CN115411278A - Method for improving corrosion resistance of graphite bipolar plate - Google Patents

Method for improving corrosion resistance of graphite bipolar plate Download PDF

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Publication number
CN115411278A
CN115411278A CN202211251751.1A CN202211251751A CN115411278A CN 115411278 A CN115411278 A CN 115411278A CN 202211251751 A CN202211251751 A CN 202211251751A CN 115411278 A CN115411278 A CN 115411278A
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graphite
bipolar plate
bismuth
temperature
plate
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孟津红
黄若云
冯玉磊
丁祖荣
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BEIJING SUNSHINE HONGZHI ELECTRICAL ENGINEERING TECHNOLOGY CO LTD
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BEIJING SUNSHINE HONGZHI ELECTRICAL ENGINEERING TECHNOLOGY CO LTD
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    • 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
    • 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
    • H01M4/8647—Inert electrodes with catalytic activity, e.g. for fuel cells consisting of more than one material, e.g. consisting of composites
    • H01M4/8657—Inert electrodes with catalytic activity, e.g. for fuel cells consisting of more than one material, e.g. consisting of composites layered
    • 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
    • H01M4/8663—Selection of inactive substances as ingredients for catalytic active masses, e.g. binders, fillers
    • 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
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • 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
    • H01M8/18—Regenerative fuel cells, e.g. redox flow batteries or secondary fuel cells
    • H01M8/184—Regeneration by electrochemical means
    • H01M8/188—Regeneration by electrochemical means by recharging of redox couples containing fluids; Redox flow type batteries
    • 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
    • H01M2004/8678—Inert electrodes with catalytic activity, e.g. for fuel cells characterised by the polarity
    • H01M2004/8684—Negative electrodes
    • 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

Abstract

The invention provides a method for improving the corrosion resistance of a graphite bipolar plate, which comprises the following operations: firstly, pretreating a graphite plate, wherein the pretreatment is to soak the graphite plate in sulfuric acid; secondly, selecting one surface of the graphite plate to coat bismuth by using a bismuth coating solution, wherein the bismuth coating solution contains Bi 2 O 3 (ii) a Thirdly, pressurizing and leaching, wherein the pressure of the pressurizing and leaching is 0.1-0.3 Mpa; and fourthly, cleaning and drying. The bipolar plate prepared by the method for improving the corrosion resistance of the graphite bipolar plate has excellent conductivity, chemical corrosion resistance and electrochemical corrosion resistance, has lower contact resistance with an electrode, reduces the ohmic internal resistance of the all-vanadium redox flow battery, and improves the energy efficiency and the electricity of the redox flow batteryAnd (4) pressing efficiency.

