Composite graphite-based material for bipolar plate and preparation method of composite graphite-based material

Abstract

The invention provides a composite graphite-based material for a bipolar plate and a preparation method thereof, and the composite graphite-based material for the bipolar plate is prepared from the following raw materials in parts by weight: 80 to 100 parts of graphite, 8 to 15 parts of 4-(1-naphthyloxy-5-decyloxy) butyl trimethyl ammonium bromide, 5 to 10 parts of conductive agent and 10 to 30 parts of resin. The composite graphite-based material for the bipolar plate has good conductivity, air tightness and mechanical strength.

Description

Technical Field

[0001] The present invention relates to the technical field of bipolar plate materials for fuel cells, and in particular to a composite graphite-based material for bipolar plates and a preparation method thereof. Background Art

[0002] Fuel cells are a key industry in the new energy sector, with widespread applications in the automotive, aerospace, military, and various electronic smart devices. Bipolar plates are core components of fuel cells, separating and evenly introducing reactant gases, collecting and conducting current, supporting the membrane electrode, and enabling rapid drainage and heat dissipation within the fuel cell system.

[0003] Currently, the most widely used bipolar plate material is graphite, including carved hard graphite bipolar plates, flexible graphite bipolar plates, and composite graphite bipolar plates. Composite graphite bipolar plates offer advantages such as one-step molding and simple manufacturing processes, making them promising for large-scale industrial production.

[0004] Composite graphite-based materials are made by hot-pressing graphite powder mixed with a binder resin. Graphite powder has good electrical conductivity, but pure graphite plates have poor mechanical strength and are difficult to meet the airtightness requirements of bipolar plates. Therefore, a binder resin is added to improve both mechanical strength and airtightness. High conductivity in bipolar plates requires a higher graphite content, while improved airtightness and mechanical strength require a higher resin content.

[0005] In view of this, there is an urgent need to propose a composite graphite-based material for bipolar plates that can better balance the conductivity, air tightness and mechanical strength of the bipolar plates. Summary of the Invention

[0006] The object of the present invention is to provide a composite graphite-based material for bipolar plates to solve the problem in the prior art that composite graphite-based materials are difficult to achieve a balance between electrical conductivity, air tightness and mechanical strength of bipolar plates.

[0007] In order to solve the above technical problems, the technical solutions of the present invention are as follows:

[0008] A composite graphite-based material for bipolar plates, comprising the following raw materials in parts by weight:

[0009] 80-100 parts of graphite, 8-15 parts of 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, 5-10 parts of conductive agent, and 10-30 parts of resin.

[0010] Preferably, the resin is a phenolic resin or a mixture of a phenolic resin and an epoxy resin.

[0011] Preferably, the conductive agent is polyaniline.

[0012] Preferably, the composite graphite-based material for bipolar plates further comprises 0.6-1.8 parts of an intercalation regulator; the intercalation regulator is one or more of 1-naphthyl ammonium bromide, 2-naphthyl ammonium bromide, and 1-(naphthyloxy) hydrazine acetate.

[0013] Preferably, the intercalation regulator is a mixture of 1-naphthyl ammonium bromide and 1-(naphthyloxy) hydrazine acetate in a weight ratio of 1:(3.2-3.8).

[0014] Preferably, the intercalation regulator is a mixture of 2-naphthyl ammonium bromide and 1-(naphthyloxy) hydrazine acetate in a weight ratio of 1:(2.5-3.0).

[0015] Preferably, the composite graphite-based material for bipolar plates further comprises 1-3 parts of 1,4-diamino-2,3-dihydroanthraquinone.

[0016] The present invention provides a method for preparing a composite graphite-based material for a bipolar plate, comprising the following steps: uniformly mixing graphite, 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, a conductive agent, and a resin, and hot-pressing the mixture.

[0017] Preferably, the method for preparing the composite graphite-based material for bipolar plates comprises the following steps:

[0018] (1) taking graphite, 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, and water, and mixing them uniformly to obtain a mixed solution;

[0019] (2) taking a resin, a conductive agent, and a dispersant, mixing them uniformly, adding them to the mixed solution obtained in step (1), and mixing them uniformly to obtain a mixed slurry;

[0020] (3) drying and hot pressing the mixed slurry obtained in step (2) to obtain the product.

