CN118027587A

CN118027587A - Ion exchange compound, ion exchange membrane, and preparation method and application thereof

Info

Publication number: CN118027587A
Application number: CN202410153173.0A
Authority: CN
Inventors: 焦佳佳; 刘昊; 张泽天; 刘卫霞; 周明正; 常磊; 鹿传睿; 张亚欢
Original assignee: Foshan Lvdong Hydrogen Energy Technology Co ltd; Spic Hydrogen Energy Technology Development Co Ltd
Current assignee: Foshan Lvdong Hydrogen Energy Technology Co ltd; Spic Hydrogen Energy Technology Development Co Ltd
Priority date: 2024-02-02
Filing date: 2024-02-02
Publication date: 2024-05-14

Abstract

The invention discloses an ion exchange compound, an ion exchange membrane, a preparation method and application thereof, wherein the ion exchange compound comprises the following components: an ion exchange resin and a cerium complex, wherein the cerium complex comprises a metal ion of a coordination center comprising cerium ions and a ligand comprising at least one of bridged polyphenols, tea polyphenols, tannins, tetrahydrofuran, or curcumin. In the ion exchange compound, the cerium complex has good dispersibility in the ion exchange resin, and can also avoid the reduction of conductivity caused by the fact that cerium ions are directly contacted with sulfonic acid functional groups in the ion exchange resin to generate counter ion crosslinking. The cerium ion and the ligand in the cerium complex have synergistic effect, the quenching effect is strong, the action time is long, and the chemical durability of the ion exchange complex can be obviously improved.

Description

Ion exchange compound, ion exchange membrane, and preparation method and application thereof

Technical Field

The invention relates to the field of high polymer materials, in particular to an ion exchange compound, an ion exchange membrane, a preparation method and application thereof.

Background

The ion exchange membrane is widely applied to the fields of fuel cell proton exchange membranes, chlor-alkali industrial membranes, flow battery membranes, water electrolysis hydrogen production proton exchange membranes, separation membranes, protective materials and the like. Taking a fuel cell as an example, the degradation of other components such as a catalyst and a gas diffusion layer generally only leads to the reduction of the performance of the cell, but the damage of a proton exchange membrane directly leads to the mixing of cathode and anode reaction gases, so that the direct failure of the cell and even safety accidents occur, and therefore, the preparation of the proton exchange membrane with high performance and high durability is very important for the development of the fuel cell. In the operation process of the fuel cell, the proton exchange membrane is easy to attack by hydroxyl radicals, so that the performance of the proton exchange membrane is reduced, even perforations appear, and the degradation of the proton exchange membrane and even the failure of the cell are caused. Therefore, there is a need to overcome the problems of performance decay and shortened lifetime caused by hydroxyl radical attack in proton exchange membranes, and to improve their chemical durability.

The metal salt, oxide, hydroxide, perovskite and complex of cerium are used as free radical quenchers to be doped into the ion exchange membrane, so that the chemical durability of the proton exchange membrane of the fuel cell can be effectively improved. The metal salts, oxides, hydroxides, perovskite, and the like of cerium have poor compatibility with resins and cannot be uniformly dispersed in the resin matrix. Another class of radical quenchers are organic compounds. However, organic compounds have the disadvantages of easy loss, easy decomposition after quenching free radicals and limited action time as free radical quenchers. In addition, for ion exchange membranes, as little free radical quencher content as possible is required to achieve efficient, durable free radical quenching. Current cerium-containing compounds and organic compounds applied to ion exchange membranes have drawbacks in efficiency or duration of action.

Disclosure of Invention

The present invention has been made based on the findings and knowledge of the inventors regarding the following facts and problems: ion exchange membranes need to have good chemical stability and be resistant to attack by hydroxyl radicals. Cerium-containing compounds or organic compounds, for example, phenolic hydroxyl-containing organic compounds, are doped into ion exchange resins to act as radical quenchers and thereby increase the chemical stability of the proton exchange membrane. However, for ion exchange membranes, as little free radical quencher content as possible is required to achieve efficient, durable free radical quenching, and cerium-containing compounds and organic compounds currently applied to ion exchange membranes have drawbacks in efficiency or duration of action.

The present invention aims to solve at least one of the technical problems in the related art to some extent. Therefore, the embodiment of the invention provides an ion exchange compound, an ion exchange membrane, a preparation method and application thereof, wherein cerium complex has good dispersibility in ion exchange resin, and can also avoid the reduction of conductivity caused by the direct contact of cerium ions and sulfonic acid functional groups in the ion exchange resin to generate counter ion crosslinking. The cerium ion and the ligand in the cerium complex have synergistic effect, the quenching effect is strong, the action time is long, and the chemical durability of the ion exchange complex can be obviously improved.

An embodiment of the present invention provides an ion exchange composite comprising: an ion exchange resin and a cerium complex, wherein the cerium complex comprises a metal ion of a coordination center comprising cerium ions and a ligand comprising at least one of bridged polyphenols, tea polyphenols, tannins, tetrahydrofuran, or curcumin.

The ion exchange compound provided by the embodiment of the invention has the advantages and technical effects that: the ion exchange composite includes a cerium complex and an ion exchange resin. The ligand of the cerium complex can be uniformly dispersed in the ion exchange resin, so that cerium element has good dispersibility in the ion exchange resin, the problem of uneven dispersion of cerium-based metal salt and metal oxide in the ion exchange resin is solved, and the performances of chemical durability, electrochemical performance and the like of the ion exchange composite are further improved. The cerium complex and the ion exchange resin have good compatibility, and the blending proportion is more controllable. And the problem of conductivity reduction caused by the fact that cerium ions are directly contacted with sulfonic acid functional groups in ion exchange resin to generate counter ion crosslinking can be avoided.

In the embodiment of the invention, the ligand comprises bridged polyphenol, tea polyphenol, tannin, tetrahydrofuran and curcumin, and can form a stable complex with cerium ions. The introduction of the cerium complex can enhance the radical resistance of the ion exchange complex. Cerium ions in the coordination center of the cerium complex can be used as a hydroxyl radical quencher, so that the chemical durability of the complex is remarkably improved; the ligand of the cerium complex also has hydroxyl radical quenching capability, and the ligand and the coordinated center cerium ion cooperate to further enhance the radical quenching effect of the cerium complex. In the use process, cerium ions and ligands have good free radical quenching effect, and the chemical stability of the material is improved. Complexing of ligands such as tea polyphenol, tannin and the like mainly occurs on two adjacent phenolic hydroxyl groups in molecules, uncomplexed phenolic hydroxyl groups have free radical quenching capacity, and can also cooperate with cerium ions in a coordination center to further enhance the free radical quenching effect of the complex. The cerium complex can be well dispersed in a processing solvent of ion exchange resin, is easy to blend with the ion exchange resin and process and mold, is uniformly dispersed after molding, and has low mobility (loss rate) in the use process. Therefore, the cerium complex has the advantages of good processability, high and durable free radical quenching efficiency, good compatibility in ion exchange resin, low mobility and the like.

