Solid oxide battery fuel electrode, half-cell and battery preparation method

Abstract

The present invention provides a solid oxide cell fuel electrode, a half-cell, and a cell preparation method, belonging to the field of solid oxide fuel cell technology. Under a reducing atmosphere, the solid oxide cell fuel electrode comprises nickel particles and an oxygen ion conductor oxide. The surface of the nickel particles has a Ni-Fe or Ni-Cu alloy layer; the Ni-Fe or Ni-Cu alloy layer has a thickness of 10-200 nm. By forming the Ni-Fe or Ni-Cu alloy layer on the surface of the nickel particles in the fuel electrode, the problem of cracks forming at the interface between the nickel particles and the oxygen ion conductor oxide during reduction and operation is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid oxide fuel cells, and in particular relates to a solid oxide fuel cell fuel electrode, a half-cell and a cell preparation method. Background Art

[0002] Solid oxide cells (SOCs), all-solid-state ceramic devices, combine the functions of solid oxide fuel cells (SOFCs) and solid oxide electrolyzers (SOECs). They offer broad application prospects and are a foundational core technology for the future hydrogen and power industries. SOFCs can directly convert the chemical energy in fuels into electrical energy, unconstrained by the Carnot cycle. This results in extremely high energy conversion efficiency, enabling efficient and rapid conversion between fuel and electricity. They are a key low-carbon energy technology and can significantly alleviate the significant energy losses and ecological damage associated with the combustion of traditional fuels such as coal and oil.

[0003] In the electrolytic cell mode, SOEC is a reversible process of SOFC, which can effectively convert electrical energy (especially electrical energy obtained from intermittent renewable energy sources such as solar and wind power) into chemical energy (such as H2, CO, etc.). Under external electrical load, SOEC can electrolyze H2O or CO2 to generate H2 or CO and O2. At the same time, the all-solid-state characteristics of SOC have the advantages of simple preparation method, easy operation, high reliability and easy maintenance, and have received widespread attention and research. However, in a reducing atmosphere, NiO is reduced to Ni. When the SOC operates in the electrolysis condition, obvious gaps or peeling will occur between the Ni particles in its fuel electrode and the oxygen ion conductor oxide, such as Figure 1 As shown in the figure, separation reduces the electrochemical reaction interface, leading to performance degradation. Therefore, the structure of solid oxide batteries should be improved to better combine metal and ceramic, alleviate the problem of metal-ceramic interface separation, and improve battery stability. Summary of the Invention

[0004] In response to the above-mentioned deficiencies in the prior art, the present invention provides a solid oxide battery fuel electrode, a half-cell and a battery preparation method, by preparing a Ni-Fe or Ni-Cu alloy layer on the surface of the Ni particles of the fuel electrode to solve the problem of cracks generated at the interface between the Ni particles and the oxygen ion conductor oxide during electrolysis in a reducing atmosphere.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] In one aspect, the present invention provides a solid oxide fuel cell electrode,

[0007] Under a reducing atmosphere, the fuel electrode of the solid oxide cell comprises Ni particles and oxygen ion conductor oxide, wherein the surface of the Ni particles has a Ni-Fe or Ni-Cu alloy layer; and the thickness of the Ni-Fe or Ni-Cu alloy layer is 10-200 nm.

[0008] Furthermore, the oxygen ion conductor oxide is YSZ or GDC.

[0009] On the other hand, the present invention discloses a method for preparing the above-mentioned solid oxide cell fuel electrode, comprising: preparing alloy powder; mixing the alloy powder with oxygen ion conductor oxide powder to prepare a fuel electrode membrane; sintering the fuel electrode membrane; and obtaining the above-mentioned fuel electrode under a reducing atmosphere.

[0010] Furthermore, the preparation method of the alloy powder includes: mixing NiO powder with a nitrate solution of Fe or Cu, separating the solid, drying and calcining to obtain alloy powder; or mixing NiO powder with a nitrate solution of Fe or Cu, separating the solid, drying, and calcining to obtain an alloy powder intermediate; repeating the following process no more than three times: mixing the alloy powder intermediate with a nitrate solution of Fe or Cu, separating the solid, drying and calcining; and finally obtaining alloy powder.