[0021] Preferably, the method for preparing the composite graphite-based material for bipolar plates comprises the following steps:

[0022] (1) taking graphite, 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, an intercalation regulator, and water, and mixing them uniformly to obtain a mixed solution;

[0023] (2) taking a resin, a conductive agent, and a dispersant, mixing them uniformly, adding them to the mixed solution obtained in step (1), and mixing them uniformly to obtain a mixed slurry;

[0024] (3) drying and hot pressing the mixed slurry obtained in step (2) to obtain the product.

[0025] Preferably, in step (1), the mass percentage of water in the mixed liquid is 10-15 wt%.

[0026] Preferably, step (1) is as follows: graphite, 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide and water are mixed evenly, and the obtained mixture is ball-milled at a rotation speed of 500-800 r / min for 30-90 min.

[0027] Preferably, in step (2), the dispersant is acetone; and the mass ratio of the acetone to the resin is (1.5-2.0):1.

[0028] Preferably, in step (3), the drying temperature is 60-70° C. and the drying time is 2-4 h.

[0029] Preferably, in step (3), the hot pressing molding is carried out at a pressure of 30-50 MPa and a temperature of 160-180° C. for 30-60 minutes.

[0030] The above solution of the present invention includes at least the following beneficial effects:

[0031] (1) The composite graphite-based material for bipolar plates of the present invention comprises the following raw materials in parts by weight: 80-100 parts of graphite, 8-15 parts of 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, 5-10 parts of a conductive agent, and 10-30 parts of a resin. The composite graphite-based material for bipolar plates has excellent electrical conductivity, airtightness, and mechanical strength.

[0032] Wherein, the 4-(1-naphthyloxy-5-decyloxy) butyltrimethylammonium bromide as an intercalant has trimethylammonium ions, which can penetrate into the interlayer of the graphite through the cation-π effect, reduce the surface energy of the system, greatly improve the dispersibility of graphite in water, and reduce the agglomeration of graphite. At the same time, the naphthalene ring of the naphthyloxy group as a condensed ring aromatic hydrocarbon has a conjugated structure with the layered structure of graphite, has good interfacial bonding force with the interlayer of graphite, and can maintain a relatively stable dispersed state. At the same time, the 4-(1-naphthyloxy-5-decyloxy) butyltrimethylammonium bromide as a surfactant has good compatibility with the resin, improves the contact area between the graphite and the resin in the mixed slurry, so that after hot pressing, a conductive path can be more fully formed to improve conductivity.

[0033] In particular, when the resin is a phenolic resin or contains a phenolic resin, the long-chain decyloxy and naphthyloxy groups of the 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide can be brought into close proximity with the phenolic resin under a hydrophobic effect, thereby reducing the interfacial gap between the graphite and the resin, thereby reducing the interfacial resistance. In addition, the molecular structure of the phenolic resin is a network, and after molding, a three-dimensional network structure with a high degree of cross-linking is formed between the molecules, which has high mechanical strength and rigidity, strong stability, good heat resistance and chemical corrosion resistance, and no by-products are generated during the curing process. However, due to its large number of rigid benzene ring structures, the resulting bipolar plate has greater brittleness. The 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide has a flexible long-chain alkyl group that can form a cross-linked structure with the resin, effectively transferring stress, improving the toughness of the composite material, and greatly improving the mechanical properties of the bipolar plate.

[0034] In addition, the 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide enhances the interfacial bonding force between the graphite and the resin and adjusts the three-dimensional cross-linked structure formed by the resin, thereby making the structure of the sheet material after thermosetting molding more uniform and dense, and can effectively reduce the permeation channels of gas molecules, thereby improving air tightness.

[0035] (2) The composite graphite-based material for bipolar plates of the present invention, wherein the conductive agent is polyaniline. The 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide located between the graphite layers has quaternary ammonium salt molecules and can be combined with the polyaniline particles through electrostatic interaction or hydrogen bonding, so that the polyaniline is evenly distributed on the graphite surface, filling the gaps between the graphite particles, increasing the conductive contact points, and forming a more continuous and compact conductive network. At the same time, the steric hindrance effect generated by the long chain structure of the 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide is conducive to maintaining a certain distance between the polyaniline particles, so that they are evenly dispersed.

