom to the stability of free radical cracking, without the limitation of the prior art. Longer service life when the increase of stability is reflected in the film in for fuel cell.

Therefore, the first object of the present invention is the mixed oxide of Si Yu at least one metal M, and the oxide includes nothing Machine group-SO₃H.Metal M is selected from by the 4th race, the 5th race, the 6th race, the 7th race, the 8th race, the 9th race, the 10th race, the 11st race Element, Zn, Al, the group of La and Ce composition.Group-SO₃H is integrated at least one of the mixed oxide via sulphur atom On Si, metal M or oxygen atom.

The second object of the present invention is a kind of method of mixed oxide for being used to prepare first purpose.

The third object of the present invention is a kind of mixing comprising at least one fluorinated polymer and at least one first purpose The composition of oxide, the fluorinated polymer include-SO₂X functional group, wherein X is selected from X ' or selected from OZ and wherein X ' is selected from It is selected from by F, Cl, Br, I group formed and Z by H, alkali metal, NH₄The group of composition.

Another object of the present invention is the film of a kind of product, especially one or an electrocatalyst layers, includes institute as above At least one of definition contains-SO₂The fluorinated polymer of X functional group and at least one mixed oxide.

The disclosure content of invention

The first object of the present invention is the mixed oxide [MO] of a kind of Si and at least one metal M, the mixed oxide Include inorganic group-SO₃H。

With reference to the mixed oxide [MO], term " inorganic group-SO₃H " is used herein to instruction in the mixed oxide Group-SO present in [MO]₃H is not joined to organic moiety, wherein statement " organic moiety " instruction is former containing at least one carbon Any part of son.All group-SO in the mixed oxide [MO]₃H is inorganic group-SO₃H。

Without being limited by theory, it is believed that group-SO₃H is integrated to mixed oxide surface via sulphur atom.Group-SO₃H warp It is integrated to by sulphur atom at least one Si in the mixed oxide, metal M or oxygen atom.Typically, group-SO₃H via Sulphur atom is integrated at least part of the metal M in the mixed oxide [MO].In conjunction with group-SO₃H is in mixed oxidization The x-ray photoelectron spectroscopy of the oxygen atom in presence and mixed oxide [MO] on the surface of object [MO] is relative to SiO₂Those of It is associated that offset can be worth towards higher combination.Such as in ARICO ', the inorganic filler of A.S. et al. is in composite membrane-direct methanol Surface characteristic in fuel cells applications, energy periodical (Surface properties of inorganic fillers for application in composite membranes-direct methanol fuel cells.J.Power Sources), volume 2004,128, the 113-118 pages is discussed, this offset may be with the higher acid of oxide surface It spends related.

It is selected from least one of the mixed oxide [MO] metal M by the 4th race of periodic table, the 5th race, the 6th race, the The element of 7 races, the 8th race, the 9th race, the 10th race, the 11st race, Al, Zn, the group of La and Ce composition.To avoid doubt, periodic table Label " N race " refer to element standard IUPAC name.As an example, states " the 4th race's element " and be intended to refer to element Ti, Zr and Hf.

Preferably, at least one metal M be selected from the group consisting of: Zr, Hf, V, Nb, Ta, Cr, Mo,W,Mn,Re,Ru,Co,Rh,Ir,Ni,Pd,Pt,Cu,Ag,Au,Zn,Al,La,Ce.It is highly preferred that at least one metal M It is selected from the group consisting of: Cr, Mo, W, Mn, Re, Ru, Co, Rh, Ir, Ni, Pd, Pt, Ag, Au, Ce.Even It is highly preferred that at least one metal M is selected from the group consisting of: Co, Cr, Ce and Mn.

When at least one metal M is Ce or Cr, in a kind of reduced degradation side of fluorinated ion-exchange polymer Face has been obtained for good result.

More than one metal M can be existed simultaneously in mixed oxide [MO].Appointing for more than one metal M can be used What combination and any ratio.The suitable combination of more than one metal M is for example selected from those of the group being made of the following terms: Ce and any one selected from the metal by Cr, Mo, W, Mn, Re, Ru, Co, Rh, Ir, Ni, Pd, Pt, Ag, Au group formed Combination；Cr and any one selected from the metal by Ce, Mo, W, Mn, Re, Ru, Co, Rh, Ir, Ni, Pd, Pt, Ag, Au group formed The combination of kind；Mn and appointing selected from the metal by Cr, Mo, W, Ce, Re, Ru, Co, Rh, Ir, Ni, Pd, Pt, Ag, Au group formed A kind of what combination；Co with selected from by Cr, Mo, W, Mn, Re, Ru, Ce, Rh, Ir, Ni, Pd, Pt, Ag, Au group formed metal Any combination.Preferred combination is selected from those of the group being made of the following terms: Ce with selected from by Cr, Co, Mn Any combination of the metal of the group of composition；The group of Co and any one selected from the metal by Cr, Ce, Mn group formed It closes；The combination of Cr and any one selected from the metal by Ce, Co, Mn group formed；Mn with selected from being made of Cr, Co, Ce Any combination of the metal of group.