[0011] Furthermore, the NiO powder is immersed in a 0.5-2.0 mol / L Fe or Cu nitrate solution, stirred at 70-120° C. and a stirring speed of 300-500 r / min for at least 3 hours; and then dried and calcined at 700-900° C. for 5-6 hours.

[0012] Furthermore, the alloy powder and the oxygen ion conductor oxide powder are mixed to prepare a fuel electrode membrane, including: adding the alloy powder and the oxygen ion conductor oxide powder at a mass ratio of 66: (30-40) of the alloy powder to the oxygen ion conductor oxide powder, adding a binder, a plasticizer and a dispersant to obtain a fuel electrode slurry and make a fuel electrode membrane.

[0013] Furthermore, the fuel electrode membrane sintering process is: heating to 1200-1500° C. at a rate of no more than 20° C. / min and maintaining for 5-20 hours.

[0014] In another aspect, the present invention discloses a method for preparing a solid oxide half-cell, comprising: preparing a fuel electrode support layer; preparing a fuel electrode, wherein the fuel electrode is the fuel electrode described above or a fuel electrode prepared by the above preparation method; preparing an electrolyte layer; and performing a multi-step hot isostatic pressing process on the support layer, fuel electrode, and electrolyte layer, followed by sintering.

[0015] Furthermore, the hot isostatic pressing process is: maintaining the temperature at 50-85° C. and a pressure of 10-60 MPa for at least 30 minutes.

[0016] Finally, the present invention discloses a method for preparing a solid oxide battery, comprising: preparing a solid oxide half-cell using any of the above-mentioned preparation methods; preparing an oxygen electrode functional layer on the surface of the electrolyte layer of the solid oxide half-cell by screen printing, and then sintering at a temperature of 1000-1150°C for 1.5-3.0h.

[0017] Compared with the prior art, the technical solution provided by the present invention brings the following beneficial effects: the present invention solves the problem of cracks generated at the interface between Ni particles and oxygen ion conductor oxides in the prior art by preparing Ni-Fe and Ni-Cu alloys on the surface of Ni particles in the fuel electrode. Specifically, in a reducing atmosphere, NiO coated with Fe2O3 or CuO is reduced to generate Ni particles coated with Ni-Fe and Ni-Cu. Electrochemical drive in the electrolysis mode causes separation of Ni from the oxide interface. The Ni-Fe and Ni-Cu alloy layers can improve the interface between Ni particles and oxygen ion conductor oxide ceramics. The wettability of the porcelain matrix improves the bonding ability between the two and reduces the probability of cracks in the subsequent redox cycle. Secondly, the Ni-Fe and Ni-Cu layers have a certain coordination ability to coordinate the deformation between the two phases. In order to achieve the above technical effects, the present application limits the thickness of the Ni-Fe and Ni-Cu alloy layers. If the thickness is too thin, the coordination effect is limited. If the thickness is too thick, the electrochemical activity of the solid oxide cell is affected. When the solid oxide cell provided by the present invention is used for electrolysis of water, the degradation rate is not greater than 0.025V / kh, and the voltage value at 1000h is not greater than 1.3V. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 This is a SEM image of a fuel electrode in the prior art, where the ellipse marks the location where the crack occurs;

[0020] Figure 2 A schematic structural diagram of a solid oxide half-cell provided in Example 1 of the present invention;

[0021] Figure 3 This is a SEM image of the solid oxide half-cell provided in Example 1 of the present invention;

[0022] Figure 4 This is an SEM image of the fuel electrode of the solid oxide cell provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0023] To make the objectives, technical solutions, and advantages of the present invention more apparent, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The specific implementation methods of the present invention are not limited to the specific embodiments given herein, and those skilled in the art may make similar improvements without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used are only for describing specific embodiments and do not limit the present invention.