[0036] (3) The composite graphite-based material for bipolar plates of the present invention further comprises 0.5-1.8 parts of an intercalation regulator; the intercalation regulator is one or more of 1-naphthyl ammonium bromide, 2-naphthyl ammonium bromide, and 1-(naphthyloxy) acetic acid hydrazine. When the intercalation regulator is 1-naphthyl ammonium bromide or 2-naphthyl ammonium bromide, since its structure is smaller than that of the 4-(1-naphthyloxy-5-decyloxy) butyltrimethylammonium bromide, it is easier to enter the narrow position between the graphite layers through the cation-π interaction, and cooperate with the long-chain structure of the 4-(1-naphthyloxy-5-decyloxy) butyltrimethylammonium bromide to increase the intercalation uniformity of the graphite and improve the intercalation effect. When the intercalation modifier is 1-(naphthyloxy)hydrazine acetate, the ball milling process will cause more defects and edge sites in the graphite. The hydrazine group has certain chemical activity and electron-donating ability, which easily combines with the defects and edge sites of the graphite, forming charge centers in the graphite, which originally has a relatively uniform surface charge distribution. This enhances the interaction between the charged intercalation agents, changes the charge distribution on the graphite surface, and thus guides the intercalation agents to more easily approach the graphite surface and diffuse between the layers. When the intercalation modifier is 1-naphthyl ammonium bromide, 1-(naphthyloxy)hydrazine acetate, or 2-naphthyl ammonium bromide, 1-(naphthyloxy)hydrazine acetate, and when they cooperate with each other, they can improve the intercalation effect and optimize the electron transport channel with the 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide. The resulting intercalated graphite has better conductivity when formed into a composite material with the resin.

[0037] (4) The preparation method of the composite graphite-based material for bipolar plates of the present invention, step (1) is as follows: take graphite, 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide and water, mix them evenly, and ball mill the obtained mixture at a speed of 500-800 r / min for 30-90 minutes. The physical shear force generated by ball milling causes the graphite layer to slide, thereby causing the 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide to be more tightly and fully combined with the layered structure of the graphite, so that the 4-

[0038] (1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide is uniformly intercalated between the layers of the graphite. DETAILED DESCRIPTION

[0039] In the examples of the present invention, if specific conditions are not specified, the experiments were carried out under conventional conditions or the conditions recommended by the manufacturer. Reagents or instruments used without specifying the manufacturer are all commercially available conventional products. Raw materials of different manufacturers and types do not affect the implementation of the technical solutions of the present invention and the achievement of the technical effects.

[0040] The 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide described in the following examples has the structure shown in formula (I):

[0041]

[0042] The 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide is a product of the prior art and can also be prepared using the prior art. For example, it can be synthesized in the following manner:

[0043]

[0044] The structural formula of the 1,4-diamino-2,3-dihydroanthraquinone is as follows:

[0045]

[0046] The CAS number of the 2-naphthyl ammonium bromide is 148819-80-1; the CAS number of the 1-(naphthyloxy)hydrazine acetate is 24310-15-4.

[0047] Example 1

[0048] The composite graphite-based material for bipolar plates in this embodiment includes the following raw materials in parts by weight:

[0049] 80 parts of graphite, 8 parts of 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, 10 parts of conductive agent, and 20 parts of resin.

[0050] Wherein, the resin is phenolic resin and the conductive agent is polyaniline.

[0051] The method for preparing the composite graphite-based material for bipolar plates described in this embodiment includes the following steps:

[0052] (1) Graphite, 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, and water were mixed uniformly, and the resulting mixture was ball-milled at a speed of 600 r / min for 30 min;

[0053] The mass percentage of water in the mixed liquid is 15 wt %.

[0054] (2) taking a resin, a conductive agent, and a dispersant, mixing them uniformly, adding them to the mixed solution obtained in step (1), and mixing them uniformly to obtain a mixed slurry;

[0055] Wherein, the dispersant is acetone; the mass ratio of the acetone to the resin is 1.5:1.

[0056] (3) drying and hot pressing the mixed slurry obtained in step (2) to obtain the product.