In the embodiment of the invention, the cerium complex has the advantages of both cerium ions and ligand two free radical quenchers, and the formed synergistic effect enables the complex to have high-efficiency and durable free radical quenching effect, the quenching effect is strong, the action time is long, and the chemical durability of the ion exchange complex can be obviously improved. The ion exchange compound can be used in a plurality of fields such as diaphragms, proton exchange membranes, polyelectrolytes, sensors and the like, and has wide application prospect.

In some embodiments, 90 to 99.99% ion exchange resin and 0.01 to 10% cerium complex are included by mass percent.

In some embodiments, the bridged polyphenol comprises at least one of a bridged triphenol, a bridged diphenol.

In some embodiments, the metal ion of the coordination center of the cerium complex comprises at least one of Ce ³⁺ or Ce ⁴⁺;

And/or the ion exchange resin comprises at least one of perfluorosulfonic acid resin, perfluorosulfonimide resin, polyacid side chain type perfluororesin, sulfonated polytrifluorostyrene, sulfonated polysulfone, sulfonated polyethersulfone, sulfonated polyetheretherketone, sulfonated polyaryletherketone, sulfonated polyarylethernitrile, sulfonated polyphosphazene, sulfonated polyphenylene oxide, sulfonated polyphenylnitrile, sulfonated polyimide or sulfonated polybenzimidazole.

The embodiment of the invention provides an ion exchange membrane, which comprises the ion exchange compound disclosed by the embodiment of the invention.

In the embodiment of the invention, the cerium complex is used as a free radical quencher to be applied to the ion exchange membrane, and the complex has the advantages of both cerium ions and ligand free radical quenchers, has strong quenching effect and long action time, and can obviously improve the chemical durability and chemical stability of the ion exchange membrane. The ion exchange membrane can be used in a plurality of fields such as diaphragms, proton exchange membranes, polyelectrolytes, sensors and the like, and has wide application prospect.

In some embodiments, the ion exchange membrane comprises 90 to 99.99% ion exchange resin and 0.01 to 10% cerium complex, by mass percent;

And/or the film thickness of the ion exchange film is 3-500 μm;

And/or the ion exchange capacity of the ion exchange membrane is 0.1-4.2 mmol/g;

and/or the ion exchange membrane further comprises a reinforcing membrane.

In some embodiments, the material of the reinforcement film comprises at least one of a non-fluorinated polyolefin, a fluoropolymer, or an aromatic polymer;

and/or the mass of the reinforced membrane is 0.1-90% of the mass of the ion exchange membrane;

And/or the thickness of the reinforced film is 2-400 μm.

The embodiment of the invention provides a preparation method of an ion exchange membrane, which comprises the following steps:

(1) Dispersing ion exchange resin and cerium complex in a solvent to obtain a dispersion;

(2) And (3) forming and drying the dispersion liquid to obtain the ion exchange membrane.

In the embodiment of the invention, the cerium complex and the ion exchange resin are dispersed in the solvent, and the dispersion liquid is molded and dried to obtain the ion exchange membrane, so that the prepared ion exchange membrane has better flatness, uniform thickness distribution and better performance; simple process, convenient operation, high production efficiency and convenient wide application in industrial production. The dispersion liquid in the preparation process can also be used for preparing coating layers, hydrogel and adhesive of porous membranes such as desalination membranes (nanofiltration membranes), ultra/micro filtration membranes and the like, and various fabrics and protective equipment such as surgical gloves, protective clothing, sterile cloth sheets and the like, and has wide application prospect.

In some embodiments, in step (1), in step (2), the shaping comprises at least one of casting, or coating;

And/or, in the step (2), the drying temperature is 20-180 ℃;

and/or, in the step (2), a reinforcing film is further included, the dispersion liquid is coated on one side or two sides of the reinforcing film, and the ion exchange film is obtained after drying.

The embodiment of the invention provides an application of an ion exchange compound or an ion exchange membrane, which is used for at least one of chlor-alkali industry, water electrolysis, batteries, supercapacitors, electrodialysis, sensors, desalination membranes, ultrafiltration membranes, microfiltration membranes, coatings, hydrogels, adhesives, fabrics and protective equipment. In the embodiment of the present invention, all advantages of the ion exchange composite or the ion exchange membrane are provided, and detailed description thereof is omitted.

Drawings

FIG. 1 is a cross-sectional SEM image of C-PEM-3 prior to Fenton reagent treatment.

FIG. 2 is a cross-sectional SEM of the C-PEM-3 after Fenton reagent treatment.

FIG. 3 is a cross-sectional SEM image of D-C-PEM-6 prior to Fenton reagent treatment.

FIG. 4 is a cross-sectional SEM image of the D-C-PEM-6 after Fenton reagent treatment.

FIG. 5 is a graph of voltage-current density and internal resistance-current density for C-PEM-5 and D-C-PEM-4 before and after Fenton reagent treatment.

FIG. 6 is a TEM image of a C-PEM-3.

FIG. 7 is a TEM image of a D-C-PEM-6.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.

An ion exchange composite of an embodiment of the present invention includes: an ion exchange resin and a cerium complex, wherein the cerium complex comprises a metal ion of a coordination center comprising cerium ions and a ligand comprising at least one of bridged polyphenols, tea polyphenols, tannins, tetrahydrofuran, or curcumin.

The ion exchange composite of the embodiment of the invention comprises a cerium complex and ion exchange resin. The ligand of the cerium complex can be uniformly dispersed in the ion exchange resin, so that cerium element has good dispersibility in the ion exchange resin, the problem of uneven dispersion of cerium-based metal salt and metal oxide in the ion exchange resin is solved, and the performances of chemical durability, electrochemical performance and the like of the ion exchange composite are further improved. The cerium complex and the ion exchange resin have good compatibility, and the blending proportion is more controllable. And the problem of conductivity reduction caused by the fact that cerium ions are directly contacted with sulfonic acid functional groups in ion exchange resin to generate counter ion crosslinking can be avoided.

In the embodiment of the invention, the ligand comprises bridged polyphenol, tea polyphenol, tannin, tetrahydrofuran and curcumin, and can form a stable complex with cerium ions. The introduction of the cerium complex can enhance the radical resistance of the ion exchange complex. Cerium ions in the coordination center of the cerium complex can be used as a hydroxyl radical quencher, so that the chemical durability of the complex is remarkably improved; the ligand of the cerium complex also has hydroxyl radical quenching capability, and the ligand is synergistic with cerium ions in a coordination center to further enhance the radical quenching effect of the cerium complex. In the use process, cerium ions and ligands have good free radical quenching effect, and the chemical stability of the material is improved. Complexing of ligands such as tea polyphenol, tannin and the like mainly occurs on two adjacent phenolic hydroxyl groups in molecules, uncomplexed phenolic hydroxyl groups have free radical quenching capacity, and can also cooperate with cerium ions in a coordination center to further enhance the free radical quenching effect of the complex. The cerium complex can be well dispersed in a processing solvent of ion exchange resin, is easy to blend with the ion exchange resin and process and mold, is uniformly dispersed after molding, and has low mobility (loss rate) in the use process. Therefore, the cerium complex has the advantages of good processability, high and durable free radical quenching efficiency, good compatibility in ion exchange resin, low mobility and the like.

