Modified nano cerium oxide as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of fuel cells, and particularly relates to modified nano cerium oxide as well as a preparation method and application thereof. The modified nano cerium oxide comprises nano cerium oxide and a conductive material layer coating the nano cerium oxide. The modified nano cerium oxide has the beneficial effects that the antioxidant nano cerium oxide in the modified nano cerium oxide is wrapped by the conductive material, so that when the proton exchange membrane slurry is prepared, the nano cerium oxide can be uniformly distributed in the proton exchange membrane slurry, and the content of the nano cerium oxide can be accurately controlled; free radicals produced at all positions in the proton exchange membrane can be consumed more effectively, oxidative degradation of the free radicals to sulfonic acid groups and fluorocarbon main chains in the proton membrane is reduced, and the problems that the proton exchange membrane becomes thin and perforated or the proton conductivity is reduced are solved. Meanwhile, the water storage capacity of the nano cerium oxide can relieve embrittlement and cracks caused by dehydration of the membrane, and the service life of the proton exchange membrane under extreme working conditions is prolonged.

Description

Technical Field

[0001] The present application belongs to the field of fuel cell technology, and specifically relates to a modified nano-cerium oxide and its preparation method and application. Background Art

[0002] During the operation of the fuel cell, the electrode reaction will produce intermediate products such as hydrogen peroxide, which will further decompose to produce strong oxidizing free radicals such as hydroxyl radicals. The polymer chains in the proton exchange membrane are easily attacked by these free radicals, resulting in chemical bond breakage and degradation reactions, thereby reducing the durability of the membrane. However, the durability of the proton exchange membrane has a vital impact on downstream products such as fuel cell vehicles, stationary fuel cell power generation systems, and portable fuel cells, such as the cruising range, maintenance costs, and safety performance of fuel cell vehicles. For the automotive field, the life of the proton exchange membrane is generally required to be greater than 5,000 hours. Common methods to improve durability include: adding free radical scavengers (such as cerium dioxide, doped perovskite free radical quenchers, etc.), optimizing membrane structure design (ePTFE reinforcement layer, etc.), surface treatment of perfluorosulfonic acid resin membranes or adding functional additives, optimizing fuel cell operating conditions, etc.

[0003] Prior art proposes a method for preparing an antioxidant proton exchange membrane. This involves dispersing cerium oxide nanoparticles in an ammonium persulfate hydrochloric acid solution, mixing it with an aniline hydrochloric acid solution, and then adding the mixture to both sides of a sulfonated poly(biphenyl indole) proton exchange membrane. The membrane is then placed in a refrigerator to allow in situ growth of a conductive polyaniline doped with cerium oxide on the membrane surface. The conductive polymer layer and the cerium oxide nanoparticles, a free radical scavenger, effectively enhance the membrane's antioxidant properties without compromising conductivity. However, this method, in which the cerium oxide-polyaniline antioxidant layer is grown on the membrane surface, makes it difficult to ensure the thickness and uniformity of the in situ growth. Furthermore, the lack of a free radical scavenger within the membrane makes it difficult to effectively scavenge free radicals. Furthermore, this in situ growth method is difficult to commercialize and mass-produce. Prior art also proposes surface modification of nano-cerium dioxide using acetic acid and then sodium dodecylbenzenesulfonate, modification of polyethylene glycol by the addition of cyclodextrin, modification of agarose by grafting carboxyl and amino groups, and modification of agarose by the addition of nano-activated carbon fibers. Finally, the modified nano-cerium oxide, polyethylene glycol, agarose, nano-titanium dioxide and water are mixed in a certain proportion to obtain a dispersion, and the polytetrafluoroethylene fiber membrane pretreated with bacterial cellulose fermentation liquid is repeatedly dipped in the mixed dispersion, and the modified microporous membrane is obtained after drying. Because the raw materials used in the above technical scheme need to undergo relatively complex modification or pretreatment, it is difficult to achieve large-scale production in terms of process. Moreover, the thickness of the film is difficult to accurately control by repeated dipping during the film formation process, and the content of the loaded antioxidant nano-cerium oxide is difficult to control, so the uniformity of product performance is difficult to guarantee. Summary of the Invention

[0004] The present application provides a modified nano-cerium oxide and a preparation method and application thereof.

[0005] In a first aspect, the present application provides a modified nano-cerium oxide, comprising nano-cerium oxide and a conductive material layer coating the nano-cerium oxide.