When the combination of Ce and Cr is used as at least one metal M, in a kind of reduction of fluorinated ion-exchange polymer Degradation in terms of, have been obtained for good result.Typically, ratio Ce: Cr can be in the range of from 15: 1 to 1: 15.

In some embodiments, preferably with the mixed oxide [MO] of only one kind of metal M.

(wherein M refers to any metal M's in the mixed oxide to weight ratio Si/M in mixed oxide [MO] Total amount) it is at least 1, preferably at least 1.5, more preferably at least 2.Weight ratio Si/M is typically not greater than 40, it is preferable that it is no more than 25.Typically, the range of weight ratio Si/M is from 2.5 to 20.

Inorganic group-SO in mixed oxide [MO]₃The amount of H is typically the metal M in the mixed oxide [MO] Atom total amount at least 0.2%, preferably at least 0.5%.Inorganic group-SO in mixed oxide [MO]₃The amount of H relative to The atom total amount of metal M in the mixed oxide can be up to 50%, up to 100% and even higher than 100%, because Inorganic group-SO₃H can be incorporated on Si or oxygen atom in the mixed oxide [MO].

Inorganic group-SO in mixed oxide [MO]₃H, the amount of metal M and Si can pass through such as those skilled in the art Generally known x-ray fluorescence measures.

Preferably, which does not include any organic moiety as defined above.

Mixed oxide [MO] of the invention can be prepared by a kind of method, method includes the following steps:

A) provide includes SiO₂, at least one metal M water soluble salt and at least one inorganic group-SO₃The source of H Aqueous suspension；

B) make the suspension 30 DEG C to 100 DEG C at a temperature of reaction to form gel；And

C) heat treatment should under 180 DEG C to 350 DEG C of second temperature at a first temperature of 30 DEG C to 180 DEG C and then Gel to obtain the mixed oxide [MO] in solid form.

In the step a) of this method, a kind of aqueous suspension is by by the water soluble salt of at least one metal M and extremely A kind of few inorganic group-SO₃The source of H is dispersed in water phase SiO₂Middle preparation.The water phase can optionally comprising polar solvent such as Alcohols.

Any kind of SiO₂It can be used for preparing mixed oxide, such as colloidal silicon dioxide, fumed silica and class Like object.Preferably, there is the SiO of the partial size from 1nm to 100nm, preferably from 5 to 50nm₂It is preferred.

It is used to prepare the inorganic group-SO of mixed oxide [MO]₃The suitable source of H is for example selected from by (NH₄)₂SO₃· H₂O、NH₄SO₃NH₂、HSO₃Cl、Na₂S₂O₅/NaHSO₃、(NH₄)HSO₃、H₂SO₄Those of group of composition.Preferably, inorganic base Group-SO₃The source of H is (NH₄)₂SO₃·H₂O。

Statement " water soluble salt of metal M " is used herein to refer to that its solubility in water at 20 DEG C is at least 10g/ Any salt of any metal M of the water of 100mL.The noticeable example of water soluble salt be such as nitrate, sulfate and Chloride, preferably nitrate.

At least one metal M is selected from the 4th race, the 5th race, the 6th race, the 7th race, the 8th race, the 9th race, the 10th by periodic table The element of race, the 11st race, Al, Zn, the group of La and Ce composition.

In an advantageous embodiment of the invention, which is selected from and is made of Co, Cr, Ce and Mn Group.The non-limiting example for being used to prepare the suitable salt of corresponding mixed oxide [MO] is: Ce (NO₃)₃·6H₂O、Cr (NO₃)₃·9H₂O、Co(NO₃)₂·6H₂O、Mn(NO₃)₂·4H₂O。

In the step a) of this method, SiO₂Typically be added the total amount of the reagent in the aqueous suspension from 70wt% to 90wt%, preferably 75wt% are to 85wt%.

The salt of at least one metal M be typically the total amount of reagent being added in the aqueous suspension slave 8wt% to 20wt%, preferably 10wt% are to 18wt%.

Inorganic group-SO₃The source of H be typically the total amount of reagent being added in the aqueous suspension slave 2wt% to 10wt%, preferably 5wt% are to 7wt%.

The aqueous suspension can be by being added SiO in any order₂, at least one metal M water soluble salt and this extremely A kind of few inorganic group-SO₃Source (preferably (the NH of H₄)₂SO₃·H₂O it) prepares.

The step b) of this method be including at 30 DEG C to 100 DEG C, preferably at 50 DEG C to 90 DEG C typically under stiring At a temperature of carry out.SiO₂, at least one metal M water soluble salt and at least one inorganic group-SO₃The source of H allows Reaction at least 10 minutes, preferably at least one hour.Generally, the reaction time, typically it is small to be no more than 15 for it no more than 20 hours When.

The reaction leads to the formation of gel.If a kind of two-phase system is formed, including gel and liquid phase, the separation of gel can It is carried out according to any program as known in the art.

Then the gel obtained in step b) is made to be subjected to a two-step thermal processing process.First heat treatment is to be included in 30 DEG C to 180 DEG C, preferably 60 DEG C to 180 DEG C, more preferably 100 DEG C to 170 DEG C at a temperature of carry out.It carries out at first heat Reason continues one section and is enough the time for removing water from gel obtained in step b).Typically, which carries out extremely It is 30 minutes and typically up to 10 hours few.Preferably, the temperature of gel is made gradually to be increased to the first heat treatment temperature from room temperature Degree, such as by increasing temperature with the rate of 1 to 5 DEG C/min.

