Sulfonated carbon nanoflower-modified polymer hybrid proton exchange membrane and its preparation

Abstract

This invention belongs to the field of membrane technology and discloses a polymer hybrid proton exchange membrane modified with sulfonated carbon nanoflowers and its preparation. The preparation method includes the following steps: (1) adding acrylonitrile and azobisisobutyronitrile to acetone solvent and carrying out a polymerization reaction to obtain polyacrylonitrile (PACN); (2) stabilizing PACN and then carbonizing it to obtain carbon nanoflowers (CNF); (3) reacting CN with concentrated sulfuric acid to obtain sulfonated carbon nanoflowers (SCNF); (4) using SCNF to prepare a casting solution and form a membrane material, thereby obtaining a polymer hybrid proton exchange membrane modified with sulfonated carbon nanoflowers. This invention improves the structure and composition of key functional components in the proton exchange membrane and introduces sulfonated carbon nanoflowers (SCNF) into the proton exchange membrane, which can effectively improve the proton conductivity of the obtained proton exchange membrane and also has excellent stability.

Description

Technical Field

[0001] This invention belongs to the field of membrane technology, and more specifically, relates to a polymer hybrid proton exchange membrane modified with sulfonated carbon nanoflowers and its preparation. By introducing sulfonated carbon nanoflowers (SCNF) to modify the polymer hybrid proton exchange membrane, the proton conductivity of the prepared proton exchange membrane can be effectively improved. Background Technology

[0002] Proton exchange membrane fuel cells (PEMFCs) possess advantages such as being environmentally friendly, starting rapidly, and highly efficient. They can directly convert the chemical energy of fuel into electrical energy without combustion, making them one of the most promising energy conversion devices and attracting widespread attention. The proton exchange membrane (PEM) is one of the core components of a PEMFC, transferring protons while preventing fuel leakage between the anode and cathode. Proton conductivity is a key factor affecting the performance of PEMFCs, and improving proton conductivity is an effective means of obtaining high-performance PEMs.

[0003] In recent years, carbon nanomaterials have attracted much attention for improving proton conduction in proton exchange membranes due to their excellent stability, unique characteristics, and multiple structural selectivity. Currently, one-dimensional (1D) and two-dimensional (2D) carbon nanomaterials have been proven to effectively enhance the proton conductivity of proton exchange membranes. For example, carbon nanotubes (CNTs) possess the typical characteristics of good flexibility, high aspect ratio, and a continuous 1D structure, which allows for more continuous ion clusters in proton exchange membranes, thus reducing proton transfer resistance. Graphene oxide (GO) possesses the typical characteristics of high specific surface area, abundant functional groups, and a continuous 2D structure; due to its microscopic and nanoscopic extensibility, it can be used to construct long-range ion channels in proton exchange membranes. For example, the paper "Polymer electrolytefuel cells using Nafion-based composite membranes with functionalized carbon nanotubes" (Angew. Chem. Int. Ed 47 (2008) 2653–2656) reported the preparation of S-SWCNTs / Nafion hybrid membranes by adding sulfonated single-walled CNTs (S-SWCNTs) to the perfluorosulfonic acid resin Nafion. This membrane exhibited a proton conductivity of 0.0155 S / cm at ~80°C and 100% RH, which is 0.53 times higher than that of Nafion 1135 membranes. The article "histidine-functionalized carbon nanotubes: High-performance fuel cell membranes" (International Journal of Hydrogen Energy 38(2013)5894-5902) reported the addition of histidine-modified CNTs (Im-CNTs) to perfluorosulfonic acid resins. Made in China A hybrid membrane was prepared by adding phosphonic acid-functionalized carbon nanotubes (PCNTs) to sulfonated polyether ether ketone (SPEEK) to prepare a PCNT / SPEEK hybrid membrane. The proton conductivity of this membrane was 0.16 S / cm at 100 °C, which is about 0.07 times higher than that of the Nafion 117 membrane. The paper "Strengthen the performance of sulfonated poly(ether ether ketone) as proton exchange membranes with phosphonic acid functionalized carbon nanotubes" (Ionics 23(2017)2103-2112) reported that the PCNT / SPEEK hybrid membrane was prepared by adding phosphonic acid functionalized CNTs (PCNTs) to sulfonated polyether ether ketone (SPEEK). The proton conductivity of this membrane was 0.16 S / cm at 60 °C and 100% RH, which is about 2.02 times higher than that of the pure SPEEK membrane. The paper "Graphite oxide / Nafion composite membranes for polymer electrolytefuel cells" (RSC Advances 2 (2012) 8777-8782) reported the preparation of a GO / Nafion hybrid membrane by incorporating GO into Nafion. This membrane exhibited a proton conductivity of 0.078 S / cm at 30 °C and 100% RH, which was 0.81 times higher than that of a pure Nafion membrane. The paper "Enhancement of proton conductivity of chitosan membrane enabled by sulfonated graphene oxide under both hydrated and anhydrous conditions" (Journal of Power Sources 269 (2014) 898-911) reported the preparation of an SGO / CS hybrid membrane by adding sulfonated GO (SGO) to chitosan (CS). This membrane exhibited a proton conductivity of 0.0612 S / cm at 85 °C and 100% RH. -1The proton conductivity is approximately 1.42 times higher than that of pure CS membrane. The paper "Enhanced proton conductivity of Nafion nanohybrid membrane incorporated with phosphonic acid functionalized graphene oxide at elevated temperature and low humidity" (Journal of Membrane Science 518(2016)243-253) reports the preparation of a PGO / Nafion hybrid membrane by incorporating phosphonic acid functionalized graphene oxide into Nafion. This membrane exhibits a proton conductivity of 0.241 S / cm at 90 °C and 95% RH, approximately 0.9 times higher than that of pure Nafion membrane.

[0004] Compared to 1D and 2D carbon nanomaterials, certain three-dimensional (3D) carbon nanomaterials possess higher porosity and multidirectional ion conduction channels, which are more conducive to improving the proton conductivity of proton exchange membranes. However, there are few reports on the application of 3D carbon nanomaterials in promoting proton conduction in proton exchange membranes, mainly due to the difficulty in controlling the microstructure and maintaining the stability of certain 3D carbon nanomaterials.

[0005] Furthermore, the inventors' previous research, "Polymer Hybrid Proton Exchange Membrane Synergistically Modified with PCNT and PGO and its Preparation Method" (see Chinese Patent Application No. 202210167901.4), mainly focused on the synergistic effect of two key functional components, 1D phosphorylated carbon nanotubes (PCNT) and 2D phosphorylated GO (PGO), in a polymer matrix to form multi-level coherent proton transport channels, effectively reducing the proton transport resistance in the proton exchange membrane and thus greatly improving the proton conductivity of the proton exchange membrane. Although this previous research effectively improved the proton conductivity of the proton exchange membrane, the optimal proton conductivity of the proton exchange membrane prepared in the examples was 0.282 S / cm (conditions: 90℃, 95% RH), indicating room for improvement. Summary of the Invention

[0006] In view of the above-mentioned defects or improvement needs of the prior art, the purpose of this invention is to provide a polymer hybrid proton exchange membrane modified with sulfonated carbon nanoflowers and its preparation. By improving the structure and composition of the key functional components in the proton exchange membrane and introducing sulfonated carbon nanoflowers (SCNF) into the proton exchange membrane, the proton conductivity of the obtained proton exchange membrane can be effectively improved, and the stability in use is also excellent.

[0007] To achieve the above objectives, according to one aspect of the present invention, a method for preparing a polymer hybrid proton exchange membrane modified with sulfonated carbon nanoflowers is provided, characterized by comprising the following steps:

[0008] (1) Acrylonitrile and azobisisobutyronitrile were added to acetone solvent and polymerized at 30-120°C for 0.5-8 h under a protective gas atmosphere; after the reaction, polyacrylonitrile (PACN) was obtained by separation and drying.

[0009] (2) The polyacrylonitrile (PACN) obtained in step (1) is stabilized in air at 150-300°C for 0.5-8 hours; then, it is carbonized at 700-1100°C for 0.5-8 hours under a protective gas atmosphere; then, the obtained product is washed, separated and dried to obtain carbon nanoflowers (CNF).

[0010] (3) The carbon nanoflowers (CNF) obtained in step (2) are reacted with concentrated sulfuric acid at 50-130°C for 8-24 hours under a protective gas atmosphere; after the reaction, they are washed, separated and dried to obtain sulfonated carbon nanoflowers (SCNF); wherein the concentration of the concentrated sulfuric acid is 12-18.4 mol / L.

[0011] (4) The sulfonated carbon nanoflowers (SCNF) obtained in step (3) are added to the sulfonated polymer solution and ultrasonically treated to obtain a uniformly dispersed casting solution. Then, the casting solution is used to form a membrane material. After drying, the membrane is then subjected to hydrogen peroxide solution, acid and deionized water immersion treatment in sequence to obtain a polymer hybrid proton exchange membrane modified with sulfonated carbon nanoflowers.

[0012] As a further preferred embodiment of the present invention, in step (4), the mass of the sulfonated carbon nanoflower (SCNF) accounts for 0.7 to 2.1 wt% of the mass of the polymer matrix contained in the sulfonated polymer solution;

[0013] Preferably, the sulfonated carbon nanoflowers (SCNF) account for 1.1 to 1.7 wt% of the polymer matrix contained in the sulfonated polymer solution.

[0014] As a further preferred embodiment of the present invention, in step (1), the concentration of the azobisisobutyronitrile in the reaction system before the polymerization reaction occurs is 0.2 to 1.5 mg / mL;

[0015] The protective gas is either nitrogen or argon;

[0016] The drying process specifically employs vacuum drying; preferably, it involves drying in a vacuum oven at 35–140°C for 2–30 hours.

[0017] As a further preferred embodiment of the present invention, in step (2), the heating rate of the stabilization treatment is less than 1°C / min, more preferably less than 0.5°C / min;

[0018] The protective gas is either nitrogen or argon;

[0019] The drying process specifically employs vacuum drying; preferably, it involves drying in a vacuum oven at 35–140°C for 2–30 hours.

[0020] The heating rate of the carbonization process is less than 10°C / min, more preferably 3 to 7°C / min;

[0021] The cleaning process involves first cleaning with hydrochloric acid aqueous solution, followed by cleaning with deionized water and methanol; wherein the concentration of the hydrochloric acid aqueous solution is 0.04–1 mol / L.

[0022] As a further preferred embodiment of the present invention, in step (3), the protective gas is either nitrogen or argon;

[0023] The ratio of the amount of carbon nanoflowers (CNF) to the amount of concentrated sulfuric acid is (1-4 mg): (1 mL);

[0024] The cleaning process involves sequentially washing with deionized water and methanol.

[0025] The drying process specifically employs vacuum drying; preferably, it involves drying in a vacuum oven at 35–140°C for 2–30 hours.

[0026] As a further preferred embodiment of the present invention, in step (4), the sulfonated polymer solution is one of a homogeneous solution of perfluorosulfonic acid resin, sulfonated polyether ether ketone, sulfonated polybenzimidazole, sulfonated polyether sulfone, or sulfonated polyimide; the concentration of the sulfonated polymer solution is 1 to 40 wt%.

[0027] The casting solution is used to form a film material, specifically by coating the casting solution into a film, thereby forming a film material.

[0028] The drying process involves placing the membrane material in an oven at 50–80°C, raising the temperature to 110–150°C, and then maintaining the temperature for 12–36 hours. Preferably, the heating rate is less than 0.5°C / min, and more preferably 0.1–0.5°C / min.