Description

Method for improving corrosion resistance of graphite bipolar plate
Technical Field
The invention belongs to the technical field of energy storage, and particularly relates to a surface treatment method of a bipolar plate of a flow battery.
Background
The full Vanadium Flow Battery (VFB) is a storage battery using vanadium ion solution as positive and negative electrode active materials, and has a series of advantages of long service life, fast response speed, no cross contamination, deep discharge, easy increase and decrease of battery power and capacity, and the like. The all-vanadium redox flow battery has extremely good application prospect in the fields of wind power, photovoltaic power generation, power grid peak regulation and the like. All-vanadium flow batteries generally use sulfuric acid as a supporting electrolyte, and VO in the positive electrolyte is generated when the battery is charged 2+ Is oxidized into VO 2 + The color of the electrolyte gradually changes from blue to yellow; v in the negative electrode electrolyte 3+ Is reduced into V 2+ The electrolyte gradually changes from dark green to purple; in contrast, VO in the positive electrolyte when the battery is discharged 2+ The obtained electrons are reduced to VO 2+ V in the negative electrode electrolyte 2+ Oxidation of lost electrons to V 3+ . During the charging and discharging process, the positive and negative electrolytes carry out proton exchange through a cation exchange membrane.
The structure of the all-vanadium redox flow battery pile is formed by assembling a plurality of single batteries or even tens of single batteries according to a filter press mode. The middle of the single cell is provided with an ion exchange membrane, two sides of the membrane are respectively provided with an electrode, and then a bipolar plate is respectively arranged. The bipolar plate realizes the connection between the monocells in the galvanic pile, isolates the positive electrolyte and the negative electrolyte between the adjacent monocells, and collects the current generated by the electrode reaction at the two sides of the bipolar plate. The bipolar plate has excellent electrical conductivity and requires a low contact (interface) resistance between the bipolar plate and the electrode. The bipolar plates also have good acid and corrosion resistance. In the all-vanadium redox flow battery, one side of a bipolar plate is connected with positive pentavalent vanadium ions (VO) of a strong oxidant 2 + ) The solution is directly contacted, and the other side of the solution is connected with a strongly reducing cathode divalent vanadium (V) 2+ ) The solutions are contacted directly. If the resistance of the graphite plate is too large, the ohmic internal resistance of the battery is increased, and the chemical and electrochemical corrosion probability of the surface of the graphite plate is increased.
In addition, a side reaction of electrolyzing water (hydrogen is generated at the negative electrode and oxygen is generated at the positive electrode) occurs in a minute amount at the time of charging the vanadium battery, and such a side reaction inevitably occurs. Despite various measures, minor side reactions always occur. And the valence state of vanadium ions in the electrolyte is unbalanced with the long-time operation of the vanadium battery. Research shows that the performance of the material directly influences the difficulty of gas production reaction; has high surface area and good electronic conductivity, and can reduce the occurrence of gas generation side reaction of the material. Therefore, the invention reduces the electrochemical corrosion of the electrolyte to the graphite bipolar plate by improving the electronic conductivity of the graphite bipolar plate and increasing the hydrogen evolution overpotential at the negative electrode side, thereby improving the overall performance of the vanadium redox flow battery.
Disclosure of Invention
In view of the shortcomings of the prior art, it is a first object of the present invention to provide a method for improving the corrosion resistance of a graphite bipolar plate.
The second purpose of the invention is to provide the graphite bipolar plate prepared by the method.
The technical scheme for realizing the above purpose of the invention is as follows:
a method of improving the corrosion resistance of a graphite bipolar plate comprising the acts of:
(1) Firstly, pretreating a graphite plate, wherein the pretreatment is to soak the graphite plate in sulfuric acid;
(2) Secondly, selecting one surface of the graphite plate to coat bismuth by using a bismuth coating solution, wherein the bismuth coating solution contains Bi 2 O 3 ；
(3) Thirdly, pressurizing and leaching, wherein the pressure of the pressurizing and leaching is 0.1-0.3 Mpa;
(4) And fourthly, cleaning and drying.
In the first step, 60-80% sulfuric acid is used, the pre-treatment temperature is 150-170 ℃, and the pre-treatment time is 5-10 hours.
Preferably, in the first step, sulfuric acid with the mass concentration of 70% is used, the pretreatment temperature is 150-170 ℃, the pretreatment time is 8 hours, and the temperature is reduced to room temperature and the cleaning is carried out after the pretreatment is finished.
In the second step, the bismuth coating solution contains the following components in parts by mass0.2 to 0.8 of Bi 2 O 3 60 to 80 portions of diethylene glycol, 20 to 40 portions of water and 0.2 to 1.0 portion of amino acid, wherein the amino acid is cysteine and/or cystine and is amino acid with reducibility.
Cysteine has reducibility, bismuth oxide has oxidability, cysteine can reduce bismuth oxide into zero-valent bismuth, and diethylene glycol has certain viscosity and is easy to adhere to a graphite plate. Further preferably, the bismuth coating liquid is 0.8 part of Bi through tests 2 O 3 0.8 portion of cysteine is dispersed in 65-70 portions of diethylene glycol and 30 portions of water.
In the second step, one side of the graphite plate is selected to be coated with bismuth, the reaction time after bismuth coating is 2-4 hours, and the reaction temperature is 10-40 ℃.
Wherein, in the third step, the time of the pressure leaching is 6 to 10 hours, and the temperature of the pressure leaching is 110 to 140 ℃.
