CN116985478A - Conductive carbon paper for electrochemical equipment and preparation method thereof - Google Patents

Conductive carbon paper for electrochemical equipment and preparation method thereof Download PDF

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Publication number
CN116985478A
CN116985478A CN202310978647.0A CN202310978647A CN116985478A CN 116985478 A CN116985478 A CN 116985478A CN 202310978647 A CN202310978647 A CN 202310978647A CN 116985478 A CN116985478 A CN 116985478A
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carbon fiber
fiber sheet
layer
carbon
polymer film
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朱才镇
纪穆为
胡彦钊
刘会超
徐坚
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Shenzhen University
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Shenzhen University
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B9/00—Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00
    • B32B9/005—Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00 comprising one layer of ceramic material, e.g. porcelain, ceramic tile
    • B32B9/007—Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00 comprising one layer of ceramic material, e.g. porcelain, ceramic tile comprising carbon, e.g. graphite, composite carbon
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B37/00—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
    • B32B37/06—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the heating method
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B37/00—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
    • B32B37/10—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the pressing technique, e.g. using action of vacuum or fluid pressure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B9/00—Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00
    • B32B9/04—Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00 comprising such particular substance as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B9/047—Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00 comprising such particular substance as the main or only constituent of a layer, which is next to another layer of the same or of a different material made of fibres or filaments
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/8605—Porous electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/88—Processes of manufacture
    • H01M4/8803—Supports for the deposition of the catalytic active composition
    • H01M4/8807—Gas diffusion layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M8/1004—Fuel cells with solid electrolytes characterised by membrane-electrode assemblies [MEA]
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2250/00—Layers arrangement
    • B32B2250/42—Alternating layers, e.g. ABAB(C), AABBAABB(C)
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2262/00—Composition or structural features of fibres which form a fibrous or filamentary layer or are present as additives
    • B32B2262/10—Inorganic fibres
    • B32B2262/106—Carbon fibres, e.g. graphite fibres
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Ceramic Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Inert Electrodes (AREA)
  • Fuel Cell (AREA)

Abstract

The application provides a conductive carbon paper for electrochemical equipment, which comprises at least one carbon fiber sheet carbonization layer and at least one polymer film carbonization layer which are alternately laminated and compounded. The conductive carbon paper is compounded with the carbon fiber sheet by adopting the polymer film, so that the conductive carbon paper has good conductivity in the plane direction and the thickness direction so as to meet the conductive requirement of the conductive carbon paper for electrochemical equipment, and meanwhile, the polymer film and the carbon fiber sheet can be compounded to be used as an adhesive of carbon fibers in the carbon fiber sheet, so that the problem of loosening of the carbon fiber sheet is solved, and the preparation process flow of the carbon paper is simple and the cost is low. The application also provides a preparation method of the carbon paper, and a membrane electrode and electrochemical equipment comprising the carbon paper.

Description

Conductive carbon paper for electrochemical equipment and preparation method thereof
Technical Field
The embodiment of the application relates to the technical field of conductive carbon paper preparation, in particular to conductive carbon paper for electrochemical equipment and a preparation method thereof.
Background
Carbon paper is an important raw material for capacitors and electrocatalytic electrodes, and is also one of the key materials for gas diffusion layers of metal-air batteries and fuel cells. For example, the gas diffusion layer in the current material battery mainly uses carbon paper as a substrate layer, and the substrate layer is used for guiding the gas in the bipolar plate to the catalytic layer to react, and simultaneously transferring the water generated by the reaction in the catalytic layer to the bipolar plate, so as to prevent the accumulation of the product in the catalytic layer, namely, the flooding phenomenon. However, it is difficult for the existing carbon paper to combine high conductivity with good air permeability and water repellency. The preparation method of the carbon paper widely applied to the market at present mainly comprises a wet process, namely a papermaking process, and mainly comprises the processes of carbon fiber papermaking, composite resin, hot press solidification, high-temperature carbonization and the like, and has long process flow chain and complex production links.
Disclosure of Invention
In view of the above, the application provides a conductive carbon paper for electrochemical equipment and a preparation method thereof, wherein the conductive carbon paper is compounded with a carbon fiber sheet by adopting a polymer film, so that the conductive carbon paper has good conductive performance in the plane direction and the thickness direction so as to meet the conductive requirement of the conductive carbon paper for electrochemical equipment, and meanwhile, the polymer film and the carbon fiber sheet can be compounded to be used as an adhesive of carbon fibers in the carbon fiber sheet, thereby improving the problem of loosening of the carbon fiber sheet.
The application provides conductive carbon paper for electrochemical equipment, which comprises at least one carbon fiber sheet carbonization layer and at least one polymer film carbonization layer which are alternately laminated and compounded, wherein the carbon fiber sheet carbonization layer comprises a polymer sol carbonization layer and a plurality of carbon fibers arranged in the polymer sol carbonization layer, the carbon fibers extend along the plane direction of the carbon fiber sheet carbonization layer, and the resistance value of the polymer film carbonization layer in the thickness direction is less than or equal to 1 omega.
In the conductive carbon paper for electrochemical equipment, the conductive carbon paper is obtained by laminating at least one layer of carbon fiber sheet and at least one layer of polymer film through composite treatment, and the composite treatment comprises hot pressing treatment, pre-oxidation treatment and carbonization treatment which are sequentially carried out.
In the conductive carbon paper for electrochemical devices, the carbon content in the carbon fiber sheet is 90% or more.
In the conductive carbon paper for electrochemical equipment, the thickness of each layer of carbon fiber sheet is 0.1mm-1mm.
In the conductive carbon paper for electrochemical equipment, the plurality of carbon fibers are uniformly dispersed in the plane direction of the carbon fiber sheet, and the length of the carbon fibers is 1cm-10cm.
In the conductive carbon paper for electrochemical equipment, the polymer sol carbonization layer is obtained by carbonizing polymer sol; the polymer sol comprises one or more of polyimide, epoxy resin, polyester resin and phenolic resin.
In the application, the conductive carbon paper for electrochemical equipment is characterized in that the polymer film carbonization layer is obtained by carbonizing a polymer film; the polymer film comprises a thermoplastic polymer film and/or a thermosetting polymer film; the thermoplastic polymer film comprises a thermoplastic polyimide film, a polyamide film, a polyether-ether-ketone film and a polyphenylene sulfide film; the thermosetting polymer film comprises a polyester resin film, an epoxy resin film, a vinyl ester film, a bismaleimide film, a thermosetting polyimide film and a cyanate ester film
In the conductive carbon paper for electrochemical devices, the thickness of each polymer film carbonized layer is 1-50 μm.