In some embodiments, from 90 to 99.99% (specifically, e.g., 90%,91%,92%,95%,97%,99%, 99.99%) of the ion exchange resin and from 0.01 to 10% (specifically, e.g., 0.01%,1%,3%,5%,8%,9%, 10%) of the cerium complex, in mass percent; preferably, the ion exchange resin comprises 97 to 99.99 percent of ion exchange resin and 0.01 to 3 percent of cerium complex in percentage by mass. In the embodiment of the invention, the content of the cerium complex is optimized, so that the effect on the electrical property of the complex can be slowed down and the efficient and durable free radical quenching effect can be realized by introducing the content of the free radical quencher as small as possible.

In some embodiments, the metal ion of the coordination center of the cerium complex comprises at least one of Ce ³⁺ or Ce ⁴⁺.

In some embodiments, the ligand comprises at least one of a bridged triphenol, a bridged diphenol, tetrahydrofuran, tea polyphenol, or tannin. In the embodiment of the invention, by further optimizing the ligand of the cerium complex, the complexing effect of the ligand on metal ions is enhanced, and more stable chelate or complex can be formed.

In a preferred embodiment, the structural formula of the bridged triphenols includes at least one of the following structural formulas:

wherein each R ₁～R₂₅ is independently selected from H, methyl, ethyl, n-propyl, isopropyl, n-butyl, or tert-butyl;

in a preferred embodiment, the bridged diphenol has a structural formula comprising at least one of the following structural formulas:

Wherein q is 0 or 1; r ₂₆～R₄₄ is each independently selected from H, methyl, ethyl, n-propyl, isopropyl, n-butyl or tert-butyl; r ₄₅、R₄₆ is each independently selected from H, methyl, n-butyl or tert-butyl; r ₄₇ is selected from methoxy, -N (CH ₃)₂、-N(CH₂CH₃)₂、-CH₂N(CH₃)₂ or-CH ₂N(CH₂CH₃)₂;

In a preferred embodiment, the tea polyphenols comprise at least one of epicatechin, epigallocatechin, epicatechin gallate, epigallocatechin gallate, gallocatechin, quercetin, rutin, gallic acid, caffeic acid, p-coumaric acid, anthocyanin, or anthocyanidin.

In a preferred embodiment, the tannin comprises at least one of Tannic Acid (TA) or myricetin (BT). Tannic acid belongs to hydrolyzed tannins, and myricetin belongs to condensed tannins.

In a more preferred embodiment, the ligand of the cerium complex includes at least one of bridged triphenols, bridged diphenols, tetrahydrofuran, tea polyphenols, tannins, and in particular, for example, the ligand of the cerium complex shown in table 1.

In some embodiments, the ligand of the cerium complex further comprises at least one of tris (2-aminoethyl) amine, chlorine, O, tetrahydrofuran.

In some embodiments, the cerium complex includes at least one of cerium complexes 1-9 in table 1:

TABLE 1

The organic compounds before and after formation of the complex are referred to as ligands and can be represented by H _x L or L in the coordination chemistry. The uncomplexed ligand is not dehydrogenated, for example, for ligand of complex 1, the formula is shown as H ₃L¹, after formation of the complex, the ligand is stripped of 3 hydrogen atoms and the ligand structure is L ¹.

Complexes 1 to 9 can be prepared by existing methods, in particular, for example:

Coordination center of complex 1 was Ce ³⁺ and complex was CeL ¹, prepared from Ce (CF ₃SO₃)₃ complex and bridged triphenol ligand H ₃L¹. Specific preparation was by adding appropriate amount of triethylamine to a hot solution of H ₃L¹ (157 mg,0.25mmo 1) and Ce (CF ₃SO₃)₃ (147 mg,0.25mmo 1) in methanol (25 ml,60 ℃), stirring the reaction mixture under Ar atmosphere for 30min, then cooling the solution, and recrystallising the filtered orange solid from acetonitrile under Ar atmosphere to give red complex 1 crystals.

The coordination center of the complex 2 is Ce ⁴⁺, the complex is CeL ² Cl, and the complex is prepared from CeCl ₃, 3, 5-di-tert-butyl salicylaldehyde and tri (2-aminoethyl) amine. The preparation method comprises the following steps: 0.709g (0.002 mol) CeCl ₃(H₂O)₆ was dissolved in 250mL methanol and 1.406g (0.006 mol) 3, 5-di-tert-butylsalicylaldehyde was added. After stirring the reaction mixture under reflux for 1 hour, 0.467g (0.0032 mol) of tris (2-aminoethyl) amine in 50mL of methanol was added dropwise, the solution was refluxed for 20 hours, the color of the solution changed from bright yellow to orange, red to dark brown, the reaction mixture was cooled to 5 ℃ without stirring, and the white precipitate was removed by filtration. After removal of the solvent under vacuum, a dark purple solid was obtained, which was dissolved in 50mL of acetonitrile at 70 ℃ and then filtered to remove undissolved residues. Crystallization at room temperature gives dark violet cube complex 2.

The coordination center of complex 3 was Ce ³⁺, the complex was CeL ³, and it was prepared from Ce (CF ₃SO₃)₃ and bridged triphenol ligand H ₃L³) by the same method as complex 1 except that the ligand was different.

The coordination center of the complex 4 is Ce ⁴⁺, and the complex is Ce ₂L⁴ ₂ O. The preparation method comprises the following steps: into an anhydrous and anaerobic reaction flask was weighed ammonium cerium nitrate (1.114 g,2.03 mmol), about 20mL of Tetrahydrofuran (THF) was added, and the mixture was stirred to give an orange clear solution. A solution of 0.5692mol/L sodium tert-butoxide in THF (21.4 mL,12.18 mmol) was injected and immediately changed to a yellow turbidity with an exotherm. Stirring for 24H at normal temperature under the condition of wrapping black cloth, centrifuging to remove white precipitate to obtain yellow clear liquid, and transferring the clear liquid into 0.703g (2.03 mmol) of weighed bridged triphenol ligand H ₃L⁴. After the solvent of the reaction solution is removed, a proper amount of toluene solvent is added, and the mixture is centrifuged, and the clear liquid is deeply frozen, so that columnar orange complex 4 crystals are separated out after 72 hours.