[0029] As a further preferred embodiment of the present invention, in step (4), the concentration of the hydrogen peroxide aqueous solution is 1 to 10 wt%.

[0030] The acid solution is specifically a mixture of one or more of hydrochloric acid, sulfuric acid, and phosphoric acid, and the concentration of the acid solution is 0.4 to 4 mol / L.

[0031] According to another aspect of the present invention, the present invention provides a polymer hybrid proton exchange membrane modified with sulfonated carbon nanoflowers obtained by the above preparation method.

[0032] According to another aspect of the present invention, the present invention provides the application of the above-mentioned sulfonated carbon nanoflower modified polymer hybrid proton exchange membrane in a proton exchange membrane fuel cell.

[0033] Compared with existing technologies, the present invention, through the above-described technical solution, effectively improves the proton conductivity of the proton exchange membrane by introducing sulfonated carbon nanoflowers (SCNF) into the proton exchange membrane, and also exhibits excellent stability in use. The sulfonated carbon nanoflowers (SCNF) prepared by this invention are porous carbon nanomaterials with a 3D flower-like structure, high surface roughness, high specific surface area, and multidirectional ion transport channels. They have more interaction sites with the polymer matrix, allowing for better control of microphase separation in the hybrid membrane to optimize the proton transport pathway. Furthermore, the sulfonated -SO3H can provide additional proton transport sites. The combined effect of these aspects enables SCNF to effectively enhance the proton conductivity of the proton exchange membrane. In addition, SCNF exhibits excellent water, thermal, and chemical stability, which further contributes to the excellent stability of the resulting hybrid proton exchange membrane in use (as described below). Figure 4 (As shown).

[0034] The preparation method of this invention first prepares sulfonated carbon nanoflowers (SCNF), and then does it into a polymer to obtain a polymer hybrid proton exchange membrane modified with sulfonated carbon nanoflowers (SCNF). Specifically, for SCNF, acrylonitrile is first polymerized to obtain polyacrylonitrile (PACN), then PACN is stabilized and carbonized to obtain carbon nanoflowers (CNF), and finally CN is sulfonated with concentrated sulfuric acid to obtain sulfonated carbon nanoflowers (SCNF). By using PACN, good morphology controllability can be obtained during the preparation process. Using acetone as a solvent, flower-shaped PACN can be obtained. Furthermore, PACN can maintain its original shape well during the preparation of carbon nanoparticles as a carbon source, resulting in carbon materials with high porosity and specific surface area.

[0035] Taking Example 5 below as an example, compared with the inventors' previous study "Polymer Hybrid Proton Exchange Membrane with Synergistic Modification of PCNT and PGO and its Preparation Method" (hereinafter referred to as the previous study), the proton conductivity of the proton exchange membrane obtained in Example 5 of this invention is 0.292 S / cm, which is the best among all examples, and is also higher than the best proton conductivity of the proton exchange membrane obtained in the previous study under the same temperature and humidity (90℃, 95%RH) test conditions: 0.282 S / cm. While both this invention and previous research involve the preparation of hybrid proton exchange membranes using carbon nanomaterials, the former focused primarily on the synergistic effect of two key functional components, 1D phosphorylated carbon nanotubes (PCNTs) and 2D phosphorylated GO (PGO), within a polymer matrix to form multi-level, coherent proton transport channels, thereby significantly enhancing the proton conductivity of the proton exchange membrane. This invention, however, focuses on the interaction between a single key functional component, 3D carbon nanoflowers, and the polymer matrix, introducing multi-directional proton transport channels and sites. This effectively reduces the proton transport resistance within the proton exchange membrane, thereby greatly promoting the proton conduction of the resulting hybrid membrane. Furthermore, this invention avoids the tedious investigation of the doping ratio of the two functional components required in previous studies.

[0036] Compared to other existing technologies, such as the prior art "Composition with Enhanced Proton Conductivity" (see Chinese Patent Application No. 200980108962.6), which involves a composition of a polymer containing a proton-containing ionizable group (A) and a carbon nanostructure functionalized with a proton-containing ionizable group (B), and where the carbon nanostructure is in the form of a single tube, rod, or particle, or a combination thereof (tube- or rod-shaped carbon nanostructures belong to 1D carbon nanomaterials), this prior art focuses on the effect of different combinations of A and B on enhanced proton conduction. In contrast, this invention focuses on the improvement of proton conduction of sulfonated polymer proton exchange membranes by a single-component sulfonated carbon nanoflower (SCNF) (belonging to 3D carbon nanomaterials). The doped particles used do not involve combinations of different morphologies or components, making it simpler.

[0037] Compared with existing technology, Nafion TMCompared to the modified carbon quantum dot-polymer hybrid proton exchange membrane and its preparation method (see Chinese patent document application number 201611003722.8), the prior art involves 0D carbon quantum dots as carbon nanomaterials, while the carbon nanomaterials involved in this invention are 3D carbon nanoflowers. Furthermore, the prior art focuses on improving the proton conductivity of the proton exchange membrane at lower humidity (40% RH), while this invention focuses on improving the proton conductivity of the proton exchange membrane at higher humidity (95% RH), which is a more common application scenario. Furthermore, the existing technology mainly utilizes the good compatibility between carbon quantum dots and polymer matrices, and the oxygen-containing functional groups of carbon quantum dots to enhance the water retention rate of the membrane, thereby improving the proton conductivity of the proton exchange membrane. In contrast, this invention is based on sulfonated carbon nanoflowers (SCNFs), a porous carbon nanomaterial with a 3D flower-like structure. SCNFs have a large surface roughness, high specific surface area, and multidirectional ion transport channels, resulting in more interaction sites with the polymer matrix. This allows for better control of the hybrid membrane microphase separation to optimize the proton conduction path and thus improve the proton conductivity of the proton exchange membrane. Therefore, the two technologies differ significantly in their mechanisms for improving the proton conductivity of the proton exchange membrane.

[0038] Compared to the existing technology "CNT@Fe3O4@C Modified Polymer Hybrid Proton Exchange Membrane and Preparation Method Thereof" (see Chinese Patent Document No. 201611108984.0), the prior art involves 1D CNT@Fe3O4@C carbon nanomaterials, in which Fe3O4 is one of the composite components, and the carbon nanomaterial is a composite material of carbon nanotubes (CNTs) and Fe3O4; while the carbon nanomaterial involved in this invention is a 3D carbon nanoflower, a pure carbon nanomaterial, not a composite material combined with other particles. Furthermore, the prior art mainly utilizes the orientational arrangement of CNT@Fe3O4@C under the influence of a magnetic field to significantly improve the probability of proton conduction in the thickness direction of the membrane; while this invention is based on sulfonated carbon nanoflowers (SCNF), a 3D flower-like porous carbon nanomaterial with high surface roughness, high specific surface area, and multidirectional ion transport channels, resulting in more interaction sites with the polymer matrix. This allows for better control of the microphase separation of the hybrid membrane to optimize the proton conduction path and improve the proton conductivity of the proton exchange membrane. Therefore, it is evident that the two methods differ significantly in their mechanisms for improving the proton conductivity of proton exchange membranes. Furthermore, the existing technology produces an anisotropic hybrid membrane due to the orientation and alignment of CNT@Fe3O4@C under the influence of a magnetic field; while the hybrid membrane obtained in this invention is an isotropic membrane.

[0039] Compared to the existing technology "High-Performance Lightly Reduced Graphene Oxide Composite Proton Exchange Membrane and Preparation Method Thereof" (see Chinese Patent Application No. 201611155939.0), the carbon nanomaterial involved in the prior art is lightly reduced graphene oxide, with a morphology mainly characterized by 2D features, while the carbon nanomaterial involved in this invention is a 3D carbon nanoflower. Furthermore, the prior art mainly utilizes the long-range proton transport channels of polymers, which are hundreds of nanometers long, in the graphene oxide nanocomposite to construct extremely continuous proton transport channels within the membrane, greatly improving the mechanism of proton transport within and between sheets to promote the proton conductivity of the proton exchange membrane; while this invention is based on sulfonated carbon nanoflowers (SCNF), a porous carbon nanomaterial with a 3D flower-like structure, large surface roughness, high specific surface area, and multidirectional ion transport channels, with more interaction sites with the polymer matrix, which can better regulate the microphase separation of the hybrid membrane to optimize the proton conduction path and improve the proton conductivity of the proton exchange membrane. Therefore, it is evident that the two technologies differ significantly in their mechanisms for improving the proton conductivity of proton exchange membranes. Furthermore, the prior art focuses on improving the proton conductivity of proton exchange membranes at lower humidity (40% RH), while the present invention focuses on improving the proton conductivity of proton exchange membranes at higher humidity (95% RH), which is a more common application scenario.

[0040] Compared with the prior art "Copolymer Material of Highly Sulfonated Polyetheretherketone and Graphene Oxide and Preparation Method of Proton Exchange Membrane Thereof" (see Chinese Patent Document No. 201711108376.4), which involves a proton exchange membrane of a copolymer of highly sulfonated polyetheretherketone grafted onto graphene oxide (GO-g-SPEEK), this invention relates to a hybrid proton exchange membrane of sulfonated carbon nanoflowers (SCNF) doped with sulfonated polymers. The two inventions differ significantly in the way they introduce inorganic functional components (GO and SCNF). The former is through a grafting reaction of the polymer onto GO, while the latter is through simple doping. It is evident that this invention is simpler in membrane preparation. Furthermore, the existing technology mainly utilizes GO to improve the proton conductivity of proton exchange membranes by enhancing the hydrophilicity of the membrane and controlling the state of water fixed in ion channels within the polymer matrix. In contrast, this invention is based on sulfonated carbon nanoflowers (SCNFs), a porous carbon nanomaterial with a 3D flower-like structure. SCNFs have a large surface roughness, high specific surface area, and multidirectional ion transport channels, resulting in more interaction sites with the polymer matrix. This allows for better control of the hybrid membrane microphase separation to optimize the proton conduction path and thus improve the proton conductivity of the proton exchange membrane. Therefore, the mechanisms by which the two technologies improve the proton conductivity of proton exchange membranes are significantly different. Moreover, the optimal proton conductivity of the existing technology is ~0.23 S / cm, significantly lower than the optimal proton conductivity of 0.292 S / cm of this invention.

[0041] Compared to the prior art "A Composite Membrane for Direct Methanol Fuel Cells and Its Preparation Method" (see Chinese Patent Document No. 202110487620.2), which involves 1D carbon nanofibers, the carbon nanomaterials involved in this invention are 3D carbon nanoflowers. Furthermore, the prior art mainly utilizes carboxylation and sulfidation to modify the surface of CNFs, thereby enabling them to disperse well in the polymer. Additionally, sulfonated polyether sulfone (SPES) can be grafted onto the CNFs surface to improve their dispersibility. Simultaneously, SPES possesses unique sulfonic acid groups, which can improve ionic conductivity, thus enhancing the proton conductivity of the proton exchange membrane. In contrast, this invention is based on sulfonated carbon nanoflowers (SCNFs), a 3D flower-like porous carbon nanomaterial with high surface roughness, high specific surface area, and multidirectional ion transport channels. It has more interaction sites with the polymer matrix, allowing for better control of the hybrid membrane microphase separation to optimize the proton conduction path and improve the proton conductivity of the proton exchange membrane. Therefore, it is evident that the two methods differ significantly in their mechanisms for improving the proton conductivity of the proton exchange membrane. Furthermore, the optimal proton conductivity of the prior art (0.101 S / cm) is significantly lower than the optimal proton conductivity of the present invention (0.292 S / cm).