In the conductive carbon paper for electrochemical equipment, the thickness of the conductive carbon paper is 0.35-0.5 mm; the resistance in the thickness direction is 1.0Ω -5.0Ω; the resistivity in the plane direction is 1mΩ·cm-10mΩ·cm; pores of the materialThe rate is 40% -60%; the moisture permeability was 50 g/(m) 2 ·h)-100g/(m 2 ·h)。
A second aspect of the present application provides a method for preparing the conductive carbon paper for electrochemical devices according to the first aspect, the method comprising the steps of:
preparing a polymer sol and a plurality of carbon fibers into a carbon fiber sheet, wherein the plurality of carbon fibers are arranged in the polymer sol along the plane direction of the carbon fiber sheet;
superposing at least one layer of carbon fiber sheet and at least one layer of polymer film in a die of a die press, and obtaining composite carbon paper after hot pressing treatment;
and sequentially performing pre-oxidation treatment and carbonization treatment on the composite carbon paper to convert the carbon fiber sheet into a carbon fiber sheet carbonization layer, and converting the polymer film into a polymer film carbonization layer to prepare the conductive carbon paper for the electrochemical equipment.
In the application, the hot pressing temperature of the hot pressing treatment is 200-360 ℃; the hot pressing pressure of the hot pressing treatment is 1MPa-10 MPa; the hot pressing time of the hot pressing treatment is 5-30 min.
In the application, the temperature of the pre-oxidation treatment is 200-400 ℃; the pre-oxidation treatment time is 80-100 min;
in the application, the carbonization treatment temperature is 1000-1800 ℃; the carbonization treatment time is 300-600 min.
The third aspect of the application provides a membrane electrode, which comprises a proton exchange membrane, a catalytic layer and a gas diffusion layer which are sequentially laminated, wherein the gas diffusion layer comprises a substrate layer formed by the conductive carbon paper according to the first aspect of the embodiment of the application.
A fourth aspect of the present application provides an electrochemical device comprising the conductive carbon paper according to the first aspect of the present application or the membrane electrode according to the third aspect of the present application.
Drawings
FIG. 1 is a schematic diagram of a conductive carbon paper layer according to an embodiment of the present application;
FIG. 2 is a Scanning Electron Microscope (SEM) image of a cross section of a conductive carbon paper according to one embodiment of the present application;
FIG. 3 is a schematic diagram showing the arrangement of carbon fibers in the planar direction of a carbon fiber sheet according to an embodiment of the present application;
FIG. 4 is a schematic diagram showing the arrangement of carbon fibers in the planar direction of a carbon fiber sheet according to another embodiment of the present application;
FIG. 5 shows the resistivity of carbonized carbon fiber sheets in different angles parallel to the carbon fibers according to an embodiment of the present application;
FIG. 6 is a schematic structural diagram of a membrane electrode according to an embodiment of the present application;
FIG. 7 is a photograph of conductive carbon paper prepared in example 1 of the present application;
fig. 8 is a graph showing the electrochemical performance comparison test of the conductive carbon paper prepared in example 1 of the present application and the commercial carbon paper.
Description of the reference numerals
100-conductive carbon paper; a carbonization layer of a carbon fiber sheet; 102-a polymer film carbonization layer; 20-conductive adhesive tape; 101' -carbon fiber sheet; 1011-carbon fiber; 1012 a polymeric sol layer; 200-membrane electrode; 201-proton exchange membrane; 202-a catalytic layer; 203-gas diffusion layer.
Detailed Description
The present application will be described in further detail with reference to preferred embodiments, but the scope of the present application is not limited to the following specific embodiments.
In the present application, all terms of art have the same meaning as those commonly understood by those skilled in the art, and the terms of art used herein are for the purpose of describing the specific embodiments only and are not intended to limit the scope of the present application.
The fuel cell is a power generation device for directly converting chemical energy existing in fuel and oxidant into electric energy, and has the advantages of high power generation efficiency, less environmental pollution and the like. The membrane electrode is the most core component of the proton exchange fuel cell and accounts for 60% of the cost of the fuel cell, and the gas diffusion layer is structurally and directly connected with the bipolar plate and the catalytic layer of the fuel cell and plays important roles in supporting the catalytic layer, collecting current, conducting gas and discharging water which is a reaction product in the operation of the fuel cell. Carbon paper is one of the most common base materials for gas diffusion layers in fuel cell membrane electrodes, and its electrical conductivity and gas permeability and hydrophobicity play a critical role in the use of the fuel cell. The carbon fiber sheet prepared by arranging carbon fibers in the plane direction has good conductivity in the plane direction, but has poor conductivity in the thickness direction, and is difficult to meet the conductivity requirement of the conductive carbon paper for the fuel cell. In addition, the carbonized carbon fiber sheets are loose due to the low content of the polymer resin in the carbon fiber sheets.
According to the conductive carbon paper for the electrochemical equipment and the preparation method thereof, the conductive carbon paper is compounded with the carbon fiber sheet by adopting the polymer film, so that the conductive carbon paper has good conductive performance in the plane direction and the thickness direction so as to meet the conductive requirement of the conductive carbon paper for the electrochemical equipment, meanwhile, the polymer film and the carbon fiber sheet can be compounded to be used as an adhesive of carbon fibers in the carbon fiber sheet, the problem of loosening of the carbon fiber sheet is solved, and the preparation process flow of the carbon paper is simple and the cost is low.