And in the third step, the graphite bipolar plate is placed in a steam sterilizer for pressure leaching, wherein the pressure leaching temperature is 130 ℃, the pressure is 0.2MPa, and the time is 8 hours.
Wherein, in the fourth step, the solvent used for cleaning is ethanol, and the drying temperature after cleaning is 40-65 ℃.
The graphite bipolar plate prepared by the method is provided by the invention.
The invention has the beneficial effects that:
it is known that metal Bi has a high hydrogen evolution overpotential, can inhibit hydrogen evolution side reactions, and is non-toxic. In the early test, bi ions are added into the electrolyte, and the fact that Bi nanoparticles are generated on the surface of the graphite felt of the negative electrode when the all-vanadium redox flow battery is charged is found, so that the catalytic activity of the graphite felt of the negative electrode on the redox reaction of di-and trivalent vanadium ions is greatly improved. Therefore, the technical scheme tests the bismuth modified graphite bipolar plate surface.
According to the method for improving the corrosion resistance of the graphite bipolar plate, the prepared bipolar plate has excellent conductivity, chemical corrosion resistance and electrochemical corrosion resistance, and has lower contact resistance with an electrode, so that the ohmic internal resistance of the all-vanadium flow battery is reduced, and the energy efficiency and the voltage efficiency of the flow battery are improved.
Drawings
FIG. 1 electron spectrum of the treated bipolar plate;
FIG. 2 comparison of cyclic voltammetry tests;
fig. 3 comparison, comparison of electrochemical ac impedance data (EIS) before and after treatment: (A) a positive electrode electrolyte; (B) a negative electrode electrolyte;
figure 4 is a comparison of the voltage efficiencies of,
FIG. 5 comparison of energy efficiency.
Figure 6 photographs of the assembled stack after 2500 hours of operation with the comparative bipolar plates disassembled.
Detailed Description
The following examples are intended to illustrate the invention, but are not intended to limit the scope of the invention.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
The invention provides a method for improving the corrosion resistance of a graphite bipolar plate for a flow battery, which comprises the following steps:
(1) Firstly, using 60-80% sulfuric acid by mass concentration to pretreat a graphite plate at 150-160 ℃, wherein the pretreatment time is 5-10 hours;
(2) Second, selecting one side of the graphite plate to be coated with bismuth, using the concentration of Bi of 0.2% -0.8% 2 O 3 The suspension of (4). The solvent is 60-80% of diglycol, 20-40% of water and 0.2-1.0% of amino acid. The graphite plate coated with bismuth is horizontally placed, the reaction time is 2-4 hours, and the reaction temperature is 10-30 ℃.
(3) Thirdly, the graphite plate coated with bismuth is put into a steam sterilizer for pressurized leaching for 6 to 10 hours at the pressure of 0.1 to 0.3Mpa and the temperature of 110 to 140 ℃.
(4) And fourthly, taking out the graphite plate after the pressure leaching from the steam cabinet, airing to room temperature, cleaning the graphite plate by using ethanol, and then drying at the temperature of 40-45 ℃.
In order to further illustrate the performance of the graphite bipolar plate prepared by the invention, the prepared graphite bipolar plate is subjected to performance test.
1. The test method comprises the following steps: the following performance tests are carried out according to the NB/T42007-2013 standard of the test method of the bipolar plate for the all-vanadium redox flow battery:
(1) Volume resistivity: the resistivity per unit cross-sectional area per unit length of the bipolar plate is given in units of Ω · cm.
(2) Contact resistance: resistance between contact portions of two materials in units of Ω · cm 2 。
(3) Corrosion current density: under the specified conditions, the current value of the bipolar plate per unit area of the battery is generated by the damage caused by electrochemical action under the corrosion potential, and the unit is muA/cm 2 。
2. Test samples: the bipolar plate for the all-vanadium redox flow battery prepared by the preparation method provided by the embodiment of the invention is used as a test sample, and the graphite bipolar plate before treatment is used as a control group.
Example 1
Putting a 0.28m multiplied by 0.28m graphite plate into 10L of 70% concentrated sulfuric acid, heating to 150 ℃, treating for 5 hours, cooling to room temperature after the reaction time, washing with deionized water, and airing at room temperature;
preparing a bismuth coating solution: 2gBi 2 O 3 2g of cysteine were dispersed in 696g of diethylene glycol and 300g of water. Uniformly coating the bismuth coating liquid on one surface of a graphite plate to be activated, putting the graphite plate into an oven to react for 4 hours, and controlling the temperature to be 30 ℃;
the bismuth-coated bipolar plate is put into a steam sterilizer (WDZX-300 KC, shanghai Shenan medical instrument factory) and is pressed and dissolved at the temperature of 121 ℃ and the pressure of 0.2MPa for 8 hours.
Cooling to room temperature, washing with alcohol, and stoving at 40-45 deg.c.
The obtained bipolar plate was characterized and the electron spectrum showed the presence of three elements C, O and Bi in the bipolar plate, as shown in fig. 1.
The volume resistivity of the bipolar plate prepared by the embodiment is reduced from 0.65 omega cm to 0.45 omega cm by 30.8%; contact resistance is from 220 omega cm 2 Reduced to 140cm 2 The reduction is 36.4%; the corrosion current density is from 0.50 muA/cm 2 Reduced to 0.25. Mu.A/cm 2 And the reduction is 50.0%.
Example 2
Putting a 0.28m multiplied by 0.28m graphite plate into 10L of 70% concentrated sulfuric acid, heating to 140 ℃, treating for 6 hours, reducing the reaction time to room temperature, washing with deionized water, and airing at room temperature;
preparing bismuth coating solution, 2gBi 2 O 3 2g of cysteine were dispersed in 694g of diethylene glycol and 300g of water. Uniformly coating the bismuth coating solution on one surface of an activated graphite plate, putting the graphite plate into a drying oven to react for 4 hours, and controlling the temperature to be 30 ℃;
