A method for the production of a solid oxide fuel cell metallic support

Abstract

The application discloses a preparation method of a solid oxide fuel cell metal support, which comprises the following steps: preparing a nickel chloride / polyaniline matrix, low-temperature reduction and carbonization reaction. The application adopts the nickel chloride / polyaniline matrix as the precursor of the metal support for the first time, reduces the reduction temperature of the metal support to below 1200 DEG C, avoids the problems of the reduction of the strength of the Ni-based or Fe-based bipolar plate caused by the reaction at 1400 DEG C due to high-temperature sintering, and is higher in reduction efficiency; through the low-temperature reduction and the medium-temperature carbonization, the further decomposition or carbonization reaction of the polyaniline in the process of glue removal and co-sintering is combined, a high-specific-surface-area multi-stage gas channel structure is formed, a new method and a new idea are provided for the preparation of the solid oxide fuel cell metal support, and the application range and the prospect of the solid oxide fuel cell are expanded.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solid oxide fuel cell materials, and particularly relates to a preparation method of a solid oxide fuel cell metal support. BACKGROUND

[0002] A solid oxide fuel cell (SOFC) is mainly composed of an electrolyte, an anode, a cathode, a support and a barrier layer.

[0003] A traditional support generally adopts a ceramic support structure, but in recent years, a metal support structure SOFC has been developed more greatly because it has the following advantages: 1) low cost: the price of a metal material is much lower than that of a ceramic material used for an anode, a cathode and an electrolyte; 2) fast start: the good thermal conductivity of the metal can ensure the fast start performance of the metal support SOFC, so that it can be applied to a mobile field; 3) processability: the metal stainless steel material has good ductility, which greatly reduces the difficulty of SOFC processing; 4) easy sealing: the mature sealing technology of the metal material can avoid the difficult sealing problem of the traditional SOFC.

[0004] At present, according to the support material, the metal support type SOFC is mainly divided into two types of Fe-based supports and Ni-based supports, and some researches also start to develop the following Fe-Ni alloy base by comprehensively considering the performance of the two. The preparation method of the metal support SOFC is generally to use NiO or Fe2O3 as the raw material of the support, to flow cast NiO-Fe2O3 or NiO-GDC and GDC blanks, and then to obtain a half cell through lamination, co-firing and the like, and finally to deposit a BSCF cathode on the electrolyte through screen printing to obtain a cell.

[0005] In theory, the cell can automatically reduce the Ni-Fe oxide base into a Ni-Fe alloy by using a high-temperature reducing fuel gas when the cell is started, and the shrinkage of the base during the reduction can obtain a large enough porosity, so as to meet the transmission of the fuel gas of the cell. However, in actual cell preparation, in order to ensure the reduction activity of the support base, most of the cell supports are burned or co-fired at a high temperature in a reducing atmosphere to obtain a reduced metal surface, and the reduction temperature (> 1200 DEG C) is high, which is easy to cause the reduction of the strength of the metal support, and therefore, a new process for preparing the metal support under a low-temperature environment is urgently needed. SUMMARY

[0006] The present application aims at solving the problems in the prior art, and provides a preparation method of a solid oxide fuel cell metal support.

[0007] In order to achieve the above object, the present application adopts the following technical solutions:

[0008] The present application first proposes a preparation method of a solid oxide fuel cell metal support, comprising the following steps:

[0009] S1, preparation of a nickel chloride / polyaniline matrix:

[0010] S101, camphorsulfonic acid, nickel chloride and aniline monomers and water are mixed in a flask according to a solute to solvent mass ratio of 1:50, the flask is shaken uniformly, then placed in liquid nitrogen for quick freezing, taken out and placed in a normal temperature ultrasonic tank, ultrasonic treatment for 10-15 min to obtain a completely dissolved monomer solution; ammonium persulfate and water are prepared into a catalyst solution with the same volume as the monomer solution, the catalyst solution is added dropwise into the monomer solution at a speed of 9 ml / min, and the temperature of the system is controlled at 5℃ during the dropwise adding process;

