A method for producing an anode support for SOFC

Abstract

This invention discloses a method for preparing an anode support for SOFC, comprising the following steps: preparing a support clay material, wherein the support clay material includes aggregate particles, a binder, and a pore-forming agent; the binder includes binder A and / or binder B; the pore-forming agent has a particle size of less than 100 nm and includes a metal element; preparing a wet support blank from the support clay material; drying the wet support blank to obtain a dry support blank; removing the binder from the dry support blank and performing segmented sintering to obtain the SOFC anode support; the SOFC anode support has a porosity of 48-52%, a flexural strength of 18-22 MPa, and a permeability μ = (1-2) × 10⁻⁶. ‑8 m·m 3 / m 2 •Pa·s; This avoids the problem of easy agglomeration of pore-forming agents during the preparation process, thereby avoiding the problem of uneven grain size and pore size inside the anode support, and avoiding product cracking and partial lattice instability caused by difficult glue removal.

Description

Technical Field

[0001] This invention relates to the field of solid oxide fuel cells, and more specifically to the field of electrode supports. Background Technology

[0002] Solid oxide fuel cells (SOFCs) are energy conversion devices that directly convert the chemical energy in fuel into electrical energy. A typical SOFC consists of a support and a functional layer. The support or functional layer, together with a metal connector, forms the battery structure. SOFCs can be used in portable power supplies, combined heat and power (CHP) systems, and large-scale power generation equipment. They are highly efficient, pollution-free, have a wide range of fuel options, and have broad application prospects. SOFCs enable efficient and rapid conversion of fuel into electricity, making them an important low-carbon energy technology.

[0003] To improve the efficiency of electron and gas flow in the anode support, it is necessary to prepare anode supports with smaller grains, higher porosity, and uniform pore distribution.

[0004] Therefore, SOFC anode supports are prepared using submicron or even nano-sized powder particles. Due to the small size of the powder particles, they are prone to agglomeration when pore-forming agents are added during the preparation process, resulting in uneven grain size and pore size inside the anode support, as well as difficulties in debinding, product cracking, and some lattice instability.

[0005] Therefore, how to manufacture anode supports with small grains, stable grain structure, uniform and stable distribution, and small and uniform internal pores has become a technical problem that needs to be solved in this field. Summary of the Invention

[0006] The purpose of this invention is to provide a method for manufacturing an anode support with small, stable, and uniformly distributed grain structure and small, uniformly distributed internal pores. The method includes the following steps: preparing a support slurry comprising aggregate particles, a binder, and a pore-forming agent; the binder comprising binder A and / or binder B; preparing a wet support blank from the support slurry; and drying the wet support blank to obtain a dry support blank. This method avoids the problem of easy agglomeration of the pore-forming agent during the preparation process, thereby avoiding uneven grain size and pore size within the anode support, and preventing product cracking and partial lattice instability caused by difficult binder removal.

[0007] To achieve the above objectives, the present invention provides a method for preparing an anode support for SOFC, characterized by comprising the following steps: preparing a support clay material, wherein the support clay material includes aggregate particles, a binder, and a pore-forming agent; the binder includes binder A and / or binder B; the pore-forming agent has a particle size of less than 100 nm and includes a metal element; preparing a wet support blank from the support clay material; drying the wet support blank to obtain a dry support blank; removing the binder from the dry support blank and then performing segmented sintering to obtain the anode support for SOFC; the anode support for SOFC has a porosity of 48-52%, a flexural strength of 18-22 MPa, and a permeability μ = (1-2) × 10⁻⁶. -8 m·m 3 / m 2 The permeability test method is carried out in accordance with GB / T 1969 Test Method for Permeability of Porous Ceramics. Preferably, the aggregate particle size is 30-100 nm, the aggregate particle composition is a mixture of nickel oxide and zirconium oxide powder, and the mass ratio of nickel oxide to zirconium oxide powder is (54-58):(42-46).

[0008] Compared with the prior art, the beneficial effect of the technical solution of the present invention is that, by using aggregate particles with a particle size of 30-100nm and pore-forming agent particles with a particle size of less than 100nm, it is beneficial to achieve small grain size of anode support for SOFC.