the bismuth-coated bipolar plate is put into a steam sterilizer (WDZX-300 KC, shanghai Shenan medical instrument factory) and is pressed and dissolved at the temperature of 121 ℃ and the pressure of 0.2MPa for 6 hours. Cooling to room temperature, washing with alcohol, and stoving at 40-45 deg.c.
The volume resistivity of the bipolar plate prepared by the embodiment is reduced from 0.65 omega cm to 0.43 omega cm, and is reduced by 33.8%; contact resistance is from 220 omega cm 2 Reduced to 140cm 2 The reduction is 36.4%; the corrosion current density is from 0.50 muA/cm 2 Reduced to 0.24 muA/cm 2 And the reduction is 52.0 percent.
Example 3
Putting a 0.28m multiplied by 0.28m graphite plate into 10L of 70% concentrated sulfuric acid, heating to 160 ℃, treating for 8 hours, reducing the reaction time to room temperature, washing with deionized water, and airing at room temperature;
preparing bismuth coating solution, 4gBi 2 O 3 4g of cysteine were dispersed in 692g of diethylene glycol and 300g of water. Uniformly coating the bismuth coating liquid on one surface of an activated graphite plate, putting the activated graphite plate into a drying oven to react for 4 hours, and controlling the temperature to be 30 ℃;
the bismuth-coated bipolar plate is put into a steam sterilizer (WDZX-300 KC, shanghai Shenan medical instrument factory) and is pressed and dissolved at the temperature of 130 ℃ and the pressure of 0.2MPa for 8 hours. When the time is up, the temperature is reduced to the room temperature, the mixture is cleaned by ethanol and dried at the temperature of 40-45 ℃.
The volume resistivity of the bipolar plate prepared by the embodiment is reduced from 0.65 omega cm to 0.43 omega cm, and is reduced by 33.8%; the contact resistance is from 220 omega cm 2 Reduced to 140cm 2 The reduction is 36.4%; the corrosion current density is from 0.50 muA/cm 2 Reduced to 0.22 muA/cm 2 And the reduction is 56.0 percent.
Example 4
Putting a 0.28m multiplied by 0.28m graphite plate into 10L of 70% concentrated sulfuric acid, heating to 160 ℃, treating for 8 hours, reducing the reaction time to room temperature, washing with deionized water, and airing at room temperature;
preparing a bismuth coating solution, 4gBi 2 O 3 4g of cysteine were dispersed in 692g of diethylene glycol and 300g of water. Uniformly coating the bismuth coating solution on one surface of an activated graphite plate, putting the graphite plate into a drying oven to react for 4 hours, and controlling the temperature to be 30 ℃;
the bismuth-coated bipolar plate is put into a steam sterilizer (WDZX-300 KC, shanghai Shenan medical instrument factory) and is pressed and dissolved at the temperature of 130 ℃ and the pressure of 0.2MPa for 8 hours. Cooling to room temperature, washing with alcohol, and stoving at 40-45 deg.c.
The volume resistivity of the bipolar plate prepared by the embodiment is reduced from 0.65 omega cm to 0.40 omega cm by 38.5 percent; contact resistance is from 220 omega cm 2 Reduced to 120cm 2 The reduction is 45.5%; the corrosion current density is from 0.50 muA/cm 2 Reduced to 0.20 muA/cm 2 And the reduction is 60.0 percent.
Example 5
Putting a 0.28m multiplied by 0.28m graphite plate into 10L of 70% concentrated sulfuric acid, heating to 160 ℃, treating for 8 hours, reducing the reaction time to room temperature, washing with deionized water, and airing at room temperature;
preparing a bismuth coating solution, 8gBi 2 O 3 8g of cysteine were dispersed in 684g of diethylene glycol and 300g of water. Uniformly coating the bismuth coating solution on one surface of an activated graphite plate, putting the graphite plate into a drying oven for reaction for 4 hours, and controlling the temperature to be 30 DEG C；
The bismuth-coated bipolar plate is put into a steam sterilizer (WDZX-300 KC, shanghai Shenan medical instrument factory) and is pressed and dissolved at the temperature of 130 ℃ and the pressure of 0.2MPa for 8 hours. Cooling to room temperature, washing with alcohol, and stoving at 40-45 deg.c.
The volume resistivity of the bipolar plate prepared by the embodiment is reduced from 0.65 omega cm to 0.40 omega cm by 38.5 percent; contact resistance is from 220 omega cm 2 Reduced to 120cm 2 The reduction is 45.5%; the corrosion current density is from 0.50 muA/cm 2 Reduced to 0.18 muA/cm 2 And the reduction is 64.0 percent.
Cyclic voltammetry and EIS tests were performed using the graphite bipolar plate prepared in example 5. As shown in fig. 2 and 3. The cyclic voltammetry test shows that the gassing peak of the graphite plate treated by the method is obviously reduced, and the electrochemical activity is obviously increased. EIS tests show that the resistance value of the graphite plate treated by the method is greatly reduced under the open-circuit voltage.
The bipolar plate prepared in example 5 was assembled into an all-vanadium flow battery, and the basic parameters of the battery are as follows:
table 1: testing battery parameters
Figure BDA0003887998730000081
The graphite plates which are not used for assembling the all-vanadium redox flow battery are used as a contrast, and the structure of the galvanic pile is completely consistent with the operation parameters.
The coulomb efficiency and energy efficiency of the two stacks after 100 charge-discharge cycles are shown in fig. 4 and 5. From the data in fig. 4 and 5, it can be seen that the voltage efficiency and the energy efficiency of the all-vanadium redox flow battery composed of the graphite bipolar plate prepared by the invention are obviously improved. The test cell and the control cell were run for 2500 hours and a comparison of the disassembled bipolar plates is shown in figure 6. The left photo is the bipolar plate of the vanadium battery assembled by the graphite plate treated by the method after 2500 hours of operation, the surface is smooth and flat, and the corrosion phenomenon does not occur. The right photo is the bipolar plate of the vanadium battery assembled by the graphite plate which is not treated by the method after 2500 hours of operation. The surface of the bipolar plate in contact with the negative electrolyte has been corroded to show mud-like substances. As can be seen from the physical photograph of FIG. 6, the corrosion resistance of the graphite bipolar plate treated by the method is obviously enhanced.
Although the present invention has been described in the foregoing by way of examples, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.