The coordination center of the complex 5 is Ce ⁴⁺ and the complex is CeL ⁵ ₂. The preparation method comprises the following steps: into an anhydrous and anaerobic reaction flask was weighed ammonium cerium nitrate (1.184 g,2.16 mmol), approximately 20ml of LTHF was added, and the orange clear solution was allowed to stir. A THF solution (12 mL,12.96 mmol) of sodium tert-butoxide at a concentration of 1.080mol/L was injected, and the reaction mixture immediately became a yellow turbid liquid, and an exothermic phenomenon was observed. Stirring for 24H at normal temperature under the condition of wrapping black cloth, centrifuging to remove white precipitate to obtain yellow clear liquid, transferring the clear liquid into 2.328g (4.32 mmol) of weighted bridged diphenol H ₂L⁵, and turning the color into dark brown black without obvious exothermic phenomenon. After stirring and reacting for 24 hours, the solvent is pumped down, about 20mL of ethylene glycol dimethyl ether is added, the mixture is centrifuged, the clear liquid is deep frozen, and black blocky complex 5 crystals appear after 72.

The coordination center of the complex 6 is Ce ⁴⁺ and the complex is CeL ⁶ ₂(THF)₂. The preparation method comprises the following steps: a reaction flask, free of water and oxygen, was charged with 40mL (4.0 mmol) of tris (cyclopentadienyl) cerium (III) in THF and 10mL (0.49 g,4.0 mmol) of bridged diphenol H ₂L⁶ in THF was added with constant stirring. Reacting for 24h at 50 ℃, and centrifuging to obtain yellow clear liquid. THF was removed, extracted with DME solution, centrifuged, and the supernatant concentrated until a small amount of powder precipitated and stopped. Heating to dissolve the powder, sealing the tube, and standing at room temperature. After 24h, crystals of complex 6 were precipitated.

The coordination center of the complex 7 is Ce ³⁺, and the complex is Ce ₂L⁷ ₂(THF)₄. The preparation method comprises the following steps: the bridged triphenol ligand H ₃L⁷ (0.96 g,1.5 mmol) is taken and dissolved in 20mL anhydrous THF, excessive metallic sodium with fresh surface is added, stirring reaction is carried out for 12H under the protection of argon, and white precipitate obtained after centrifugation is the intermediate product of carbon bridged tri (3, 5-di-tert-butylphenol sodium). The intermediate product is directly used for the next reaction without separation. The intermediate (2.5 g,2 mmol) was added to 50mL of a solution of CeCl ₃ (4 mmol) in THF under argon, the reaction flask was sealed and stirred at 70℃for 72h. Cooling, centrifuging, collecting supernatant, and precipitating complex 7 crystal at 0deg.C.

The coordination center of complex 8 is Ce ³⁺, the complex is CeL ⁸ ₃, and one coordination center is coordinated with 3 ligands. The preparation method comprises the following steps: 45mL of aqueous solution containing CeCl ₃ (1 mmol) and the same volume of aqueous solution of tea polyphenol ligand H ₂L⁸ (3 mmol) are mixed at room temperature, pH is adjusted to 6-7 by 5% sodium hydroxide, stirring is carried out for 6H to fully react, filtering is carried out, filter residues are washed by a small amount of distilled water for more than 3 times, and vacuum drying is carried out until no chlorine is detected, thus obtaining complex 8 solid powder.

The main component of the tea polyphenol ligand used for preparing the complex 8 is epigallocatechin gallate, which has 2 end groups containing 3 phenolic hydroxyl groups, and in the process of forming the complex, 2 adjacent phenolic hydroxyl groups in the 3 adjacent phenolic hydroxyl groups remove hydrogen and complex with cerium ions. As shown in formula (1), the end group A and the end group B can be complexed with cerium ions, and the ligand L ⁸ in the complex CeL ⁸ ₃ has 2 structures according to the difference of the complexed end groups, and L ⁸ is selected from at least one of the 2 structures.

The coordination center of complex 9 is Ce ³⁺, the complex is CeL ⁹ ₃, and one coordination center is coordinated with 3 ligands. The preparation method comprises the following steps: 25mL of tannic acid ligand H ₂L⁹ aqueous solution (24 mmol/L) is mixed with equal volume of Ce (NO ₃)₃ aqueous solution) with equal concentration, stirring is carried out for 6H at high speed, then the solution is centrifuged, supernatant is removed, the process is repeated for five times, and then the mixture is put into a vacuum drying oven for drying, thus obtaining complex 9 solid powder.

L ⁹ in the chemical structure of complex 9 depends on the chemical structure of the ligand tannic acid TA, which has 5 terminal groups containing 3 phenolic hydroxyl groups. As shown in formula (2), the end groups A, A ', B, B' and C can each be complexed with cerium ions. The ligand L ⁹ in the complex CeL ⁹ ₃ has 5 structures according to the difference of the complexing end groups, and L ⁹ is selected from at least one of the 5 structures.

In the embodiment of the invention, the kind of cerium complex is further optimized, which is favorable for enhancing the complexing of metal ions, and in some ligands such as tea polyphenol and tannin, the complexing mainly occurs on two adjacent phenolic hydroxyl groups of polyphenol molecules, and the number and the position of the phenolic hydroxyl groups also influence the complexing effect.

In some embodiments, the ion exchange resin comprises at least one of perfluorosulfonic acid resin, perfluorosulfonimide resin, polyacid side chain type perfluororesin, sulfonated polytrifluorostyrene, sulfonated polysulfone, sulfonated polyethersulfone, sulfonated polyetheretherketone, sulfonated polyaryletherketone, sulfonated polyarylethernitrile, sulfonated polyphosphazene, sulfonated polyphenylene ether, sulfonated polyphenylnitrile, sulfonated polyimide, or sulfonated polybenzimidazole; preferably, the resin composition comprises at least one of perfluorinated sulfonic acid resin, perfluorinated sulfimide resin, polyacid side chain type perfluorinated resin, sulfonated polytrifluorostyrene, sulfonated polyether ether ketone, sulfonated polyarylether ketone and sulfonated polyarylether nitrile; more preferably, at least one of perfluorosulfonic acid resin, perfluorosulfonimide resin, polyacid side chain type perfluororesin, sulfonated polytrifluorostyrene is included.