[0057] The drying temperature is 65° C. and the drying time is 2 hours. The hot pressing molding is carried out at a pressure of 40 MPa and a temperature of 160° C. for 45 minutes.

[0058] Example 2

[0059] The composite graphite-based material for bipolar plates in this embodiment includes the following raw materials in parts by weight:

[0060] 100 parts of graphite, 10 parts of 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, 5 parts of conductive agent, and 30 parts of resin.

[0061] The resin is a mixture of phenolic resin and epoxy resin in a weight ratio of 1:1. The conductive agent is polyaniline.

[0062] The method for preparing the composite graphite-based material for bipolar plates described in this embodiment includes the following steps:

[0063] (1) Graphite, 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, and water were mixed uniformly, and the resulting mixture was ball-milled at a speed of 800 r / min for 90 min;

[0064] The mass percentage of water in the mixed liquid is 12 wt %.

[0065] (2) taking a resin, a conductive agent, and a dispersant, mixing them uniformly, adding them to the mixed solution obtained in step (1), and mixing them uniformly to obtain a mixed slurry;

[0066] Wherein, the dispersant is acetone; the mass ratio of the acetone to the resin is 2.0:1.

[0067] (3) drying and hot pressing the mixed slurry obtained in step (2) to obtain the product.

[0068] The drying temperature is 70° C. and the drying time is 4 hours. The hot pressing molding is carried out at a pressure of 30 MPa and a temperature of 180° C. for 60 minutes.

[0069] Example 3

[0070] The composite graphite-based material for bipolar plates in this embodiment includes the following raw materials in parts by weight:

[0071] 90 parts of graphite, 15 parts of 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, 8 parts of conductive agent, and 10 parts of resin.

[0072] Wherein, the resin is phenolic resin and the conductive agent is polyaniline.

[0073] The method for preparing the composite graphite-based material for bipolar plates described in this embodiment includes the following steps:

[0074] (1) Graphite, 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, and water were mixed uniformly, and the resulting mixture was ball-milled at a speed of 500 r / min for 60 min;

[0075] The mass percentage of water in the mixed liquid is 10 wt %.

[0076] (2) taking a resin, a conductive agent, and a dispersant, mixing them uniformly, adding them to the mixed solution obtained in step (1), and mixing them uniformly to obtain a mixed slurry;

[0077] Wherein, the dispersant is acetone; the mass ratio of the acetone to the resin is 1.8:1.

[0078] (3) drying and hot pressing the mixed slurry obtained in step (2) to obtain the product.

[0079] The drying temperature is 60° C. and the drying time is 3 hours. The hot pressing molding is carried out at a pressure of 50 MPa and a temperature of 170° C. for 30 minutes.

[0080] Example 4

[0081] The composite graphite-based material for bipolar plates in this embodiment includes the following raw materials in parts by weight:

[0082] 100 parts of graphite, 12 parts of 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, 10 parts of conductive agent, and 20 parts of resin.

[0083] Wherein, the resin is phenolic resin and the conductive agent is polyaniline.

[0084] The method for preparing the composite graphite-based material for bipolar plates described in this embodiment includes the following steps:

[0085] (1) Graphite, 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, and water were mixed uniformly, and the resulting mixture was ball-milled at a speed of 800 r / min for 90 min;

[0086] The mass percentage of water in the mixed liquid is 15 wt %.

[0087] (2) taking a resin, a conductive agent, and a dispersant, mixing them uniformly, adding them to the mixed solution obtained in step (1), and mixing them uniformly to obtain a mixed slurry;

[0088] Wherein, the dispersant is acetone; the mass ratio of the acetone to the resin is 1.6:1.

[0089] (3) drying and hot pressing the mixed slurry obtained in step (2) to obtain the product.

[0090] The drying temperature is 70° C. and the drying time is 4 hours. The hot pressing molding is carried out at a pressure of 50 MPa and a temperature of 175° C. for 60 minutes.

[0091] Example 5

[0092] The composite graphite-based material for bipolar plates in this embodiment includes the following raw materials in parts by weight:

[0093] 100 parts of graphite, 12 parts of 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, 10 parts of conductive agent, 20 parts of resin, and 0.6 parts of intercalation regulator.