The conductive carbon paper 100 for electrochemical devices provided by the application comprises at least one carbon fiber sheet carbonization layer 101 and at least one polymer film carbonization layer 102 which are alternately laminated and compounded. Referring to fig. 1, fig. 1 is a schematic diagram of a stacked structure of conductive carbon paper 100 according to an embodiment of the application. In this embodiment, the conductive carbon paper 100 includes a carbon fiber sheet carbonized layer 101 and a polymer film carbonized layer 102. Fig. 2 is a Scanning Electron Microscope (SEM) image of a cross section of a conductive carbon paper 100 according to an embodiment of the present application, wherein 101 is a carbon fiber sheet carbonized layer, 102 is a polymer film carbonized layer, and 20 is a conductive adhesive tape. As shown in fig. 3 and fig. 4, fig. 3 and fig. 4 are schematic diagrams of carbon fiber arrangement modes in the plane direction of the carbon fiber sheet according to the embodiment of the present application. The carbon fiber sheet carbonization layer 101 is obtained by carbonizing a carbon fiber sheet 101', and the carbon fiber sheet 101' includes a polymer sol layer 1012 and a plurality of carbon fibers 1011 arranged in the polymer sol layer 1012, the plurality of carbon fibers 1011 extending in a plane direction of the carbon fiber sheet 101 '. In the embodiment shown in fig. 3, the plurality of carbon fibers 1011 are uniformly arranged along a certain fixed direction in the plane direction of the carbon fiber sheet 101', and in the embodiment shown in fig. 4, the plurality of carbon fibers 1011 are uniformly arranged in a crisscross manner in the plane direction of the carbon fiber sheet 101'.
It should be noted that fig. 3 and fig. 4 are schematic diagrams of the arrangement of the carbon fibers, which do not limit the arrangement configuration of the carbon fibers, and in actual production, the carbon fibers may not be arranged in a regular manner as shown in fig. 3 and fig. 4.
According to the conductive carbon paper 100 for the electrochemical equipment, provided by the embodiment of the application, the polymer film carbonization layer 102 and the carbon fiber sheet carbonization layer 101 are compounded, so that the conductive carbon paper has good conductive performance in the plane direction and the thickness direction. On the one hand, the carbon fiber sheet carbonized layer 101 has good conductivity in the plane direction; on the other hand, the addition of the polymer film carbonization layer 102 can effectively improve the conductivity of the conductive carbon paper 100 in the thickness direction so as to make up for the defect of the conductivity of the carbon fiber sheet 101 in the thickness direction and meet the conductive requirement of the membrane electrode on the conductive carbon paper; in addition, the addition of the polymer carbonization layer 102 can bond loose carbon fibers in the carbon fiber sheet, so that the toughness of the conductive carbon paper is improved. Based on the special design, the conductive carbon paper provided by the embodiment of the application has high conductivity and good mechanical property.
In the embodiment of the present application, the conductive carbon paper 100 includes at least one carbon fiber sheet carbonized layer 101 and at least one polymer thin film carbonized layer 102 alternately stacked. The carbon fiber sheet carbonized layer 101 may be one or more (two or more) layers, and the polymer film carbonized layer 102 may be one or more layers. The carbon fiber sheet carbonized layer 101 is denoted as a, the polymer thin film carbonized layer 102 is denoted as B, and the carbon fiber sheet carbonized layer 101 and the polymer thin film carbonized layer 102 are alternately stacked, for example, by: A-B, A-B-A, B-A-B, A-B-A-B, A-B-A-B-A, B-A-B-A-B, A-B-A-B-A-B. Fig. 1 shows the case of a-B.
In an embodiment of the present application, the carbon fiber sheet 101' includes a polymer sol layer 1012 and a plurality of carbon fibers 1011 arranged in the polymer sol layer 1012. In some embodiments, the carbon fibers 1011 may be uniformly aligned in the planar direction of the carbon fiber sheet in the same direction in the planar direction as shown in fig. 4; or may be uniformly arranged in a crossing manner in the plane direction, for example, as shown in fig. 5; or the two layers can be randomly and uniformly distributed in the plane direction. The carbon fibers 1011 are uniformly arranged in the plane direction of the carbon fiber sheet so that the produced carbon fiber sheet has good conductivity in the horizontal direction but lacks conductivity in the thickness direction thereof.
In the embodiment of the present application, the porosity of the carbon fiber sheet 101' is 70% to 85%. In some embodiments, the porosity of carbon fiber sheet 101' may be 70%, 72%, 75%, 78%, 80%, 82%, 85%.
In the embodiment of the application, the conductive carbon paper is obtained by laminating at least one layer of carbon fiber sheet and at least one layer of polymer film through composite treatment, and the composite treatment comprises hot pressing treatment, pre-oxidation treatment and carbonization treatment which are sequentially carried out.
On the one hand, the hot pressing treatment can quickly and effectively fully fuse the carbon fiber sheet and the polymer film, so that the carbon fiber sheet and the surface of the polymer film are tightly connected. The carbon fiber sheet becomes a carbon fiber sheet carbonized layer 101 through a pre-oxidation treatment and a carbonization treatment; the polymer film and the carbon fiber sheet can be compounded to be used as an adhesive for carbon fibers in the carbon fiber sheet, so that the problem of loosening of the carbon fiber sheet is solved, and the polymer film carbonized layer 102 taking carbon as a main component is formed after the polymer film is carbonized and is connected with the carbon fiber sheet carbonized layer 101 in the thickness direction of the conductive carbon paper 100, so that the conductivity of the conductive carbon paper 100 in the thickness direction is greatly improved.
In the embodiment of the present application, the carbon content in the carbon fiber sheet 101' is greater than or equal to 90%, the plurality of carbon fibers are uniformly dispersed in the plane direction of the carbon fiber sheet, and the length of the carbon fibers is 1cm to 10cm. In some embodiments, the length of the carbon fiber may be 1cm, 2cm, 3cm, 5cm, 6cm, 8cm, 10cm. On the one hand, the high concentration of carbon content provides good conductivity to the carbon fiber sheet 101', but on the other hand, the plurality of carbon fibers 1011 uniformly dispersed in the plane direction of the carbon fiber sheet are interlaced and connected only in the horizontal direction, and do not form a significantly continuous conductive path in the thickness direction, so that the produced carbon fiber sheet 101' has good conductivity in the plane direction and poor conductivity in the thickness direction.
In an embodiment of the present application, the thickness of each carbon fiber sheet 101' may be 0.1mm to 1mm. In some embodiments, the thickness of the carbon fiber sheet may be, for example, 0.1mm, 0.2mm, 0.3mm, 0.5mm, 0.6mm, 0.8mm, 1mm. The carbon fiber sheet 101 has excellent conductivity in the plane direction, but has poor conductivity in the thickness direction, and the thickness of the carbon fiber sheet is controlled within the range of 0.1mm-1mm, so that the conductivity of the conductive carbon paper in the thickness direction can be ensured to meet the actual use requirement, and the thickness is convenient for subsequent actual production and application.