[0006] According to some embodiments of the modified nano-cerium oxide described in the present application, the particle size of the nano-cerium oxide is 2-15 nm.

[0007] According to some embodiments of the modified nano-cerium oxide described in this application, the specific surface area of ​​the nano-cerium oxide is 420-50m 2 / g.

[0008] According to some embodiments of the modified nano-cerium oxide described in the present application, the conductive material layer includes a conductive material and a surfactant.

[0009] According to some embodiments of the modified nano-cerium oxide described in the present application, the conductive material includes polyaniline.

[0010] According to some embodiments of the modified nano-cerium oxide described in the present application, the surfactant includes a nonionic surfactant.

[0011] According to some embodiments of the modified nano-cerium oxide described in the present application, the nonionic surfactant includes one or more of Tween 80, Tween 20, octylphenol polyoxyethylene ether-10, polyvinyl pyrrolidone and Triton X100.

[0012] According to some embodiments of the modified nano-cerium oxide described in the present application, the mass ratio of the nano-cerium oxide to the polyaniline is 1:(3-10).

[0013] According to some embodiments of the modified nano-cerium oxide described in the present application, the mass ratio of the nano-cerium oxide to the surfactant is (1-10):1.

[0014] According to some embodiments of the modified nano-cerium oxide described in the present application, the particle size of the modified nano-cerium oxide is 100-500 nm.

[0015] The second aspect of the present application provides a method for preparing the modified nano-cerium oxide described in the first aspect of the present application, comprising the following steps:

[0016] (1) mixing nano-cerium oxide, a conductive material, and a benign solvent to obtain a first mixed solution;

[0017] (2) mixing the surfactant and the non-benign solvent to obtain a second mixed solution;

[0018] (3) contacting the first mixed solution with the second mixed solution to obtain the modified nano-cerium oxide.

[0019] According to some embodiments of the method for preparing modified nano-cerium oxide described in the present application, in step (1), the benign solvent includes one or more of dimethyl sulfoxide, acetone and tetrahydrofuran.

[0020] According to some embodiments of the method for preparing modified nano-cerium oxide described in the present application, the solid content of the first mixed solution is 30%-75%.

[0021] According to some embodiments of the method for preparing modified nano-cerium oxide described in the present application, the mass ratio of nano-cerium oxide to conductive material in the first mixed solution is 1:(3-10).

[0022] According to some embodiments of the method for preparing modified nano-cerium oxide described in the present application, in step (2), the non-benign solvent includes water and / or ethanol.

[0023] According to some embodiments of the method for preparing modified nano-cerium oxide described in the present application, the non-benign solvent includes water and ethanol.

[0024] According to some embodiments of the method for preparing modified nano-cerium oxide described in the present application, the non-benign solvent includes water and ethanol in a volume ratio of (1-6):3.

[0025] According to some embodiments of the method for preparing modified nano-cerium oxide described in the present application, the solid content of the second mixed solution is 0.1%-1%.

[0026] According to some embodiments of the method for preparing modified nano-cerium oxide described in the present application, in step (3), the volume ratio of the first mixed liquid to the second mixed liquid is 1:(3-9).

[0027] According to some embodiments of the method for preparing modified nano-cerium oxide described in the present application, the temperature at which the first mixed solution and the second mixed solution come into contact is 25-60° C., and the contact time is 3-12 hours.

[0028] According to some embodiments of the method for preparing modified nano-cerium oxide described in the present application, step (3) further includes centrifuging the contacted product and washing the centrifugal precipitate.

[0029] According to some embodiments of the method for preparing modified nano-cerium oxide described in the present application, the detergent used for washing is ethanol.

[0030] The third aspect of the present application provides an application of the modified nano-cerium oxide described in the first aspect of the present application or the modified nano-cerium oxide obtained by the preparation method described in the second aspect of the present application in a proton exchange membrane.