[0025] like Figure 2 The present invention provides a solid oxide cell fuel electrode. Under a reducing atmosphere, the fuel electrode of the solid oxide cell comprises Ni particles and an oxygen ion conductor oxide, and the surface of the Ni particles has a Ni-Fe or Ni-Cu alloy layer; the thickness of the Ni-Fe or Ni-Cu alloy layer is 10-200 nm.

[0026] The present invention solves the problem of cracks generated at the interface between Ni particles and oxygen ion conductor oxide phases in the prior art by preparing Ni-Fe and Ni-Cu alloys on the surface of Ni particles in the fuel electrode. Specifically, in a reducing atmosphere, NiO coated with Fe2O3 or CuO is reduced to generate Ni particles coated with Ni-Fe and Ni-Cu. Electrochemical drive in the electrolysis mode causes separation of Ni from the oxide interface. The Ni-Fe and Ni-Cu alloy layers can improve the wettability of the Ni particles with the oxygen ion conductor oxide ceramic matrix, enhance the bonding ability between the two, and reduce the probability of cracks in the subsequent redox cycle. Secondly, the Ni-Fe and Ni-Cu layers have a certain coordination ability to coordinate the deformation between the two phases. To achieve the above technical effects, the present application limits the thickness of the Ni-Fe and Ni-Cu alloy layers. If the thickness is too thin, the coordination effect is limited. If the thickness is too thick, the electrochemical activity of the solid oxide cell is affected. When the solid oxide cell provided by the present invention is used for water electrolysis, the degradation rate is no more than 0.025V / kh, and the voltage at 1000h is no more than 1.3V.

[0027] Specifically, the oxygen ion conductor oxide is YSZ or GDC, and preferably, YSZ is 8YSZ.

[0028] The present invention also provides a method for preparing the solid oxide fuel cell fuel electrode, comprising:

[0029] S10 prepares alloy powder.

[0030] The preparation methods of the alloy powder include two methods:

[0031] The first method is to mix NiO powder with Fe or Cu nitrate solution, separate the solid, dry it and calcine it to obtain alloy powder;

[0032] The second method is to mix NiO powder with a nitrate solution of Fe or Cu, separate the solid and dry it, and then calcine it after drying to obtain an alloy powder intermediate; repeat the following process no more than three times: mix the alloy powder intermediate with a nitrate solution of Fe or Cu, separate the solid and dry and calcine it; finally, obtain the alloy powder.

[0033] Specifically, the NiO powder is immersed in a 0.5-2.0 mol / L Fe or Cu nitrate solution, stirred at 70-120° C. and a stirring speed of 300-500 r / min for at least 3 hours; and then dried and calcined at 700-900° C. for 5-6 hours.

[0034] The nitrate solution of Fe or Cu generates NiO coated with Fe2O3 or CuO during the subsequent calcination process. It should be pointed out that the calcination in this application can be carried out in an air atmosphere or an oxygen atmosphere. This application limits the calcination temperature and calcination time. Fe2O3 or CuO is deposited on the NiO surface through calcination. However, it should be noted that at this time, Fe2O3 or CuO and NiO do not form a diffusion layer. This is mainly due to the atomic diffusion caused by heating during the subsequent preparation of solid oxide batteries. If the alloy composition close to the ceramic phase does not meet the design requirements, the wettability is still poor, so it is difficult to control.

[0035] S11: mixing the alloy powder with oxygen ion conductor oxide powder to prepare a fuel electrode membrane.