[0094] The resin is phenolic resin, the conductive agent is polyaniline, and the intercalation regulator is 1-naphthyl ammonium bromide.

[0095] The method for preparing the composite graphite-based material for bipolar plates described in this embodiment includes the following steps:

[0096] (1) Graphite, 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, an intercalation regulator, and water were mixed uniformly, and the resulting mixture was ball-milled at a speed of 800 r / min for 90 min;

[0097] The mass percentage of water in the mixed liquid is 15 wt %.

[0098] (2) taking a resin, a conductive agent, and a dispersant, mixing them uniformly, adding them to the mixed solution obtained in step (1), and mixing them uniformly to obtain a mixed slurry;

[0099] Wherein, the dispersant is acetone; the mass ratio of the acetone to the resin is 1.6:1.

[0100] (3) drying and hot pressing the mixed slurry obtained in step (2) to obtain the product.

[0101] The drying temperature is 70° C. and the drying time is 4 hours. The hot pressing molding is carried out at a pressure of 50 MPa and a temperature of 175° C. for 60 minutes.

[0102] Example 6

[0103] The composite graphite-based material for bipolar plates in this embodiment includes the following raw materials in parts by weight:

[0104] 100 parts of graphite, 12 parts of 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, 10 parts of conductive agent, 20 parts of resin, and 1.2 parts of intercalation regulator.

[0105] The resin is phenolic resin, the conductive agent is polyaniline, and the intercalation regulator is 2-naphthyl ammonium bromide.

[0106] The method for preparing the composite graphite-based material for bipolar plates described in this embodiment includes the following steps:

[0107] (1) Graphite, 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, an intercalation regulator, and water were mixed uniformly, and the resulting mixture was ball-milled at a speed of 800 r / min for 90 min;

[0108] The mass percentage of water in the mixed liquid is 15 wt %.

[0109] (2) taking a resin, a conductive agent, and a dispersant, mixing them uniformly, adding them to the mixed solution obtained in step (1), and mixing them uniformly to obtain a mixed slurry;

[0110] Wherein, the dispersant is acetone; the mass ratio of the acetone to the resin is 1.6:1.

[0111] (3) drying and hot pressing the mixed slurry obtained in step (2) to obtain the product.

[0112] The drying temperature is 70° C. and the drying time is 4 hours. The hot pressing molding is carried out at a pressure of 50 MPa and a temperature of 175° C. for 60 minutes.

[0113] Example 7

[0114] The composite graphite-based material for bipolar plates in this embodiment includes the following raw materials in parts by weight:

[0115] 100 parts of graphite, 12 parts of 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, 10 parts of conductive agent, 20 parts of resin, and 1.8 parts of intercalation regulator.

[0116] The resin is phenolic resin, the conductive agent is polyaniline, and the intercalation regulator is 1-(naphthyloxy) hydrazine acetate.

[0117] The method for preparing the composite graphite-based material for bipolar plates described in this embodiment includes the following steps:

[0118] (1) Graphite, 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, an intercalation regulator, and water were mixed uniformly, and the resulting mixture was ball-milled at a speed of 800 r / min for 90 min;

[0119] The mass percentage of water in the mixed liquid is 15 wt %.

[0120] (2) taking a resin, a conductive agent, and a dispersant, mixing them uniformly, adding them to the mixed solution obtained in step (1), and mixing them uniformly to obtain a mixed slurry;

[0121] Wherein, the dispersant is acetone; the mass ratio of the acetone to the resin is 1.6:1.

[0122] (3) drying and hot pressing the mixed slurry obtained in step (2) to obtain the product.

[0123] The drying temperature is 70° C. and the drying time is 4 hours. The hot pressing molding is carried out at a pressure of 50 MPa and a temperature of 175° C. for 60 minutes.

[0124] Example 8

[0125] The composite graphite-based material for bipolar plates in this embodiment includes the following raw materials in parts by weight:

[0126] 100 parts of graphite, 12 parts of 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, 10 parts of conductive agent, 20 parts of resin, and 1.2 parts of intercalation regulator.

[0127] The resin is phenolic resin, the conductive agent is polyaniline, and the intercalation regulator is a mixture of 1-naphthylammonium bromide and 1-(naphthyloxy)hydrazine acetate in a weight ratio of 1:3.5.