[0009] By using the binder, which includes binder A and / or binder B, the viscosity of the binder can be kept low during the preparation of the support clay precursor, thereby avoiding the agglomeration of aggregate particles and pore-forming agent, and achieving high viscosity and high strength in the subsequently prepared support wet blank.

[0010] The support, which includes a pore-forming agent and a metal element, not only enables pore formation in the SOFC anode support but also contributes to grain stability within the SOFC anode support.

[0011] After the dry blank of the support body is debonded, sintering is carried out, which is beneficial to the uniformity of pores in the SOFC anode support body and avoids problems such as cracking.

[0012] The final SOFC anode support has a porosity of 48-52%, a flexural strength of 18-22 MPa, and a permeability of μ = (1-2) × 10⁻⁶. -8 m·m 3 / m 2 The ·Pa·s means that the SOFC anode support has high strength and long lifespan, while also achieving high efficiency in the passage of electrode electrons and gas, which is beneficial to improving its performance.

[0013] Further, the pore-forming agent preparation method involves mixing dimethylimidazole, cobalt, and methanol, reacting at room temperature for 11.5-12.5 hours, washing with anhydrous ethanol, and then drying to obtain a pore-forming agent precursor. The pore-forming agent precursor is then calcined under an inert gas atmosphere to obtain the pore-forming agent. Preferably, the calcination temperature of the pore-forming agent precursor is 780-820°C, and the calcination time is 1.8-2.2 hours. More preferably, the pore-forming agent precursor is calcined under an argon atmosphere. Preferably, the molar mass ratio of dimethylimidazole to cobalt is 100:(38-42), and the cobalt is a cobalt salt, preferably cobalt nitrate hexahydrate.

[0014] The beneficial effect of adopting the above-mentioned further technical solution is that the pore-forming agent prepared by the pore-forming agent preparation method includes small and uniform nano-sized carbon particles, which is beneficial to the pore-forming agent in creating small and uniform pore sizes in the SOFC anode support. The pore-forming agent prepared by the pore-forming agent preparation method includes Co element, which is beneficial to achieving grain stability in the SOFC anode support.

[0015] Furthermore, the binder A comprises cellulose and / or PVA; the mass ratio of the aggregate particles, binder A, and pore-forming agent is (95-105):(6-8):(7-9).

[0016] The beneficial effects of adopting the above-mentioned further technical solution are that it helps to improve the viscosity of the support clay, facilitates the forming of the support wet blank, and the type and amount of the added binder A avoids the occurrence of agglomeration or clustering in the subsequently prepared support clay precursor.

[0017] Furthermore, the adhesive B comprises one or more of methacrylic acid, trimethylolpropane triacrylate, and acrylamide;

[0018] The mass ratio of the aggregate particles, binder A, binder B, and pore-forming agent is (95-105):(6-8):(1.5-2.5):(7-9).

[0019] The beneficial effect of adopting the above-mentioned further technical solution is that, by using binder B, which includes one or more of methacrylic acid, trimethylolpropane triacrylate, and acrylamide, the viscosity of each material during the preparation of the support clay is not high, that is, the viscosity of binder B is low. This avoids agglomeration or clumping during the preparation of the support clay precursor. However, the prepared support wet blank has high strength, avoiding cracking problems caused by low strength of the support wet blank during the subsequent dry blank glue removal process.

[0020] Furthermore, in the preparation process of the support clay, the aggregate particles, binder, and pore-forming agent are mixed and then a bonding aid is added and mixed again to obtain the support clay precursor; the bonding aid is hydrogen peroxide; the mass ratio of binder B to bonding aid is 100:(3-5).

[0021] The beneficial effect of adopting the above-mentioned further technical solution is that, by using hydrogen peroxide as the bonding agent and the mass ratio of the binder B to the bonding agent being 100:(3-5), the viscosity of each material during the mixing process of the support body clay material preparation is not high, but the cross-linking viscosity of the binder B in the prepared support body wet blank increases, thereby achieving high strength of the support body wet blank. At the same time, it avoids problems such as cracking of the support body wet blank or excessively large molecular weight of the binder B after cross-linking due to its large cross-linking molecular weight or rapid reaction.