In the embodiment of the present application, the resistance value of the polymer carbonized thin film layer 102 in the thickness direction is less than or equal to 1Ω. In order to make up for the defect of the conductivity of the carbon fiber sheet in the thickness direction, the carbonized polymer film and the carbon fiber sheet are subjected to hot-pressing compounding, and then subjected to pre-oxidation treatment and carbonization treatment, so that the polymer film is carbonized to obtain a polymer film carbonized layer 102, and part of non-carbon atoms of an organic polymer is lost to form an organic carbonized layer taking carbon as a main component, thereby the prepared conductive carbon paper 100 forms a continuous conductive path in the thickness direction, can still have good conductivity in the thickness direction, and meets the conductive requirement of the conductive carbon paper in the use process of a membrane electrode.
In embodiments of the present application, the thickness of each polymer film carbonized layer 102 may be 1 μm to 50 μm. In some embodiments, the thickness of the polymer film carbonized layer may be, for example, 1 μm, 2 μm, 5 μm, 8 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm. The application controls the thickness of the polymer film carbonization layer within the range of 1-50 mu m, is beneficial to enabling the conductive carbon paper 100 to form a continuous conductive path in the thickness direction, makes up the defect of the conductive performance of the carbon fiber sheet 101' in the thickness direction, obtains the conductive carbon paper 100 with excellent conductive performance in the plane direction and the thickness direction, and meets the conductive requirement of the conductive carbon paper in the use process of the membrane electrode. Meanwhile, loose carbon fibers in the carbon fiber sheet can be bonded after the polymer film is melted, so that the toughness of the conductive carbon paper is improved.
In the embodiment of the present application, the conductive carbon paper 100 has a thickness of 0.35mm to 0.5mm. In some embodiments, the thickness of the conductive carbon paper may be 0.35mm, 0.36mm, 0.38mm, 0.4mm, 0.42mm, 0.45mm, 0.48mm, 0.5mm.
The resistance in the thickness direction is 1.0Ω -5.0Ω; the resistivity in the plane direction is 1mΩ·cm-10mΩ·cm; the porosity is 40% -60%; the moisture permeability was 50 g/(m) 2 ·h)-100g/(m 2 H). In some embodiments, the thickness direction resistance of the conductive carbon paper may be 1.0Ω, 1.2Ω, 1.5Ω, 1.8Ω, 2.0Ω, 2.5Ω, 3.0Ω, 3.5Ω, 4.0Ω, 4.5Ω, 5.0Ω; the resistivity in the plane direction may be 1mΩ·cm, 2mΩ·cm, 3mΩ·cm, 5mΩ·cm, 6mΩ·cm, 8mΩ·cm, 9mΩ·cm, 10mΩ·cm; the porosity may be 40%, 41%, 42%, 45%, 48%, 50%, 55%, 60%; the moisture permeability may be 50 g/(m) 2 ·h)、55g/(m 2 ·h)、60g/(m 2 ·h)、65g/(m 2 ·h)、70g/(m 2 ·h)、75g/(m 2 ·h)、80g/(m 2 ·h)、90g/(m 2 ·h)、100g/(m 2 H). The conductive carbon paper has excellent conductivity in the original plane direction of the carbon fiber sheet, meanwhile, the polymer film is compounded, loose carbon fibers in the original carbon fiber sheet are bonded, and after carbonization, a polymer carbonized layer is formed, so that the conductivity of the conductive carbon paper in the thickness direction is improved.
The application also provides a preparation method of the conductive carbon paper for the electrochemical equipment, which comprises the following steps:
preparing a polymer sol and a plurality of carbon fibers into a carbon fiber sheet, wherein the plurality of carbon fibers are arranged in the polymer sol along the plane direction of the carbon fiber sheet;
superposing at least one layer of carbon fiber sheet and at least one layer of polymer film in a die of a die press, and obtaining composite carbon paper after hot pressing treatment;
and sequentially performing pre-oxidation treatment and carbonization treatment on the composite carbon paper to convert the carbon fiber sheet into a carbon fiber sheet carbonization layer, and converting the polymer film into a polymer film carbonization layer to prepare the conductive carbon paper for the electrochemical equipment.
The polymer film carbonized layer may be formed by carbonizing one polymer film or may be formed by carbonizing a plurality of (two or more) polymer films.
In the embodiment of the present application, the carbon fiber sheet 101' is made of a polymer sol and a plurality of carbon fibers arranged in the plane direction of the carbon fiber sheet. The polymer sol can be one or more of polyimide, epoxy resin, polyester resin and phenolic resin. The polymer sol can be combined with the carbon fibers in any of coating, sizing and impregnating modes. The polymer sol has certain viscosity, and the plurality of carbon fibers can be uniformly distributed in the polymer sol layer along the plane direction of the carbon fiber sheet by means of coating, sizing, dipping and the like, so that the plurality of carbon fibers are adhered and aggregated into the sheet-shaped carbon fiber sheet. The prepared carbon fiber sheet can be cut into a certain size and shape according to actual requirements, so that the carbon fiber sheet is convenient to be alternately overlapped and compounded with a polymer film, and the carbon fiber sheet carbonization layer 101 is obtained after pre-oxidation treatment and carbonization treatment.
In embodiments of the present application, the polymer film may be a thermoplastic polymer film and/or a thermosetting polymer film. In some embodiments, the thermoplastic polymer film may be a thermoplastic polyimide film, a polyamide film, a polyetheretherketone film, a polyphenylene sulfide film; the thermosetting polymer film may be a polyester resin film, an epoxy resin film, a vinyl ester film, a bismaleimide film, a thermosetting polyimide film, or a cyanate ester film. According to the application, after the polymer film and the carbon fiber sheet are compounded through hot pressing treatment, pre-oxidation treatment and carbonization treatment, the thermoplastic polymer film can be used as an adhesive to adhere loose carbon fibers in the carbon fiber sheet after being melted, and the thermosetting polymer film and the carbon fiber sheet provide excellent conductive performance and good mechanical property for conductive carbon paper after being carbonized. The polymer film may be either commercially available or self-prepared. In some embodiments, the polymer film may be prepared using a casting process.
In an embodiment of the present application, the thickness of the polymer film may be controlled to be 1 μm to 50 μm. In some embodiments, the thickness of the polymer film may be 1 μm, 2 μm, 5 μm, 8 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 40 μm, 50 μm.