[0042] Furthermore, compared with current research on non-flower-shaped carbon nanospheres (such as fullerenes) in promoting the proton conductivity of polymer hybrid membranes, the carbon nanoflowers prepared in this invention have a more significant advantage in improving the proton conductivity of polymer hybrid membranes. For example, the existing study "Fullerene composite proton conducting membranes for polymerelectrolyte fuel cells operating under low humidity conditions" (Journal of Membrane Science 281 (2006) 570-580) reported the use of C 60 Join C was prepared in 117 60 / Nafion hybrid membrane, which has a proton conductivity of 0.087 S cm⁻¹ at 80 °C and 95% RH. -1 This is much smaller than the optimal proton conductivity of 0.292 S cm⁻¹ in the embodiments of the present invention. -1The paper "Fabrication and characterization of fullerene–Nafion composite membranes" (Polymer 48(2007)4438-4448) reports the preparation of a fullerene / Nafion hybrid membrane by adding a polyhydroxyfullerene to Nafion. The membrane exhibits a proton conductivity of 0.046 S cm⁻¹ at room temperature and 80% RH. -1 This is significantly lower than the optimal proton conductivity of 0.292 S cm⁻¹ in the embodiments of the present invention. -1 .

[0043] In summary, this invention, by introducing 3D carbon nanomaterials into a proton exchange membrane, yields a modified proton exchange membrane that exhibits excellent performance in both proton transport and stability. This provides a valuable reference for the rational design and construction of carbon nanomaterials to enhance the proton conductivity of proton exchange membranes. The invention is extremely simple to operate, has low production costs, mild preparation conditions, and is easy to mass-produce, possessing a solid foundation for industrial production and broad application prospects. Attached Figure Description

[0044] Figure 1 The images are transmission electron microscope (TEM) images of sulfonated carbon nanoflowers (SCNF) obtained in Example 1 of this invention at different magnifications.

[0045] Figure 2 This is a comparison of the temperature-dependent proton conductivity (95% RH, RH: relative humidity) of the sulfonated carbon nanoflower (SCNF) hybrid proton exchange membranes (with doping amounts of 0.7, 1.4, and 2.1 wt% of the Nafion matrix, respectively) and the unhybridized proton exchange membranes obtained in Examples 1, 2, and 3 of this invention. In the figures, "RN" represents the unhybridized proton exchange membrane; "SCNF / RN-0.7" represents the SCNF hybrid proton exchange membrane with SCNF doping amount of 0.7 wt% of the Nafion matrix (i.e., the sample obtained in Example 1); "SCNF / RN-1.4" represents the SCNF hybrid proton exchange membrane with SCNF doping amount of 1.4 wt% of the Nafion matrix (i.e., the sample obtained in Example 2); and "SCNF / RN-2.1" represents the SCNF hybrid proton exchange membrane with SCNF doping amount of 2.1 wt% of the Nafion matrix (i.e., the sample obtained in Example 3).

[0046] Figure 3The graph shows a comparison of the temperature-dependent proton conductivity (95% RH) of CNF- and SCNF-hybridized proton exchange membranes (both doped at 1.4 wt% of the Nafion matrix mass) with and without the CNF- and SCNF-hybridized proton exchange membranes. In the graph, "RN" represents the unhybridized proton exchange membrane, "CNF / RN-1.4" represents the CNF-hybridized proton exchange membrane with CNF doping at 1.4 wt% of the Nafion matrix mass, and "SCNF / RN-1.4" represents the SCNF-hybridized proton exchange membrane with SCNF doping at 1.4 wt% of the Nafion matrix mass (i.e., the sample obtained in Example 2).

[0047] Figure 4 This is a schematic diagram of the proton conductivity stability of a hybrid proton exchange membrane with SCNF doping at 1.4 wt% of the Nafion matrix (i.e., the sample obtained in Example 2) at 90 °C and 95% RH. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0049] In general, the preparation of the sulfonated carbon nanoflower-modified polymer hybrid proton exchange membrane in this invention involves first obtaining sulfonated carbon nanoflowers (SCNF), and then doping them into a polymer to obtain the sulfonated carbon nanoflower-modified polymer hybrid proton exchange membrane. For example, it may include the following steps: (1) Acrylonitrile is polymerized to obtain polyacrylonitrile (PACN) flower-like material. (2) PACN is stabilized and carbonized to convert it into carbon nanoflowers (CNF). (3) CN is sulfonated to convert it into sulfonated carbon nanoflowers (SCNF). (4) SCNF is added to a sulfonated polymer solution to form a casting solution and a membrane material, which is then soaked in hydrogen peroxide, acid, and deionized water to obtain the sulfonated carbon nanoflower-modified polymer hybrid proton exchange membrane.

[0050] The following are specific examples:

[0051] Example 1

[0052] 1. Add 500 mL of acrylonitrile and 500 mg of azobisisobutyronitrile (azobisisobutyronitrile concentration in the reaction system before polymerization is ~0.5 mg / mL) to 500 mL of acetone solvent. Then, carry out the polymerization reaction at 70 °C and under N2 protection for 2 h to obtain polyacrylonitrile (PACN).

[0053] 2. The obtained PACN was first placed in a muffle furnace and stabilized in air at 230°C for 2 hours. Then it was transferred to a tube furnace and carbonized at 1000°C for 2 hours. It was first washed with 0.1 mol / L hydrochloric acid aqueous solution, then washed with deionized water and methanol in sequence. Finally, it was dried in a vacuum oven at 70°C for 10 hours to obtain carbon nanoflowers (CNF).

[0054] 3. Weigh 120 mg CNF and place it in 50 mL of 18.4 mol / L concentrated sulfuric acid (the concentration of CNF in concentrated sulfuric acid is 2.4 mg / mL). Stir and reflux for 15 h under N2 protection at 120 °C. Centrifuge to separate the product, wash it with deionized water and methanol in sequence, and then dry it in a vacuum oven at 70 °C for 10 h to obtain sulfonated carbon nanoflowers (SCNF).

[0055] 4. Take 4 mL of commercially available Nafion solution (5 wt%), evaporate it into a gel, add 4 mL of DMF, and continue evaporating for 10 min. Add 0.7 wt% SCNF to the Nafion solution and sonicate for 1 h to disperse it evenly. Carefully pour the dispersion into a mold and quickly place it in an 80°C oven. Start at 80°C for 1.5 h, then slowly increase the temperature to 120°C and maintain it for 24 h. Finally, soak the membrane in 3 wt% H2O2 solution at 80°C for 1 h, then acidify it with 1 M H2SO4 at 80°C for 1 h to convert the membrane to H2O. + The membrane is then soaked in deionized water to obtain the SCNF hybrid proton exchange membrane.

[0056] The proton exchange membrane prepared in this embodiment exhibits a proton conductivity of 0.223 S / cm at 90°C and 95% RH, which is approximately 0.53 times higher than that of the unmodified Nafion proton exchange membrane (0.146 S / cm). Figure 2 As shown, at 90°C and 95% RH for approximately 1604 min, the proton conductivity showed almost no decrease.

[0057] Example 2

[0058] 1. Add 500 mL of acrylonitrile and 500 mg of azobisisobutyronitrile (azobisisobutyronitrile concentration in the reaction system before polymerization is ~0.5 mg / mL) to 500 mL of acetone solvent. Then, carry out the polymerization reaction at 70 °C and under N2 protection for 2 h to obtain polyacrylonitrile (PACN).

[0059] 2. The obtained PACN was first placed in a muffle furnace and stabilized in air at 230°C for 2 hours. Then it was transferred to a tube furnace and carbonized at 1000°C for 2 hours. It was first washed with 0.1 mol / L hydrochloric acid aqueous solution, then washed with deionized water and methanol in sequence. Finally, it was dried in a vacuum oven at 70°C for 10 hours to obtain carbon nanoflowers (CNF).

[0060] 3. Weigh 120 mg CNF and place it in 50 mL of 18.4 mol / L concentrated sulfuric acid (the concentration of CNF in concentrated sulfuric acid is 2.4 mg / mL). Stir and reflux for 15 h under N2 protection at 120 °C. Centrifuge to separate the product, wash it with deionized water and methanol in sequence, and then dry it in a vacuum oven at 70 °C for 10 h to obtain sulfonated carbon nanoflowers (SCNF).

[0061] 4. Take 4 mL of commercially available Nafion solution (5 wt%), evaporate it into a gel, add 4 mL of DMF, and continue evaporating for 10 min. Add SCNF (1.4 wt% of the Nafion solution solute) to the above Nafion solution and sonicate for 1 h to disperse it evenly. Carefully pour the dispersion into a mold and quickly place it in an 80°C oven. Start at 80°C for 1.5 h, then slowly increase the temperature to 120°C and maintain it for 24 h. Finally, soak the membrane in 3 wt% H2O2 solution at 80°C for 1 h, then acidify it with 1 M H2SO4 at 80°C for 1 h to convert the membrane to H2O. + The membrane is then soaked in deionized water to obtain the SCNF hybrid proton exchange membrane.

[0062] The proton exchange membrane prepared in this embodiment exhibits a proton conductivity of 0.260 S / cm at 90°C and 95% RH, which is approximately 0.78 times higher than that of the unmodified Nafion proton exchange membrane (0.146 S / cm). Figure 2 As shown. At 90°C and 95% RH for approximately 1604 min, the proton conductivity showed almost no decrease, as... Figure 4 As shown.

[0063] Example 3

[0064] 1. Add 500 mL of acrylonitrile and 500 mg of azobisisobutyronitrile (azobisisobutyronitrile concentration in the reaction system before polymerization is ~0.5 mg / mL) to 500 mL of acetone solvent. Then, carry out the polymerization reaction at 70 °C and under N2 protection for 2 h to obtain polyacrylonitrile (PACN).

[0065] 2. The obtained PACN was first placed in a muffle furnace and stabilized in air at 230°C for 2 hours. Then it was transferred to a tube furnace and carbonized at 1000°C for 2 hours. It was first washed with 0.1 mol / L hydrochloric acid aqueous solution, then washed with deionized water and methanol in sequence. Finally, it was dried in a vacuum oven at 70°C for 10 hours to obtain carbon nanoflowers (CNF).

[0066] 3. Weigh 120 mg CNF and place it in 50 mL of 18.4 mol / L concentrated sulfuric acid (the concentration of CNF in concentrated sulfuric acid is 2.4 mg / mL). Stir and reflux for 15 h under N2 protection at 120 °C. Centrifuge to separate the product, wash it with deionized water and methanol in sequence, and then dry it in a vacuum oven at 70 °C for 10 h to obtain sulfonated carbon nanoflowers (SCNF).

[0067] 4. Take 4 mL of commercially available Nafion solution (5 wt%), evaporate it into a gel, add 4 mL of DMF, and continue evaporating for 10 min. Add SCNF (2.1 wt% of the Nafion solution solute) to the above Nafion solution and sonicate for 1 h to disperse it evenly. Carefully pour the dispersion into a mold and quickly place it in an 80°C oven. Start at 80°C for 1.5 h, then slowly increase the temperature to 120°C and maintain it for 24 h. Finally, soak the membrane in 3 wt% H2O2 solution at 80°C for 1 h, then acidify it with 1 M H2SO4 at 80°C for 1 h to convert the membrane to H2O. + The membrane is then soaked in deionized water to obtain the SCNF hybrid proton exchange membrane.

[0068] The proton exchange membrane prepared in this embodiment exhibits a proton conductivity of 0.225 S / cm at 90°C and 95% RH, which is approximately 0.54 times higher than that of the unmodified Nafion proton exchange membrane (0.146 S / cm). Figure 2 As shown, at 90°C and 95% RH for approximately 1604 min, the proton conductivity showed almost no decrease.