[0022] Furthermore, during the preparation of the support clay material, the aggregate particles, binder, and pore-forming agent are mixed and then water-retaining agent, lubricant, and water-reducing agent are added to obtain the support clay material precursor.

[0023] The supporting clay precursor is aged to obtain the supporting clay material. The aging process is carried out at a temperature of 22-40℃ for 24-48 hours. Preferably, the water-retaining agent is glycerin, the lubricant is white oil, and the water-reducing agent is tung oil. The mass ratio of the aggregate particles, water-retaining agent, lubricant, and water-reducing agent is (95-105):(1-20):(0-10):(0-15). More preferably, when the binder only includes binder A, the mass ratio of the aggregate particles, water-retaining agent, lubricant, and water-reducing agent is (95-105):(5-20):(2-10):(10-15). When the binder only includes binder A and binder B, the mass ratio of the aggregate particles, water-retaining agent, lubricant, and water-reducing agent is (95-105):(1-3):(0-2):(0-2).

[0024] The beneficial effect of adopting the above-mentioned further technical solution is that the clay material of the support obtained through aging is more uniform.

[0025] Furthermore, the preparation process of the wet blank of the support body involves extruding the support body clay material into a wet blank using an extrusion molding equipment; the support body clay material undergoes a first-stage temperature control, a second-stage temperature control, and a third-stage temperature control sequentially during the molding process.

[0026] Furthermore, the first temperature control is 40-60℃, the second temperature control is 60-80℃, and the third temperature control is 0-30℃.

[0027] The beneficial effects of adopting the above-mentioned further technical solution are that segmented temperature control during the forming process of the wet blank of the support body is conducive to the slow cross-linking of the binder B during the process, avoiding violent reaction that could cause cracking of the wet blank of the support body. At the same time, when achieving high strength of the wet blank of the support body, it avoids the problem of difficulty in removing glue from the dry blank of the support body due to excessively large molecular weight of the binder, or the problem of large porosity in the anode support body for SOFC.

[0028] By controlling the temperature in the first stage at 40-60℃ and the second stage at 60-80℃, the cross-linking of the adhesive is achieved uniformly and slowly. By controlling the temperature in the third stage at 0-30℃, the molecular weight of the adhesive after cross-linking is controlled to avoid the molecular weight from becoming too large.

[0029] Furthermore, the drying temperature of the wet blank of the support is 22-26℃, and the drying time is 12-24h; and / or

[0030] The glue removal process of the dry blank of the support body goes through three stages in sequence: first stage glue removal, second stage glue removal, and third stage glue removal.

[0031] The first stage of glue removal has a temperature of 90-120℃, with a heating rate of 8-9℃ / min from room temperature to 90-120℃; the second stage of glue removal has a temperature of 180-220℃, with a heating rate of 5-7℃ / min from 90-120℃ to 180-220℃; and the third stage of glue removal has a temperature of 280-300℃, with a heating rate of 3-4℃ / min from 180-220℃ to 280-300℃.

[0032] The beneficial effect of adopting the above-mentioned further technical solution is that, by segmented debinding, the gradual debinding is achieved. In the first debinding process, the volatile substances with small molecular weight are rapidly volatilized, creating uniform and moderate pores, avoiding the pores being too small caused by the volatile substances with small molecular weight, which is conducive to the smooth volatilization of the volatile substances with larger molecular weight in the second debinding process. Through the second and third debinding processes, the volatilization of the volatile substances with large molecular weight is achieved without the pores being too large due to volatilization.

[0033] Furthermore, the segmented sintering includes single-stage sintering, double-stage sintering, and triple-stage sintering;

[0034] The first-stage sintering temperature is 380-400℃, with a heating rate of 8-9℃ / min to reach 380-400℃, and a sintering time of 17-19h. The second-stage sintering temperature is 950-1050℃, with a heating rate of 5-6℃ / min to reach 950-1050℃, and a sintering time of 6-8h. The third-stage sintering temperature is 1200-1250℃, with a heating rate of 3-4℃ / min to reach 1200-1250℃, and a sintering time of 9-10h.