[0031] The beneficial effects of the present application include: the antioxidant nano-cerium oxide in the modified nano-cerium oxide described in the present application is wrapped by a conductive material. When preparing the proton exchange membrane slurry, the nano-cerium oxide can be evenly distributed in the proton exchange membrane slurry and its content can be precisely controlled. It can more effectively consume the free radicals produced at various positions in the proton exchange membrane, reduce the oxidative degradation of the sulfonic acid groups and carbon-fluorine main chains in the proton membrane by free radicals, and delay the problem of thinning, perforation or decreased proton conductivity of the proton exchange membrane. At the same time, the water storage capacity of the nano-cerium oxide can alleviate the embrittlement and cracking caused by membrane dehydration, and extend the life of the proton exchange membrane under extreme working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a scanning electron microscope image of nano-cerium oxide used in Example 1 of the present application;

[0033] Figure 2 This is an electron microscope scanning image of the modified nano-cerium oxide prepared in Example 1 of the present application. DETAILED DESCRIPTION

[0034] The embodiments of the present invention are described in detail below. The examples of the embodiments are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0035] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0036] The embodiment of the present application provides a modified nano-cerium oxide, comprising nano-cerium oxide and a conductive material layer coating the nano-cerium oxide.

[0037] The antioxidant nano-cerium oxide in the modified nano-cerium oxide described in this application is coated with a conductive material. When preparing a proton exchange membrane slurry, the nano-cerium oxide can be evenly distributed in the slurry and its content can be precisely controlled. It can more effectively consume free radicals produced at various locations within the proton exchange membrane, reduce the oxidative degradation of sulfonic acid groups and carbon-fluorine backbones in the proton exchange membrane by free radicals, and delay the thinning, perforation, or decrease in proton conductivity of the proton exchange membrane. At the same time, the water storage capacity of the nano-cerium oxide can alleviate the embrittlement and cracking caused by membrane dehydration, extending the life of the membrane under extreme working conditions.

[0038] In some embodiments of the present application, the particle size of the nano-cerium oxide is 2-15 nm, for example, 2 nm, 5 nm, 8 nm, 10 nm, 12 nm, 15 nm, etc.

[0039] In some embodiments of the present application, the specific surface area of ​​the nano-cerium oxide is 420-50m 2 / g, for example: 420m 2 / g、416m 2 / g、379m 2 / g, 238m 2 / g、168m 2 / g、84m 2 / g, 50m 2 / g etc.;

[0040] In some embodiments of the present application, the conductive material layer includes a conductive material and a surfactant.

[0041] In some embodiments of the present application, the conductive material includes polyaniline.

[0042] In some embodiments of the present application, the surfactant includes a nonionic surfactant; more preferably, the nonionic surfactant includes one or more of Tween 80, Tween 20, octylphenol polyoxyethylene ether-10, polyvinyl pyrrolidone, and Triton X100. Nonionic surfactants are soluble in water and ethanol solvents, providing dispersion stability for the polyaniline-coated cerium oxide nanoparticles while also having a certain effect on the particle size of the nanoparticles.

[0043] In some embodiments of the present application, the mass ratio of the nano-cerium oxide to the polyaniline is 1:(3-10), for example, 1:3, 1:5, 1:7, 1:9, 1:10, etc. Within this mass range, polyaniline has a good coating effect on the nano-cerium oxide, and the nano-cerium oxide particles are evenly distributed.

[0044] In some embodiments of the present application, the mass ratio of the nano-cerium oxide to the surfactant is (1-10):1.

[0045] In some embodiments of the present application, the particle size of the modified nano-cerium oxide is 100-500 nm, for example, 100 nm, 150 nm, 180 nm, 230 nm, 260 nm, 320 nm, 380 nm, 460 nm, 500 nm, etc.

[0046] The present embodiment also provides a method for preparing the modified nano-cerium oxide described in the first aspect of the present application, comprising the following steps:

[0047] (1) mixing nano-cerium oxide, a conductive material, and a benign solvent to obtain a first mixed solution;

[0048] (2) mixing the surfactant and the non-benign solvent to obtain a second mixed solution;

[0049] (3) contacting the first mixed solution with the second mixed solution to obtain the modified nano-cerium oxide.

[0050] The modified nano-cerium oxide obtained by the preparation method described in the present application can be uniformly dispersed in the slurry solvent system and is not easy to agglomerate.

[0051] In some embodiments of the present application, in step (1), the benign solvent includes one or more of dimethyl sulfoxide, acetone and tetrahydrofuran.

[0052] In some embodiments of the present application, the solid content of the first mixed liquid is 30%-75%, for example, 30%, 40%, 50%, 60%, 70%, 75%, etc.

[0053] In some embodiments of the present application, the mass ratio of nano-cerium oxide to the conductive material in the first mixed solution is 1:(3-10); for example, 1:3, 1:5, 1:7, 1:9, 1:10, etc.