This first heat treatment after be one be included in 180 DEG C to 350 DEG C, preferably 200 DEG C to 330 DEG C, more preferably 250 DEG C to 320 DEG C at a temperature of second heat treatment.Typically, this second heat treatment carry out at least 30 minutes and usually It is no more than 10 hours, preferably from 1 to 5 hour.Preferably, make the temperature gradually from first heat treatment temperature be increased to this Two heat treatment temperatures, such as by increasing temperature with the rate of 1 to 5 DEG C/min.It is obtained at the end of heat treatment in solid shape The mixed oxide [MO] of formula.

Before the use, mixed oxide [MO] can use a kind of aqueous H₂SO₄Solution is handled and is subsequently dried to incite somebody to action All groups on the surface of the mixed oxide [MO] are converted into acid groups and additionally remove any metal, metal ion And/or ion on the surface thereof may be adsorbed.The aqueous H₂SO₄Solution typically has from 0.1 to 3M, preferably from 0.2 to 2M Concentration.Acid processing can from 40 DEG C to 80 DEG C at a temperature of carry out.

Another object of the present invention be it is a kind of comprising at least one fluorinated polymer and it is at least one as set forth in more detail above Mixed oxide [MO] composition, the fluorinated polymer include-SO₂X functional group, wherein X be selected from X ' or selected from OZ and Wherein X ', which is selected from, is selected from by F, Cl, Br, I group formed and Z by H, alkali metal, NH₄The group of composition.

Statement " fluorinated " be used herein to refer to or fully or partly it is fluorinated (that is, it is wherein all or Only a part hydrogen atom has been replaced by fluorine atoms) compound (such as compound, polymer, monomer etc.).Preferably, term " fluorinated " refers to that the compound comprising fluorine atom more higher proportion of than hydrogen atom, the more preferably term refer to completely not Hydrogen atoms, i.e., the compound that wherein all hydrogen atom has been replaced by fluorine atoms.

In the context of the present invention, statement "at least one", which is worked as, refers to " fluorinated polymer " and/or " mixed oxide A kind of or more than one polymer and/or mixed oxide [MO] are intended to refer to when [MO] ".Polymer and/or mixed oxide A variety of mixtures of [MO] may be advantageously used with the purpose of the present invention.

The composition may include at least one fluorinated polymer for the form of being in neutrality, wherein statement " neutral form " instruction In-SO₂X is X ' in X functional group and X ' is selected from the group being made of F, Cl, Br, I.Preferably X ' is selected from F or Cl.More preferably X ' is F.

Alternatively, the composition may include at least one fluorinated polymer in ion (acid or at salt) form, Wherein statement " ionic species " instruction is in-SO₂X is OZ in X functional group and Z is selected from by H, alkali metal, NH₄The group of composition.

To avoid doubt, term " alkali metal " is intended to refer to following metal: Li, Na, K, Rb, Cs hereby.Preferably, should Alkali metal is selected from Li, Na, K.

Comprising-SO₃The fluorinated polymer (wherein X=OZ) of Z functional group typically via method as known in the art by Comprising-SO₂X ' functional group, preferably-SO₂It is prepared by the fluorinated polymer of F functional group.

It accordingly include-SO by being handled with a kind of highly basic (such as NaOH, KOH)₂X ' functional group, typically-SO₂F function The polymer of group, can obtain the fluorinated polymer in the form of it is at salt, i.e., wherein Z is a kind of selected from by NH₄With alkali metal group At group cation.

By handling the salifie form of corresponding polymer with a kind of acid solution of concentration, the fluorine can be obtained in the form of its acid Fluidized polymer, i.e., wherein Z are H.

It suitably include-SO₂The fluorinated polymer of X ' functional group is those following polymer, they include being derived from least one Kind includes at least one-SO₂The repetition list of the ethylenic bond unsaturation fluorinated monomer (monomer (A) as defined below) of X ' functional group Member and the repetitive unit for being derived from least one ethylenic bond unsaturation fluorinated monomer (monomer (B) as defined below).

With reference to the monomer of (A) and (B) both types, phrase " at least one monomer " is used to refer to each type herein One kind or more than one monomer can reside in the polymer.Hereinafter term monomer will be used to refer to one kind of given type With more than one both monomers.

The non-limiting example of suitable monomer (A) is:

Sulfonic acid halide fluoroolefins class with following formula: CF₂=CF (CF₂)_pSO₂X ', wherein p is one between 0 and 10 Integer, preferably between 1 and 6, more preferable p is equal to 2 or 3, and wherein preferably X '=F；

The fluoride-based ethers of sulfonic acid halide with following formula: CF₂=CF-O- (CF₂)_mSO₂X ', wherein m is between 1 and 10 An integer, preferably between 1 and 6, more preferably between 2 and 4, even more preferably m is equal to 2, and wherein preferred X '= F；

Sulfonic acid halide Fluoroalkyloxy vinyl ethers with following formula:

CF₂=CF- (OCF₂CF(R_F1))_w-O-CF₂(CF(R_F2))_ySO₂X’

Wherein w is an integer between 0 and 2, R_F1And R_F2, it is same or different to each other, is independently F, Cl or one C₁-C₁₀Fluoroalkyl is optionally replaced by one or more ether oxygens, and y is an integer between 0 and 6；Preferably w is 1, R_F1 It is-CF₃, y is 1 and R_F2It is F, and wherein preferred X '=F；

There is formula CF₂=CF-Ar-SO₂The sulfonic acid halide aromatic series fluoroolefins class of X ', wherein Ar is a C₅-C₁₅Aromatic series Or heteroaromatic substituent group, and wherein preferred X '=F.