[0069] Example 4

[0070] 1. Add 500 mL of acrylonitrile and 500 mg of azobisisobutyronitrile (azobisisobutyronitrile concentration in the reaction system before polymerization is ~0.5 mg / mL) to 500 mL of acetone solvent. Then, carry out the polymerization reaction at 70 °C and under N2 protection for 2 h to obtain polyacrylonitrile (PACN).

[0071] 2. The obtained PACN was first placed in a muffle furnace and stabilized in air at 230°C for 2 hours. Then it was transferred to a tube furnace and carbonized at 700°C for 2 hours. It was first washed with 0.1 mol / L hydrochloric acid aqueous solution, then washed with deionized water and methanol in sequence. Finally, it was dried in a vacuum oven at 70°C for 10 hours to obtain carbon nanoflowers (CNF).

[0072] 3. Weigh 120 mg CNF and place it in 50 mL of 18.4 mol / L concentrated sulfuric acid (the concentration of CNF in concentrated sulfuric acid is 2.4 mg / mL). Stir and reflux for 15 h under N2 protection at 120 °C. Centrifuge to separate the product, wash it with deionized water and methanol in sequence, and then dry it in a vacuum oven at 70 °C for 10 h to obtain sulfonated carbon nanoflowers (SCNF).

[0073] 4. Take 4 mL of commercially available Nafion solution (5 wt%), evaporate it into a gel, add 4 mL of DMF, and continue evaporating for 10 min. Add SCNF (1.4 wt% of the Nafion solution solute) to the above Nafion solution and sonicate for 1 h to disperse it evenly. Carefully pour the dispersion into a mold and quickly place it in an 80°C oven. Start at 80°C for 1.5 h, then slowly increase the temperature to 120°C and maintain it for 24 h. Finally, soak the membrane in 3 wt% H2O2 solution at 80°C for 1 h, then acidify it with 1 M H2SO4 at 80°C for 1 h to convert the membrane to H2O. + The membrane is then soaked in deionized water to obtain the SCNF hybrid proton exchange membrane.

[0074] The proton exchange membrane prepared in this embodiment exhibits a proton conductivity of 0.212 S / cm at 90°C and 95% RH, which is approximately 0.45 times higher than that of the unmodified Nafion proton exchange membrane (0.146 S / cm). After being kept constant at 90°C and 95% RH for approximately 1604 min, the proton conductivity showed almost no decrease.

[0075] Example 5

[0076] 1. Add 500 mL of acrylonitrile and 500 mg of azobisisobutyronitrile (azobisisobutyronitrile concentration in the reaction system before polymerization is ~0.5 mg / mL) to 500 mL of acetone solvent. Then, carry out the polymerization reaction at 70 °C and under N2 protection for 2 h to obtain polyacrylonitrile (PACN).

[0077] 2. The obtained PACN was first placed in a muffle furnace and stabilized in air at 230°C for 2 hours. Then it was transferred to a tube furnace and carbonized at 1100°C for 2 hours. It was first washed with 0.1 mol / L hydrochloric acid aqueous solution, then washed with deionized water and methanol in sequence. Finally, it was dried in a vacuum oven at 70°C for 10 hours to obtain carbon nanoflowers (CNF).

[0078] 3. Weigh 120 mg CNF and place it in 50 mL of 18.4 mol / L concentrated sulfuric acid (the concentration of CNF in concentrated sulfuric acid is 2.4 mg / mL). Stir and reflux for 15 h under N2 protection at 120 °C. Centrifuge to separate the product, wash it with deionized water and methanol in sequence, and then dry it in a vacuum oven at 70 °C for 10 h to obtain sulfonated carbon nanoflowers (SCNF).

[0079] 4. Take 4 mL of commercially available Nafion solution (5 wt%), evaporate it into a gel, add 4 mL of DMF, and continue evaporating for 10 min. Add SCNF (1.4 wt% of the Nafion solution solute) to the above Nafion solution and sonicate for 1 h to disperse it evenly. Carefully pour the dispersion into a mold and quickly place it in an 80°C oven. Start at 80°C for 1.5 h, then slowly increase the temperature to 120°C and maintain it for 24 h. Finally, soak the membrane in 3 wt% H2O2 solution at 80°C for 1 h, then acidify it with 1 M H2SO4 at 80°C for 1 h to convert the membrane to H2O. + The membrane is then soaked in deionized water to obtain the SCNF hybrid proton exchange membrane.

[0080] The proton exchange membrane prepared in this embodiment exhibits a proton conductivity of up to 0.292 S / cm at 90°C and 95% RH, which is approximately 1.00 times higher than that of the unmodified Nafion proton exchange membrane (0.146 S / cm). After being kept constant at 90°C and 95% RH for approximately 1604 min, the proton conductivity showed almost no decrease.

[0081] Example 6

[0082] 1. Add 500 mL of acrylonitrile and 500 mg of azobisisobutyronitrile (azobisisobutyronitrile concentration in the reaction system before polymerization is ~0.5 mg / mL) to 500 mL of acetone solvent. Then, carry out the polymerization reaction at 70 °C and under N2 protection for 2 h to obtain polyacrylonitrile (PACN).

[0083] 2. The obtained PACN was first placed in a muffle furnace and stabilized in air at 230°C for 2 hours. Then it was transferred to a tube furnace and carbonized at 1000°C for 0.5 hours. It was first washed with 0.1 mol / L hydrochloric acid aqueous solution, then washed with deionized water and methanol in sequence. Finally, it was dried in a vacuum oven at 70°C for 10 hours to obtain carbon nanoflowers (CNF).

[0084] 3. Weigh 120 mg CNF and place it in 50 mL of 18.4 mol / L concentrated sulfuric acid (the concentration of CNF in concentrated sulfuric acid is 2.4 mg / mL). Stir and reflux for 15 h under N2 protection at 120 °C. Centrifuge to separate the product, wash it with deionized water and methanol in sequence, and then dry it in a vacuum oven at 70 °C for 10 h to obtain sulfonated carbon nanoflowers (SCNF).

[0085] 4. Take 4 mL of commercially available Nafion solution (5 wt%), evaporate it into a gel, add 4 mL of DMF, and continue evaporating for 10 min. Add SCNF (1.4 wt% of the Nafion solution solute) to the above Nafion solution and sonicate for 1 h to disperse it evenly. Carefully pour the dispersion into a mold and quickly place it in an 80°C oven. Start at 80°C for 1.5 h, then slowly increase the temperature to 120°C and maintain it for 24 h. Finally, soak the membrane in 3 wt% H2O2 solution at 80°C for 1 h, then acidify it with 1 M H2SO4 at 80°C for 1 h to convert the membrane to H2O. + The membrane is then soaked in deionized water to obtain the SCNF hybrid proton exchange membrane.

[0086] The proton exchange membrane prepared in this embodiment exhibits a proton conductivity of up to 0.165 S / cm at 90°C and 95% RH, which is approximately 0.13 times higher than that of the unmodified Nafion proton exchange membrane (0.146 S / cm). After being kept constant at 90°C and 95% RH for approximately 1604 min, the proton conductivity showed almost no decrease.

[0087] Example 7

[0088] 1. Add 500 mL of acrylonitrile and 500 mg of azobisisobutyronitrile (azobisisobutyronitrile concentration in the reaction system before polymerization is ~0.5 mg / mL) to 500 mL of acetone solvent. Then, carry out the polymerization reaction at 70 °C and under N2 protection for 2 h to obtain polyacrylonitrile (PACN).

[0089] 2. The obtained PACN was first placed in a muffle furnace and stabilized in air at 230°C for 2 hours. Then it was transferred to a tube furnace and carbonized at 1000°C for 8 hours. It was first washed with 0.1 mol / L hydrochloric acid aqueous solution, then washed with deionized water and methanol in sequence. Finally, it was dried in a vacuum oven at 70°C for 10 hours to obtain carbon nanoflowers (CNF).

[0090] 3. Weigh 120 mg CNF and place it in 50 mL of 18.4 mol / L concentrated sulfuric acid (the concentration of CNF in concentrated sulfuric acid is 2.4 mg / mL). Stir and reflux for 15 h under N2 protection at 120 °C. Centrifuge to separate the product, wash it with deionized water and methanol in sequence, and then dry it in a vacuum oven at 70 °C for 10 h to obtain sulfonated carbon nanoflowers (SCNF).

[0091] 4. Take 4 mL of commercially available Nafion solution (5 wt%), evaporate it into a gel, add 4 mL of DMF, and continue evaporating for 10 min. Add SCNF (1.4 wt% of the Nafion solution solute) to the above Nafion solution and sonicate for 1 h to disperse it evenly. Carefully pour the dispersion into a mold and quickly place it in an 80°C oven. Start at 80°C for 1.5 h, then slowly increase the temperature to 120°C and maintain it for 24 h. Finally, soak the membrane in 3 wt% H2O2 solution at 80°C for 1 h, then acidify it with 1 M H2SO4 at 80°C for 1 h to convert the membrane to H2O. + The membrane is then soaked in deionized water to obtain the SCNF hybrid proton exchange membrane.

[0092] The proton exchange membrane prepared in this embodiment exhibits a proton conductivity of 0.269 S / cm at 90°C and 95% RH, which is approximately 0.84 times higher than that of the unmodified Nafion proton exchange membrane (0.146 S / cm). After being kept constant at 90°C and 95% RH for approximately 1604 min, the proton conductivity showed almost no decrease.

[0093] Example 8

[0094] 1. Add 500 mL of acrylonitrile and 500 mg of azobisisobutyronitrile (azobisisobutyronitrile concentration in the reaction system before polymerization is ~0.5 mg / mL) to 500 mL of acetone solvent. Then, carry out the polymerization reaction at 70 °C and under N2 protection for 2 h to obtain polyacrylonitrile (PACN).

[0095] 2. The obtained PACN was first placed in a muffle furnace and stabilized in air at 150°C for 2 hours. Then it was transferred to a tube furnace and carbonized at 1000°C for 8 hours. It was first washed with 0.1 mol / L hydrochloric acid aqueous solution, then washed with deionized water and methanol in sequence. Finally, it was dried in a vacuum oven at 70°C for 10 hours to obtain carbon nanoflowers (CNF).

[0096] 3. Weigh 120 mg CNF and place it in 50 mL of 18.4 mol / L concentrated sulfuric acid (the concentration of CNF in concentrated sulfuric acid is 2.4 mg / mL). Stir and reflux for 15 h under N2 protection at 120 °C. Centrifuge to separate the product, wash it with deionized water and methanol in sequence, and then dry it in a vacuum oven at 70 °C for 10 h to obtain sulfonated carbon nanoflowers (SCNF).

[0097] 4. Take 4 mL of commercially available Nafion solution (5 wt%), evaporate it into a gel, add 4 mL of DMF, and continue evaporating for 10 min. Add SCNF (1.4 wt% of the Nafion solution solute) to the above Nafion solution and sonicate for 1 h to disperse it evenly. Carefully pour the dispersion into a mold and quickly place it in an 80°C oven. Start at 80°C for 1.5 h, then slowly increase the temperature to 120°C and maintain it for 24 h. Finally, soak the membrane in 3 wt% H2O2 solution at 80°C for 1 h, then acidify it with 1 M H2SO4 at 80°C for 1 h to convert the membrane to H2O. + The membrane is then soaked in deionized water to obtain the SCNF hybrid proton exchange membrane.