[0128] The method for preparing the composite graphite-based material for bipolar plates described in this embodiment includes the following steps:

[0129] (1) Graphite, 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, an intercalation regulator, and water were mixed uniformly, and the resulting mixture was ball-milled at a speed of 800 r / min for 90 min;

[0130] The mass percentage of water in the mixed liquid is 15 wt %.

[0131] (2) taking a resin, a conductive agent, and a dispersant, mixing them uniformly, adding them to the mixed solution obtained in step (1), and mixing them uniformly to obtain a mixed slurry;

[0132] Wherein, the dispersant is acetone; the mass ratio of the acetone to the resin is 1.6:1.

[0133] (3) drying and hot pressing the mixed slurry obtained in step (2) to obtain the product.

[0134] The drying temperature is 70° C. and the drying time is 4 hours. The hot pressing molding is carried out at a pressure of 50 MPa and a temperature of 175° C. for 60 minutes.

[0135] Example 9

[0136] The composite graphite-based material for bipolar plates in this embodiment includes the following raw materials in parts by weight:

[0137] 100 parts of graphite, 12 parts of 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, 10 parts of conductive agent, 20 parts of resin, and 0.6 parts of intercalation regulator.

[0138] The resin is phenolic resin, the conductive agent is polyaniline, and the intercalation regulator is a mixture of 2-naphthylammonium bromide and 1-(naphthyloxy)acetic acid hydrazine in a weight ratio of 1:2.6.

[0139] The method for preparing the composite graphite-based material for bipolar plates described in this embodiment includes the following steps:

[0140] (1) Graphite, 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, an intercalation regulator, and water were mixed uniformly, and the resulting mixture was ball-milled at a speed of 800 r / min for 90 min;

[0141] The mass percentage of water in the mixed liquid is 15 wt %.

[0142] (2) taking a resin, a conductive agent, and a dispersant, mixing them uniformly, adding them to the mixed solution obtained in step (1), and mixing them uniformly to obtain a mixed slurry;

[0143] Wherein, the dispersant is acetone; the mass ratio of the acetone to the resin is 1.6:1.

[0144] (3) drying and hot pressing the mixed slurry obtained in step (2) to obtain the product.

[0145] The drying temperature is 70° C. and the drying time is 4 hours. The hot pressing molding is carried out at a pressure of 50 MPa and a temperature of 175° C. for 60 minutes.

[0146] Example 10

[0147] The composite graphite-based material for bipolar plates in this embodiment includes the following raw materials in parts by weight:

[0148] 100 parts of graphite, 12 parts of 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, 10 parts of conductive agent, 20 parts of resin, 0.6 parts of intercalation regulator, and 2 parts of 1,4-diamino-2,3-dihydroanthraquinone.

[0149] The resin is phenolic resin, the conductive agent is polyaniline, and the intercalation regulator is a mixture of 2-naphthylammonium bromide and 1-(naphthyloxy)acetic acid hydrazine in a weight ratio of 1:2.6.

[0150] The method for preparing the composite graphite-based material for bipolar plates described in this embodiment includes the following steps:

[0151] (1) Graphite, 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, an intercalation regulator, 1,4-diamino-2,3-dihydroanthraquinone, and water were mixed uniformly, and the resulting mixture was ball-milled at a speed of 800 r / min for 90 min;

[0152] The mass percentage of water in the mixed liquid is 15 wt %.

[0153] (2) taking a resin, a conductive agent, and a dispersant, mixing them uniformly, adding them to the mixed solution obtained in step (1), and mixing them uniformly to obtain a mixed slurry;

[0154] Wherein, the dispersant is acetone; the mass ratio of the acetone to the resin is 1.6:1.

[0155] (3) drying and hot pressing the mixed slurry obtained in step (2) to obtain the product.

[0156] The drying temperature is 70° C. and the drying time is 4 hours. The hot pressing molding is carried out at a pressure of 50 MPa and a temperature of 175° C. for 60 minutes.

[0157] Comparative Example 1

[0158] The composite graphite-based material for bipolar plates in this comparative example is the same as that in Example 4 and is prepared by the same method, except that the 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide is not included.

