Fuel cell carbon paper modification method
By depositing amorphous carbon on fuel cell carbon paper, the problems of insufficient conductivity and drainage performance of carbon paper are solved, the battery performance and carbon paper life are significantly improved, and an efficient and low-cost modification process is achieved.
Patent Information
- Application Number
- CN202311354721.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-10-19
- Publication Date
- 2025-04-22
AI Technical Summary
The carbon paper of existing fuel cells has poor conductivity and poor wetting properties, which leads to difficulty in drainage, which easily causes water flooding, reduces the life of carbon paper, and leads to degradation of battery performance.
Through the drying and deposition steps, amorphous carbon is effectively deposited on carbon paper, improving its conductivity and drainage properties. The specific steps include drying the carbon paper raw material in an oven, and then performing carbon deposition in a deposition furnace under an atmosphere of inert gas and carbon source.
It improves the conductivity and drainage performance of carbon paper, extends the service life of carbon paper, and improves the overall performance of fuel cells. This method is simple and easy to operate, has low cost, high production efficiency and finished product yield.
Smart Images
Figure CN119864426A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a fuel cell, in particular to a method for modifying carbon paper for a fuel cell. Background Art
[0002] Proton exchange membrane fuel cell (PEMFC) is a power generation device that uses a proton-conducting polymer membrane as an electrolyte to directly convert the chemical energy in the fuel into electrical energy through an electrochemical reaction.
[0003] The basic structure of PEMFC is mainly bipolar plates (BPP) and membrane electrode assembly (MEA), where the membrane electrode includes cathode, anode and polymer electrolyte membrane (PEM). In the fuel cell, the cathode and anode are usually porous structures, generally referred to as electrodes, and are composed of a gas diffusion layer (GDL) and a catalyst layer (CL). When the battery is running, the reactants enter the catalyst layer through the polar plates and the gas diffusion layer, and electrochemical reactions occur under the action of the electrocatalyst; oxidation reactions occur at the anode, such as hydrogen oxidation reaction (HOR) and methanol oxidation reaction (MOR), and reduction reactions occur at the cathode, usually oxygen reduction reaction (ORR).
[0004] The gas diffusion layer is the core component of the fuel cell. Carbon paper is an important material for preparing the gas diffusion layer. It has a uniform porous structure, good strength and excellent electrical conductivity. It can support the catalyst layer and provide electron channels, gas channels and drainage channels for electrode reactions. Therefore, the development of excellent fuel cell carbon paper is a hot topic in the industry.
[0005] At present, common fuel cell carbon paper is mainly composite carbon paper material, which is made of carbonizable fibers such as carbon fiber, wood pulp, cellulose fiber or poly(ethylene acid) short fiber mixed to make pulp, and then made into carbon paper. The carbon paper obtained by this process has a large carbon paper fiber content of less than 90% because more non-conductive materials are added to ensure the strength of the carbon paper. This results in a large resistance, unreasonable porosity and structure, and due to the low surface energy of carbon fiber and poor wettability with water, the carbon paper is difficult to drain and easily causes flooding, which reduces the service life of the carbon paper and causes a decrease in the current efficiency of the battery.
[0006] Therefore, seeking a fuel cell carbon paper modification method with easy-to-control product quality, simple process, energy saving and environmental protection has become a key issue that needs to be solved urgently. Summary of the invention
[0007] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a method for modifying fuel cell carbon paper, which is simple and easy to operate, low cost, high efficiency and finished product yield. It solves the defects of the existing carbon paper, such as poor conductivity and poor water wettability, which leads to drainage difficulties, easy flooding, reduced carbon paper life, and reduced battery performance.
[0008] The specific plan is as follows: A method for modifying fuel cell carbon paper, comprising: Drying steps: Place the carbon paper raw material in an oven and set the oven temperature to 110℃~130℃; Deposition steps: The dried carbon paper raw material is placed in a deposition furnace, an inert protective gas and a carbon source gas are introduced into the deposition furnace, the temperature in the furnace is 600°C to 1200°C, and the deposition furnace is sealed with an inert gas curtain or a furnace door; In an atmosphere of inert gas and carbon source gas, carbon deposition is performed for a period of time; After the deposition is completed, the finished carbon paper is obtained.
[0009] In some embodiments, the oven drying time is 4 hours or more.
[0010] In some embodiments, the carbon deposition temperature in the deposition furnace is 800-1050°C.
[0011] In some embodiments, the elevated temperature is maintained in the furnace for 30 min to 300 min for carbon deposition.
[0012] In some embodiments, the carbon deposition forms amorphous carbon.
[0013] Furthermore, the mass proportion of the amorphous carbon is about 1-10%.
[0014] Furthermore, the amorphous carbon has a thickness of 5-20 nm.
[0015] In some embodiments, the inert gas includes nitrogen and / or argon, and the carbon source gas is at least one of methane, acetylene, ethylene, propylene, benzene or toluene.