[0098] The proton exchange membrane prepared in this embodiment exhibits a proton conductivity of 0.229 S / cm at 90°C and 95% RH, which is approximately 0.57 times higher than that of the unmodified Nafion proton exchange membrane (0.146 S / cm). After being held constant at 90°C and 95% RH for approximately 1604 min, the proton conductivity showed almost no decrease.

[0099] Example 9

[0100] 1. Add 500 mL of acrylonitrile and 500 mg of azobisisobutyronitrile (azobisisobutyronitrile concentration in the reaction system before polymerization is ~0.5 mg / mL) to 500 mL of acetone solvent. Then, carry out the polymerization reaction at 70 °C and under N2 protection for 2 h to obtain polyacrylonitrile (PACN).

[0101] 2. The obtained PACN was first placed in a muffle furnace and stabilized in air at 300°C for 2 hours. Then it was transferred to a tube furnace and carbonized at 1000°C for 8 hours. It was first washed with 0.1 mol / L hydrochloric acid aqueous solution, then washed with deionized water and methanol in sequence. Finally, it was dried in a vacuum oven at 70°C for 10 hours to obtain carbon nanoflowers (CNF).

[0102] 3. Weigh 120 mg CNF and place it in 50 mL of 18.4 mol / L concentrated sulfuric acid (the concentration of CNF in concentrated sulfuric acid is 2.4 mg / mL). Stir and reflux for 15 h under N2 protection at 120 °C. Centrifuge to separate the product, wash it with deionized water and methanol in sequence, and then dry it in a vacuum oven at 70 °C for 10 h to obtain sulfonated carbon nanoflowers (SCNF).

[0103] 4. Take 4 mL of commercially available Nafion solution (5 wt%), evaporate it into a gel, add 4 mL of DMF, and continue evaporating for 10 min. Add SCNF (1.4 wt% of the Nafion solution solute) to the above Nafion solution and sonicate for 1 h to disperse it evenly. Carefully pour the dispersion into a mold and quickly place it in an 80°C oven. Start at 80°C for 1.5 h, then slowly increase the temperature to 120°C and maintain it for 24 h. Finally, soak the membrane in 3 wt% H2O2 solution at 80°C for 1 h, then acidify it with 1 M H2SO4 at 80°C for 1 h to convert the membrane to H2O. + The membrane is then soaked in deionized water to obtain the SCNF hybrid proton exchange membrane.

[0104] The proton exchange membrane prepared in this embodiment exhibits a proton conductivity of up to 0.264 S / cm at 90°C and 95% RH, which is approximately 0.81 times higher than that of the unmodified Nafion proton exchange membrane (0.146 S / cm). After being kept constant at 90°C and 95% RH for approximately 1604 min, the proton conductivity showed almost no decrease.

[0105] Example 10

[0106] 1. Add 500 mL of acrylonitrile and 500 mg of azobisisobutyronitrile (azobisisobutyronitrile concentration in the reaction system before polymerization is ~0.5 mg / mL) to 500 mL of acetone solvent. Then, carry out the polymerization reaction at 70 °C and under N2 protection for 2 h to obtain polyacrylonitrile (PACN).

[0107] 2. The obtained PACN was first placed in a muffle furnace and stabilized in air at 230°C for 0.5 h. Then it was transferred to a tube furnace and carbonized at 1000°C for 8 h. It was first washed with 0.1 mol / L hydrochloric acid aqueous solution, then washed with deionized water and methanol in sequence. Finally, it was dried in a vacuum oven at 70°C for 10 h to obtain carbon nanoflowers (CNF).

[0108] 3. Weigh 120 mg CNF and place it in 50 mL of 18.4 mol / L concentrated sulfuric acid (the concentration of CNF in concentrated sulfuric acid is 2.4 mg / mL). Stir and reflux for 15 h under N2 protection at 120 °C. Centrifuge to separate the product, wash it with deionized water and methanol in sequence, and then dry it in a vacuum oven at 70 °C for 10 h to obtain sulfonated carbon nanoflowers (SCNF).

[0109] 4. Take 4 mL of commercially available Nafion solution (5 wt%), evaporate it into a gel, add 4 mL of DMF, and continue evaporating for 10 min. Add SCNF (1.4 wt% of the Nafion solution solute) to the above Nafion solution and sonicate for 1 h to disperse it evenly. Carefully pour the dispersion into a mold and quickly place it in an 80°C oven. Start at 80°C for 1.5 h, then slowly increase the temperature to 120°C and maintain it for 24 h. Finally, soak the membrane in 3 wt% H2O2 solution at 80°C for 1 h, then acidify it with 1 M H2SO4 at 80°C for 1 h to convert the membrane to H2O. + The membrane is then soaked in deionized water to obtain the SCNF hybrid proton exchange membrane.

[0110] The proton exchange membrane prepared in this embodiment exhibits a proton conductivity of 0.233 S / cm at 90°C and 95% RH, which is approximately 0.60 times higher than that of the unmodified Nafion proton exchange membrane (0.146 S / cm). After being kept constant at 90°C and 95% RH for approximately 1604 min, the proton conductivity showed almost no decrease.

[0111] Example 11

[0112] 1. Add 500 mL of acrylonitrile and 500 mg of azobisisobutyronitrile (azobisisobutyronitrile concentration in the reaction system before polymerization is ~0.5 mg / mL) to 500 mL of acetone solvent. Then, carry out the polymerization reaction at 70 °C and under N2 protection for 2 h to obtain polyacrylonitrile (PACN).

[0113] 2. The obtained PACN was first placed in a muffle furnace and stabilized in air at 230°C for 8 hours. Then it was transferred to a tube furnace and carbonized at 1000°C for 8 hours. It was first washed with 0.1 mol / L hydrochloric acid aqueous solution, then washed with deionized water and methanol in sequence. Finally, it was dried in a vacuum oven at 70°C for 10 hours to obtain carbon nanoflowers (CNF).

[0114] 3. Weigh 120 mg CNF and place it in 50 mL of 18.4 mol / L concentrated sulfuric acid (the concentration of CNF in concentrated sulfuric acid is 2.4 mg / mL). Stir and reflux for 15 h under N2 protection at 120 °C. Centrifuge to separate the product, wash it with deionized water and methanol in sequence, and then dry it in a vacuum oven at 70 °C for 10 h to obtain sulfonated carbon nanoflowers (SCNF).

[0115] 4. Take 4 mL of commercially available Nafion solution (5 wt%), evaporate it into a gel, add 4 mL of DMF, and continue evaporating for 10 min. Add SCNF (1.4 wt% of the Nafion solution solute) to the above Nafion solution and sonicate for 1 h to disperse it evenly. Carefully pour the dispersion into a mold and quickly place it in an 80°C oven. Start at 80°C for 1.5 h, then slowly increase the temperature to 120°C and maintain it for 24 h. Finally, soak the membrane in 3 wt% H2O2 solution at 80°C for 1 h, then acidify it with 1 M H2SO4 at 80°C for 1 h to convert the membrane to H2O. + The membrane is then soaked in deionized water to obtain the SCNF hybrid proton exchange membrane.

[0116] The proton exchange membrane prepared in this embodiment exhibits a proton conductivity of 0.267 S / cm at 90°C and 95% RH, which is approximately 0.83 times higher than that of the unmodified Nafion proton exchange membrane (0.146 S / cm). After being kept constant at 90°C and 95% RH for approximately 1604 min, the proton conductivity showed almost no decrease.

[0117] Example 12

[0118] 1. Add 500 mL of acrylonitrile and 500 mg of azobisisobutyronitrile (azobisisobutyronitrile concentration in the final reaction system before polymerization is ~0.5 mg / mL) to 500 mL of acetone solvent. Then, carry out the polymerization reaction at 70 °C and under N2 protection for 2 h to obtain polyacrylonitrile (PACN).

[0119] 2. The obtained PACN was first placed in a muffle furnace and stabilized in air at 230°C for 2 hours. Then it was transferred to a tube furnace and carbonized at 1000°C for 8 hours. It was first washed with 0.1 mol / L hydrochloric acid aqueous solution, then washed with deionized water and methanol in sequence. Finally, it was dried in a vacuum oven at 70°C for 10 hours to obtain carbon nanoflowers (CNF).

[0120] 3. Weigh 120 mg CNF and place it in 50 mL of 18.4 mol / L concentrated sulfuric acid (the concentration of CNF in concentrated sulfuric acid is 2.4 mg / mL). Stir and reflux for 15 h under N2 protection at 50 °C. Centrifuge to separate the product, wash it with deionized water and methanol in sequence, and then dry it in a vacuum oven at 70 °C for 10 h to obtain sulfonated carbon nanoflowers (SCNF).

[0121] 4. Take 4 mL of commercially available Nafion solution (5 wt%), evaporate it into a gel, add 4 mL of DMF, and continue evaporating for 10 min. Add SCNF (1.4 wt% of the Nafion solution solute) to the above Nafion solution and sonicate for 1 h to disperse it evenly. Carefully pour the dispersion into a mold and quickly place it in an 80°C oven. Start at 80°C for 1.5 h, then slowly increase the temperature to 120°C and maintain it for 24 h. Finally, soak the membrane in 3 wt% H2O2 solution at 80°C for 1 h, then acidify it with 1 M H2SO4 at 80°C for 1 h to convert the membrane to H2O. + The membrane is then soaked in deionized water to obtain the SCNF hybrid proton exchange membrane.

[0122] The proton exchange membrane prepared in this embodiment exhibits a proton conductivity of up to 0.216 S / cm at 90°C and 95% RH, which is approximately 0.48 times higher than that of the unmodified Nafion proton exchange membrane (0.146 S / cm). After being kept constant at 90°C and 95% RH for approximately 1604 min, the proton conductivity showed almost no decrease.

[0123] Example 13

[0124] 1. Add 500 mL of acrylonitrile and 500 mg of azobisisobutyronitrile (azobisisobutyronitrile concentration in the reaction system before polymerization is ~0.5 mg / mL) to 500 mL of acetone solvent. Then, carry out the polymerization reaction at 70 °C and under N2 protection for 2 h to obtain polyacrylonitrile (PACN).

[0125] 2. The obtained PACN was first placed in a muffle furnace and stabilized in air at 230°C for 2 hours. Then it was transferred to a tube furnace and carbonized at 1000°C for 8 hours. It was first washed with 0.1 mol / L hydrochloric acid aqueous solution, then washed with deionized water and methanol in sequence. Finally, it was dried in a vacuum oven at 70°C for 10 hours to obtain carbon nanoflowers (CNF).

[0126] 3. Weigh 120 mg CNF and place it in 50 mL of 18.4 mol / L concentrated sulfuric acid (the concentration of CNF in concentrated sulfuric acid is 2.4 mg / mL). Stir and reflux for 15 h under N2 protection at 130 °C. Centrifuge to separate the product, wash it with deionized water and methanol in sequence, and then dry it in a vacuum oven at 70 °C for 10 h to obtain sulfonated carbon nanoflowers (SCNF).

[0127] 4. Take 4 mL of commercially available Nafion solution (5 wt%), evaporate it into a gel, add 4 mL of DMF, and continue evaporating for 10 min. Add SCNF (1.4 wt% of the Nafion solution solute) to the above Nafion solution and sonicate for 1 h to disperse it evenly. Carefully pour the dispersion into a mold and quickly place it in an 80°C oven. Start at 80°C for 1.5 h, then slowly increase the temperature to 120°C and maintain it for 24 h. Finally, soak the membrane in 3 wt% H2O2 solution at 80°C for 1 h, then acidify it with 1 M H2SO4 at 80°C for 1 h to convert the membrane to H2O. + The membrane is then soaked in deionized water to obtain the SCNF hybrid proton exchange membrane.