[0159] Comparative Example 2

[0160] This comparative example is the same as the composite graphite-based material for bipolar plates in Example 4 and is prepared by the same method, with the only difference being that the 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide is replaced with 4-(1-naphthyloxy-5-octyloxy)butyltrimethylammonium bromide.

[0161] The 4-(1-naphthyloxy-5-octyloxy)butyltrimethylammonium bromide has the following structural formula:

[0162]

[0163] Comparative Example 3

[0164] The composite graphite-based material for bipolar plates in this comparative example is the same as that in Example 4 and is prepared by the same method, with the only difference being that the conductive agent is not included.

[0165] Comparative Example 4

[0166] The composite graphite-based material for bipolar plates in this comparative example is the same as that in Example 4 and is prepared by the same method, with the only difference being that the polyaniline in the conductive agent is replaced by conductive carbon black.

[0167] Comparative Example 5

[0168] This comparative example is the same as the composite graphite-based material for bipolar plates in Example 4 and is prepared by the same method, with the only difference being that the amount of 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide used is 6 parts.

[0169] Comparative Example 6

[0170] This comparative example is the same as the composite graphite-based material for bipolar plates in Example 4 and is prepared by the same method, with the only difference being that the amount of 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide used is 20 parts.

[0171] Comparative Example 7

[0172] This comparative example is the same as the composite graphite-based material for bipolar plates in Example 4 and is prepared by the same method, with the only difference being that the 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide is replaced by dodecyltrimethylammonium bromide.

[0173] Comparative Example 8

[0174] The composite graphite-based material for bipolar plates in this comparative example is the same as that in Example 10 and is prepared by the same method, with the only difference being that the intercalation regulator is not included.

[0175] Effect Experiment Example

[0176] To verify the technical effect of the composite graphite-based material for bipolar plates described in the present invention, the following experiments were conducted:

[0177] The composite graphite-based materials for bipolar plates prepared in Examples 1-10 and Comparative Examples 1-8 were formed into plates with a thickness of 1.2 mm as samples. The conductivity was measured using a conductivity meter, the flexural strength was measured using an electronic universal testing machine, the hydrogen permeability was measured using a permeation cell and a gas chromatograph, and the heat deformation temperature of the samples was tested using the method in "GB / T1634.1-2004 Determination of Heat Deformation Temperature of Plastics under Load".

[0178] After experimentation, the results are as follows:

[0179]

[0180] According to the results of Examples 1-4 and Comparative Examples 1-6, the composite graphite-based material for bipolar plates of the present invention has good electrical conductivity, mechanical properties, air tightness, and thermal stability.

[0181] According to the results of Example 4 and Comparative Examples 1, 5, and 6, the addition of 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide has a significant effect on the electrical conductivity, flexural strength, and hydrogen permeability of the material. If the amount of 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide is too small, the effect of improving the electrical conductivity, flexural strength, and air tightness of the material is not significant enough. If the amount of 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide is too large, the electrical conductivity, flexural strength, and air tightness of the material will be reduced to a certain extent, especially the electrical conductivity will decrease significantly.

[0182] According to the results of Example 4 and Comparative Example 2, replacing the 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide with 4-(1-naphthyloxy-5-octyloxy)butyltrimethylammonium bromide, that is, reducing the length of the long chain, will lead to a decrease in the overall performance of the bipolar plate. This may be due to certain differences in the steric hindrance generated and the interfacial interaction sites provided by alkyl chains of different lengths.

[0183] According to the results of Example 4 and Comparative Examples 3 and 4, the use of polyaniline as a conductive agent not only has a significant impact on the conductivity of the material, but also has a certain impact on the mechanical properties and air tightness of the material.

[0184] According to the results of Examples 4 and 5-9, the addition of the intercalation regulator has little effect on the airtightness and thermal stability of the material. Although the mechanical properties of the obtained material are reduced to a certain extent, the conductive properties can be significantly improved. In particular, in Examples 8-9, when the intercalation regulator is a mixture of 2-naphthylammonium bromide and 1-(naphthyloxy)acetic acid hydrazine or 1-naphthylammonium bromide and 1-(naphthyloxy)acetic acid hydrazine, the conductive properties are significantly improved.