Preferably, monomer (A) is selected from the group of perfluorobutanesulfonyl fluoride, i.e., wherein X '=F.

It is highly preferred that monomer (A), which is selected from, has formula CF₂=CF-O- (CF₂)_m-SO₂The group of the fluoride-based ethers of F, wherein M is an integer between 1 and 6, preferably between 2 and 4.

Even further preferably, monomer (A) is CF₂=CFOCF₂CF₂-SO₂F (perfluoro -5- perfluorobutanesulfonyl fluoride -3- oxygen Miscellaneous -1- amylene).

The non-limiting example of the suitably ethylenic bond unsaturation fluorinated monomer of (B) type is:

-C₂-C₈Fluoroolefins class, such as tetrafluoroethene, pentafluoropropene, hexafluoropropene and hexafluoro-isobutene；

Vinylidene fluoride；

-C₂-C₈Chloro-and/or bromo-and/or iodo-fluoroolefins class, such as chloro trifluoro ethylene and bromo trifluoro second Alkene；

There is formula CF₂=CFOR_f1Perfluoroalkylvinyl ethers, wherein R_f1It is a C₁-C₆Fluoroalkyl, such as-CF₃,- C₂F₅,-C₃F₇；

There is formula CF₂=CFOR_O1Fluoro- alkoxy vinyl ethers class, wherein R_O1Being one has one or more ethers The C of group₁-C₁₂Fluoroalkyloxy, such as perfluor -2- propoxyl group-propyl；

There is formula CF₂=CFOCF₂OR_f2Fluoroalkyl-Methoxy-vinyl ethers, wherein R_f2It is a C₁-C₆Fluothane Base, such as-CF₃,-C₂F₅,-C₃F₇An or C with one or more ether groups₁-C₆Fluoroalkyloxy, as-C₂F₅-O-CF₃；

Fluorine dioxole class with following formula:

Wherein R_f3、R_f4、R_f5、R_f6It is same or different to each other, is a fluorine atom, a C each independently₁-C₆Fluothane Base, optionally comprising one or more oxygen atoms, such as-CF₃、-C₂F₅、-C₃F₇、-OCF₃、-OCF₂CF₂OCF₃。

Preferably, monomer (B) is selected from:

-C3-C₈Fluoroolefins class, preferably tetrafluoroethene and/or hexafluoropropene；

Chloro-and/or bromo-and/or iodo-C₂-C₆Fluoroolefins class, as chloro trifluoro ethylene and/or bromo trifluoro second Alkene；

There is formula CF₂=CFOR_f1Perfluoroalkylvinyl ethers, wherein R_f1It is C₁-C₆Fluoroalkyl, such as-CF₃、- C₂F₅、-C₃F₇；

There is formula CF₂=CFOR_O1Fluoro- alkoxy vinyl ethers class, wherein R_O1Being one has one or more ethers The C of group₁-C₁₂Fluoroalkyloxy, as perfluoro -2- propoxyl group-propyl.

It is highly preferred that monomer (B) is tetrafluoroethene.

Comprising-SO₂The fluorinated polymer of X ' functional group can be prepared by any polymerization as known in the art.With In the suitable method of the preparation of this quasi polymer be for example in 1323751 A of EP (solvay sulexi company (SOLVAY SOLEXIS SPA)) described in 02.07.2003 and EP 1172382 A (solvay sulexi company) 16.11.2002 that A bit.

Mixed oxide [MO] is to be present in group with any amount for being enough to reduce the free radical cracking degree of fluorinated polymer It closes in object.

The amount of mixed oxide [MO] in the composition is such, that is, so that relative in the fluorinated polymer- SO₂The molal quantity of the metal M of the molal quantity of X functional group is at least 0.1%, preferably at least 0.2%, more preferably at least 0.5%.Just Relative to-the SO in the fluorinated polymer₂For the molal quantity of the metal M of the molal quantity of X functional group, mixed oxide [MO] exists Amount in composition is typically not greater than 20%, it is preferable that it is no more than 15%, it is highly preferred that it is no more than 10%.

Conventional method preparation can be used in the composition.

When both fluorinated polymer and mixed oxide [MO] are all in solid form, such as with powder, pellet or particle When form provides, the composition can be used such as dry-mixed multiple technologies, melt blending or extrude preparation.

Alternatively, the fluorinated polymer and at least one mixed oxide [MO] can be in the presence of suitable solvent Lower blending is to provide a kind of liquid composition.This method includes-SO for preparing the wherein fluorinated polymer₃Z functional group, Middle Z is as defined above, and especially-SO₃The composition of H functional group is advantageous.