[0011] S102, after the dropwise adding is completed, the stirring is stopped, and the mixed solution system is continuously placed at 5℃ for 16 h of reaction to obtain a sol;

[0012] S103, a foamed iron-nickel plate (foamed iron-nickel plate, pore size: 0.10-0.15 mm, high-conductivity porous structure, Hebei Ruizun Screen Printing Technology Co., Ltd.) is prepared into a laminated filter plate, the sol obtained in S2 is placed in the laminated filter plate for suction filtration, and after the suction filtration, deionized water and anhydrous ethanol are used for washing until the filtrate is colorless, and the filter cake and the foamed iron-nickel plate are freeze-dried to obtain a nickel chloride / polyaniline matrix, one side of which is a bare iron-nickel mesh and the other side is a nickel chloride / polyaniline porous structure;

[0013] S2, low-temperature reduction:

[0014] The nickel chloride / polyaniline matrix is placed in a tube furnace, heated to 250-350℃ at a heating rate of 5℃ / min under a reducing atmosphere, and kept for 3 h of reaction, until a metallic luster appears on the surface of the nickel chloride / polyaniline matrix, and the conductivity of the side of the nickel chloride / polyaniline is greatly improved compared with that before reduction;

[0015] Through a comparative test, white smoke is generated near 50℃ at a low temperature of 250-350℃, which is detected as HCl, a small amount of ammonia and ammonium chloride, near 200℃, camphorsulfonic acid begins to decompose into SO2, CO2 and H2O, and the initial pore is formed, and the free acid (HCl and water) can promote the conversion of polyaniline body to a reduced state under a reducing atmosphere and at 250-350℃, and the electron-donating ability of the reduced polyaniline promotes the conversion efficiency of nickel chloride to nickel, and CO is increased in the reducing atmosphere to generate a Ni-CO coordination bond on the surface of the nickel metal, which reserves reducing gas and prevents the oxidation of the metal support in the subsequent battery calcination process;

[0016] Ni oxidation resistance test: the reduced Ni prepared under the reaction condition without polyaniline body or CO is calcined at 500℃ in air atmosphere for 15-30 min, and the distribution area and electrical conductivity of the ash white metal color are observed, both of which are less than the above-mentioned nickel chloride / polyaniline body,

[0017] S3, carbonization reaction:

[0018] Continuously heating to 700-750℃ at a heating rate of 10℃ / min under a reducing atmosphere, and holding for 3-4h to obtain a metal support, one side of which is a bare iron-nickel mesh and the other side is a Ni / C composite porous layer;

[0019] After 400℃, the polyaniline body starts to decompose to produce CO2 and NH3, etc., further producing gas pores; after 650℃, the polyaniline surface carbonizes to produce N-doped carbon material in a graphite structure, enhancing the electrical conductivity and structural strength; on the other hand, the remaining nickel chloride is continuously reduced, so that the nickel chloride in the body is substantially completely reduced, further improving the electrical conductivity, and the electrical conductivity of the N-doped carbon material side is close to that of the foam iron-nickel plate.

[0020] Preferably, the molar ratio of camphor sulfonic acid, nickel chloride, aniline monomer and ammonium persulfate in S101 is 1:5-8:3-5:3-5.

[0021] Preferably, the cooling and drying process in S103 is: freezing the filter cake and the foam iron-nickel plate at -10℃ for 10h, and then taking out and freeze-drying at -30℃ for 8h to obtain the nickel chloride / polyaniline body;

[0022] Preferably, the reducing atmosphere in S2 and S3 is composed of H2, CO and N2 in a volume ratio of 0.5-1:0.1-1:8, and the gas is replaced every 30min.