[0185] According to the results of Example 4, Examples 9, 10, and Comparative Example 8, when the intercalation modifier and the 1,4-diamino-2,3-dihydroanthraquinone are added (Example 10), not only can the flexural strength of the material be greatly improved without affecting the electrical conductivity of the material, solving the problem of the intercalation modifier causing the mechanical properties of the material to deteriorate, but also the thermal stability of the material is significantly improved. When only the 1,4-diamino-2,3-dihydroanthraquinone is added without the intercalation modifier (Comparative Example 8), the electrical conductivity and flexural strength of the material are significantly reduced, almost equivalent to Example 4 without the addition of the 1,4-diamino-2,3-dihydroanthraquinone and the intercalation modifier. This may be because although the intercalation regulator can improve the electrical conductivity, the binding force between it and the resin is relatively weak, which will lead to a decrease in the mechanical properties of the material. The 1,4-diamino-2,3-dihydroanthraquinone can play a "bridging" role and combine with the phenolic resin through the amino group. At the same time, the anthraquinone planar conjugated system it has has good interface binding properties with the naphthyl and naphthoxy groups of the intercalation regulator, which can synergistically optimize the cross-linked network formed with the resin and improve the overall performance of the material. However, in the absence of the intercalation regulator, although the 1,4-diamino-2,3-dihydroanthraquinone can also have a certain effect on the flexural strength of the material, it cannot significantly improve the flexural strength of the material.

[0186] It is understood from common knowledge in the art that the present invention may be implemented by other embodiments that do not depart from its spirit or essential features. Therefore, the embodiments disclosed above are, in all respects, illustrative only and not exclusive. All modifications within the scope of the present invention or equivalent to the scope of the present invention are intended to be encompassed by the present invention.

Claims

1. A composite graphite-based material for bipolar plates, characterized in that: The invention comprises the following raw materials in parts by weight: 80-100 parts of graphite, 8-15 parts of 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, 5-10 parts of conductive agent, and 10-30 parts of resin.

2. The composite graphite-based material for bipolar plates according to claim 1, characterized in that: The resin is a phenolic resin or a mixture of a phenolic resin and an epoxy resin; Optionally, the conductive agent is polyaniline.

3. The composite graphite-based material for bipolar plates according to claim 1, characterized in that: Also includes 0.6-1.8 parts of an intercalation regulator; The intercalation regulator is one or more of 1-naphthyl ammonium bromide, 2-naphthyl ammonium bromide, and 1-(naphthyloxy) hydrazine acetate.

4. A method for preparing a composite graphite-based material for a bipolar plate according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: uniformly mixing graphite, 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, a conductive agent and a resin, and hot pressing and forming the mixture.

5. The method for preparing a composite graphite-based material for a bipolar plate according to claim 4, wherein: The steps include: (1) taking graphite, 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide, and water, and mixing them uniformly to obtain a mixed solution; (2) taking a resin, a conductive agent, and a dispersant, mixing them uniformly, adding them to the mixed solution obtained in step (1), and mixing them uniformly to obtain a mixed slurry; (3) drying and hot pressing the mixed slurry obtained in step (2) to obtain the product.

6. The method for preparing a composite graphite-based material for a bipolar plate according to claim 5, characterized in that: In step (1), the mass percentage of water in the mixed solution is 10-15wt%.

7. The method for preparing a composite graphite-based material for a bipolar plate according to claim 5, characterized in that: Step (1) is specifically as follows: graphite, 4-(1-naphthyloxy-5-decyloxy)butyltrimethylammonium bromide and water are mixed evenly, and the resulting mixture is ball-milled at a rotation speed of 500-800 r / min for 30-90 min.

8. The method for preparing a composite graphite-based material for a bipolar plate according to claim 5, wherein: In step (2), the dispersant is acetone; the mass ratio of the acetone to the resin is (1.5-2.0):

1.

9. The method for preparing a composite graphite-based material for a bipolar plate according to claim 5, wherein: In step (3), the drying temperature is 60-70° C. and the drying time is 2-4 h.

10. The method for preparing a composite graphite-based material for a bipolar plate according to claim 5, characterized in that: In step (3), the hot pressing molding is carried out at a pressure of 30-50 MPa and a temperature of 160-180° C. for 30-60 minutes.

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