In some embodiments, the perfluorinated sulfonic acid resin includes at least one of an acid type perfluorinated sulfonic acid resin, an alkali metal type perfluorinated sulfonic acid resin, or other cationic perfluorinated sulfonic acid resin according to the difference of cations, wherein the acid type perfluorinated sulfonic acid resin has a structural formula of:

Wherein m=0 to 6 and n=2 to 5; x determines the ion exchange Equivalent (EW) of the acid form of the perfluorosulfonic acid resin, and y determines the molecular weight of the acid form of the perfluorosulfonic acid resin;

The structural general formula of the alkali metal type perfluorinated sulfonic acid resin or other cationic perfluorinated sulfonic acid resins is as follows:

wherein m=0 to 6, n=2 to 5, and m is at least one selected from lithium, sodium, potassium, rubidium, cesium and other cations; x determines the EW of the resin and y determines the molecular weight of the resin;

And/or, depending on the cation, the perfluorosulfonimide resin includes at least one of an acid type perfluorosulfonimide resin, an alkali metal type perfluorosulfonimide resin, or other cationic perfluorosulfonimide resin;

the structural general formula of the perfluorinated sulfonyl imide resin is as follows:

Wherein m=0 to 6, n=2 to 5, p=0 to 5, and m' is at least one selected from hydrogen, lithium, sodium, potassium, rubidium, cesium and other cations; x 'determines the EW of the perfluorosulfonimide resin and y' determines the molecular weight of the perfluorosulfonimide resin;

and/or, depending on the cation, the polyacid side-chain type perfluorinated resin includes at least one of acid type polyacid side-chain type perfluorinated resin, alkali metal type polyacid side-chain type perfluorinated resin, or other cationic type polyacid side-chain type perfluorinated resin;

the polyacid side chain type perfluorinated resin has a structural general formula:

Wherein m=0 to 6, n=2 to 5, p=0 to 5, and m' is at least one selected from hydrogen, lithium, sodium, potassium, rubidium, cesium, and other cations; x 'determines the EW of the polyacid side-chain type perfluorinated resin, and y' determines the molecular weight of the polyacid side-chain type perfluorinated resin;

And/or, the sulfonated polytrifluorostyrene has a structural general formula:

Wherein M '"is selected from at least one of hydrogen, lithium, sodium, potassium, rubidium, cesium or other cations, X ₁ is selected from at least one of H, F or CF ₃, and X'", y '"and z'" determine the molecular weight and EW of the sulfonated polytrifluorostyrene;

wherein the other cations include at least one of ammonium ion, alkaline earth metal ion, iron ion, vanadium ion, titanium ion, cobalt ion, chromium ion, nickel ion, copper ion, aluminum ion, silver ion, zinc ion, manganese ion, and tin ion.

The ion exchange membrane comprises the ion exchange compound disclosed by the embodiment of the invention.

In some embodiments, the ion exchange membrane comprises 90 to 99.99% (specifically, for example, 90%,91%,92%,95%,97%,99%, 99.99%) ion exchange resin and 0.01 to 10% (specifically, for example, 0.01%,1%,3%,5%,8%,9%, 10%) cerium complex, preferably, 97 to 99.99% ion exchange resin and 0.01 to 3% cerium complex, in mass percent. In the embodiment of the invention, the content of the cerium complex is optimized, so that the capability of resisting free radicals of the ion exchange membrane can be improved, the increase of turbidity of the ion exchange membrane caused by introducing excessive additives can be reduced, the influence on the electrical performance of the ion exchange membrane can be reduced, and the efficient and durable free radical quenching effect can be realized.

In some embodiments, the ion exchange membrane has a film thickness of 3 to 500 μm, specifically, for example, 3 μm,4 μm,5 μm,100 μm,160 μm,200 μm,300 μm,320 μm,500 μm, preferably, 4 to 320 μm, more preferably, 5 to 160 μm; and/or the ion exchange capacity of the ion exchange membrane is 0.1 to 4.2mmol/g, specifically, for example, 0.1mmol/g,0.15mmol/g,0.2mmol/g,1mmol/g,2mmol/g,2.5mmol/g,3mmol/g,4mmol/g,4.2mmol/g, preferably, 0.15 to 3.0mmol/g, more preferably, 0.2 to 2.5mmol/g.

In some embodiments, the ion exchange membrane further comprises a reinforcing membrane; preferably, the reinforcing membrane is a porous membrane; preferably, the material of the reinforced film comprises at least one of a non-fluorinated polyolefin, a fluoropolymer, or an aromatic polymer;

Further preferably, the non-fluorinated polyolefin comprises at least one of polyethylene, polypropylene or ethylene-propylene copolymer; the fluorine-containing polymer comprises at least one of polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-propylene copolymer, ethylene-tetrafluoroethylene copolymer, tetrafluoroethylene-hexafluoropropylene-ethylene copolymer, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer, polyvinyl fluoride, polychlorotrifluoroethylene or ethylene-chlorotrifluoroethylene copolymer; the aromatic polymer membrane comprises at least one of polyaryletherketone, polysulfone, polyethersulfone ketone, polybenzimidazole, polyaramid, polyimide or polyetheretherketone.

In some embodiments, the mass of the enhancement film is 0.1-90% of the mass of the ion exchange film, specifically, for example, 0.1%,1%,3%,10%,30%,50%,70%,90%, further preferably, 1-70%, more preferably, 3-50%; preferably, the thickness of the reinforcement film is 2 to 400 μm, specifically, for example, 2 μm,50 μm,100 μm,180 μm,200 μm,300 μm,400 μm, further preferably 2 to 300 μm, more preferably 2 to 180 μm.

The preparation method of the ion exchange membrane provided by the embodiment of the invention comprises the following steps:

In some embodiments, in step (1), the solvent comprises at least one of water, a high boiling point organic solvent, tetrahydrofuran, a lower aliphatic alcohol; the high boiling point organic solvent comprises at least one of ethylene glycol, propylene glycol, glycerol, DMF, DMAC, DMSO, hexamethylphosphoric triamide and NMP, and the lower aliphatic alcohol comprises at least one of methanol, ethanol, isopropanol and n-propanol.

In some embodiments, in step (1), the mass ratio of the ion exchange resin to the solvent is 1:1.5 to 19, specifically, for example, 1:1.5,1:3,1:5,1:8,1:10,1:15,1:19.

In some embodiments, in step (1), the dispersing temperature is 10 to 240 ℃, specifically, for example, 10 ℃,30 ℃,50 ℃,100 ℃,240 ℃; the pressure of the dispersion is from normal pressure to 20MPa, specifically, for example, normal pressure, 0.5MPa,1MPa,5MPa,10MPa,20MPa; the dispersion time is 0.1 to 24 hours, specifically, for example, 0.1 hours, 1 hour, 6 hours, 12 hours, 24 hours; the dispersing may be performed by at least one of stirring, shaking or ultrasonic.

In some embodiments, in step (2), the shaping comprises at least one of casting, or coating;

And/or, in the step (2), the drying temperature is 20 to 180 ℃, specifically, for example, 20 ℃,30 ℃,50 ℃,100 ℃,180 ℃;

And/or, in the step (2), a reinforcing film is further included, the dispersion liquid is coated on one side or two sides of the reinforcing film, and the ion exchange film is obtained after drying; the coating includes at least one of dipping, knife coating, slot coating.

The application of the ion exchange compound or the ion exchange membrane in the embodiment of the invention is used for at least one of chlor-alkali industry, water electrolysis, batteries, supercapacitors, electrodialysis, sensors, desalination membranes, ultrafiltration membranes, microfiltration membranes, coatings, hydrogels, adhesives, fabrics and protective equipment. In the embodiment of the present invention, all advantages of the ion exchange composite or the ion exchange membrane are provided, and detailed description thereof is omitted.