In the embodiment of the present application, when the carbon fiber sheet carbonized layer 101 and the polymer thin film carbonized layer 102 are alternately laminated, the carbon fiber sheet carbonized layer 101 may be one or more (two or more) layers, and the polymer thin film carbonized layer 102 may be one or more layers. The carbon fiber sheet carbonized layer 101 is denoted as a, the polymer thin film carbonized layer 102 is denoted as B, and the carbon fiber sheet carbonized layer 101 and the polymer thin film carbonized layer 102 are alternately stacked, for example, by: A-B, A-B-A, B-A-B, A-B-A-B, A-B-A-B-A, B-A-B-A-B, A-B-A-B-A-B. Fig. 1 shows the case of a-B. In the embodiment of the present application, the carbon fiber sheet carbonized layer 101 may be located at the outermost side of the conductive carbon paper 100, or the polymer thin film carbonized layer 102 may be located at the outermost side. In the embodiment of the present application, the total number of carbon fiber sheet carbonization layers 101 in the conductive carbon paper 100 may be the same as or different from the total number of polymer film carbonization layers 102 by one. When the total number of carbon fiber sheet carbonized layers 101 and the total number of polymer film carbonized layers 102 in the conductive carbon paper differ by one layer, the total number of carbon fiber sheet carbonized layers 101 may be one more than the total number of polymer film carbonized layers 102, or the total number of carbon fiber sheet carbonized layers 101 may be one less than the total number of polymer film carbonized layers 102. In some embodiments, one thermocompression bonding may not sufficiently bond the carbon fiber sheet and the polymer film, and thus may be performed by laminating and bonding a plurality of thin layers of the polymer film, that is, one polymer film carbonized layer may be formed by carbonizing a plurality of (two or more) polymer films. The multiple layers (two or more layers) of polymer films may be the same material or may be made of multiple materials.
In some embodiments of the present application, the polymer film carbonization layer 102 of the conductive carbon paper 100 may be prepared using a polymer film. In other embodiments of the present application, the polymer film carbonization layer 102 of the conductive carbon paper 100 may be prepared using two or more polymer films, which may be thermoplastic polymer films and/or thermosetting polymer films. For example, the thermoplastic polyimide B1, the polyamide film B2, and the thermosetting polyimide film B3 may be alternately laminated with the carbon fiber sheet 101 and the polymer carbonized layer 102: A-B1-A, A-B1-B3, A-B2-B3-A, B-A-B2, B3-B1-A-B1-A. According to the application, after the polymer film and the carbon fiber sheet are compounded through hot pressing treatment, pre-oxidation treatment and carbonization treatment, the thermoplastic polymer film can be used as an adhesive to adhere loose carbon fibers in the carbon fiber sheet after being melted, and the thermosetting polymer film and the carbon fiber sheet provide excellent conductive performance and good mechanical property for conductive carbon paper after being carbonized. Therefore, in the lamination, the thermoplastic polymer film as an adhesive should be in contact with the carbon fiber sheet.
In some embodiments of the present application, the total number of carbon fiber sheet carbonization layers 101 and polymer film carbonization layers 102 is 2-6 when stacked alternately. The above examples are for more vividly describing the manner in which the carbon fiber sheet carbonization 101 and the polymer film carbonization layer 102 are alternately laminated, and in practical embodiments, the manner in which they are alternately laminated includes, but is not limited to, the above examples.
In the embodiment of the application, when the carbon fiber sheet and the polymer film are alternately laminated and hot-pressed, the lamination angle is not particularly limited, and may be any lamination angle. In some embodiments, the plurality of carbon fiber sheets are stacked at different angles, for example, when the first carbon fiber sheet and the second carbon fiber sheet are stacked, carbon fibers in the first carbon fiber sheet extend in a first direction, and carbon fibers in the second carbon fiber sheet extend in a second direction, and the first direction is perpendicular to the second direction. As shown in fig. 5, in some embodiments, by testing the resistivity of the carbon fiber sheet after carbonization in different angles with respect to the parallel arrangement direction of the carbon fibers, it is found that the conductivity has significant anisotropy, that is, the conductivity in the parallel arrangement direction of the carbon fibers is optimal, and the conductivity in the direction perpendicular to the parallel arrangement direction of the carbon fibers is worst, so in order to ensure the overall conductivity uniformity of the conductive carbon paper, when a plurality of carbon fibers are uniformly arranged in a certain fixed direction in the plane direction of the carbon fiber sheet, two adjacent carbon fiber sheets are stacked in a 90 ° direction.
In the embodiment of the application, the hot press treatment process conditions are as follows: the hot pressing temperature is 200-360 ℃, the hot pressing pressure is 1-10 MPa, and the hot pressing time is 5-30 min. In some embodiments, the hot pressing temperature may be 200 ℃, 220 ℃, 250 ℃, 280 ℃, 300 ℃, 350 ℃, 360 ℃, the hot pressing pressure may be 1MPa, 2MPa, 3MPa, 5MPa, 8MPa, 10MPa, and the hot pressing time may be 5min, 10min, 15min, 20min, 25min, 30min. According to the application, through the hot pressing treatment under the proper conditions, the carbon fiber sheet and the polymer film can be fully fused, and on one hand, the polymer film can be used as an adhesive to adhere loose carbon fibers in the carbon fiber sheet after being fused; on the other hand, after the hot press treatment is convenient for the subsequent pre-oxidation treatment and carbonization treatment, the polymer film carbonization layer 102 is connected with the carbon fibers in the carbon fiber sheet carbonization layer 101, so that the conductive carbon paper 100 has good conductivity in the thickness direction, and the conductive carbon paper with excellent conductivity and toughness is obtained. The preparation method is different from the traditional papermaking process, has simpler process flow and lower cost, and is beneficial to large-scale production.
In the embodiment of the application, the temperature of the pre-oxidation treatment is 200-400 ℃; the pre-oxidation treatment time is 80min-100min. In some embodiments, the temperature of the pre-oxidation treatment may be 200 ℃, 220 ℃, 250 ℃, 280 ℃, 300 ℃, 320 ℃, 350 ℃, 380 ℃, 400 ℃, and the time of the pre-oxidation treatment may be 80min, 85min, 90min, 95min, 100min.