The liquid composition can be prepared by a kind of dissolving method, wherein fluorinated polymer and a kind of liquid medium is made to exist It is contacted under the conditions of suitable temperature.

Generally, which includes that water or water/alcohol mixture are used as liquid medium, it is optional comprising additionally at Point and/or additive.

The suitable alcohol that can be used is notably methanol, ethyl alcohol, propyl alcohol especially as water/alcohol mixture (i.e. isopropanol, normal propyl alcohol), ethylene glycol, diethylene glycol.

Other liquid mediums that can be used are polar non-proton organic solvent such as ketones, as acetone, methyl ethyl ketone； Esters, as methyl acetate, dimethyl carbonate, diethyl carbonate, ethyl acetate；Nitrile, as acetonitrile；Sulfoxide type, as dimethyl sulfoxide； Amides, as n,N-Dimethylformamide, n,N-dimethylacetamide；Pyrrolidinone compounds, as N-Methyl pyrrolidone, N- ethyl Pyrrolidones.

Using the mixture that the wherein liquid medium is water or a kind of water and alcohol, (preferably water and one or more propyl alcohol is mixed Close object) liquid composition have been obtained for good result.

The liquid composition can advantageous by make the mixture of the fluorinated polymer and water or a kind of water and alcohol one In the at a temperature of contact preparation from 40 DEG C to 300 DEG C in a autoclave.

Can by mixed oxide [MO] with it is pure or first be suspended in advance a kind of solvent (it is all as described above that It is added after in a bit) in the liquid composition that this includes fluorinated polymer.

Another object of the present invention is a kind of liquid composition, which includes: at least one includes-SO₂X The fluorinated polymer of functional group and a kind of at least one mixed oxide [MO] being dispersed or dissolved in liquid medium.It is typical Ground, the liquid medium are the mixture of water or a kind of water and alcohol.

Preferably, the fluorinated polymer in the liquid composition is in its ionic species, i.e., it includes-SO₃Z functional group, Wherein Z is as defined above, and especially-SO₃H functional group.

Liquid composition comprising at least one fluorinated polymer He at least one mixed oxide [MO] can appoint Selection of land includes additional ingredient.

Composition of the invention is particularly suitable for preparing the proton exchange membrane and electro-catalysis that use in fuel cell applications Layer improves because the presence of mixed oxide [MO] of the invention has been shown comprising-SO₂The fluorinated polymer of X functional group To the tolerance of free radical cracking, such as shown by the longer service life of the proton exchange membrane by its acquisition under conditions of use 's.

Another object of the present invention is a kind of product, and it includes-SO which, which includes at least one as defined above,₂X The fluorinated polymer of functional group and at least one mixed oxide [MO].

In a first embodiment, which is a kind of proton exchange membrane for fuel cells applications, is also referred to as herein For " film ".

Comprising at least one fluorinated polymer, typically contain-SO₂X ' functional group, preferably-SO₂F functional group, and should It can be converted into advantageous by conventional extruding technology in the composition of at least one mixed oxide [MO] of solid form Film.

The film of extrusion can be then ion-conductive membranes, i.e.-SO by hydrolysis₂X ' functional group conversions be it is corresponding- SO₃H functional group, as discussed above.

Film can typically contain-SO from comprising at least one fluorinated polymer₃Z functional group, preferably-SO₃H function The liquid composition of group and at least one mixed oxide [MO] uses technology as known in the art, such as dipping, stream Prolong, be coated with (such as roller coating, intaglio plate coating, reverse roll coating, dip-coating, spraying) acquisition.

These films can optionally for example by the extruded film is laminated on a suitable enhancing carrier or is passed through by The liquid composition, which is impregnated on a porous carrier, to be enhanced.Suitable carrier can be made of various components.These Porous carrier can be by polymerized hydrocarbon species (such as woven or nonwoven polyolefin film, such as polyethylene or polypropylene) or polyester Class (such as poly- (ethylene terephthalate)) is made.The porous carrier of fluorinated polymer is because their high chemical inertness is usual It is preferred for using in fuel cell applications.The PTFE porous carrier (being in addition also called ePTFE membrane) of twin shaft expansion is it In preferred carrier.These carriers are notably in product nameUnder can quotient Purchase.

In a second embodiment, which is a kind of Electrocatalytic Layer.

Electrocatalytic Layer can be prepared advantageously since a kind of liquid composition, and the liquid composition is in addition at least one Fluorinated polymer typically contains-SO₃Z functional group, preferably-SO₃H functional group and at least one mixed oxide [MO] Except include catalyst granules.The liquid composition is commonly known as " catalysis ink ".Typical catalyst granules includes one kind Reactive compound, the reactive compound are selected from: metal, as iron, manganese, cobalt, nickel, platinum, ruthenium, gold, palladium, rhodium, iridium, their conductive oxygen Compound and alloy.The reactive compound is typically supported in a kind of suitable material, is referred to herein as " carrier ", the carrier is excellent Selection of land is conductive.The carrier is advantageously selected from carbon dust, such as carbon black.