[0128] The proton exchange membrane prepared in this embodiment exhibits a proton conductivity of 0.271 S / cm at 90°C and 95% RH, which is approximately 0.86 times higher than that of the unmodified Nafion proton exchange membrane (0.146 S / cm). After being kept constant at 90°C and 95% RH for approximately 1604 min, the proton conductivity showed almost no decrease.

[0129] Example 14

[0130] 1. Add 500 mL of acrylonitrile and 500 mg of azobisisobutyronitrile (azobisisobutyronitrile concentration in the reaction system before polymerization is ~0.5 mg / mL) to 500 mL of acetone solvent. Then, carry out the polymerization reaction at 70 °C and under N2 protection for 2 h to obtain polyacrylonitrile (PACN).

[0131] 2. The obtained PACN was first placed in a muffle furnace and stabilized in air at 230°C for 2 hours. Then it was transferred to a tube furnace and carbonized at 1000°C for 8 hours. It was first washed with 0.1 mol / L hydrochloric acid aqueous solution, then washed with deionized water and methanol in sequence. Finally, it was dried in a vacuum oven at 70°C for 10 hours to obtain carbon nanoflowers (CNF).

[0132] 3. Weigh 120 mg CNF and place it in 50 mL of 18.4 mol / L concentrated sulfuric acid (the concentration of CNF in concentrated sulfuric acid is 2.4 mg / mL). Stir and reflux for 8 h under N2 protection at 120 °C. Centrifuge to separate the product, wash it with deionized water and methanol in sequence, and then dry it in a vacuum oven at 70 °C for 10 h to obtain sulfonated carbon nanoflowers (SCNF).

[0133] 4. Take 4 mL of commercially available Nafion solution (5 wt%), evaporate it into a gel, add 4 mL of DMF, and continue evaporating for 10 min. Add SCNF (1.4 wt% of the Nafion solution solute) to the above Nafion solution and sonicate for 1 h to disperse it evenly. Carefully pour the dispersion into a mold and quickly place it in an 80°C oven. Start at 80°C for 1.5 h, then slowly increase the temperature to 120°C and maintain it for 24 h. Finally, soak the membrane in 3 wt% H2O2 solution at 80°C for 1 h, then acidify it with 1 M H2SO4 at 80°C for 1 h to convert the membrane to H2O. + The membrane is then soaked in deionized water to obtain the SCNF hybrid proton exchange membrane.

[0134] The proton exchange membrane prepared in this embodiment exhibits a proton conductivity of 0.241 S / cm at 90°C and 95% RH, which is approximately 0.65 times higher than that of the unmodified Nafion proton exchange membrane (0.146 S / cm). After being kept constant at 90°C and 95% RH for approximately 1604 min, the proton conductivity showed almost no decrease.

[0135] Example 15

[0136] 1. Add 500 mL of acrylonitrile and 500 mg of azobisisobutyronitrile (azobisisobutyronitrile concentration in the reaction system before polymerization is ~0.5 mg / mL) to 500 mL of acetone solvent. Then, carry out the polymerization reaction at 70 °C and under N2 protection for 2 h to obtain polyacrylonitrile (PACN).

[0137] 2. The obtained PACN was first placed in a muffle furnace and stabilized in air at 230°C for 2 hours. Then it was transferred to a tube furnace and carbonized at 1000°C for 8 hours. It was first washed with 0.1 mol / L hydrochloric acid aqueous solution, then washed with deionized water and methanol in sequence. Finally, it was dried in a vacuum oven at 70°C for 10 hours to obtain carbon nanoflowers (CNF).

[0138] 3. Weigh 120 mg CNF and place it in 50 mL of 18.4 mol / L concentrated sulfuric acid (the concentration of CNF in concentrated sulfuric acid is 2.4 mg / mL). Stir and reflux for 24 h at 120 °C under N2 protection. Centrifuge to separate the product, wash it with deionized water and methanol in sequence, and then dry it in a vacuum oven at 70 °C for 10 h to obtain sulfonated carbon nanoflowers (SCNF).

[0139] 4. Take 4 mL of commercially available Nafion solution (5 wt%), evaporate it into a gel, add 4 mL of DMF, and continue evaporating for 10 min. Add SCNF (1.4 wt% of the Nafion solution solute) to the above Nafion solution and sonicate for 1 h to disperse it evenly. Carefully pour the dispersion into a mold and quickly place it in an 80°C oven. Start at 80°C for 1.5 h, then slowly increase the temperature to 120°C and maintain it for 24 h. Finally, soak the membrane in 3 wt% H2O2 solution at 80°C for 1 h, then acidify it with 1 M H2SO4 at 80°C for 1 h to convert the membrane to H2O. + The membrane is then soaked in deionized water to obtain the SCNF hybrid proton exchange membrane.

[0140] The proton exchange membrane prepared in this embodiment exhibits a proton conductivity of 0.272 S / cm at 90°C and 95% RH, which is approximately 0.86 times higher than that of the unmodified Nafion proton exchange membrane (0.146 S / cm). After being kept constant at 90°C and 95% RH for approximately 1604 min, the proton conductivity showed almost no decrease.

[0141] Example 16

[0142] 1. Add 500 mL of acrylonitrile and 500 mg of azobisisobutyronitrile (azobisisobutyronitrile concentration in the reaction system before polymerization is ~0.5 mg / mL) to 500 mL of acetone solvent. Then, carry out the polymerization reaction at 30 °C under N2 protection for 2 h to obtain polyacrylonitrile (PACN).

[0143] 2. The obtained PACN was first placed in a muffle furnace and stabilized in air at 230°C for 2 hours. Then it was transferred to a tube furnace and carbonized at 1000°C for 8 hours. It was first washed with 0.1 mol / L hydrochloric acid aqueous solution, then washed with deionized water and methanol in sequence. Finally, it was dried in a vacuum oven at 70°C for 10 hours to obtain carbon nanoflowers (CNF).

[0144] 3. Weigh 120 mg CNF and place it in 50 mL of 18.4 mol / L concentrated sulfuric acid (the concentration of CNF in concentrated sulfuric acid is 2.4 mg / mL). Stir and reflux for 15 h under N2 protection at 120 °C. Centrifuge to separate the product, wash it with deionized water and methanol in sequence, and then dry it in a vacuum oven at 70 °C for 10 h to obtain sulfonated carbon nanoflowers (SCNF).

[0145] 4. Take 4 mL of commercially available Nafion solution (5 wt%), evaporate it into a gel, add 4 mL of DMF, and continue evaporating for 10 min. Add SCNF (1.4 wt% of the Nafion solution solute) to the above Nafion solution and sonicate for 1 h to disperse it evenly. Carefully pour the dispersion into a mold and quickly place it in an 80°C oven. Start at 80°C for 1.5 h, then slowly increase the temperature to 120°C and maintain it for 24 h. Finally, soak the membrane in 3 wt% H2O2 solution at 80°C for 1 h, then acidify it with 1 M H2SO4 at 80°C for 1 h to convert the membrane to H2O. + The membrane is then soaked in deionized water to obtain the SCNF hybrid proton exchange membrane.

[0146] The proton exchange membrane prepared in this embodiment exhibits a proton conductivity of up to 0.165 S / cm at 90°C and 95% RH, which is approximately 0.13 times higher than that of the unmodified Nafion proton exchange membrane (0.146 S / cm). After being kept constant at 90°C and 95% RH for approximately 1604 min, the proton conductivity showed almost no decrease.

[0147] Example 17

[0148] 1. Add 500 mL of acrylonitrile and 500 mg of azobisisobutyronitrile (azobisisobutyronitrile concentration in the reaction system before polymerization is ~0.5 mg / mL) to 500 mL of acetone solvent. Then, carry out the polymerization reaction at 120 °C under N2 protection for 2 h to obtain polyacrylonitrile (PACN).

[0149] 2. The obtained PACN was first placed in a muffle furnace and stabilized in air at 230°C for 2 hours. Then it was transferred to a tube furnace and carbonized at 1000°C for 8 hours. It was first washed with 0.1 mol / L hydrochloric acid aqueous solution, then washed with deionized water and methanol in sequence. Finally, it was dried in a vacuum oven at 70°C for 10 hours to obtain carbon nanoflowers (CNF).

[0150] 3. Weigh 120 mg CNF and place it in 50 mL of 18.4 mol / L concentrated sulfuric acid (the concentration of CNF in concentrated sulfuric acid is 2.4 mg / mL). Stir and reflux for 15 h under N2 protection at 120 °C. Centrifuge to separate the product, wash it with deionized water and methanol in sequence, and then dry it in a vacuum oven at 70 °C for 10 h to obtain sulfonated carbon nanoflowers (SCNF).

[0151] 4. Take 4 mL of commercially available Nafion solution (5 wt%), evaporate it into a gel, add 4 mL of DMF, and continue evaporating for 10 min. Add SCNF (1.4 wt% of the Nafion solution solute) to the above Nafion solution and sonicate for 1 h to disperse it evenly. Carefully pour the dispersion into a mold and quickly place it in an 80°C oven. Start at 80°C for 1.5 h, then slowly increase the temperature to 120°C and maintain it for 24 h. Finally, soak the membrane in 3 wt% H2O2 solution at 80°C for 1 h, then acidify it with 1 M H2SO4 at 80°C for 1 h to convert the membrane to H2O. + The membrane is then soaked in deionized water to obtain the SCNF hybrid proton exchange membrane.

[0152] The proton exchange membrane prepared in this embodiment exhibits a proton conductivity of 0.169 S / cm at 90°C and 95% RH, which is approximately 0.16 times higher than that of the unmodified Nafion proton exchange membrane (0.146 S / cm). After being kept constant at 90°C and 95% RH for approximately 1604 min, the proton conductivity showed almost no decrease.

[0153] Example 18

[0154] 1. Add 500 mL of acrylonitrile and 500 mg of azobisisobutyronitrile (azobisisobutyronitrile concentration in the reaction system before polymerization is ~0.5 mg / mL) to 500 mL of acetone solvent. Then, carry out the polymerization reaction at 70 °C and under N2 protection for 0.5 h to obtain polyacrylonitrile (PACN).

[0155] 2. The obtained PACN was first placed in a muffle furnace and stabilized in air at 230°C for 2 hours. Then it was transferred to a tube furnace and carbonized at 1000°C for 8 hours. It was first washed with 0.1 mol / L hydrochloric acid aqueous solution, then washed with deionized water and methanol in sequence. Finally, it was dried in a vacuum oven at 70°C for 10 hours to obtain carbon nanoflowers (CNF).

[0156] 3. Weigh 120 mg CNF and place it in 50 mL of 18.4 mol / L concentrated sulfuric acid (the concentration of CNF in concentrated sulfuric acid is 2.4 mg / mL). Stir and reflux for 15 h under N2 protection at 120 °C. Centrifuge to separate the product, wash it with deionized water and methanol in sequence, and then dry it in a vacuum oven at 70 °C for 10 h to obtain sulfonated carbon nanoflowers (SCNF).

[0157] 4. Take 4 mL of commercially available Nafion solution (5 wt%), evaporate it into a gel, add 4 mL of DMF, and continue evaporating for 10 min. Add SCNF (1.4 wt% of the Nafion solution solute) to the above Nafion solution and sonicate for 1 h to disperse it evenly. Carefully pour the dispersion into a mold and quickly place it in an 80°C oven. Start at 80°C for 1.5 h, then slowly increase the temperature to 120°C and maintain it for 24 h. Finally, soak the membrane in 3 wt% H2O2 solution at 80°C for 1 h, then acidify it with 1 M H2SO4 at 80°C for 1 h to convert the membrane to H2O. + The membrane is then soaked in deionized water to obtain the SCNF hybrid proton exchange membrane.