In the embodiment of the application, the carbonization treatment temperature is 1000-1800 ℃; the carbonization treatment time is 300min-600min. In some embodiments, the carbonization temperature may be 1000 ℃, 1100 ℃, 1200 ℃, 1300 ℃, 1500 ℃, 1700 ℃, 1800 ℃, and the carbonization time may be 300min, 320min, 350min, 400min, 450min, 500min, 550min, 600min. And (3) performing high-temperature carbonization treatment on the carbon paper precursor subjected to hot-press compounding under the protection of inert atmosphere after performing pre-oxidation treatment, and changing the carbonized polymer sol into a carbonized polymer sol layer. The carbon fiber sheet becomes a carbon fiber sheet carbonized layer 101 after carbonization; an organic carbonized layer taking carbon as a main component is formed after the polymer film is carbonized, so that a polymer film carbonized layer 102 is obtained, and the polymer film carbonized layer is connected with carbon fibers in a carbon fiber sheet carbonized layer 101 in the thickness direction of the conductive carbon paper, so that the conductivity of the conductive carbon paper in the thickness direction is greatly improved.
Referring to fig. 6, an embodiment of the present application also provides a membrane electrode 200. The membrane electrode 200 includes a proton exchange membrane 201, and a catalytic layer 202 and a gas diffusion layer 203 laminated in this order on both sides thereof. The gas diffusion layer 203 includes a base layer and a microporous layer supported on the base layer. The substrate layer comprises the conductive carbon paper 100 provided by the application.
The present application also provides an electrochemical device including the conductive carbon paper 100 provided by the present application. The electrochemical device may be a fuel cell, a metal-air cell, a capacitor, an electrocatalytic electrode, or the like. When the electrochemical device is a fuel cell, the fuel cell includes the membrane electrode 200 provided by the present application.
The application is further illustrated in the following examples:
example 1
Preparing a plurality of carbon fibers uniformly distributed along a certain fixed direction in a plane direction into carbon fiber sheets with the thickness of 1mm by using polyimide sol in a sizing mode, cutting the prepared carbon fiber sheets, paving a carbon fiber sheet layer with the area of 70mm, covering the surface of the carbon fiber sheet layer with a thermoplastic polyimide resin film with the thickness of 50 mu m, paving a carbon fiber sheet layer in the direction of 90 degrees with the first carbon fiber sheet layer, superposing the carbon fiber sheet layer in a 100mm 0.5mm molding press die, performing mold pressing at the hot pressing temperature of 360 ℃,10 MPa and 30min, performing pre-oxidation treatment for 80min at 400 ℃, and performing carbonization treatment for 300min at 1500 ℃ to prepare the conductive carbon paper for electrochemical equipment. Fig. 7 is a photograph of the conductive carbon paper prepared in embodiment 1 of the present application, and it can be seen that the plane of the prepared conductive carbon paper is relatively flat, and the conductive carbon paper is suitable for supporting the catalytic layer when being applied to the membrane electrode in the following.
Example 2
Preparing a plurality of carbon fibers which are uniformly distributed in a crisscross manner along two fixed directions perpendicular to each other in a plane direction into a carbon fiber sheet with the thickness of 1mm by using polyimide sol in a sizing manner, cutting the prepared carbon fiber sheet, paving a carbon fiber sheet layer with the area of 70mm, covering the surface of the carbon fiber sheet layer with a thermoplastic polyimide resin film with the thickness of 50 mu m, paving a carbon fiber sheet layer in the same direction as the first carbon fiber sheet layer, superposing the carbon fiber sheet layer in a 100mm 0.5mm molding press die, performing mold pressing at the hot pressing temperature of 360 ℃,10 MPa and 30min, performing pre-oxidation treatment for 80min at 400 ℃, and performing carbonization treatment for 300min at the temperature of 1500 ℃ to prepare the conductive carbon paper for electrochemical equipment.
Example 3
Preparing a plurality of carbon fibers which are randomly and uniformly distributed along the plane direction into carbon fiber sheets with the thickness of 1mm by using polyimide sol in a sizing way, cutting the prepared carbon fiber sheets, paving the carbon fiber sheets into carbon fiber sheets with the area of 70mm, covering the surfaces of the carbon fiber sheets with a thermoplastic polyimide resin film with the thickness of 50 mu m, paving a layer of carbon fiber sheets in the same direction as the first layer of carbon fiber sheets, superposing the carbon fiber sheets in a 100mm 0.5mm molding press die, performing mold pressing at the hot pressing temperature of 360 ℃,10 MPa and 30min, performing pre-oxidation treatment for 80min at 400 ℃, and performing carbonization treatment for 300min at 1500 ℃ to prepare the conductive carbon paper for electrochemical equipment.
Example 4
Preparing a plurality of carbon fibers uniformly distributed along a certain fixed direction in a plane direction into carbon fiber sheets with the thickness of 1mm by using polyimide sol in a sizing mode, cutting the prepared carbon fiber sheets, paving a carbon fiber sheet layer with the area of 70mm, covering the surface of the carbon fiber sheet layer with a thermoplastic polyimide resin film with the thickness of 5 mu m, paving a carbon fiber sheet layer in a direction of 90 degrees with the first carbon fiber sheet layer, superposing the carbon fiber sheet layer in a 100mm 0.5mm molding press die, performing mold pressing at the hot pressing temperature of 360 ℃,10 MPa and 30min, performing pre-oxidation treatment for 80min at 400 ℃, and performing carbonization treatment for 300min at 1500 ℃ to prepare the conductive carbon paper for electrochemical equipment.
Example 5
Preparing a plurality of carbon fibers uniformly distributed along a certain fixed direction in a plane direction into carbon fiber sheets with the thickness of 1mm by using polyimide sol in a sizing mode, cutting the prepared carbon fiber sheets, paving a carbon fiber sheet layer with the area of 70mm, covering the surface of the carbon fiber sheet layer with a thermoplastic polyimide resin film with the thickness of 10 mu m, paving a carbon fiber sheet layer in the direction of 90 degrees with the first carbon fiber sheet layer, superposing the carbon fiber sheet layer in a 100mm 0.5mm molding press die, performing mold pressing at the hot pressing temperature of 360 ℃,10 MPa and 30min, performing pre-oxidation treatment for 80min at 400 ℃, and performing carbonization treatment for 300min at 1500 ℃ to prepare the conductive carbon paper for electrochemical equipment.