Claims (10)

1. A method of improving the corrosion resistance of a graphite bipolar plate comprising the acts of:
(1) Firstly, pretreating a graphite plate, wherein the pretreatment is to soak the graphite plate in sulfuric acid;
(2) Secondly, selecting one surface of the graphite plate to coat bismuth by using a bismuth coating solution, wherein the bismuth coating solution contains Bi 2 O 3 ；
(3) Thirdly, pressurizing and leaching, wherein the pressure of the pressurizing and leaching is 0.1-0.3 Mpa;
(4) And fourthly, cleaning and drying.
2. The method according to claim 1, wherein in the first step, sulfuric acid with a mass concentration of 60% to 80% is used, the pretreatment temperature is 150 to 170 ℃, and the pretreatment time is 5 to 10 hours.
3. The method as claimed in claim 2, wherein in the first step, sulfuric acid with a mass concentration of 70% is used, the pretreatment temperature is 150 to 170 ℃, the pretreatment time is 8 hours, and after the pretreatment is completed, the temperature is reduced to room temperature and the washing is carried out.
4. The method according to claim 1, wherein in the second step, the bismuth coating solution contains 0.2 to 0.8 parts by weight of Bi 2 O 3 60 to 80 portions of diglycol, 20 to 40 portions of water, 0.2 to 1.0 portion of ammoniaAn amino acid, which is cysteine and/or cystine.
5. The method according to claim 4, wherein in the second step, the bismuth coating solution is 0.8 parts of Bi 2 O 3 0.8 portion of cysteine is dispersed in 65-70 portions of diethylene glycol and 30 portions of water.
6. The method of claim 1, wherein in the second step, one side of the graphite plate is selected to be coated with bismuth, the reaction time after bismuth coating is 2 to 4 hours, and the reaction temperature is 10 to 40 ℃.
7. The method according to claim 1, wherein in the third step, the pressure leaching time is 6 to 10 hours, and the pressure leaching temperature is 110 to 140 ℃.
8. The method as claimed in claim 7, wherein the graphite bipolar plate is subjected to pressure leaching in a steam sterilizer at a temperature of 130 ℃ and a pressure of 0.2MPa for 8 hours in the third step.
9. The method according to any one of claims 1 to 8, wherein the solvent used for the washing in the fourth step is ethanol, and the drying temperature after the washing is 40 to 65 ℃.
10. A graphite bipolar plate produced by the method of any one of claims 1 to 9.
CN202211251751.1A 2022-10-13 2022-10-13 Method for improving corrosion resistance of graphite bipolar plate Pending CN115411278A (en)

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