In some embodiments, the ion exchange composites are used in at least one of chlor-alkali industry, water electrolysis, batteries, supercapacitors, electrodialysis, sensors, desalination membranes, ultrafiltration membranes, microfiltration membranes, coatings, hydrogels, adhesives, fabrics, protective equipment, preferably in at least one of fuel cell proton exchange membranes, flow battery membranes, polyelectrolyte membranes for chlor-alkali industry, proton exchange membranes for hydrogen production by water electrolysis, acid primary battery membranes, lithium battery membranes, polyelectrolytes in supercapacitors, polyelectrolyte membranes for electrodialysis.

In some embodiments, the ion exchange membrane is used in at least one of the chlor-alkali industry, water electrolysis, batteries, supercapacitors, electrodialysis, sensors, desalination membranes, ultrafiltration membranes, microfiltration membranes, preferably in fuel cell proton exchange membranes, flow cell membranes, polyelectrolyte membranes for chlor-alkali industry, proton exchange membranes for hydrogen production by water electrolysis, acid primary cell membranes, lithium cell membranes, polyelectrolytes in supercapacitors, polyelectrolyte membranes for electrodialysis.

The invention will now be described with reference to specific examples, which are intended to be illustrative only and not limiting in any way.

The cerium salt, the cerium complex and the organic ligand used in the embodiment of the invention are derived from chemical reagent suppliers such as Allatin and Michelin reagents; the perfluorosulfonic acid resin is derived from komu, 3M and sorrow; polyacid side chain type perfluorinated resins are derived from 3M; the perfluorinated sulfonimide resin and the porous polytetrafluoroethylene membrane (ePTFE) are self-made, and other solvents are common chemical reagents.

The perfluorinated sulfonyl imide resin is prepared by free radical copolymerization of perfluorinated sulfonyl imide vinyl ether monomer and tetrafluoroethylene monomer:

The preparation method comprises the steps of continuously copolymerizing perfluoro-sulfonyl imide vinyl ether monomer and tetrafluoroethylene monomer (TFE) in Na ₂HPO₄/NaH₂PO₄ buffer solution by using (NH ₄)₂S₂O₈/NaHSO₃ as an initiator, firstly, fully dissolving Na ₂HPO₄·7H₂ O and NaH ₂PO₄ in de-aerated deionized water (an appropriate amount of surfactant can be added) to prepare solution 1, then, adding the perfluoro-sulfonyl imide vinyl ether monomer 1 into the solution 1, continuously introducing nitrogen to cool the solution to 8 ℃, vacuumizing an autoclave, adding the initiator into the solution 1 after 3 times of purging with nitrogen in 5 minutes to prepare solution 2, adding the solution 2 into a metering pump storage, and degassing with helium for more than 20 minutes, sucking the solution 2 into a fully vacuumized autoclave, adding an appropriate amount of de-aerated deionized water to enable the volume of the solution to be half of that of a reactor, when the temperature of the reactor reaches 10 ℃, adding TFE to 150psi and starting a continuous adding pump to enable the pressure to be kept between 145 psi and 150psi in the whole process, finally, acidifying with 70% hydrochloric acid to obtain a precipitated polymer, washing the polymer to be in water, and drying the perfluoro-imide resin in a total vacuum state for more than 12 hours under the condition of water.

Porous polytetrafluoroethylene film (e-PTFE-1) was prepared by a common biaxially stretching method: (1) 75 parts of PTFE powder (Cormu 605 XTX) and 25 parts of auxiliary oil (aviation kerosene) are mixed and stirred uniformly, and then cured, shaped and extruded for calendering to prepare a calendering belt containing the auxiliary oil; (2) Drying the calendaring belt to obtain a degreasing film, stretching the degreasing film in the MD direction, stretching the degreasing film in the TD direction, and performing heat setting to obtain the porous polytetrafluoroethylene film. The MD stretch ratio was 8 times and the TD stretch ratio was 30 times. Wherein the direction of the mechanical force is MD, and the direction transverse to the mechanical force is TD. The e-PTFE-1 had a thickness of 3.+ -. 1.5. Mu.m, a porosity of 78.1% and an average pore diameter of 278nm.

The porous polytetrafluoroethylene membrane (ePTFE-2) was prepared in substantially the same manner as ePTFE-1, except that: the MD stretch ratio was 7 times and the TD stretch ratio was 22 times. The e-PTFE-2 had a thickness of 7.+ -. 2. Mu.m, a porosity of 71.7% and an average pore diameter of 252nm.

The porous polytetrafluoroethylene membrane (ePTFE-3) was prepared in substantially the same manner as ePTFE-1, except that: the MD stretch ratio was 5.5 times and the TD stretch ratio was 20 times. The e-PTFE-3 had a thickness of 12.+ -. 2. Mu.m, a porosity of 72.8% and an average pore diameter of 261nm.

The test methods of conductivity, EW, IEC, water absorption and mechanical properties are described in section 3 of proton exchange membrane fuel cell: proton exchange membrane test methods. Wherein the conductivity is measured at 80℃and 95% relative humidity.

Fuel cell polarization curve: test methods refer to GB/T20042.5-2022 section 5 of proton exchange Membrane Fuel cell: membrane electrode test methods.

Radical resistance of ion exchange membranes: the ion exchange membrane was immersed in Fenton (Fenton) reagent at 80℃for 8 hours, and mass loss and conductivity decay before and after immersion were compared. Preparation of Fenton reagent: and (3) dropwise adding 0.1mL of Fe ²⁺ solution with the mass concentration of 0.01mol/L into 50mL of H ₂O₂ solution with the mass fraction of 3%, thus obtaining the Fenton reagent which is prepared as the current use. The smaller the percent mass loss, the better the durability. The smaller the conductivity decay of the ion exchange membrane after Fenton reagent treatment is, the better the free radical resistance is.

Example 1

Preparation of ion exchange membrane:

50mg of each of complex 1, complex 2 and complex 3 (diluted in 0.5mL of tetrahydrofuran) was weighed and added to 200g of a D520 resin dispersion (Kemu, perfluorosulfonic acid resin mass content 5%, EW 980g/mol, solvent water, ethanol and n-propanol mixed solvent) respectively. Stirring and mixing at room temperature for 24 hours, scraping on a release film by a scraper, drying at 80 ℃ for 1 hour, and heat treating at 150 ℃ for 15 minutes to obtain ion exchange films with the thickness of 50+/-3 mu m, namely PEM-1, PEM-2 and PEM-3.

The chemical structure of the perfluorosulfonic acid resin in the D520 resin dispersion liquid is as follows:

Example 2

Preparation of ion exchange membrane:

3g of 3M800 resin (3M Co., EW: 800 g/mol) was weighed and dissolved in 12mL of DMSO at 80℃with stirring, 0.3mg, 30mg and 90mg of complex 4 (complex 4 diluted in 3mL of DMSO) were added, respectively, and dispersed by sonication for 10min to obtain a dispersion. The dispersion was cast into an ultra-flat petri dish and dried at 180℃for 6 hours to give ion exchange membranes of 150.+ -.5 μm thickness, PEM-4, PEM-5, PEM-6 respectively.