[0054] In some embodiments of the present application, in step (2), the non-benign solvent includes water and / or ethanol.

[0055] In some embodiments of the present application, the non-benign solvent includes water and ethanol; more preferably, the non-benign solvent includes water and ethanol in a volume ratio of (1-6):3, such as 1:3, 2:3, 1:1, 5:3, 6:3, etc. The non-benign solvent described in the present application can be directly mixed with the proton exchange membrane slurry solvent system.

[0056] In some embodiments of the present application, the solid content of the second mixed liquid is 0.1%-1%, for example, 0.1%, 0.3%, 0.5%, 0.7%, 0.9%, 1%, etc.

[0057] In some embodiments of the present application, in step (3), the volume ratio of the first mixed liquid to the second mixed liquid is 1:(3-9), for example: 1:3, 1:5, 1:7, 1:9, etc.

[0058] In some embodiments of the present application, the temperature at which the first mixed liquid and the second mixed liquid come into contact is 25-60°C, for example: 25°C, 30°C, 32°C, 38°C, 43°C, 47°C, 56°C, 60°C, etc., and the contact time is 3-12h, for example 3h, 5h, 8h, 10h, 12h, etc.

[0059] In some embodiments of the present application, step (3) further includes centrifuging the contacted product and washing the centrifugal precipitate.

[0060] In some embodiments of the present application, the washing agent used is ethanol. After washing, to ensure that the modified nano-cerium oxide is completely separated from the detergent, centrifugation is performed, with the centrifugal speed set to 5000-15000 rpm and the centrifugation time set to 5-15 minutes. It is only necessary to ensure that the centrifugation is successful and has no effect on the material itself.

[0061] The embodiments of the present application also provide an application of the modified nano-cerium oxide described in the first aspect of the present application or the modified nano-cerium oxide obtained by the preparation method described in the second aspect of the present application in a proton exchange membrane. The modified nano-cerium oxide described in the present application can be evenly distributed in the slurry and its content can be precisely controlled. It can more effectively consume the free radicals produced at various positions in the proton exchange membrane, reduce the oxidative degradation of the sulfonic acid groups and carbon-fluorine main chains in the proton exchange membrane by free radicals, and delay membrane thinning, perforation or a decrease in proton conductivity. At the same time, the water storage capacity of nano-cerium oxide can alleviate the embrittlement and cracking caused by membrane dehydration, and extend the life of the membrane under extreme working conditions.

[0062] In some embodiments of the present application, the mass proportion of the modified nano-cerium oxide in the proton exchange membrane is 3%-8%, for example, 3%, 5%, 6%, 8%, etc.

[0063] The technical solution of this application is further described below with reference to specific embodiments.

[0064] Example 1

[0065] A method for preparing modified nano-cerium oxide comprises the following steps:

[0066] Dissolve 10g of oleylamine in 12ml of xylene solvent, then add 1g of cerium acetate and ultrasonically disperse at 25℃ for 10min. Heat and stir to 90℃. When the temperature reaches 90℃, add 1g of deionized water to the xylene solution. The xylene solution changes from grayish white to yellow. Turn off the stirring and age the yellow mixture at 90℃ for 5h to obtain a transparent yellow colloid. Add the transparent yellow colloid to the ethanol solution for mixed precipitation, and then centrifuge at a centrifugal speed of 10,000 rpm for 10min to obtain nanoparticles. Wash with ethanol three times to obtain nano-cerium oxide with a particle size of 8±1.5nm and a specific surface area of ​​105m 2 / g.

[0067] The nano-cerium oxide was dispersed in dimethyl sulfoxide to obtain a dispersion A with a solid content of 30%.

[0068] Polyaniline was stirred and dissolved in dimethyl sulfoxide to obtain a dispersion B with a solid content of 70%, and then the dimethyl sulfoxide dispersion A of nanocerium oxide and the polyaniline dispersion B were fully mixed at a volume ratio of 1:3 to obtain a mixed solution C (the mass ratio of nanocerium oxide to polyaniline in the mixed solution C was 1:7).

[0069] A nonionic surfactant, Tween 80, was added to a mixed solvent of deionized water and ethanol in a volume ratio of 1:1, and the mixture was stirred to dissolve and disperse the surfactant, thereby obtaining a surfactant dispersion D with a solid content of 0.5%.