Total weight of the amount based on catalysis ink of catalyst granules (if any, then including carrier) in catalysis ink Generally at least 1wt%.Preferably, it is at least 3wt% and more preferably at least 5wt%.Catalyst particles in catalysis ink The amount of grain (if any, then including carrier) is advantageously most 50wt% based on the total weight of catalysis ink, preferably most More 40wt% and more preferably up to 30wt%.

It can be for example by the way that the catalysis ink silk-screen printing or solution coating be made on a kind of surface of proton exchange membrane These standby Electrocatalytic Layers.The proton exchange membrane may include a kind of mixed oxide [MO], the mixed oxide [MO] have with The identical or different composition of mixed oxide [MO] present in catalysis ink or it can be free of mixed oxide [MO]。

In a 3rd embodiment, which is a kind of membrane electrode assembly piece installing.The membrane electrode assembly piece installing includes a tool There is the film on the first and second surfaces, first Electrocatalytic Layer for adhering to the first surface and one adhere to described second Second Electrocatalytic Layer on surface, wherein at least one of the film, the first or second Electrocatalytic Layer include as defined above At least one include-SO₂The fluorinated polymer of X functional group and at least one mixed oxide [MO].When the mixed oxide It can be same or different when [MO] is present in the more than one component of the membrane electrode assembly piece installing.

Previously undefined it was defined and preference in the background of mixed oxide [MO] or the method for its preparation It is suitable for inclusion in the composition of the mixed oxide and a kind of fluorinated polymer component and is suitable for containing the composition Any product.

The present invention is more described in detail now with reference to following instance, the purpose of these examples is only illustrative and is not intended to limit The scope of the present invention processed.

If the disclosure content in any patent, patent application and the publication that are incorporated herein by reference illustrates phase with this The degree of conflict may make a term unclear to it, then this explanation should be preferential.

Example

Characterization

X-ray fluorescence (XRF) analysis be carried out on mixed oxide sample according to standardization program with determine Si, S, with And the amount of metal M.The XRF analysis of sample be with one under the power of 1kW operation and equipped with Rh x-ray source, LiF 220 What crystal analyzer and the Bruker AXS S4 detector spectrum instrument of 0.12 ° of diverging collimator carried out.

X-ray photoelectron spectroscopy (XPS) analysis is carried out to characterize table of the mixed oxide in oxidation state and in terms of combining energy Face characteristic.XPS measuring is carried out by using physical electronic (PHI) 5800-01 spectrometer.Monochromatic Al K α X-ray Source uses under the power of 350W.Using the 58.7eV for elemental analysis (composition) and for measuring oxidation state The logical of 11.75eV can obtain spectrum.Pressure in measurement process in the analysis room of spectrometer is 1 × 10^-9Support.Argon sputters it Afterwards, the peak Ag 3d5/2 of Ag foil is taken to check the calibration in conjunction with energy scale.The qualitative assessment at each peak is by integrating peak face What product was obtained divided by atomic sensitivity factor, these atomic sensitivity factors are deep from ionization cross section, average free electron escape Spend the transfer function calculating of the measurement of (mean free electron escape depth) and spectrometer.XPS data are logical It crosses using the online of the oxidation state implemented in 6.1 software of PHI MULTIPAK and the PHI handbook of X-ray photoelectron spectroscopy What library was interpreted.Deconvoluting for XPS spectrum is carried out by using MULTIPAK software.

Example 1- is used to prepare the general program of mixed oxide according to the present invention [MO]

In a closed container, by SiO₂(by Cabot Co., Ltd (Cabot Corp.) supplyEH- 5), the water-soluble inorganic salt and (NH of metal M₄)₂SO₃·H₂O suspends in water.

SiO₂: the salt of metal M: (NH₄)₂SO₃·H₂The weight ratio of O is 8: 1.5: 0.5.The slurry stirs 10h at 80 DEG C A kind of gel is provided.The gel so obtained is heat-treated according to following condition:

From room temperature to 150 DEG C (slope 1h, 2.5 DEG C/min)；

The 2h at 150 DEG C；

From 150 DEG C to 300 DEG C (slope 1h, 2.5 DEG C/min)；

The 2h at 300 DEG C.

The powder obtained at the end of heat treatment is cooled to room temperature and then with 0.5M H₂SO₄Solution is washed at 70 DEG C It washs until the amount of metal M and sulphur is not changed by the XRF analysis measurement of sample.The powder is dry at 80 DEG C under vacuum 2h and then in a planetary ball mill with 200rpm grind 2h.

Table 1 lists the mixed oxide and their composition of preparation.

Table 1

The mixed oxide of Ce and Cr is to be passed through according to identical general program in water with SiO₂: Ce salt: Cr salt: (NH₄)₂SO₃·H₂The weight ratio that O is 8: 0.75: 0.75: 0.5 mixes SiO₂、Ce(NO₃)₃·6H₂O、Cr(NO₃)₃·9H₂O and (NH₄)₂SO₃·H₂O preparation.Ce: the Cr ratio in obtained mixed oxide [MO-Ce-Cr] is 1: 9.

Example 2- includes-SO₃The preparation of the fluorinated polymer (P1) of H functional group

Following reagent is added in the autoclave of a 22L:

11.5L demineralized water；

980g has the monomer of following formula: CF₂=CF-O-CF₂CF₂-SO₂F

The CF of 5% weight of one kind of 3100g₂ClO(CF₂CF(CF₃)O)_n(CF₂O)_mCF₂COOK (average molecular weight=521, Ratio n/m=10) solution in water.