[0035] The beneficial effect of adopting the above-mentioned further technical solution is that the segmented sintering is conducive to achieving small grains in the anode support for SOFC; that is, the rapid heating during the first-stage sintering avoids grain growth, and the slower heating rate during the third-stage sintering avoids the phenomenon of encapsulated pores during grain growth. This is conducive to small grains and stable grain structure, and also avoids the increase of closed pore rate in the anode support for SOFC. Detailed Implementation

[0036] To better understand the technical solution of the present invention, the present invention will be further described below with reference to specific embodiments.

[0037] Example 1:

[0038] This embodiment provides a method for preparing an anode support for SOFC, comprising the following steps: preparing a support slurry, wherein the support slurry includes aggregate particles, a binder, and a pore-forming agent; the binder includes binder A and binder B; the pore-forming agent has a particle size of less than 100 nm and includes Co element; the anode support for SOFC has a porosity of 50%, a flexural strength of 19 MPa, and a permeability μ = 1.4 × 10⁻⁶. -8 m·m 3 / m 2 The permeability test method is in accordance with GB / T 1969 Test Method for Permeability of Porous Ceramics. The aggregate particle size is 40 nm. The aggregate particle composition is a mixture of nickel oxide and zirconium oxide powder. The mass ratio of nickel oxide to zirconium oxide powder is 56:44.

[0039] The method for preparing the pore-forming agent is as follows: dimethylimidazole, cobalt, and methanol are mixed and reacted at room temperature. After reacting for 12 hours, the mixture is washed with anhydrous ethanol and then dried to obtain a pore-forming agent precursor. The pore-forming agent precursor is then calcined under an argon atmosphere to obtain the pore-forming agent. Specifically, 1.6 g of dimethylimidazole and 1.4 g of cobalt nitrate hexahydrate are dissolved in 40 ml of methanol solution, and then the two are thoroughly stirred and mixed. After reacting at room temperature for 12 hours, the mixture is washed with anhydrous ethanol and dried at 60°C for 12 hours to obtain a pore-forming agent precursor. The pore-forming agent precursor is then calcined at 800°C for 2 hours under an argon atmosphere to obtain the pore-forming agent.

[0040] In the preparation process of the support body clay, the aggregate particles, binder, and pore-forming agent are mixed and then water-retaining agent, lubricant, and water-reducing agent are added and mixed to obtain the support body clay; the binder includes binder A; the mass ratio of the aggregate particles, binder, pore-forming agent, water-retaining agent, lubricant, and water-reducing agent is 100:7:8:18:8:12;

[0041] The support clay material is obtained by aging the precursor clay material of the support body. The aging process is carried out at a temperature of 35°C for 35 hours.

[0042] The binder A comprises cellulose; the water-retaining agent is glycerin; the lubricant is white oil; and the water-reducing agent is tung oil.

[0043] The support clay material is used to prepare a wet support blank. The preparation process of the wet support blank is to extrude the support clay material into a wet support blank using an extrusion molding equipment; the wet support blank is then dried to obtain a dry support blank; the drying temperature of the wet support blank is 24℃ and the drying time is 18h.

[0044] The glue removal process of the dry blank of the support body goes through three stages in sequence: first stage glue removal, second stage glue removal, and third stage glue removal.

[0045] The first stage of glue removal has a temperature of 110℃, and the heating rate from room temperature to 110℃ is 8.5℃ / min; the second stage of glue removal has a temperature of 200℃, and the heating rate from 110℃ to 200℃ is 6℃ / min; the third stage of glue removal has a temperature of 290℃, and the heating rate from 200℃ to 290℃ is 3.5℃ / min.