[0070] The mixed solution C was slowly and uniformly added to the uniformly stirred surfactant dispersion D through a separatory funnel (the volume ratio of the mixed solution C to the mixed solution D was 1:5, and the mass ratio of nano-cerium oxide and the non-ionic surfactant Tween 80 in the mixed solution was 3:1). After all the mixed solution C was added, stirring was continued at 30°C for 4 hours. After the stirring was stopped, the lower layer of nanoparticles was separated by high-speed centrifugation and washed three times with ethanol solvent to obtain the modified cerium oxide with a particle size of 275±55 nm.

[0071] Example 2

[0072] The only difference between the preparation method of the modified nano-cerium oxide described in Example 2 and that of Example 1 is that the particle size of the nano-cerium oxide used in the preparation process of the modified nano-cerium oxide described in Example 2 is 2±1.5 nm.

[0073] Example 3

[0074] The only difference between the preparation method of the modified nano-cerium oxide described in Example 3 and that of Example 1 is that the particle size of the nano-cerium oxide used in the preparation process of the modified nano-cerium oxide described in Example 3 is 12±1.5 nm.

[0075] Example 4

[0076] The only difference between the preparation method of modified nano-cerium oxide described in Example 4 and that of Example 1 is that the mass ratio of nano-cerium oxide to polyaniline in the mixed solution C during the preparation process of modified nano-cerium oxide described in Example 4 is 1:3.

[0077] Example 5

[0078] The only difference between the preparation method of modified nano-cerium oxide described in Example 5 and that of Example 1 is that the mass ratio of nano-cerium oxide to polyaniline in the mixed solution C during the preparation process of modified nano-cerium oxide described in Example 5 is 1:5.

[0079] Example 6

[0080] The only difference between the preparation method of modified nano-cerium oxide described in Example 6 and that of Example 1 is that the mass ratio of nano-cerium oxide to polyaniline in the mixed solution C during the preparation process of modified nano-cerium oxide described in Example 6 is 1:10.

[0081] Example 7

[0082] The only difference between the preparation method of modified nano-cerium oxide described in Example 7 and that of Example 1 is that the volume ratio of deionized water and ethanol in the dispersion D during the preparation process of modified nano-cerium oxide described in Example 7 is 1:2.

[0083] Example 8

[0084] The only difference between the preparation method of modified nano-cerium oxide described in Example 8 and that of Example 1 is that the volume ratio of deionized water and ethanol in the dispersion D during the preparation process of modified nano-cerium oxide described in Example 8 is 1:3.

[0085] Example 9

[0086] The only difference between the preparation method of modified nano-cerium oxide described in Example 9 and that of Example 1 is that the volume ratio of deionized water and ethanol in the dispersion D during the preparation process of modified nano-cerium oxide described in Example 9 is 2:1.

[0087] Example 10

[0088] The only difference between the preparation method of the modified nano-cerium oxide described in Example 10 and that of Example 1 is that the benign solvent used in the preparation process of the modified nano-cerium oxide described in Example 10 is tetrahydrofuran.

[0089] Because nano-cerium oxide has poor dispersibility in tetrahydrofuran, turbidity occurs. During the nanoprecipitation process, nano-cerium oxide is not wrapped inside the polyaniline but attached to the surface of the polyaniline microspheres.

[0090] 1. The electron microscope scanning images of the nano-cerium oxide and the modified nano-cerium oxide described in Example 1 of the present application are as follows: Figure 1 and Figure 2 shown.

[0091] from Figure 1 It can be seen that the nano-cerium oxide used in Example 1 of the present application has uniform size; Figure 2 It can be seen that the polyaniline encapsulates nano-cerium oxide, and the size of the encapsulated nano-cerium oxide remains basically unchanged. The obtained modified nano-cerium oxide is uniformly spherical and there is no agglomeration between the particles.

[0092] 2. Performance study of modified nano-cerium oxide applied to proton exchange membranes as described in Examples 1-9 of this application:

[0093] The modified nano-cerium oxide described in Examples 1-9 was mixed with perfluorosulfonic acid, and the mixture was added to a mixture of water and ethanol in a volume ratio of 1:1 to obtain a slurry. The content of the modified nano-cerium oxide in the slurry was 5 wt %. The above slurries were coated on release films through metering pumps, and then coated for the second time through a reinforcing film. The slurries were then dried to obtain a uniform distribution of the nano-cerium oxide exchange membrane.