The autoclave is stirred with 470rpm, is heated at 60 DEG C.By the potassium peroxydisulfate with 6g/L based on the molten of water Liquid is added with the amount of 150mL.Keep pressure in the value of 12 bars (abs) by charging tetrafluoroethene.

It is added after the tetrafluoroethene of 1200g in the reactor, the tetrafluoroethene that every 200g is fed into autoclave is added The CF of 220g₂=CF-O-CF₂CF₂-SO₂F monomer.

By stopping stirring after 280 minutes, reduced by autoclave cooling and by discharge tetrafluoroethene internal Pressure stops reaction；The tetrafluoroethene for amounting to 4000g is fed.

Then by freeze and thaws make latex solution condense and recycle polymer with water washing and at 150 DEG C dry 24 hours.Then the polymer is handled 8 hours at 80 DEG C with fluorine gas in a canister, then purged with nitrogen several Hour is to remove any remaining unstable end group.

By the polymer so obtained at a kind of middle dipping of KOH solution (by weight 10%) 8 hours at 80 DEG C, then It is washed in demineralized water at room temperature.In a kind of HNO₃Impregnate 2 hours in solution (by weight 20%) at room temperature, then Being washed in demineralized water at room temperature by all functional group conversions is-SO₃H functional group.

Then resulting is in-SO₃The fluorinated polymer (P1) of H-shaped formula is dry at 80 DEG C in a vacuum drying oven.Really The equivalent weight for determining polymer (EW) is 790g/eq (being analyzed by the IR to precursor polymer).

Example 3- includes the liquid composition of P1 and the mixed oxide prepared in example 1

By the mixed oxide prepared in example 1 each be suspended at room temperature 1- propyl alcohol ([MO]/1- propyl alcohol= In 1/50w/w) and then what sonication 2h obtained the solid is completely dispersed body.It is measured using (160 DEG C, 45 minutes) of thermobalance Solid content in dispersion.Then the dispersion addition of the obtained mixed oxide is additionally comprised into 1- propyl alcohol (36g) In the aqueous dispersion of the P1 (100g) of N- ethyl pyrrolidone (15.5g).This mixture is stirred at room temperature 15 minutes and obtains A kind of clear solution.

The amount of the mixed oxide [MO] and P1 that add in the preparation of each liquid composition is calculated to obtain rubbing for metal M - SO in your number/fluorinated polymer P1₃The ultimate density of the metal that the molal quantity of H group is 1% in the composition.

Example 4- film preparation-general program

By expanded PTFE carrier (#3101), the average pore size with 0.2 μm is (such as in product data sheet In specify) and 35 ± 10 μm of thickness, be mounted on the PTFE annular frame of an internal diameter with 100mm, immersion example 3 Obtained in each liquid composition and in a kind of liquid composition only containing polymer P 1 and then in draft furnace In 65 DEG C of at a temperature of dry 1h, the dry 1h and then in 1h from 90 DEG C to 190 DEG C at 90 DEG C.

The film so obtained be it is transparent and be it is colourless, indicate the completely enclosed of the hole of carrier.The thickness of obtained film Degree is 25 ± 5 μm.

The fuel cell feature for the film that example 5- is prepared in example 4

There is 25cm at one²The monocell of effective areaMiddle assembling such as describes in example 4 Obtained film and at oneIt is tested on 50W testing stand.Use E-LT250EW gas-diffusion electrode (0.5mg/cm²Pt these films) are assembled.

After adjusting 24 hours under the fixed voltage of 0.6V, a polarization curve is determined to examine membrane properties.Hair Now the conductivity of film containing mixed-metal oxides of the invention and the conductivity of reference film (M1) are not different.

These diaphragms are tested under following operating condition:

Anode-side flow: 500sccm pure H₂, 64 DEG C of dew points, 1 bar (abs)

Cathode side flow: 500sccm it is pure 0₂, 64 DEG C of dew points, 1 bar (abs)

Battery temperature: 90 DEG C

Open circuit voltage conditions (0 ampere of=electric current).

The voltage is monitored dduring test.The end setup of test is typically assumed to refer in the voltage for being lower than 0.7V Show that aperture is formed on diaphragm.As a result it is recorded in table 2.

Table 2

Film	Reach the time (hour) of voltage < 0.7V
		M1 (reference)	230
M-Ce	1400
		M-Co	450
M-Cr	600
		M-Mn	400
MO-Ce-Cr	> 600

Relative to a kind of only comprising the film (reference film M1) of fluorinated polymer (P1), include mixed oxide of the invention Film shows dramatically increasing for stability under fuel cell operating conditions.

Example 6 and comparison example 1- include the film of [MO-Ce] and Ce (III)

A kind of liquid composition is prepared [MO-Ce] and polymer P 1 that prepare since example 1 as described in example 3 - the SO in molal quantity/fluorinated polymer P1 to obtain Ce₃The cerium that the molal quantity of H group is 2.5% is in the composition most Final concentration.