[0016] In some embodiments, the carbon paper stock is transported by a roll-to-roll mechanism with a tension control system.
[0017] Compared with the prior art, the present invention mainly has the following advantages: the present invention effectively deposits amorphous carbon on carbon paper through the above-mentioned preparation process, thereby solving the defects of the prior art carbon paper, such as poor conductivity and poor water wettability, which leads to drainage difficulties, easy flooding, reduced carbon paper life, and decreased battery performance; the production method is simple and easy to operate, low cost, and high production efficiency and finished product yield. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 This is a process flow chart of the fuel cell carbon paper modification process of the present invention. Specific embodiments
[0019] The technical solution of the present invention is further described in detail below through embodiments and in combination with the accompanying drawings, but is not limited to the contents of the embodiments. Example 1
[0020] 200 g of carbon paper raw material was weighed and placed in an oven with the oven temperature set to 120° C. for 14 h.
[0021] The deposition furnace is introduced with nitrogen protective gas, the dried carbon paper raw material is placed in the deposition furnace, the deposition furnace door is closed and tightened, and the tail gas pipeline is connected; the reaction begins, in the first stage, in the nitrogen atmosphere, the furnace temperature is raised from room temperature to 900°C at a heating rate of 5°C / min; in the second stage, the furnace temperature is maintained at 900°C, acetylene is introduced, and carbon deposition is performed for 1 hour. In the third stage, acetylene is turned off, the temperature is lowered to room temperature in a nitrogen atmosphere, the furnace cavity is opened, and the carbon paper product is taken out.
[0022] The amorphous carbon mass accounts for about 3%.
[0023] The amorphous carbon has a thickness of 10 nm. Example 2
[0024] 200 g of carbon paper raw material was weighed and placed in an oven with the oven temperature set to 120° C. for 16 h.
[0025] The deposition furnace is introduced with nitrogen protective gas, the dried carbon paper raw material is placed in the deposition furnace, the deposition furnace door is closed and tightened, and the exhaust gas pipeline is connected; the reaction begins, in the first stage, in the nitrogen atmosphere, the furnace temperature is raised from room temperature to 900°C at a heating rate of 5°C / min; in the second stage, the furnace temperature is maintained at 900°C, methane is introduced, and carbon deposition is performed for 1 hour. In the third stage, methane is turned off, the temperature is lowered to room temperature in a nitrogen atmosphere, the furnace cavity is opened, and the carbon paper product is taken out.
[0026] The amorphous carbon mass accounts for about 3%.
[0027] The amorphous carbon has a thickness of 10 nm. Example 3
[0028] 200 g of carbon paper raw material was weighed and placed in an oven with the oven temperature set to 120° C. for 14 h.
[0029] The deposition furnace is supplied with nitrogen protective gas, the dried carbon paper raw material is placed in the deposition furnace, the deposition furnace door is closed and tightened, and the tail gas pipeline is connected; the reaction begins, in the first stage, in the nitrogen atmosphere, the furnace temperature is raised from room temperature to 900°C at a heating rate of 5°C / min; in the second stage, the furnace temperature is maintained at 900°C, ethylene is introduced, and carbon deposition is performed for 1 hour. In the third stage, ethylene is turned off, the temperature is lowered to room temperature in a nitrogen atmosphere, the furnace cavity is opened, and the carbon paper product is taken out.
[0030] The amorphous carbon mass accounts for about 3%.
[0031] The amorphous carbon has a thickness of 10 nm. Example 4
[0032] Weigh 200 g of carbon paper raw material, put the carbon paper raw material into an oven, set the oven temperature to 120° C., and heat for 15 hours.
[0033] The deposition furnace is supplied with nitrogen protective gas, the dried carbon paper raw material is placed in the deposition furnace, the deposition furnace door is closed and tightened, and the tail gas pipeline is connected; the reaction begins, in the first stage, in the nitrogen atmosphere, the furnace temperature is raised from room temperature to 900°C at a heating rate of 5°C / min; in the second stage, the furnace temperature is maintained at 900°C, propylene is introduced, and carbon deposition is performed for 1 hour. In the third stage, propylene is turned off, the temperature is lowered to room temperature in a nitrogen atmosphere, the furnace cavity is opened, and the carbon paper product is taken out.
[0034] The amorphous carbon mass accounts for about 4%.
[0035] The amorphous carbon has a thickness of 12 nm. Example 5
[0036] Weigh 200 g of carbon paper raw material, put the carbon paper raw material into an oven, set the oven temperature to 120° C., and heat for 15 hours.
[0037] The deposition furnace is introduced with nitrogen protective gas, the dried carbon paper raw material is placed in the deposition furnace, the deposition furnace door is closed and tightened, and the tail gas pipeline is connected; the reaction begins, in the first stage, in the nitrogen atmosphere, the furnace temperature is raised from room temperature to 900°C at a heating rate of 5°C / min; in the second stage, the furnace temperature is maintained at 900°C, acetylene is introduced, and carbon deposition is performed for 0.5 hours. In the third stage, acetylene is turned off, the temperature is lowered to room temperature in a nitrogen atmosphere, the furnace cavity is opened, and the carbon paper product is taken out.