[0094] Table 1

[0095]

[0096]

[0097] As can be seen from Table 1, the proton exchange membrane prepared in Example 1 exhibited the best performance. The nano-cerium oxide used in the preparation of the modified nano-cerium oxide described in Example 2 had a smaller particle size, resulting in a lower tensile strength and a higher area specific resistance of the prepared proton exchange membrane. The nano-cerium oxide used in the preparation of the modified nano-cerium oxide described in Example 3 had a larger particle size, resulting in a lower cerium coating amount and poorer tensile strength and area specific resistance of the proton exchange membrane.

[0098] By comparing Example 1 with Examples 4-6, it can be seen that if the amount of polyaniline is reduced, the content of the coated cerium element will be reduced, resulting in a decrease in the durability of the proton exchange membrane; if the amount of polyaniline is increased, the amount of cerium element coated will be increased, but the tensile strength and area specific resistance performance will also deteriorate accordingly.

[0099] By comparing Example 1 with Examples 7-9, it can be seen that the proton exchange membrane prepared with modified nano-cerium oxide obtained when the volume ratio of deionized water to ethanol is 1:1 has better performance. Increasing the water capacity will reduce the tensile strength of the proton exchange membrane and the swelling rate will also increase abnormally; increasing the amount of alcohol will lead to a larger area specific resistance of the proton exchange membrane.

[0100] Although the above embodiments have been shown and described, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those skilled in the art are all within the scope of protection of the present invention.

Claims

1. A modified nano-cerium oxide, characterized in that: The invention comprises nano cerium oxide and a conductive material layer covering the nano cerium oxide.

2. The modified nano-cerium oxide according to claim 1, characterized in that: The particle size of the nano cerium oxide is 2-15 nm, and the specific surface area of ​​the nano cerium oxide is 420-50 m 2 / g; And / or, the conductive material layer includes a conductive material and a surfactant; Preferably, the conductive material comprises polyaniline; Preferably, the surfactant includes a nonionic surfactant; more preferably, the nonionic surfactant includes one or more of Tween 80, Tween 20, octylphenol polyoxyethylene ether-10, polyvinyl pyrrolidone and Triton X100.

3. The modified nano-cerium oxide according to claim 2, characterized in that: The mass ratio of the nano-cerium oxide to the polyaniline is 1:(3-10); And / or, the mass ratio of the nano-cerium oxide to the surfactant is (1-10):

1.

4. The modified nano-cerium oxide according to claim 1, characterized in that: The particle size of the modified nano-cerium oxide is 100-500 nm.

5. The method for preparing modified nano-cerium oxide according to any one of claims 1 to 4, characterized in that: The following steps are involved: (1) mixing nano-cerium oxide, a conductive material, and a benign solvent to obtain a first mixed solution; (2) mixing the surfactant and the non-benign solvent to obtain a second mixed solution; (3) contacting the first mixed solution with the second mixed solution to obtain the modified nano-cerium oxide.

6. The method for preparing modified nano-cerium oxide according to claim 5, characterized in that: In step (1), the benign solvent includes one or more of dimethyl sulfoxide, acetone and tetrahydrofuran; and / or, the solid content of the first mixed solution is 30%-75%; And / or, the mass ratio of nano-cerium oxide to conductive material in the first mixed solution is 1:(3-10).

7. The method for preparing modified nano-cerium oxide according to claim 5, characterized in that: In step (2), the non-benign solvent includes water and / or ethanol; Preferably, the non-benign solvent comprises water and ethanol; more preferably, the non-benign solvent comprises water and ethanol in a volume ratio of (1-6):3; And / or, the solid content of the second mixed liquid is 0.1%-1%.

8. The method for preparing modified nano-cerium oxide according to claim 5, characterized in that: In step (3), the volume ratio of the first mixed solution to the second mixed solution is 1:(3-9); And / or, the temperature for contact between the first mixed liquid and the second mixed liquid is 25-60° C., and the contact time is 3-12 hours.

9. The method for preparing modified nano-cerium oxide according to claim 5, characterized in that: Step (3) further includes centrifuging the contacted product and washing the centrifugal precipitate; Preferably, the detergent used in the washing is ethanol.

10. Use of the modified nano-cerium oxide according to any one of claims 1 to 4 or the modified nano-cerium oxide obtained by the preparation method according to any one of claims 5 to 8 in a proton exchange membrane; Preferably, the mass proportion of the modified nano-cerium oxide in the proton exchange membrane is 3%-8%.

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