[0023] The application also proposes the use of the metal support obtained by the above-mentioned preparation method in a solid oxide fuel cell, comprising the following steps:

[0024] 1) Anode sheet preparation:

[0025] The Ni / C composite porous layer of the metal support sequentially passes through the electrolyte slurry to form an anode functional layer and an electrolyte layer, and is heated to 500-550℃ at a heating rate of 2-4℃ / min, and held for 2h to perform degassing, to obtain an anode sheet;

[0026] The degassing process is under aerobic conditions, and part of the contacted polyaniline is decomposed into N2, CO2 and H2O to produce new gas pores;

[0027] 2) Barrier sheet preparation:

[0028] The GDC slurry is coated on a stainless steel sheet, and the temperature is raised to 450-500 DEG C at a temperature raising rate of 3-5 DEG C / min, and the temperature is kept for 1-5h, so that a barrier sheet with a GDC barrier layer is obtained;

[0029] 3) Cathode sheet preparation:

[0030] The cathode layer slurry is coated on a stainless steel sheet, and the temperature is raised to 450-500 DEG C at a temperature raising rate of 3-5 DEG C / min, and the temperature is kept for 1-5h, so that a cathode sheet is obtained;

[0031] 4) Single cell preparation by co-firing:

[0032] After the anode sheet, the barrier sheet and the cathode sheet are laminated, the lamination is placed in a reducing atmosphere, the gas is replaced every 15 min, the temperature is raised to 800-850 DEG C at a temperature raising rate of 5-8 DEG C / min, and the temperature is kept for 4-6h; the temperature is raised to 1100-1150 DEG C at a temperature raising rate of 4-6 DEG C / min, and a pressure of 0.4-0.5MPa is applied, and the temperature is kept for 1-3h, and after cooling, a single cell is obtained; the remaining polyaniline wrapped by the reduced Ni and the electrolyte is carbonized rapidly at high temperature, and new pore channels are formed, so that the gas transportation efficiency is improved, and the NiO in the anode functional layer is reduced, so that the obtained single cell does not need to be reduced by an additional anode reaction, and electricity can be generated by adding fuel.

[0033] Preferably, the electrolyte slurry in 1) is YSZ, and the thickness of the electrolyte layer is 10-15um.

[0034] Preferably, the thickness of the barrier sheet in 2) is 8-10um.

[0035] Preferably, the cathode layer slurry in 3) adopts LSCF and GDC in a mass ratio of 1:1, and the thickness of the cathode sheet is 40-45um.

[0036] Preferably, the reducing atmosphere in 4) is mixed by H2 and N2 in a volume ratio of 1:9, the high-temperature reduction process does not need CO, and the Ni-CO coordination body is easy to decompose and cannot be preserved.

[0037] Compared with the prior art, the beneficial effects of the present application are:

[0038] 1. The present application first adopts a nickel chloride / polyaniline matrix as a precursor of a metal support, cooperates with a porous nickel plate, adopts NiCl2 as a Ni reduction precursor, and high-efficiency reduction can be realized at a lower temperature, and the reduction efficiency is high.

[0039] Compared with the traditional NiO reduction, the reduction efficiency after working for 1d can be estimated as 98.2%-98.7%, which greatly improves the reduction efficiency of the anode metal, reduces the hydrogen consumption in the reduction process, and avoids the problems of metal clumping, uneven distribution and the like caused by high-temperature reduction, thereby improving the stability and consistency of the battery; in combination with the reduction under the multi-stage temperature gradient, such as low-temperature reduction and carbonization reaction in the reducing atmosphere, the nickel chloride is converted into a Ni / C composite porous layer with high electrical conductivity, and the electrical conductivity reaches 3.45*10 4 S / cm, which is close to the electrical conductivity of the foam iron-nickel plate, thereby effectively improving the overall electrical conductivity of the battery, reducing the internal resistance of the battery, and improving the output power of the battery.

[0040] 2. In the present application, the decomposition of camphor sulfonic acid, the reduction and carbonization of polyaniline and the like in the preparation process, in combination with the further decomposition or carbonization of polyaniline in the process of glue removal and co-sintering, generate CO2, NH3 and the like, thereby creating abundant pores for the metal support body and forming a multi-stage gas channel structure with high specific surface area, which is one of the important factors for improving the reaction efficiency and performance of the battery.