[0046] After the dry blank of the support body is debonded, it is sintered in stages to obtain the anode support body for SOFC; the staged sintering includes first-stage sintering, second-stage sintering, and third-stage sintering;

[0047] The first-stage sintering temperature is 390℃, the heating rate to 390℃ is 8.5℃ / min, and the sintering time is 18h; the second-stage sintering temperature is 1000℃, the heating rate from 390℃ to 1000℃ is 5.5℃ / min, and the sintering time is 7h; the third-stage sintering temperature is 1230℃, the heating rate from 1000℃ to 1230℃ is 3.5℃ / min, and the sintering time is 9.5h.

[0048] Example 2:

[0049] The same content as in Example 1 will not be repeated here; this example provides a method for preparing an anode support for SOFC, wherein the prepared anode support for SOFC has a porosity of 51%, a flexural strength of 21 MPa, and a permeability μ = 1.9 × 10⁻⁶. -8 m·m 3 / m 2 ·Pa·s;

[0050] The binder includes binder A and binder B; the mass ratio of the aggregate particles, binder A, binder B, pore-forming agent, water-retaining agent, lubricant, and water-reducing agent is 100:6.5:2:7.5:2:1:1;

[0051] In the preparation process of the support body clay, the aggregate particles, binder, and pore-forming agent are mixed, and then water-retaining agent, lubricant, and water-reducing agent are added and mixed again, followed by the addition of a bonding aid to obtain the support body clay precursor. The support body clay undergoes three temperature control stages in sequence during the molding process: a first-stage temperature control stage of 50°C, a second-stage temperature control stage of 70°C, and a third-stage temperature control stage of 20°C.

[0052] The support clay is used to prepare a wet support blank. The wet support blank is prepared by extruding the support clay into a wet support blank using an extrusion molding device. The bonding agent is hydrogen peroxide. The mass ratio of the binder B to the bonding agent is 100:4.

[0053] Example 3:

[0054] The same content as in Example 2 will not be repeated here; this example provides a method for preparing an anode support for SOFC, including the following steps: the anode support for SOFC has a porosity of 51%, a flexural strength of 20 MPa, and a permeability μ = 1.8 × 10⁻⁶. -8 m·m 3 / m 2 Pa·s; The aggregate particles have a particle size of 50 nm, and the aggregate particles are composed of a mixture of nickel oxide and zirconium oxide powder, with a mass ratio of nickel oxide to zirconium oxide powder of 55:45;

[0055] The pore-forming agent precursor was calcined at 810°C for 1.9 hours.

[0056] In the process of preparing the support clay, the aggregate particles, binder, and pore-forming agent are mixed, and then water-retaining agent, lubricant, and water-reducing agent are added and mixed. Then, a bonding aid is added and mixed again to obtain the support clay precursor.

[0057] The support clay precursor is aged to obtain the support clay material. The aging process is carried out at a temperature of 25°C for 40 hours.

[0058] The binder A comprises cellulose; the binder B comprises acrylamide and trimethylolpropane triacrylate.

[0059] The mass ratio of the aggregate particles, binder A, binder B, and pore-forming agent is 96:7:2.3:8.5. The bonding aid is hydrogen peroxide; the mass ratio of binder B to the bonding aid is 100:3.5.

[0060] The first temperature control is 45℃, the second temperature control is 65℃, and the third temperature control is 10℃.

[0061] The glue removal process of the dry blank of the support body goes through three stages in sequence: first stage glue removal, second stage glue removal, and third stage glue removal.

[0062] The first stage of glue removal has a temperature of 100℃, and the heating rate from room temperature to 100℃ is 8.2℃ / min; the second stage of glue removal has a temperature of 210℃, and the heating rate from 100℃ to 210℃ is 6.5℃ / min; the third stage of glue removal has a temperature of 290℃, and the heating rate from 210℃ to 290℃ is 3.2℃ / min.

[0063] The first-stage sintering temperature is 395℃, with a heating rate of 8.2℃ / min from room temperature to 395℃, and a sintering time of 17.5 hours. The second-stage sintering temperature is 1020℃, with a heating rate of 5.3℃ / min from 395℃ to 1020℃, and a sintering time of 6.5 hours. The third-stage sintering temperature is 1220℃, with a heating rate of 3.2℃ / min from 1020℃ to 1220℃, and a sintering time of 9.2 hours. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the specific combination of the above-mentioned technical features, but should also cover other technical solutions formed by any combination of the above-mentioned technical features or their equivalent features without departing from the inventive concept. For example, the above features have similar functions to (but are not limited to) those disclosed in this application.