[0036] The alloy powder and oxygen ion conductor oxide powder are added at a mass ratio of 66:(30-40), and a binder, plasticizer, and dispersant are added to obtain a fuel electrode slurry and a fuel electrode membrane is formed. Specifically, the binder is polyethylene glycol, added in an amount of 10-15wt%, the plasticizer is dimethyl phthalate, added in an amount of 12-15wt%, and the dispersant is triethanolamine, added in an amount of 8-12wt%. Subsequently, the slurry is ball-milled with zirconium oxide beads for at least 36 hours, wherein the material-to-ball ratio is 1:(0.9-1.1) to ensure mixing uniformity and to grind the edges and corners of the powder to improve the uniformity of the thickness of the Ni-Fe or Ni-Cu alloy layer. Preferably, when using a nitrate solution of Fe, Fe2O3 is added, and when using a nitrate solution of Cu, CuO is added. On the one hand, this has the effect of assisting sintering, and on the other hand, Ni-Fe or Ni-Cu phases are generated in a post-reducing atmosphere to facilitate the electrolysis process. In particular, the composition of the Ni-Fe alloy layer on one side combined with the ceramic must satisfy the requirement of having good wettability with the ceramic phase. Using the same source oxide for sintering assistance can reduce the difficulty of preparing an alloy layer that meets the requirements.

[0037] Preferably, the particle size range of the alloy powder in the present invention is 5-20 μm, and the particle size range of the cationic conductor oxide powder is 10-30 μm, and the above particle size ranges are achieved by sieving through a sieve.

[0038] S12: sintering the fuel electrode membrane.

[0039] The fuel electrode membrane sintering process involves heating the Ni-Fe or Ni-Cu alloy layer of the reduced Ni particles to approximately 30-70% Ni on the side closest to the ceramic substrate, improving wettability between the Ni particles and the ceramic substrate. The Ni-Fe or Ni-Cu alloy layer also coordinates the Ni particles and the ceramic substrate to prevent cracking during electrolysis.

[0040] It should be pointed out that in the embodiment of the present invention, Fe2O3 or CuO is used to form a diffusion layer with NiO. Since it is difficult to control the direct use of Fe or Cu particles to form a diffusion layer with Ni, that is, the Fe or Cu particles are too small compared to Fe2O3 or CuO, and the diffusion coefficient is large, it is difficult to control. However, the use of oxides can effectively control the thickness of the diffusion layer formed by Fe2O3 or CuO and NiO, thereby controlling the thickness of the Ni-Fe or Ni-Cu alloy layer prepared in a reducing atmosphere to 10-200nm.

[0041] An embodiment of the present invention further provides a method for preparing a half-cell, comprising:

[0042] S20 prepares a fuel electrode support layer.

[0043] S21: preparing a fuel electrode, using the above-mentioned fuel electrode or the fuel electrode prepared by the above-mentioned preparation method. It should be noted that the above-mentioned fuel electrode does not need to be reduced in a reducing atmosphere, and can be directly reduced after the solid oxide battery is prepared.

[0044] S22 prepares an electrolyte layer.

[0045] S23: performing a multi-step hot isostatic pressing treatment on the support layer, the fuel electrode and the electrolyte layer and sintering them.

[0046] The hot isostatic pressing process is: maintaining at 50-85° C. and a pressure of 10-60 MPa for at least 30 minutes. The sintering process is: maintaining at 1200-1500° C. for 5-20 hours.

[0047] The multi-step hot isostatic pressing is to stack the support layer and the fuel electrode and perform hot isostatic pressing. After the processing is completed, the electrolyte layer is placed on one side of the fuel electrode and then hot isostatic pressing is performed.

[0048] It is understandable that the preparation methods of the support layer, fuel electrode, and electrolyte layer involved in the embodiments of the present invention include but are not limited to: one or more of: tape casting, dry pressing, screen printing, spin coating, spraying, and vapor deposition.

[0049] For illustration, in an embodiment of the present invention, the fuel electrode support layer uses NiO-3YSZ, wherein NiO powder and 3YSZ powder are weighed and mixed at a mass ratio of 56:(40-50), and then a dispersant, plasticizer, and binder are added to form a fuel electrode support layer tape casting slurry. Zirconia ball milling beads are added and ball milled for at least 36 hours. The dispersant is preferably triethanolamine, added in an amount of 8-12wt%, the plasticizer is dimethyl phthalate, added in an amount of 13-17wt%, and the binder is polyethylene glycol, added in an amount of 10-15wt%.