[0041] 3. In addition, the present application introduces part of CO in the reducing atmosphere, and the formation of Ni-CO coordination bond can improve the oxidation resistance and corrosion resistance of the battery, reduce the performance degradation of the battery during operation, and improve the stable operation time and service life of the battery, which is an auxiliary factor for improving the performance of the battery.

[0042] 4. The present application reduces the reduction temperature of the metal support body to below 1200 DEG C for the first time, avoids the problems of strength reduction and the like caused by the reaction of the Ni-based or Fe-based bipolar plate at 1400 DEG C in high-temperature sintering, thereby expanding the selection range of the applicable bipolar plate material, providing more choices for the design and manufacture of the battery, and being beneficial to selecting more suitable bipolar plate material according to different application scenarios and performance requirements, and further improving the comprehensive performance and reliability of the battery.

[0043] 5. In summary, the present application provides a new method and idea for the preparation of the metal support body of the solid oxide fuel cell, enriches the technical reserves in the field, helps to promote the continuous development and progress of the solid oxide fuel cell technology, accelerates the process of practicalization and commercialization, and makes the solid oxide fuel cell have a wider application prospect in the fields of distributed power generation, portable power supply, transportation and the like. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 The figure is a curve graph of tail gas composition in the reduction process of the embodiment 2 of the present application varying with temperature;

[0045] Figure 2Thermogravimetry (TG) figure of the nickel chloride / polyaniline matrix obtained in Example 2 of the present application in a reducing atmosphere. DETAILED DESCRIPTION

[0046] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the prior art. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments.

[0047] I. Preparation of a metal support of a solid oxide fuel cell:

[0048] S1. Preparation of a nickel chloride / polyaniline matrix:

[0049] Part of the comparative examples in the preparation method of a magnetic field-induced nickel chloride / polyaniline supercapacitor electrode material in the patent CN 110148530 B:

[0050] S101. Camphor sulfonic acid, nickel chloride, aniline monomer and water are mixed in a flask at a solute to solvent mass ratio of 1:50. After the flask is shaken and placed in liquid nitrogen for quick freezing, the flask is taken out and placed in a normal temperature ultrasonic bath for ultrasonic treatment for 10-15 min to obtain a completely dissolved monomer solution. Ammonium persulfate and water are prepared into a catalyst solution with the same volume as the monomer solution. The catalyst solution is added dropwise into the monomer solution at a speed of 9 ml / min. The temperature of the system is controlled at 5℃ during the dropwise addition. The molar ratio of camphor sulfonic acid, nickel chloride, aniline monomer and ammonium persulfate is 1:5-8:3-5:3-5.

[0051] S102. After the dropwise addition is completed, stirring is stopped. The mixed solution system is continuously placed at 5℃ for 16 h of reaction to obtain a sol.

[0052] S103. A foamed iron-nickel plate (foamed iron-nickel plate, pore size: 0.10-0.15 mm, high-conductivity porous structure, Hebei Ruizun Screen Printing Technology Co., Ltd.) is prepared into a laminated filter plate. The sol obtained in S2 is placed in the laminated filter plate for suction filtration. After the suction filtration, deionized water and anhydrous ethanol are used for washing until the filtrate is colorless. The filter cake and the foamed iron-nickel plate are freeze-dried to obtain a nickel chloride / polyaniline matrix. One side of the matrix is a bare iron-nickel mesh, and the other side is a nickel chloride / polyaniline porous structure. The conductivity of the side of the nickel chloride / polyaniline is 1.23 x 10 -4 S / cm. The cooling and drying process is as follows: the filter cake and the foamed iron-nickel plate are frozen at -10℃ for 10 hours. The frozen filter cake and the foamed iron-nickel plate are taken out and freeze-dried at -30℃ for 8 hours to obtain the nickel chloride / polyaniline matrix.