[0158] The proton exchange membrane prepared in this embodiment exhibits a proton conductivity of 0.181 S / cm at 90°C and 95% RH, which is approximately 0.24 times higher than that of the unmodified Nafion proton exchange membrane (0.146 S / cm). After being kept constant at 90°C and 95% RH for approximately 1604 min, the proton conductivity showed almost no decrease.

[0159] Example 19

[0160] 1. Add 500 mL of acrylonitrile and 500 mg of azobisisobutyronitrile (azobisisobutyronitrile concentration in the reaction system before polymerization is ~0.5 mg / mL) to 500 mL of acetone solvent. Then, carry out the polymerization reaction at 70 °C and under N2 protection for 8 h to obtain polyacrylonitrile (PACN).

[0161] 2. The obtained PACN was first placed in a muffle furnace and stabilized in air at 230°C for 2 hours. Then it was transferred to a tube furnace and carbonized at 1000°C for 8 hours. It was first washed with 0.1 mol / L hydrochloric acid aqueous solution, then washed with deionized water and methanol in sequence. Finally, it was dried in a vacuum oven at 70°C for 10 hours to obtain carbon nanoflowers (CNF).

[0162] 3. Weigh 120 mg CNF and place it in 50 mL of 18.4 mol / L concentrated sulfuric acid (the concentration of CNF in concentrated sulfuric acid is 2.4 mg / mL). Stir and reflux for 15 h under N2 protection at 120 °C. Centrifuge to separate the product, wash it with deionized water and methanol in sequence, and then dry it in a vacuum oven at 70 °C for 10 h to obtain sulfonated carbon nanoflowers (SCNF).

[0163] 4. Take 4 mL of commercially available Nafion solution (5 wt%), evaporate it into a gel, add 4 mL of DMF, and continue evaporating for 10 min. Add SCNF (1.4 wt% of the Nafion solution solute) to the above Nafion solution and sonicate for 1 h to disperse it evenly. Carefully pour the dispersion into a mold and quickly place it in an 80°C oven. Start at 80°C for 1.5 h, then slowly increase the temperature to 120°C and maintain it for 24 h. Finally, soak the membrane in 3 wt% H2O2 solution at 80°C for 1 h, then acidify it with 1 M H2SO4 at 80°C for 1 h to convert the membrane to H2O. + The membrane is then soaked in deionized water to obtain the SCNF hybrid proton exchange membrane.

[0164] The proton exchange membrane prepared in this embodiment exhibits a proton conductivity of 0.268 S / cm at 90°C and 95% RH, which is approximately 0.84 times higher than that of the unmodified Nafion proton exchange membrane (0.146 S / cm). After being kept constant at 90°C and 95% RH for approximately 1604 min, the proton conductivity showed almost no decrease.

[0165] Example 20

[0166] 1. Add 500 mL of acrylonitrile and 200 mg of azobisisobutyronitrile (azobisisobutyronitrile concentration in the reaction system before polymerization is ~0.2 mg / mL) to 500 mL of acetone solvent. Then, carry out the polymerization reaction at 70 °C and under N2 protection for 2 h to obtain polyacrylonitrile (PACN).

[0167] 2. The obtained PACN was first placed in a muffle furnace and stabilized in air at 230°C for 2 hours. Then it was transferred to a tube furnace and carbonized at 1000°C for 8 hours. It was first washed with 0.1 mol / L hydrochloric acid aqueous solution, then washed with deionized water and methanol in sequence. Finally, it was dried in a vacuum oven at 70°C for 10 hours to obtain carbon nanoflowers (CNF).

[0168] 3. Weigh 120 mg CNF and place it in 50 mL of 18.4 mol / L concentrated sulfuric acid (the concentration of CNF in concentrated sulfuric acid is 2.4 mg / mL). Stir and reflux for 15 h under N2 protection at 120 °C. Centrifuge to separate the product, wash it with deionized water and methanol in sequence, and then dry it in a vacuum oven at 70 °C for 10 h to obtain sulfonated carbon nanoflowers (SCNF).

[0169] 4. Take 4 mL of commercially available Nafion solution (5 wt%), evaporate it into a gel, add 4 mL of DMF, and continue evaporating for 10 min. Add SCNF (1.4 wt% of the Nafion solution solute) to the above Nafion solution and sonicate for 1 h to disperse it evenly. Carefully pour the dispersion into a mold and quickly place it in an 80°C oven. Start at 80°C for 1.5 h, then slowly increase the temperature to 120°C and maintain it for 24 h. Finally, soak the membrane in 3 wt% H2O2 solution at 80°C for 1 h, then acidify it with 1 M H2SO4 at 80°C for 1 h to convert the membrane to H2O. + The membrane is then soaked in deionized water to obtain the SCNF hybrid proton exchange membrane.

[0170] The proton exchange membrane prepared in this embodiment exhibits a proton conductivity of 0.219 S / cm at 90°C and 95% RH, which is approximately 0.50 times higher than that of the unmodified Nafion proton exchange membrane (0.146 S / cm). After being kept constant at 90°C and 95% RH for approximately 1604 min, the proton conductivity showed almost no decrease.

[0171] Example 21

[0172] 1. Add 500 mL of acrylonitrile and 1500 mg of azobisisobutyronitrile (azobisisobutyronitrile concentration in the reaction system before polymerization is ~1.5 mg / mL) to 500 mL of acetone solvent. Then, carry out the polymerization reaction at 70 °C and under N2 protection for 2 h to obtain polyacrylonitrile (PACN).

[0173] 2. The obtained PACN was first placed in a muffle furnace and stabilized in air at 230°C for 2 hours. Then it was transferred to a tube furnace and carbonized at 1000°C for 8 hours. It was first washed with 0.1 mol / L hydrochloric acid aqueous solution, then washed with deionized water and methanol in sequence. Finally, it was dried in a vacuum oven at 70°C for 10 hours to obtain carbon nanoflowers (CNF).

[0174] 3. Weigh 120 mg CNF and place it in 50 mL of 18.4 mol / L concentrated sulfuric acid (the concentration of CNF in concentrated sulfuric acid is 2.4 mg / mL). Stir and reflux for 15 h under N2 protection at 120 °C. Centrifuge to separate the product, wash it with deionized water and methanol in sequence, and then dry it in a vacuum oven at 70 °C for 10 h to obtain sulfonated carbon nanoflowers (SCNF).

[0175] 4. Take 4 mL of commercially available Nafion solution (5 wt%), evaporate it into a gel, add 4 mL of DMF, and continue evaporating for 10 min. Add SCNF (1.4 wt% of the Nafion solution solute) to the above Nafion solution and sonicate for 1 h to disperse it evenly. Carefully pour the dispersion into a mold and quickly place it in an 80°C oven. Start at 80°C for 1.5 h, then slowly increase the temperature to 120°C and maintain it for 24 h. Finally, soak the membrane in 3 wt% H2O2 solution at 80°C for 1 h, then acidify it with 1 M H2SO4 at 80°C for 1 h to convert the membrane to H2O. + The membrane is then soaked in deionized water to obtain the SCNF hybrid proton exchange membrane.

[0176] The proton exchange membrane prepared in this embodiment exhibits a proton conductivity of up to 0.224 S / cm at 90°C and 95% RH, which is approximately 0.53 times higher than that of the unmodified Nafion proton exchange membrane (0.146 S / cm). After being kept constant at 90°C and 95% RH for approximately 1604 min, the proton conductivity showed almost no decrease.

[0177] Example 22

[0178] 1. Add 500 mL of acrylonitrile and 500 mg of azobisisobutyronitrile (azobisisobutyronitrile concentration in the reaction system before polymerization is ~0.5 mg / mL) to 500 mL of acetone solvent. Then, carry out the polymerization reaction at 70 °C under Ar protection for 2 h to obtain polyacrylonitrile (PACN).

[0179] 2. The obtained PACN was first placed in a muffle furnace and stabilized in air at 230°C for 2 hours. Then it was transferred to a tube furnace and carbonized at 1000°C for 2 hours. It was first washed with 0.1 mol / L hydrochloric acid aqueous solution, then washed with deionized water and methanol in sequence. Finally, it was dried in a vacuum oven at 70°C for 10 hours to obtain carbon nanoflowers (CNF).

[0180] 3. Weigh 120 mg CNF and place it in 50 mL of 18.4 mol / L concentrated sulfuric acid (the concentration of CNF in concentrated sulfuric acid is 2.4 mg / mL). Stir and reflux for 15 h at 120 °C under Ar protection. Centrifuge to separate the product, wash it with deionized water and methanol in sequence, and then dry it in a vacuum oven at 70 °C for 10 h to obtain sulfonated carbon nanoflowers (SCNF).

[0181] 4. Take 4 mL of commercially available Nafion solution (5 wt%), evaporate it into a gel, add 4 mL of DMF, and continue evaporating for 10 min. Add SCNF (1.4 wt% of the Nafion solution solute) to the above Nafion solution and sonicate for 1 h to disperse it evenly. Carefully pour the dispersion into a mold and quickly place it in an 80°C oven. Start at 80°C for 1.5 h, then slowly increase the temperature to 120°C and maintain it for 24 h. Finally, soak the membrane in 3 wt% H2O2 solution at 80°C for 1 h, then acidify it with 1 M H2SO4 at 80°C for 1 h to convert the membrane to H2O. + The membrane is then soaked in deionized water to obtain the SCNF hybrid proton exchange membrane.

[0182] The proton exchange membrane prepared in this embodiment exhibits a proton conductivity of up to 0.262 S / cm at 90°C and 95% RH, which is approximately 0.79 times higher than that of the unmodified Nafion proton exchange membrane (0.146 S / cm). After being kept constant at 90°C and 95% RH for approximately 1604 min, the proton conductivity showed almost no decrease.

[0183] Example 23

[0184] 1. Add 500 mL of acrylonitrile and 500 mg of azobisisobutyronitrile (azobisisobutyronitrile concentration in the reaction system before polymerization is ~0.5 mg / mL) to 500 mL of acetone solvent. Then, carry out the polymerization reaction at 70 °C and under N2 protection for 2 h to obtain polyacrylonitrile (PACN).

[0185] 2. The obtained PACN was first placed in a muffle furnace and stabilized in air at 230°C for 2 hours. Then it was transferred to a tube furnace and carbonized at 1000°C for 2 hours. It was first washed with 0.1 mol / L hydrochloric acid aqueous solution, then washed with deionized water and methanol in sequence. Finally, it was dried in a vacuum oven at 70°C for 10 hours to obtain carbon nanoflowers (CNF).

[0186] 3. Weigh 120 mg CNF and place it in 50 mL of 12 mol / L concentrated sulfuric acid (the concentration of CNF in concentrated sulfuric acid is 2.4 mg / mL). Stir and reflux for 15 h under N2 protection at 120 °C. Centrifuge to separate the product, wash it with deionized water and methanol in sequence, and then dry it in a vacuum oven at 70 °C for 10 h to obtain sulfonated carbon nanoflowers (SCNF).

[0187] 4. Take 4 mL of commercially available Nafion solution (5 wt%), evaporate it into a gel, add 4 mL of DMF, and continue evaporating for 10 min. Add SCNF (1.4 wt% of the Nafion solution solute) to the above Nafion solution and sonicate for 1 h to disperse it evenly. Carefully pour the dispersion into a mold and quickly place it in an 80°C oven. Start at 80°C for 1.5 h, then slowly increase the temperature to 120°C and maintain it for 24 h. Finally, soak the membrane in 3 wt% H2O2 solution at 80°C for 1 h, then acidify it with 1 M H2SO4 at 80°C for 1 h to convert the membrane to H2O. + The membrane is then soaked in deionized water to obtain the SCNF hybrid proton exchange membrane.