[0038] The amorphous carbon mass accounts for about 1%.
[0039] The amorphous carbon has a thickness of 5 nm. Example 6
[0040] Weigh 200 g of carbon paper raw material, put the carbon paper raw material into an oven, set the oven temperature to 120° C., and heat for 15 hours.
[0041] The deposition furnace is supplied with nitrogen protective gas, the dried carbon paper raw material is placed in the deposition furnace, the deposition furnace door is closed and tightened, and the tail gas pipeline is connected; the reaction begins, in the first stage, in the nitrogen atmosphere, the furnace temperature is raised from room temperature to 900°C at a heating rate of 5°C / min; in the second stage, the furnace temperature is maintained at 900°C, acetylene is introduced, and carbon deposition is performed for 5 hours. In the third stage, acetylene is turned off, the temperature is lowered to room temperature in a nitrogen atmosphere, the furnace cavity is opened, and the carbon paper product is taken out.
[0042] The mass percentage of amorphous carbon is about 10%.
[0043] The amorphous carbon has a thickness of 20 nm. Example 7
[0044] Weigh 200 g of carbon paper raw material, put the carbon paper raw material into an oven, set the oven temperature to 120° C., and heat for 15 hours.
[0045] The deposition furnace is introduced with nitrogen protective gas, the dried carbon paper raw material is placed in the deposition furnace, the deposition furnace door is closed and tightened, and the tail gas pipeline is connected; the reaction begins, in the first stage, in the nitrogen atmosphere, the temperature in the furnace is raised from room temperature to 800°C at a heating rate of 5°C / min; in the second stage, the temperature in the furnace is maintained at 800°C, acetylene is introduced, and carbon deposition is performed for 1 hour. In the third stage, acetylene is turned off, the temperature is lowered to room temperature in a nitrogen atmosphere, the furnace cavity is opened, and the carbon paper product is taken out.
[0046] The mass percentage of the amorphous carbon is about 2%.
[0047] The amorphous carbon has a thickness of 8 nm. Example 8
[0048] Weigh 200 g of carbon paper raw material, put the carbon paper raw material into an oven, set the oven temperature to 120° C., and heat for 15 hours.
[0049] Nitrogen protective gas is introduced into the deposition furnace, and the carbon paper raw material is transmitted through a roll-to-roll mechanism with a tension control system. The deposition furnace is sealed with an air curtain and connected to the exhaust gas pipeline; the reaction begins. In the first stage, the temperature in the furnace is increased from room temperature to 1050°C at a heating rate of 5°C / min under a nitrogen atmosphere; in the second stage, the temperature in the furnace is maintained at 1050°C, acetylene is introduced, the deposition furnace length is 30m, and carbon deposition is performed for 1 hour. In the third stage, acetylene is turned off, the temperature is lowered to room temperature under a nitrogen atmosphere, and the carbon paper product is rolled up.
[0050] The amorphous carbon mass accounts for about 5%.
[0051] The amorphous carbon has a thickness of 15 nm.
[0052] The resistivity and water contact angle of the obtained carbon paper were tested, and the test data are shown below. Comparative Example
[0053] The carbon paper raw material was tested for resistivity and water contact angle, and the test data are shown below.
[0054]
Claims
1. A method for modifying fuel cell carbon paper, characterized in that: The method includes placing the carbon paper raw material in an oven, setting the oven temperature to 110°C~130°C; placing the dried carbon paper raw material in a deposition furnace, introducing inert protective gas and carbon source gas into the deposition furnace, the temperature in the furnace is 600°C~1200°C, and sealing the deposition furnace with an inert gas curtain or a furnace door; maintaining carbon deposition for a period of time in the inert gas and carbon source gas atmosphere; after completion of deposition, obtaining a carbon paper finished product.
2. A fuel cell carbon paper modification method according to claim 1, characterized in that: The oven drying time is 4 hours or more.
3. A fuel cell carbon paper modification method according to claim 1, characterized in that: The carbon deposition temperature in the deposition furnace is 800-1050°C.
4. A fuel cell carbon paper modification method according to claim 1, characterized in that: The carbon deposition time in the deposition furnace is 30min~300min.
5. The method for modifying fuel cell carbon paper according to claim 1, characterized in that: The carbon deposition forms amorphous carbon.
6. A fuel cell carbon paper modification method according to claim 6, characterized in that: The amorphous carbon accounts for 1-10% by mass.
7. A fuel cell carbon paper modification method according to claim 6, characterized in that: The amorphous carbon has a thickness of 5-20 nm.
8. The method for modifying fuel cell carbon paper according to claim 1, characterized in that: The inert gas includes nitrogen and / or argon, and the carbon source gas is at least one of methane, acetylene, ethylene, propylene, benzene or toluene.