[0053] S2. Low-temperature reduction:

[0054] The chlorinated nickel / polyaniline matrix is placed in a tube furnace, heated to 250-350°C at a heating rate of 5°C / min under a reducing atmosphere, and kept for 3h until a metallic luster appears on the surface of the chlorinated nickel / polyaniline matrix;

[0055] Ni oxidation resistance test: the reduced Ni prepared under the reaction conditions without polyaniline matrix or CO is calcined at 500°C in an air atmosphere for 15-30min, and the distribution area of the grayish white metallic color is less than that of the chlorinated nickel / polyaniline matrix.

[0056] S3, carbonization reaction:

[0057] The temperature is continuously increased to 700-750°C at a heating rate of 10°C / min under a reducing atmosphere, and kept for 3-4h to obtain a metal support with one side being a bare iron-nickel mesh and the other side being a Ni / C composite porous layer; the reducing atmosphere in S2 and S3 is composed of H2, CO and N2 in a volume ratio of 0.5-1:0.1-1:8, and the gas is replaced every 30min;

[0058] According to the above reagent ratio and reducing atmosphere conditions, each chlorinated nickel / polyaniline matrix is prepared, as shown in Table 1 below:

[0059] Table 1. Effect of chlorinated nickel / polyaniline matrix formula and reducing atmosphere component on electrical conductivity

[0060]

[0061] It should be noted that the electrical conductivity in Table 1 refers to the electrical conductivity (four-point method) of the Ni / C composite porous layer side of the metal support.

[0062] As can be seen from Table 1, compared with Preparation Examples 4-5 and Comparative Preparation Examples 1-3, CO can also have a certain reducing effect in Preparation Example 2, and when the hydrogen content in the reducing atmosphere increases, the amount of reduced Ni increases, and when it increases to a certain extent, the effect on the electrical conductivity decreases.

[0063] Compared with Preparation Examples 6-7 and Comparative Preparation Examples 4-5, the metallic luster of the Ni / C composite porous layer gradually increases when the CO content increases under the same H2 content, but excessive CO atmosphere may cause excessive CO coordination (such as Comparative Preparation Example 5), which is easy to produce volatile Ni(CO) n The complex (also indicating that the CO coordination number is less than 3), the electrical conductivity decreases instead.

[0064] Reduced tail gas monitoring:

[0065] Taking Preparation Example 2 as an example, the tail gas discharged during the circulation of the reducing atmosphere in S2, low-temperature reduction and S3, carbonization reaction is detected, as shown in Table 2 below, together with Figure 1 ​Figure 2 Analysis of the TG curve revealed that at low temperatures of 250-350℃, white smoke was generated around 50℃, which was detected as HCl, with small amounts of ammonia and ammonium chloride. Around 200℃, camphor sulfonic acid began to decompose into SO2, CO2 and H2O, initially forming pores. The free acids (HCl and water) generated, under a reducing atmosphere and at 250-350℃, could promote the conversion of polyaniline to a reduced state. The electron-donating ability of the reduced polyaniline promoted the conversion efficiency of nickel chloride to nickel. At the same time, the addition of CO in the reducing atmosphere generated Ni-CO coordination bonds on the nickel metal surface, storing reducing gas to prevent the oxidation of the metal support during the subsequent battery calcination process.

[0066] The initial conductivity of the nickel chloride / polyaniline side of the nickel chloride / polyaniline matrix was 1.23 × 10⁻⁶. -4 The conductivity (S / cm) of the nickel chloride / polyaniline side after low-temperature reduction was 8.78 × 10⁻⁶. 2 At 400℃, the polyaniline bulk begins to decompose, producing CO2 and NH3, further creating air pockets. At 650℃, the polyaniline surface carbonizes, producing N-doped carbon material with a graphite structure, enhancing conductivity and structural strength. Meanwhile, the remaining nickel chloride is further reduced, ensuring near-complete reduction within the bulk, further improving conductivity. The conductivity on the N-doped carbon material side is measured to be 3.45 × 10⁻⁶. 4 S / cm, close to the conductivity of foamed iron-nickel plates.