Containing fluorinated polymer P1 and 2.5% mole of Ce (III) ion (relative to-SO in fluorinated polymer P1₃H The molal quantity of group) second of liquid composition be by by Ce (NO₃)₃·6H₂O is dissolved in the liquid composition of P1 and makes Standby.

A film is prepared from each liquid composition according to general program described in example 4.

These films are assembled in a single fuel cell as described in example 5 and are measured under following operating condition Each fuel cell resistance:

Anode effluent: air, cathode effluent: pure H₂,

Battery temperature: 65 DEG C

Reactant humidity level: 125% (70 DEG C of dew points)

Current strength: from 2A to 16A

Test is shown to be shown than the battery that is prepared with Ce (III) ion more with the battery for the film preparation for containing [MO-Ce] Low resistance (60 comparison 70mOhm.cm^-2).The lower resistance and higher number of film containing mixed oxide [MO] of the invention Conduction-SO in the available fluorinated polymer P1 of amount₃H group is related, that is, lower quantity with Ce ion ionic bond - SO in the fluorinated polymer P1 of ground coordination₃H group.Such as by (62 pairs of comparison between the 0h comparison 100h of fuel cell operation Compare 60mOhmcm^-2) shown, lower resistance is constant within the extended period.

Therefore, compared to the prior art systems for using the soluble form containing metal M, mixed oxide of the invention is used It is advantageous, because the metal M in mixed oxide improves the stability of film as time goes by (such as by the data in table 2 It is shown), the resistance without increasing the film.In addition, because metal M is included in mixed oxide lattice, it is believed that in fuel Exudation in the operational process of battery last a longer period of time is more stable.

Claims (16)

1. The mixed oxide of 1.Si and at least one metal M, the mixed oxide is for ion used in fuel cells applications Exchange fluorination polymer film, the oxide contain inorganic group-SO₃H the, wherein inorganic group-SO₃H is relative to mixed at this The total amount for closing the atom of the metal M in oxide is at least 0.2%, and the mixed oxide passes through method comprising the following steps Preparation: a) providing includes SiO₂, at least one metal M water soluble salt and at least one inorganic group-SO₃The source of H Aqueous suspension；B) make the suspension 30 °C to 100 °C at a temperature of reaction to form gel；C) at 30 °C to 180 ° At a first temperature of C and then the gel is heat-treated under 180 °C to 350 °C of second temperature to obtain in solid form The mixed oxide.
2. 2. mixed oxide according to claim 1 the, wherein inorganic group-SO₃H, which is not joined to, contains at least one Any part of carbon atom.
3. 3. mixed oxide according to claim 1 or 2 the, wherein inorganic group-SO₃H is integrated to this via sulphur atom On at least one Si, the metal M or oxygen atom of mixed oxide.
4. 4. mixed oxide according to claim 1 or 2, wherein weight ratio Si/M be at least 1 and it be no more than 40.
5. 5. mixed oxide according to claim 1 or 2, wherein at least one metal M be selected from periodic table the 4th race, The element of 5th race, the 6th race, the 7th race, the 8th race, the 9th race, the 10th race, the 11st race, Zn, Al, La and Ce.
6. 6. mixed oxide according to claim 1 or 2, wherein at least one metal M is selected from Ce, Co, Cr, Mn.
7. 7. a kind of method for being used to prepare mixed oxide as described in any one of the preceding claims, this method include following Step: a) providing includes SiO₂, at least one metal M water soluble salt and at least one inorganic group-SO₃The source of H Aqueous suspension；B) make the suspension 30 °C to 100 °C at a temperature of reaction to form gel；C) at 30 °C to 180 ° At a first temperature of C and then the gel is heat-treated under 180 °C to 350 °C of second temperature to obtain in solid form The mixed oxide.
8. 8. one kind includes at least one fluorinated polymer and at least one such as mixing oxygen described in any one of claims 1 to 6 The composition of compound, the composition is for ion exchange fluorinated polymer films used in fuel cells applications, the fluorinated polymers Object includes-SO₂X functional group, wherein X be selected from X ' or selected from OZ and wherein X ' be selected from F, Cl, Br, I and Z be selected from H, alkali gold Belong to, NH₄。
9. 9. composition according to claim 8, wherein at least one mixed oxide is with the molal quantity of the metal M/fluorine - SO in fluidized polymer₂The molal quantity of X functional group is at least 0.1% and the amount no more than 20% exists.
10. 10. a kind of liquid composition, it includes compositions described in the claim 8 or 9 of dispersion in liquid medium.
11. 11. liquid composition as claimed in claim 10, wherein X=OZ and Z=H in the fluorinated polymer.
12. 12. a kind of method for being used to prepare the composition according to any one of claim 8 to 11, this method includes with solid At least one mixed oxide described in any one of claims 1 to 6 and at least one is blended in body form in the solution Comprising-SO₂The fluorinated polymer of X functional group.
13. 13. a kind of product comprising composition described in claim 8 or 9.
14. 14. product according to claim 13, which is proton exchange membrane, Electrocatalytic Layer or membrane electrode assembly piece installing.
15. 15. a kind of method for being used to prepare product according to claim 13 or 14, this method includes dipping, curtain coating or coating Liquid composition described in claim 10 or 11.
16. 16. a kind of fuel cell comprising product according to claim 13 or 14.