Example 6
Preparing a plurality of carbon fibers uniformly distributed along a certain fixed direction in a plane direction into carbon fiber sheets with the thickness of 1mm by using polyimide sol in a sizing mode, cutting the prepared carbon fiber sheets, paving a carbon fiber sheet layer with the area of 70mm, covering the surface of the carbon fiber sheet layer with a thermoplastic polyimide resin film with the thickness of 20 mu m, paving a carbon fiber sheet layer in the direction of 90 degrees with the first carbon fiber sheet layer, superposing the carbon fiber sheet layer in a 100mm 0.5mm molding press die, performing mold pressing at the hot pressing temperature of 360 ℃,10 MPa and 30min, performing pre-oxidation treatment for 80min at 400 ℃, and performing carbonization treatment for 300min at 1500 ℃ to prepare the conductive carbon paper for electrochemical equipment.
Example 7
Preparing a plurality of carbon fibers uniformly distributed along a certain fixed direction in a plane direction into carbon fiber sheets with the thickness of 1mm by using polyimide sol in a sizing way, cutting the prepared carbon fiber sheets, paving a carbon fiber sheet layer with the area of 70mm, covering the surface of the carbon fiber sheet layer with a thermoplastic polyimide resin film with the thickness of 50 mu m and a thermosetting polyimide resin film with the thickness of 10 mu m, paving a carbon fiber sheet layer in a direction of 90 DEG with the first carbon fiber sheet, superposing the carbon fiber sheet layer and the thermoplastic polyimide resin film in a 100mm 0.5mm molding press die, performing mold pressing at the hot pressing temperature of 360 ℃,10 MPa and 30min, performing pre-oxidation treatment at 400 ℃ for 80min, and performing carbonization treatment at 1500 ℃ for 300min to prepare the conductive carbon paper for electrochemical equipment.
Example 8
Preparing a plurality of carbon fibers uniformly distributed along a certain fixed direction in a plane direction into a carbon fiber sheet with the thickness of 1mm by using polyimide sol in a sizing way, cutting the prepared carbon fiber sheet, paving a carbon fiber sheet layer with the area of 70mm, covering the surface of the carbon fiber sheet layer with a thermoplastic polyimide resin film with the thickness of 50 mu m, covering the surface of the thermoplastic polyimide resin film with a thermosetting polyimide resin film with the thickness of 50 mu m, superposing the thermoplastic polyimide resin film with the thermosetting polyimide resin film with the thickness of 50 mu m in a 100mm, pressing the thermoplastic polyimide resin film with the thermosetting polyimide resin film with the thickness of 50 mu m in a 100mm, pressing machine with the thermosetting polyimide resin film with the thickness of 50 mu m, and performing die pressing at the thermosetting pressing temperature of 360 ℃ for 10MPa for 30min, performing pre-oxidizing treatment for 80min at 400 ℃ and carbonization treatment for 300min, and preparing conductive carbon paper for electrochemical equipment.
Example 9
Preparing a plurality of carbon fibers uniformly distributed along a certain fixed direction in a plane direction into carbon fiber sheets with the thickness of 1mm by using polyimide sol in a sizing mode, cutting the prepared carbon fiber sheets, paving a carbon fiber sheet layer with the area of 70mm, covering the surface of the carbon fiber sheet layer with a thermoplastic polyimide resin film with the thickness of 50 mu m, paving a carbon fiber sheet layer in the direction of 90 degrees with the first carbon fiber sheet layer, superposing the carbon fiber sheet layer in a 100mm 0.5mm molding press die, performing mold pressing at the hot pressing temperature of 200 ℃,10 MPa and 30min, performing pre-oxidation treatment for 80min at 400 ℃, and performing carbonization treatment for 300min at 1500 ℃ to prepare the conductive carbon paper for electrochemical equipment.
Example 10
Preparing a plurality of carbon fibers uniformly distributed along a certain fixed direction in a plane direction into carbon fiber sheets with the thickness of 1mm by using polyimide sol in a sizing mode, cutting the prepared carbon fiber sheets, paving a carbon fiber sheet layer with the area of 70mm, covering the surface of the carbon fiber sheet layer with a thermoplastic polyimide resin film with the thickness of 50 mu m, paving a carbon fiber sheet layer in the direction of 90 degrees with the first carbon fiber sheet layer, superposing the carbon fiber sheet layer in a 100mm 0.5mm molding press die, performing mold pressing at the hot pressing temperature of 360 ℃,10 MPa and 30min, performing pre-oxidation treatment for 80min at the temperature of 200 ℃, and performing carbonization treatment for 300min at the temperature of 1500 ℃ to prepare the conductive carbon paper for electrochemical equipment.
Example 11
Preparing a plurality of carbon fibers uniformly distributed along a certain fixed direction in a plane direction into carbon fiber sheets with the thickness of 1mm by using polyimide sol in a sizing mode, cutting the prepared carbon fiber sheets, paving a carbon fiber sheet layer with the area of 70mm, covering the surface of the carbon fiber sheet layer with a thermoplastic polyimide resin film with the thickness of 50 mu m, paving a carbon fiber sheet layer in the direction of 90 degrees with the first carbon fiber sheet layer, superposing the carbon fiber sheet layer in a 100mm 0.5mm molding press die, performing mold pressing at the hot pressing temperature of 360 ℃,10 MPa and 30min, performing pre-oxidation treatment for 80min at 400 ℃, and performing carbonization treatment for 300min at 1000 ℃ to prepare the conductive carbon paper for electrochemical equipment.
The conductive carbon papers prepared in examples 1 to 11 were subjected to thickness, porosity, thickness-direction resistance, plane-direction resistivity, and moisture permeability tests according to national standard GB/T20042.7-2014 (proton exchange membrane fuel cell part 7: carbon paper characteristic test method), and the data obtained are shown in Table 1.
Comparative example 1
And (3) preparing a carbon fiber sheet precursor with the thickness of 1mm by using polyimide sol to uniformly arrange a plurality of carbon fibers along a certain fixed direction in a plane direction in a sizing mode, performing pre-oxidation treatment on the carbon fiber precursor at 400 ℃ for 80min, and performing carbonization treatment at 1500 ℃ for 300min to obtain the carbon fiber sheet. The moisture permeability, thickness direction resistance and plane direction resistivity of the obtained carbon fiber sheet are shown in Table 2.
Comparative example 2
Commercial carbon paper TGP-H-060 is selected, and the carbon paper mainly comprises resin carbon and carbon fiber, and the specific preparation method comprises the following steps: the carbon fiber paper is obtained by mixing carbon fiber with a resin solution such as phenolic resin serving as a binder and polytetrafluoroethylene with improved hydrophobicity, papermaking, and hot-pressing carbonization. The carbon paper was subjected to electrochemical performance and hydrophilic-hydrophobic performance tests, and the measured moisture permeability, thickness direction resistance and plane direction resistance are shown in table 2.