Claims

1. A method for preparing an anode support for SOFC, characterized in that, Includes the following steps: A support clay material is prepared, the support clay material comprising aggregate particles, binder, and pore-forming agent; the binder comprises binder A and binder B; The pore-forming agent has a particle size of less than 100 nm and includes a metal element. The support material is used to prepare a wet support blank, and the wet support blank is dried to obtain a dry support blank. After removing the binder from the dry blank of the support body, it is sintered in sections to obtain the anode support body for SOFC. The adhesive includes adhesive A and adhesive B, wherein adhesive B includes one or more of methacrylic acid, trimethylolpropane triacrylate, and acrylamide; The binder A comprises cellulose and / or PVA; The mass ratio of the aggregate particles, binder A, binder B, and pore-forming agent is (95-105):(6-8):(1.5-2.5):(7-9). In the process of preparing the support clay, the aggregate particles, binder, and pore-forming agent are mixed, and then water-retaining agent, lubricant, and water-reducing agent are added and mixed. Then, a bonding aid is added and mixed again to obtain the support clay precursor. The adhesive additive is hydrogen peroxide; The mass ratio of adhesive B to adhesive additive is 100:(3-5); The support clay material is obtained by aging the precursor clay material of the support body. The aging process is carried out at a temperature of 22-40℃ and for a time of 24-48h. The preparation process of the wet blank of the support body is to extrude the support body clay material into a wet blank of the support body through an extrusion molding equipment; the support body clay material undergoes a first stage of temperature control, a second stage of temperature control, and a third stage of temperature control in sequence during the molding process; the temperature of the first stage of temperature control is 40-60℃, the temperature of the second stage of temperature control is 60-80℃, and the temperature of the third stage of temperature control is 0-30℃. The mass ratio of the aggregate particles, water-retaining agent, lubricant, and water-reducing agent is (95-105):(1-3):(0-2):(0-2); The SOFC anode support has a porosity of 48-52%, a flexural strength of 18-22 MPa, and a permeability μ = (1-2) × 10⁻⁶. -8 m·m 3 / m 2 ·Pa·s; The drying temperature of the wet blank of the support is 22-26℃, and the drying time is 12-24h; The glue removal process of the dry blank of the support body goes through three stages in sequence: first stage glue removal, second stage glue removal, and third stage glue removal. The first stage of glue removal has a temperature of 90-120℃, and the heating rate from room temperature to 90-120℃ is 8-9℃ / min; the second stage of glue removal has a temperature of 180-220℃, and the heating rate from 90-120℃ to 180-220℃ is 5-7℃ / min; the third stage of glue removal has a temperature of 280-300℃, and the heating rate from 180-220℃ to 280-300℃ is 3-4℃ / min.

2. The method for preparing an anode support for SOFC according to claim 1, characterized in that, The pore-forming agent is prepared by mixing dimethylimidazole, cobalt, and methanol, reacting at room temperature, washing with anhydrous ethanol after 11.5-12.5 hours, and then drying to obtain a pore-forming agent precursor. The pore-forming agent precursor is then calcined under an inert gas atmosphere to obtain the pore-forming agent.

3. The method for preparing an anode support for SOFC according to claim 1, characterized in that, The segmented sintering includes first-stage sintering, second-stage sintering, and third-stage sintering; The first-stage sintering temperature is 380-400℃, with a heating rate of 8-9℃ / min to reach 380-400℃, and a sintering time of 17-19h. The second-stage sintering temperature is 950-1050℃, with a heating rate of 5-6℃ / min to reach 950-1050℃, and a sintering time of 6-8h. The third-stage sintering temperature is 1200-1250℃, with a heating rate of 3-4℃ / min to reach 1200-1250℃, and a sintering time of 9-10h.