[0067] Depend on Figure 2 It can be inferred that around 50℃, the reaction is likely the volatilization of free HCl, at which point a small amount of NiCl2 should be reduced to Ni; 200℃ may be the decomposition of camphor sulfonic acid; 250-350℃ is the reduction reaction of NiCl2, at which point polyaniline may also decompose slightly (the mechanism is unclear, but it may be due to ammonia decomposition); after 400℃, polyaniline decomposes extensively (reduction decomposition and carbonization, therefore the weight loss rate is much lower than that under air conditions); and at 650-750℃, the surface carbonization of polyaniline is completed (based on the weight loss rate, the carbonization loss of polyaniline is estimated to be 40-45%, and a large amount of polyaniline encapsulated on the surface has not yet been completely carbonized). It should also be noted that the CO2 in the exhaust gas may originate from the reduction carbonization decomposition of polyaniline or from CO oxidation.

[0068] II. Applications of Metal Supports in Solid Oxide Fuel Cells:

[0069] Solid oxide fuel cells were prepared using the metal supports obtained in Preparation Examples 1-7 and Comparative Preparation Examples 1-5, including the following steps:

[0070] 1) Anode preparation:

[0071] The Ni / C composite porous layer of the metal support is sequentially subjected to screen printing of an electrolyte slurry to form a YSZ electrolyte layer, the thickness of the electrolyte layer is 10-15 μm, the temperature is raised to 500-550 ℃ at a temperature raising rate of 2-4 ℃ / min, and the temperature is kept for 2 h to perform degassing, so as to obtain an anode sheet;

[0072] The degassing process is under aerobic conditions, part of the contacted polyaniline is decomposed into N2, CO2 and H2O, and new gas channels are formed;

[0073] 2) Preparation of barrier sheet:

[0074] The GDC slurry is coated on the stainless steel sheet, the temperature is raised to 450-500 ℃ at a temperature raising rate of 3-5 ℃ / min, and the temperature is kept for 1-5 h to obtain a barrier sheet with a GDC barrier layer, and the thickness of the barrier sheet is 8-10 μm;

[0075] 3) Preparation of cathode sheet:

[0076] The cathode layer slurry is coated on the stainless steel sheet, the temperature is raised to 450-500 ℃ at a temperature raising rate of 3-5 ℃ / min, and the temperature is kept for 1-5 h to obtain a cathode sheet, the cathode layer slurry is prepared by using LSCF and GDC at a mass ratio of 1:1, and the thickness of the cathode sheet is 40-45 μm;

[0077] 4) Preparation of single cell by co-firing:

[0078] After the anode sheet, the barrier sheet and the cathode sheet are stacked, they are placed in a reducing atmosphere, the gas is replaced every 15 min, the temperature is raised to 800-850 ℃ at a temperature raising rate of 5-8 ℃ / min, the temperature is kept for 4-6 h, the temperature is raised to 1100-1150 ℃ at a temperature raising rate of 4-6 ℃ / min, and a pressure of 0.4-0.5 MPa is applied, and the temperature is kept for 1-3 h, so as to obtain a single cell after cooling; the remaining polyaniline wrapped by the reduced Ni and the electrolyte is rapidly carbonized at high temperature, new pore channels are formed at the same time, the gas transportation efficiency is improved, and the NiO of the anode functional layer is reduced, so that the obtained single cell does not need to be reduced by an additional anode reaction, and electricity can be generated by adding fuel.

[0079] In order to compare the preparation of the anode support by using nickel chloride according to the present application with the prior art NiO, the following blank test of Comparative Example 6 is also provided:

[0080] Comparative Example 6: The anode functional layer slurry is coated on the foam iron-nickel plate by screen printing, the anode functional layer slurry is prepared by using NiO-8YSZ, the thickness of the NiO-8YSZ is the same as that of the Ni / C composite porous layer, the electrolyte slurry is coated on the same side to form an electrolyte layer, the temperature is raised to 500-550 ℃ at a temperature raising rate of 2-4 ℃ / min, and the temperature is kept for 2 h to perform degassing, so as to obtain a blank anode sheet;

[0081] After the blank anode sheet, the barrier sheet and the cathode sheet are overlapped, they are placed in a reducing atmosphere, heated to 900-950℃ at a heating rate of 5-8℃ / min, and kept for 4-6h; heated to 1350-1400℃ at a heating rate of 4-6℃ / min, and kept for 1-3h under a pressure of 0.4-0.5MPa, and then cooled to obtain a single cell.