TABLE 1 data relating to performance tests of conductive carbon papers prepared in examples 1-9
As can be seen from the results in table 1, the conductive carbon papers of examples 1 to 11 according to the present application have excellent conductivity and good air permeability and water repellency by alternately laminating and compounding at least one carbon fiber sheet carbonized layer and at least one polymer thin film carbonized layer, and can prevent flooding of the membrane electrode while exhibiting good conductivity and air permeability when used in the membrane electrode of an electrochemical device. And as can be seen from examples 1 and 4-6, compared with the conductive carbon paper with the polymer carbonized layer of 5 μm in example 4, the conductive carbon paper prepared in examples 1 and 5-6 according to the present application has the conductive property in the thickness direction obviously improved by controlling the thickness of the polymer carbonized layer to be 10 μm-50 μm. When the thickness of the polymer film is too large or too small, the conductive performance of the conductive carbon paper in the thickness direction is reduced.
TABLE 2 data relating to performance testing of carbon fiber sheets and conductive carbon papers of comparative examples 1-2
As can be seen from table 2, compared with comparative example 1, the carbon fiber sheet carbonized layer and the polymer thin film carbonized layer of example 1 are alternately laminated and compounded to obtain a conductive carbon paper with reduced resistance in the thickness direction and reduced resistivity in the planar direction, and on the one hand, the conductive carbon paper with obviously improved conductivity in the thickness direction after being compounded with the polymer thin film carbonized layer; on the other hand, the polymer film carbonization layer can effectively reduce the porosity of the carbon fiber sheet carbonization layer and improve the conductivity of the conductive carbon paper in the plane direction. Fig. 8 is a graph showing the electrochemical performance of the conductive carbon paper provided in example 1 and the commercial carbon paper of comparative example 2. As can be seen from fig. 8, the electrochemical performance of the conductive carbon paper for electrochemical device provided by the application is equivalent to that of commercial carbon paper, but the manufacturing cost is lower, and the preparation method is simpler.
While the preferred embodiments have been described in detail, the present application is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the application by those skilled in the art.

Claims (10)

1. The conductive carbon paper for the electrochemical equipment is characterized by comprising at least one carbon fiber sheet carbonization layer and at least one polymer film carbonization layer which are alternately laminated and compounded, wherein the carbon fiber sheet carbonization layer comprises a polymer sol carbonization layer and a plurality of carbon fibers arranged in the polymer sol carbonization layer, the carbon fibers extend along the plane direction of the carbon fiber sheet carbonization layer, and the resistance value of the polymer film carbonization layer in the thickness direction is less than or equal to 1 omega.
2. The conductive carbon paper for electrochemical devices according to claim 1, wherein the conductive carbon paper is obtained by laminating at least one carbon fiber sheet and at least one polymer film and subjecting the same to a composite treatment comprising a hot press treatment, a pre-oxidation treatment and a carbonization treatment which are sequentially performed.
3. The conductive carbon paper for electrochemical devices according to claims 1 and 2, wherein the carbon content in the carbon fiber sheet is 90% or more, the thickness of each layer of the carbon fiber sheet is 0.1mm to 1mm, the plurality of carbon fibers are uniformly dispersed in the plane direction of the carbon fiber sheet, and the length of the carbon fibers is 1cm to 10cm.
4. The conductive carbon paper for electrochemical devices according to claim 1, wherein the polymer sol carbonized layer is obtained by carbonizing a polymer sol layer; the polymer sol layer comprises one or more of polyimide, epoxy resin, polyester resin and phenolic resin.
5. The conductive carbon paper for electrochemical devices according to claim 2, wherein the polymer film carbonized layer is obtained by carbonizing a polymer film; the polymer film comprises a thermoplastic polymer film and/or a thermosetting polymer film; the thermoplastic polymer film comprises a thermoplastic polyimide film, a polyamide film, a polyether-ether-ketone film and a polyphenylene sulfide film; the thermosetting polymer film comprises a polyester resin film, an epoxy resin film, a vinyl ester film, a bismaleimide film, a thermosetting polyimide film and a cyanate ester film; the thickness of each of the polymer film carbonized layers is 1 μm to 50 μm.
6. The conductive carbon paper for electrochemical devices according to claim 1, wherein the conductive carbon paper has a thickness of 0.35mm to 0.5mm; the resistance in the thickness direction is 1.0Ω -5.0Ω; the resistivity in the plane direction is 1mΩ·cm-10mΩ·cm; the porosity is 40% -60%; the moisture permeability was 50 g/(m) 2 ·h)-100g/(m 2 ·h)。
7. The preparation method of the conductive carbon paper for the electrochemical equipment is characterized by comprising the following steps of:
preparing a polymer sol and a plurality of carbon fibers into a carbon fiber sheet, wherein the plurality of carbon fibers are arranged in the polymer sol along the plane direction of the carbon fiber sheet;
superposing at least one layer of carbon fiber sheet and at least one layer of polymer film in a die of a die press, and obtaining composite carbon paper after hot pressing treatment;
and sequentially performing pre-oxidation treatment and carbonization treatment on the composite carbon paper to convert the carbon fiber sheet into a carbon fiber sheet carbonization layer, and converting the polymer film into a polymer film carbonization layer to prepare the conductive carbon paper for the electrochemical equipment.
8. The method of claim 7, wherein the hot pressing temperature of the hot pressing process is 200 ℃ to 360 ℃; the hot pressing pressure of the hot pressing treatment is 1MPa-10 MPa; the hot pressing time of the hot pressing treatment is 5-30 min; the temperature of the pre-oxidation treatment is 200-400 ℃; the pre-oxidation treatment time is 80-100 min; the carbonization treatment temperature is 1000-1800 ℃; the carbonization treatment time is 300-600 min.
9. A membrane electrode comprising a proton exchange membrane, a catalytic layer and a gas diffusion layer comprising the conductive carbon paper for electrochemical devices according to any one of claims 1 to 6, which are laminated in this order.
10. An electrochemical device, characterized in that the electrochemical device comprises the conductive carbon paper for electrochemical device according to any one of claims 1 to 6 or the membrane electrode according to claim 9.
CN202310978647.0A 2023-08-03 2023-08-03 Conductive carbon paper for electrochemical equipment and preparation method thereof Pending CN116985478A (en)

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