The chemical structure of the 3M800 resin is:

Example 3

Preparation of ion exchange membrane:

90mg of complex 9 was weighed and dissolved in 5g of water, and the aqueous solution of complex 9 was added to 50g of D72 resin dispersion (Sorvy, perfluorosulfonic acid resin mass content 40%, EW 720g/mol, solvent water). Stirring and mixing for 24 hours at room temperature, scraping on a release film by a scraper, drying for 1 hour at 80 ℃, and heat treating for 15 minutes at 150 ℃ to obtain the ion exchange film PEM-7 with the thickness of 25+/-3 mu m.

The chemical structure of the perfluorosulfonic acid resin in the D72 resin dispersion liquid is as follows:

Example 4

The same procedure as in example 3 was followed except that 90mg of complex 5 was added to give an ion exchange membrane PEM-8 having a thickness of 25.+ -.3. Mu.m.

Example 5

Preparation of ion exchange membrane:

10g of the 3M800 resin of example 2 was weighed out, dissolved in 40g of a mixed solvent of tetrahydrofuran and DMSO (tetrahydrofuran to DMSO mass ratio 3:2) with stirring at room temperature, 360mg of complex 6 was added, and dissolved with stirring for 1h. The ion exchange membrane C-PEM-1 with the thickness of 5+/-1.5 mu m is prepared by taking a release membrane as a substrate, utilizing a scraper to scrape and coat two sides of the e-PTFE-1, drying for 15min at 100 ℃ and carrying out heat treatment for 5min at 150 ℃.

Example 6

The same procedure as in example 5 was followed except that complex 7 was used as the starting material and a release film was applied to both sides of e-PTFE-3 by doctor blade to obtain an ion exchange membrane C-PEM-2 having a thickness of 25.+ -. 2. Mu.m.

Example 7

Preparation of ion exchange membrane:

10g of ion exchange resin solid is weighed, and dissolved and dispersed in a hydroalcoholic mixed solvent (water, ethanol, n-propanol, isopropanol and n-butanol with the mass ratio of 2:1:1:1:1) at 60 ℃ to obtain resin dispersion liquid. Adding 50mg of complex 8 into the resin dispersion liquid, uniformly dispersing by ultrasonic for 15min, coating on two sides of an e-PTFE-2 membrane by a slit, drying for 3min at 90 ℃, and performing heat treatment for 10min at 180 ℃ to obtain different ion exchange membranes with the thickness of 15+/-2 mu M, wherein the ion exchange membranes are C-PEM-3, C-PEM-4, C-PEM-5 and C-PEM-6 respectively, and the ion exchange resin solids of the ion exchange membranes are 3M800, BAM3G, perfluorinated sulfonimide resin or PFIA respectively;

3M800 is the same as in example 2;

BAM3G is sulfonated polytrifluorostyrene resin from Barad with EW value of 407G/mol and structural formula:

Wherein X ₁ is F or CF ₃, and the proportion of 2 substituents is not determined;

the EW value of the perfluorinated sulfimide resin is 1200g/mol, and the structural formula is as follows:

PFIA is polyacid side chain type perfluorinated resin, from 3M, with EW value of 625g/mol, and structural formula:

Comparative example 1

The same procedure as in example 1 was followed except that the complex was not added to the dispersion to obtain an ion exchange membrane D-PEM-1 having a thickness of 50.+ -. 3. Mu.m.

Comparative example 2

The same procedure as in example 2 was followed except that the complex was not added to the dispersion to obtain an ion exchange membrane D-PEM-4 having a thickness of 150.+ -. 5. Mu.m.

Comparative example 3

The same procedure as in example 3 was followed except that the complex was not added to the dispersion to obtain an ion exchange membrane D-PEM-7 having a thickness of 25.+ -.3. Mu.m.

Comparative example 4

The same procedure as in example 5 was followed except that the complex was not added to the dispersion to prepare an ion exchange membrane D-C-PEM-1.

Comparative example 5

The same procedure as in example 6 was followed except that the complex was not added to the dispersion to prepare an ion exchange membrane D-C-PEM-2.

Comparative example 6

The same procedure as in example 7 was followed except that 50mg of nano cerium oxide (CeO ₂) was added to the dispersion without adding the complex, and ion exchange membranes D-C-PEM-3, D-C-PEM-4, D-C-PEM-5 and D-C-PEM-6 were prepared using ion exchange resins BAM3G, perfluorosulfonimide resin, PFIA and 3M800, respectively.

Comparative example 7

The same procedure as in example 3 was followed except that 90mg of complex 9 was replaced with 90mg of tannic acid to give an ion exchange membrane D-PEM-8 having a thickness of 25.+ -.3. Mu.m.

The ion exchange membranes prepared in example 1 and comparative example 1 were subjected to Fenton reagent treatment, and the mass loss after the treatment is shown in Table 2.

TABLE 2

As can be seen from the data of table 2, the mass loss of the ion exchange membrane is significantly reduced and the radical durability of the ion exchange membrane is significantly improved after doping the cerium complex, as compared to comparative example 1; the better radical durability enables better safety and reliability in long-term operation. The coordination center of the complex 2 is tetravalent cerium ion, the complex reacts with hydrogen peroxide to generate trivalent cerium ion, then reacts with free radicals to quench the free radicals, and compared with an ion exchange membrane prepared from the complex 1 and the complex 3 containing trivalent cerium ion as the coordination center, the mass loss of PEM-2 Fenton treatment is slightly higher than that of PEM-1 and PEM-3.

The ion exchange membranes of different amounts of added ion exchange membranes prepared in example 2 and comparative example 2 were tested for mass loss after IEC and Fenton reagent treatment, and the results are shown in Table 3.

TABLE 3 Table 3

As can be seen from the data of table 3, the IEC of the ion exchange membrane was less changed and the radical durability was improved after doping a small amount of cerium complex, as compared with comparative example 2; even an ion exchange membrane PEM-4 with a mass content of about 0.01% of complex 4 has a significantly reduced mass loss compared to D-PEM-4.

The ion exchange membranes prepared in example 3, example 4, comparative example 3 and comparative example 7 were treated with Fenton reagent, and the mass loss after the treatment is shown in Table 4.

TABLE 4 Table 4

	Ion exchange membrane	Coordination polymers	Loss of mass (%)
				Example 3	PEM-7	Complex 9	2.52
Example 4	PEM-8	Complex 5	2.61
				Comparative example 3	D-PEM-7	Without any means for	7.94
Comparative example 7	D-PEM-8	Ligand: tannic acid	5.31

As can be seen from the data in table 4, compared with comparative example 3, after the ion exchange membrane is doped with the water-soluble complex 5 and the complex 9, the mass loss is obviously reduced after the ion exchange membrane is treated by the Fenton reagent, the free radical resistance is obviously improved, the water-solubility of the complex 9 is convenient for the direct mixing with the aqueous solution of the ion exchange resin, the complex 9 has the advantage of good mixing uniformity, and the complex 9 has a large amount of phenolic hydroxyl groups, has extremely high free radical quenching inactivation, and the PEM-7 has lower mass loss.