[0082] The power density and polarization resistance of each single cell at an open circuit voltage of 1.0V are detected at 750℃, with 3% H2O+H2 as fuel and air as oxidizing gas, for the batteries of each example and the comparative example, as shown in Table 2:

[0083] Table 2. Battery performance of NiCl2 reduced precursor type metal supported single cell

[0084]

[0085] It should be noted that the cycle stability in Table 2 refers to the change of power density after working for 1h and 1d compared with the initial power density. It can be seen that although the NiO of Comparative Example 6 is reduced at a high temperature of 1400℃, part of the NiO still consumes hydrogen and is reduced at the initial stage of the battery work period, which also proves that the use of NiCl2 as the Ni reduction precursor in the present application can greatly improve the reduction efficiency of the anode metal. The reduction efficiency after working for 1d can be estimated to be 98.2-98.7%, that is, the reduction efficiency is improved under the condition of reducing the reduction temperature, and the battery co-sintering temperature can be reduced to below 1200℃, avoiding the reduction of the strength of the Ni-based or Fe-based bipolar plate caused by the reaction at 1400℃ during high-temperature sintering, and improving the selection range of applicable bipolar plate materials.

[0086] The Ni metal content of Comparative Examples 1-2 is low during the low-temperature reduction stage, but continues to be reduced at the subsequent high temperature, so the reduction efficiency is reduced; compared with Example 2, the anode conductivity of Examples 4-5 is reduced, resulting in a reduction in the reduction efficiency; the hydrogen is excessive in Comparative Example 3, which in turn reduces the conductivity, which may be due to the fact that the reduction rate is too fast, causing uneven distribution of reduced Ni metal or even the generation of metal clumps, thereby reducing the overall conductivity.

[0087] The CO content in the reduction atmosphere gradually increases in Comparative Example 4, Example 6, Example 2, Example 7 and Comparative Example 5, which apparently reduces the reduction efficiency, but it may be due to the fact that the increase in Ni-CO complex causes a Ni protection mechanism during the work process, i.e., the Ni-CO complex is preferentially decomposed, but too high CO during the reduction process also reduces the Ni metal sites (complex volatilization), thereby reducing the battery efficiency. Therefore, the optimal value of the CO content is around 0.5.

[0088] Compared with Examples 1-3, the working initial power density of Comparative Example 6 is lower, and increases in the later stage, but is still lower than that of the application, indicating that the application can reduce the reduction temperature and improve the battery efficiency, and is worth popularizing and using.

[0089] The above merely describes the preferred embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent replacements or changes to the technical solutions and the inventive concept of the present application within the technical scope disclosed by the present application, and all of them shall be covered within the protection scope of the present application.

Claims

1. A method for preparing a metal support for a solid oxide fuel cell, characterized in that, Includes the following steps: S1, Preparation of nickel chloride / polyaniline matrix: S101. Camphor sulfonic acid, nickel chloride, aniline monomer, and water are mixed in a flask at a solute to solvent mass ratio of 1:

50. After shaking the flask well, it is placed in liquid nitrogen for quick freezing. The flask is then removed and placed in an ultrasonic bath at room temperature for sonication for 10-15 minutes to obtain a completely dissolved monomer solution. Ammonium persulfate and water are used to prepare a catalyst solution with an equal volume to the monomer solution. The catalyst solution is added dropwise to the monomer solution at a rate of 9 ml / min, and the system temperature is controlled at 5°C during the addition process. S102. After the addition is complete, stop stirring and let the mixed solution system stand at 5°C for 16 hours to obtain a sol. S103. The foamed iron-nickel plate is made into a laminated filter plate. The sol obtained in S2 is placed in the laminated filter plate and filtered. After filtration, it is washed with deionized water and anhydrous ethanol until the filtrate is colorless. The filter cake and the foamed iron-nickel plate are freeze-dried to obtain a nickel chloride / polyaniline matrix, one side of which is an exposed iron-nickel mesh and the other side is a nickel chloride / polyaniline porous structure. S2, Low-temperature reduction: The nickel chloride / polyaniline matrix was placed in a tube furnace and heated to 250-350°C at a heating rate of 5°C / min under a reducing atmosphere. The temperature was maintained for 3 hours until a metallic luster appeared on the surface of the nickel chloride / polyaniline matrix. S3, carbonization reaction: Continue heating in a reducing atmosphere at a rate of 10℃ / min to 700-750℃, and hold for 3-4 hours to obtain a metal support with one side being an exposed iron-nickel mesh and the other side being a Ni / C composite porous layer.

2. The method for preparing a solid oxide fuel cell metal support according to claim 1, characterized in that, The molar ratio of camphor sulfonic acid, nickel chloride, aniline monomer and ammonium persulfate in S101 is 1:5-8:3-5:3-5.

3. The method for preparing a solid oxide fuel cell metal support according to claim 1, characterized in that, The cooling and drying process in S103 is as follows: the filter cake and the foamed iron-nickel plate are frozen at -10°C for 10 hours, and then taken out and freeze-dried at -30°C for 8 hours to obtain the nickel chloride / polyaniline matrix.

4. The method for preparing a metal support for a solid oxide fuel cell according to claim 1, characterized in that, The reducing atmosphere in S2 and S3 is composed of H2, CO and N2 in a volume ratio of 0.5-1:0.1-1:8, and the atmosphere is changed every 30 minutes.

5. The application of the metal support obtained by any one of the preparation methods described in claims 1-4 in a solid oxide fuel cell, characterized in that, Includes the following steps: 1) Anode preparation: Electrolyte layer is formed by screen printing electrolyte paste sequentially through the Ni / C composite porous layer of the metal support. The temperature is raised to 500-550℃ at a heating rate of 2-4℃ / min, held for 2h, and then the adhesive is removed to obtain the anode sheet. 2) Preparation of the barrier sheet: GDC slurry is coated onto a stainless steel sheet, and the temperature is raised to 450-500℃ at a heating rate of 3-5℃ / min and held for 1-5 hours to obtain a barrier sheet with a GDC barrier layer. 3) Cathode preparation: The cathode layer slurry is coated onto a stainless steel sheet, and the temperature is raised to 450-500℃ at a heating rate of 3-5℃ / min, and held for 1-5 hours to obtain the cathode sheet. 4) Co-firing to prepare single cells: After stacking the anode plate, barrier plate, and cathode plate, place them in a reducing atmosphere, ventilate every 15 minutes, heat to 800-850℃ at a heating rate of 5-8℃ / min, and hold for 4-6 hours; then heat to 1100-1150℃ at a heating rate of 4-6℃ / min, apply a pressure of 0.4-0.5MPa, hold for 1-3 hours, and cool to obtain a single cell.

6. The application of the metal support according to claim 5 in a solid oxide fuel cell, characterized in that, The electrolyte slurry in 1) is YSZ, and the thickness of the electrolyte layer is 10-15μm.

7. The application of the metal support according to claim 5 in a solid oxide fuel cell, characterized in that, The thickness of the barrier sheet in 2) is 8-10 μm.

8. The application of the metal support according to claim 5 in a solid oxide fuel cell, characterized in that, In step 3), the cathode slurry is made of LSCF and GDC in a mass ratio of 1:1, and the thickness of the cathode sheet is 40-45 μm.

9. The application of the metal support according to claim 5 in a solid oxide fuel cell, characterized in that, The reducing atmosphere in step 4) is a mixture of H2 and N2 in a volume ratio of 1:9.

Images