[0050] The electrolyte layer is made of 8YSZ, and a dispersant, plasticizer, and binder are added to form an electrolyte layer tape casting slurry. Zirconia ball milling beads are then added and ball milled for at least 36 hours. The dispersant is preferably triethanolamine, added in an amount of 8-10wt%, the plasticizer is dimethyl phthalate, added in an amount of 10-15wt%, and the binder is polyethylene glycol, added in an amount of 8-10wt%.

[0051] The thickness of the oxide battery half-cell prepared by the present invention is 210-700 μm, wherein the thickness of the fuel electrode support layer is 200-600 μm, the thickness of the fuel electrode is 5-50 μm, and the thickness of the electrolyte is 5-50 μm.

[0052] An embodiment of the present invention also provides a method for preparing a solid oxide battery, comprising: preparing a solid oxide half-cell using the above-mentioned preparation method; preparing an oxygen electrode functional layer on the surface of the electrolyte layer of the solid oxide half-cell by screen printing, and then sintering at a temperature of 1000-1150°C for 1.5-3.0 hours. In an embodiment of the present invention, ethyl cellulose and terpineol are mixed in a mass ratio of 1:10 to obtain a carrier, 30g of BSCF is weighed, 20-40wt% of the carrier by weight of the BSCF is added to prepare an oxygen electrode slurry, screen-printed on the surface of the electrolyte layer, and then sintered at 1100°C for 2 hours to obtain a solid oxide battery. The solid oxide battery prepared in this application has certain restrictions on the sintering temperature of the oxygen electrode, mainly to prevent excessive temperature from affecting the components of the Ni-Fe and Ni-Cu alloy layers generated after reduction near the ceramic phase, thereby reducing the bonding strength between the Ni particles and the ceramic phase.

[0053] For ease of understanding, the present application adopts a membrane belt casting machine to prepare the fuel electrode support layer, the functional layer and the electrolyte casting membrane.

[0054] The prepared solid oxide battery was characterized by electrolysis mode at 750 °C and a constant current density of 1.00 A cm -2 The fuel electrode was injected with 90% H2O / 10% H2, and the oxygen electrode was injected with pure O2. The degradation rate was calculated by collecting voltage information within 1000 hours and recording the voltage at 1000 hours.

[0055] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0056] Example 1

[0057] This embodiment provides a method for preparing a solid oxide battery, comprising:

[0058] S20 prepares a fuel electrode support layer.

[0059] NiO powder and 3YSZ powder were mixed in a mass ratio of 56:44, and dispersant, plasticizer and binder were added to prepare a fuel electrode support layer casting slurry. An appropriate amount of zirconium oxide ball milling beads were added and ball milled for 36 hours. Subsequently, a film belt casting machine was used to prepare the fuel electrode support layer.

[0060] S21 prepares the fuel electrode.

[0061] NiO powder was immersed in 1 mol / L ferric nitrate solution and stirred on a magnetic stirrer at 90°C and 400 r / min for 3 h. The solid product obtained after filtration was dried and heat-treated at 150°C and calcined at 800°C in a muffle furnace for 5 h to obtain Fe2O3 or CuO-coated NiO alloy powder, which was then mixed with 8YSZ powder in a mass ratio of 66:34. Dispersant, plasticizer and binder were added to make fuel electrode casting slurry. An appropriate amount of zirconia ball milling beads were added and ball milled for 36 h. Subsequently, a film belt casting machine was used to prepare the fuel electrode.

[0062] S22 prepares an electrolyte layer.

[0063] The electrolyte layer is made of 8YSZ, and a dispersant, a plasticizer and a binder are added to prepare an electrolyte layer casting slurry, and then zirconium oxide ball milling beads are added and ball milled for 36 hours, and then a membrane belt casting machine is used to prepare the electrolyte layer.