[0188] The proton exchange membrane prepared in this embodiment exhibits a proton conductivity of 0.222 S / cm at 90°C and 95% RH, which is approximately 0.52 times higher than that of the unmodified Nafion proton exchange membrane (0.146 S / cm). After being kept constant at 90°C and 95% RH for approximately 1604 min, the proton conductivity showed almost no decrease.

[0189] Comparative Example 1

[0190] 1. Add 500 mL of acrylonitrile and 500 mg of azobisisobutyronitrile (azobisisobutyronitrile concentration in the reaction system before polymerization is ~0.5 mg / mL) to 500 mL of aqueous solvent. Then, carry out the polymerization reaction at 70 °C under N2 protection for 2 h to obtain polyacrylonitrile (PACN).

[0191] 2. The obtained PACN was first placed in a muffle furnace and stabilized in air at 230°C for 2 hours. Then it was transferred to a tube furnace and carbonized at 1000°C for 2 hours. It was first washed with 0.1 mol / L hydrochloric acid aqueous solution, then washed with deionized water and methanol in sequence. Finally, it was dried in a vacuum oven at 70°C for 10 hours to obtain carbon nanospheres (CNS).

[0192] 3. Weigh 120 mg CNF and place it in 50 mL of 18.4 mol / L concentrated sulfuric acid (the concentration of CNF in concentrated sulfuric acid is 2.4 mg / mL). Stir and reflux for 15 h under N2 protection at 120 °C. Centrifuge to separate the product, wash it with deionized water and methanol in sequence, and then dry it in a vacuum oven at 70 °C for 10 h to obtain sulfonated carbon nanospheres (SCNS).

[0193] 4. Take 4 mL of commercially available Nafion solution (5 wt%), evaporate it into a gel, add 4 mL of DMF, and continue evaporating for 10 min. Add SCNS (1.4 wt% of Nafion solution solute) to the above Nafion solution and sonicate for 1 h to disperse it evenly. Carefully pour the dispersion into a mold and quickly place it in an 80°C oven. Start at 80°C for 1.5 h, then slowly increase the temperature to 120°C and maintain it for 24 h. Finally, soak the membrane in 3 wt% H2O2 solution at 80°C for 1 h, then acidify it with 1 M H2SO4 at 80°C for 1 h to convert the membrane to H2O. + The membrane is then soaked in deionized water to obtain the SCNS hybrid proton exchange membrane.

[0194] The proton exchange membrane prepared in this comparative example exhibits a proton conductivity of 0.232 S / cm at 90°C and 95% RH, approximately 0.59 times higher than that of the unmodified Nafion proton exchange membrane (0.146 S / cm). This comparative example differs from Example 2 only in the solvent used in step 1 and the resulting spherical (rather than flower-like) nanoflowers. However, the proton conductivity of this comparative example is lower than that of Example 2 (0.260 S / cm), indicating that sulfonated carbon nanoflowers are more beneficial for improving the proton conductivity of proton exchange membranes.

[0195] Comparative Example 2

[0196] 1. Add 500 mL of acrylonitrile and 500 mg of azobisisobutyronitrile (azobisisobutyronitrile concentration in the reaction system before polymerization is ~0.5 mg / mL) to 500 mL of isopropanol solvent. Then, carry out the polymerization reaction at 70 °C and under N2 protection for 2 h to obtain polyacrylonitrile (PACN).

[0197] 2. The obtained PACN was first placed in a muffle furnace and stabilized in air at 230°C for 2 hours. Then it was transferred to a tube furnace and carbonized at 1000°C for 2 hours. It was first washed with 0.1 mol / L hydrochloric acid aqueous solution, then washed with deionized water and methanol in sequence. Finally, it was dried in a vacuum oven at 70°C for 10 hours to obtain leaf-shaped carbon nanoparticles (CNL).

[0198] 3. Weigh 120 mg CNF and place it in 50 mL of 18.4 mol / L concentrated sulfuric acid (the concentration of CNF in concentrated sulfuric acid is 2.4 mg / mL). Stir and reflux for 15 h under N2 protection at 120 °C. Centrifuge to separate the product, wash it with deionized water and methanol in sequence, and then dry it in a vacuum oven at 70 °C for 10 h to obtain sulfonated leaf-shaped carbon nanoparticles (SCNL).

[0199] 4. Take 4 mL of commercially available Nafion solution (5 wt%), evaporate it into a gel, add 4 mL of DMF, and continue evaporating for 10 min. Add SCNL (1.4 wt% of the Nafion solution solute) to the above Nafion solution and sonicate for 1 h to disperse it evenly. Carefully pour the dispersion into a mold and quickly place it in an 80°C oven. Start at 80°C for 1.5 h, then slowly increase the temperature to 120°C and maintain it for 24 h. Finally, soak the membrane in 3 wt% H2O2 solution at 80°C for 1 h, then acidify it with 1 M H2SO4 at 80°C for 1 h to convert the membrane to H2O. + The membrane is then soaked in deionized water to obtain the SCNL hybrid proton exchange membrane.

[0200] The proton exchange membrane prepared in this comparative example exhibits a proton conductivity of 0.243 S / cm at 90°C and 95% RH, approximately 0.66 times higher than that of the unmodified Nafion proton exchange membrane (0.146 S / cm). This comparative example differs from Example 2 only in the solvent used in step 1 and the resulting leaf-like (rather than flower-like) structure. However, the proton conductivity of this comparative example (0.239 S / cm) is lower than that of Example 2 (0.260 S / cm), indicating that sulfonated carbon nanoflowers are more beneficial for improving the proton conductivity of the proton exchange membrane.

[0201] In addition to the above embodiments, the sulfonated polymer solution (the sulfonated polymer being the matrix material constituting the proton exchange membrane) can be any of the following besides the commercially available Nafion solution: other perfluorosulfonic acid resins, sulfonated polyether ether ketones, sulfonated polybenzimidazoles, sulfonated polyether sulfones, or sulfonated polyimides. The solvent in the sulfonated polymer solution must be capable of forming a homogeneous solution of the sulfonated polymer. Besides using 12 mol / L and 18.4 mol / L concentrated sulfuric acid solutions for sulfonation, other concentrated sulfuric acid solutions in the concentration range of 12–18.4 mol / L can also be used for sulfonation, all achieving similar sulfonation effects. In addition to N2 and Ar, other inert gases can also be used as the protective gas.

[0202] In addition, all raw materials used in the above embodiments, unless otherwise specified, were commercially available.

[0203] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a polymer hybrid proton exchange membrane modified with sulfonated carbon nanoflowers, characterized in that, Includes the following steps: (1) Acrylonitrile and azobisisobutyronitrile were added to acetone solvent and polymerized at 30 ~ 120 °C for 0.5 ~ 8 h under a protective gas atmosphere; after the reaction, polyacrylonitrile was obtained by separation and drying. (2) The polyacrylonitrile obtained in step (1) is stabilized in air at 150 ~ 300 °C for 0.5 ~ 8 h; then, it is carbonized at 700 ~ 1100 °C for 0.5 ~ 8 h under a protective gas atmosphere; then, the obtained product is washed, separated and dried to obtain carbon nanoflowers. (3) The carbon nanoflowers obtained in step (2) are reacted with concentrated sulfuric acid at 50 ~ 130 °C for 8 ~ 24 h under a protective gas atmosphere; after the reaction, they are washed, separated and dried to obtain sulfonated carbon nanoflowers; wherein the concentration of the concentrated sulfuric acid is 12 ~ 18.4 mol / L. (4) The sulfonated carbon nanoflowers obtained in step (3) are added to the sulfonated polymer solution and ultrasonically treated to obtain a uniformly dispersed casting solution. Then, the casting solution is used to form a membrane material. After drying, the membrane is then soaked in hydrogen peroxide solution, acid and deionized water in sequence to obtain a polymer hybrid proton exchange membrane modified with sulfonated carbon nanoflowers. In step (4), the mass of the sulfonated carbon nanoflowers accounts for 0.7 to 2.1 wt% of the mass of the polymer matrix contained in the sulfonated polymer solution.

2. The preparation method according to claim 1, characterized in that, In step (4), the mass of the sulfonated carbon nanoflowers accounts for 1.1 to 1.7 wt% of the mass of the polymer matrix contained in the sulfonated polymer solution.

3. The preparation method according to claim 1, characterized in that, In step (1), the concentration of the azobisisobutyronitrile in the reaction system before the polymerization reaction is 0.2 to 1.5 mg / mL; The protective gas is either nitrogen or argon; The drying process specifically employs vacuum drying.

4. The preparation method according to claim 3, characterized in that, In step (1), the drying is performed in a vacuum oven at 35 to 140°C for 2 to 30 hours.

5. The preparation method according to claim 1, characterized in that, In step (2), the heating rate of the stabilization treatment is less than 1 °C / min; The protective gas is either nitrogen or argon; The drying process specifically employs vacuum drying. The heating rate of the carbonization treatment is less than 10 °C / min; The cleaning process involves first cleaning with hydrochloric acid aqueous solution, followed by cleaning with deionized water and methanol; wherein the concentration of the hydrochloric acid aqueous solution is 0.04 ~ 1 mol / L.

6. The preparation method according to claim 5, characterized in that, In step (2), the heating rate of the stabilization treatment is less than 0.5 ℃ / min; The drying process involves drying in a vacuum oven at 35-140°C for 2-30 hours. The heating rate of the carbonization process is 3 to 7 °C / min.

7. The preparation method according to claim 1, characterized in that, In step (3), the protective gas is either nitrogen or argon. The ratio of the amount of carbon nanoflower to the amount of concentrated sulfuric acid is (1 ~ 4 mg): (1 mL); The cleaning process involves sequentially washing with deionized water and methanol. The drying process specifically employs vacuum drying.

8. The preparation method according to claim 7, characterized in that, In step (3), the drying is performed in a vacuum oven at 35 to 140°C for 2 to 30 hours.

9. The preparation method according to claim 1, characterized in that, In step (4), the sulfonated polymer solution is one of a homogeneous solution of perfluorosulfonic acid resin, sulfonated polyether ether ketone, sulfonated polybenzimidazole, sulfonated polyether sulfone, or sulfonated polyimide; the concentration of the sulfonated polymer solution is 1 to 40 wt%. The casting solution is used to form a film material, specifically by coating the casting solution into a film, thereby forming a film material. The drying process involves placing the membrane material at 50-80°C. o In an oven at temperature C, heat to 110-150°C. o C, then keep it for 12 to 36 hours.

10. The preparation method according to claim 9, characterized in that, In step (4), the heating rate is less than 0.

5. o C / min.

11. The preparation method according to claim 9, characterized in that, In step (4), the heating rate is 0.1 ~ 0.

5. o C / min.

12. The preparation method according to claim 1, characterized in that, In step (4), the concentration of the hydrogen peroxide solution is 1 ~ 10 wt%; The acid solution is specifically a mixture of one or more of hydrochloric acid, sulfuric acid, and phosphoric acid, and the concentration of the acid solution is 0.4 ~ 4 mol / L.

13. A polymer hybrid proton exchange membrane modified with sulfonated carbon nanoflowers obtained by the preparation method according to any one of claims 1-12.

14. The application of the sulfonated carbon nanoflower-modified polymer hybrid proton exchange membrane as described in claim 13 in a proton exchange membrane fuel cell.

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