The thicknesses of the ion exchange membranes and the mass loss after Fenton reagent treatment in examples 5 to 6 and comparative examples 4 to 5 were tested and are shown in Table 5.

TABLE 5

	Ion exchange membrane	Thickness (μm)	Loss of mass (%)
				Example 5	C-PEM-1	5±1.5	1.43
Example 6	C-PEM-2	25±2	0.91
				Comparative example 4	D-C-PEM-1	5±1.5	3.92
Comparative example 5	D-C-PEM-2	25±2	2.57

As can be seen from the data of table 5, the ion exchange membranes of the doped cerium complexes prepared in examples 5 to 6 have significantly reduced mass loss and significantly improved free radical resistance, as compared to the ion exchange membranes of comparative examples 4 to 5, which are not doped with cerium complexes. The enhancement layer is of a polytetrafluoroethylene structure, is not easy to attack by free radicals, and as the thickness of the enhancement layer is increased, the film thickness is increased, the mass ratio of the ion exchange resin layer which is easy to attack by the free radicals is reduced, and the mass loss after Fenton is reduced.

The ion exchange membranes of example 7 and comparative example 6 were tested for IEC, water absorption, and mass loss after Fenton reagent treatment, as shown in table 6, and for tensile strength, elongation at break, and conductivity before and after Fenton reagent treatment, as shown in table 7.

TABLE 6

TABLE 7

As can be seen from the data in table 6, the ion exchange membrane doped with complex 8 has higher IEC, water absorption and less mass loss when the ion exchange resin is the same as the ion exchange membrane doped with cerium oxide. This is because cerium oxide is converted into cerium ions under acidic conditions of the ion exchange membrane to crosslink with sulfonic acid, resulting in a decrease in IEC and water absorption, while the hydrophilic ligand of complex 8 can increase water absorption. Compared with cerium oxide, the complex 8 has the advantages that cerium ions have a free radical quenching effect, phenolic hydroxyl radical in the ligand has stronger quenching and inactivating property, so that the ion exchange membrane shows less mass loss and better durability.

As can be seen from the data in table 7, the ion exchange membrane composed of the ion exchange resin, the reinforcing layer and the complex 8 has good mechanical properties and electrical conductivity, and can be applied to the proton exchange membrane of the fuel cell. After Fenton reagent treatment, the ion exchange membrane containing the complex 8 has low conductivity reduction degree and better durability. This is because the cerium complex has good dispersion uniformity, which is advantageous for improving tensile strength; the cerium oxide particles are easy to agglomerate and doped into the ion exchange membrane, and the uniformity of the membrane is affected, so that the tensile strength is reduced. The cerium complex can avoid conductivity reduction caused by counter ion crosslinking when cerium ions are in direct contact with sulfonic acid functional groups in the ion exchange resin. C-PEM-3 has higher tensile strength, elongation at break and electrical conductivity than D-C-PEM-6 doped with cerium oxide.

SEM scans of sections of the C-PEM-3 obtained in example 7 before and after the Fenton reagent treatment were carried out, and the results are shown in FIGS. 1 and 2. SEM scans of sections of the D-C-PEM-6 obtained in comparative example 6 before and after the Fenton reagent treatment were carried out, and the results are shown in FIGS. 3 and 4. Compared with D-C-PEM-6, the morphology of the C-PEM-3 is less changed after Fenton reagent treatment, and the membrane surface ion exchange resin layer is relatively flat. After the treatment of the Fenton reagent, the ion exchange resin layer of the D-C-PEM-6 becomes uneven, has cracking defects and is greatly influenced by the attack of hydroxyl radicals.

Cell performance tests were performed on C-PEM-5 and D-C-PEM-4 before and after Fenton reagent treatment and the results are shown in FIG. 5. The performance of the single cell of the fuel cell engine of the C-PEM-5 before and after Fenton reagent treatment is better than that of the D-C-PEM-4. The introduction of the complex 8 not only improves the durability of the ion exchange membrane, but also has less influence on the electrochemical performance, and the comprehensive performance is obviously improved.

Transmission Electron Microscopy (TEM) tests were performed on the C-PEM-3 prepared in example 7 and the D-C-PEM-6 prepared in comparative example 6, as shown in FIGS. 6 and 7, respectively. Compared with D-C-PEM-6, the existence of the organic ligand in the cerium polymer in the C-PEM-3 can overcome the problem of uneven dispersion of cerium-based metal salt and metal oxide in the ion exchange resin, so that cerium element has good dispersibility in the ion exchange resin.

For purposes of this disclosure, the terms "one embodiment," "some embodiments," "example," "a particular example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

While the above embodiments have been shown and described, it should be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives, and variations of the above embodiments may be made by those of ordinary skill in the art without departing from the scope of the invention.

Claims

1. An ion exchange composite, comprising: an ion exchange resin and a cerium complex, wherein the cerium complex comprises a metal ion of a coordination center comprising cerium ions and a ligand comprising at least one of bridged polyphenols, tea polyphenols, tannins, tetrahydrofuran, or curcumin.

2. The ion exchange composite according to claim 1, comprising 90 to 99.99% of the ion exchange resin and 0.01 to 10% of the cerium complex, in mass%.

3. The ion exchange composite of claim 1, wherein the bridged polyphenol comprises at least one of a bridged triphenol, a bridged diphenol.

4. The ion exchange composite of claim 1, wherein the metal ion of the coordination center of the cerium complex comprises at least one of Ce ³⁺ or Ce ⁴⁺;

5. An ion exchange membrane comprising the ion exchange composite of any one of claims 1-4.

6. The ion exchange membrane according to claim 5, wherein the ion exchange membrane comprises 90 to 99.99% of ion exchange resin and 0.01 to 10% of cerium complex by mass percent;

And/or the film thickness of the ion exchange film is 3-500 μm;

and/or the ion exchange membrane further comprises a reinforcing membrane.

7. The ion exchange membrane of claim 6, wherein the material of the reinforcement membrane comprises at least one of a non-fluorinated polyolefin, a fluoropolymer, or an aromatic polymer;

And/or the thickness of the reinforced film is 2-400 μm.

8. A method for preparing an ion exchange membrane according to any one of claims 5 to 7, comprising the steps of:

9. The method of producing an ion exchange membrane according to claim 8, wherein in the step (2), the molding includes at least one of casting, or coating;

And/or, in the step (2), the drying temperature is 20-180 ℃;

10. Use of the ion exchange composite according to any one of claims 1 to 4, or the ion exchange membrane according to any one of claims 5 to 7, in at least one of chlor-alkali industry, water electrolysis, batteries, supercapacitors, electrodialysis, sensors, desalination membranes, ultrafiltration membranes, microfiltration membranes, coatings, hydrogels, adhesives, fabrics, protective gear.