[0064] S23 performs multi-step hot isostatic pressing treatment and sintering on the support layer, fuel electrode and electrolyte layer.

[0065] The three layers of cast membrane were stacked in the order of support layer cast membrane, functional layer cast membrane, and electrolyte cast membrane. The solid oxide battery half-cell blank was prepared using an isostatic press at 80°C and 30 MPa in a multi-step process. The hot-pressed half-cell was placed in a muffle furnace and slowly heated for debinding before being sintered at 1400°C for 10 hours.

[0066] S24: Ethyl cellulose and terpineol were mixed in a mass ratio of 1:10 to obtain a carrier. 30 g of BSCF was weighed, and 30 wt% of the carrier based on the mass of BSCF was added to prepare an oxygen electrode slurry. The slurry was screen-printed on the surface of the electrolyte layer and then sintered at 1100 °C for 2 h to obtain a solid oxide battery.

[0067] After the prepared solid oxide battery is reduced in a reducing atmosphere, Figure 3 As shown, the thickness of the Ni-Fe alloy layer is 50 nm.

[0068] The prepared solid oxide battery was used for electrolysis of water, and the degradation rate was 0.022V / kh, and the voltage at 1000h was 1.2V. The morphology of the prepared solid oxide battery was observed by SEM, as shown in FIG. Figure 4 As shown, there are no cracks in the Ni particles and 8YSZ in the fuel electrode of the prepared solid oxide battery.

[0069] Example 2

[0070] This embodiment provides a method for preparing a solid oxide battery, comprising:

[0071] S20 prepares a fuel electrode support layer.

[0072] NiO powder and 3YSZ powder were mixed in a mass ratio of 56:40, and dispersant, plasticizer and binder were added to prepare a fuel electrode support layer casting slurry. An appropriate amount of zirconium oxide ball milling beads were added and ball milled for 36 hours. Subsequently, a film belt casting machine was used to prepare the fuel electrode support layer.

[0073] S21 prepares the fuel electrode.

[0074] NiO powder was immersed in 0.5 mol / L ferric nitrate solution and stirred on a magnetic stirrer at 70°C and 300 r / min for 3 h. The solid product obtained after filtration was dried and heat-treated at 120°C and calcined at 700°C in a muffle furnace for 5 h to obtain NiFe alloy powder. It was then mixed with 8YSZ powder in a mass ratio of 66:30, and a dispersant, plasticizer and binder were added to make a fuel electrode casting slurry. An appropriate amount of zirconia ball milling beads was added and ball milled for 36 h. Subsequently, a film belt casting machine was used to prepare the fuel electrode.

[0075] S22 prepares an electrolyte layer.

[0076] The electrolyte layer is made of 8YSZ, and a dispersant, a plasticizer and a binder are added to prepare an electrolyte layer casting slurry, and then zirconium oxide ball milling beads are added and ball milled for 36 hours, and then a membrane belt casting machine is used to prepare the electrolyte layer.

[0077] S23 performs multi-step hot isostatic pressing treatment and sintering on the support layer, fuel electrode and electrolyte layer.

[0078] The three layers of cast membrane were stacked in the order of support layer cast membrane, functional layer cast membrane, and electrolyte cast membrane. The solid oxide battery half-cell blank was prepared using an isostatic press at 50°C and 10 MPa in multiple steps. The hot-pressed half-cell was placed in a muffle furnace and slowly heated for debinding before being sintered at 1200°C for 5 hours.

[0079] S24: Ethyl cellulose and terpineol were mixed in a mass ratio of 1:10 to obtain a carrier. 30 g of BSCF was weighed, and 20 wt% of the carrier based on the mass of BSCF was added to prepare an oxygen electrode slurry. The slurry was screen-printed on the surface of the electrolyte layer and then sintered at 1100 °C for 1.5 h to obtain a solid oxide battery.

[0080] After reduction in a reducing atmosphere, the thickness of the Ni-Fe alloy layer in the prepared solid oxide cell was 12 nm. During water electrolysis, the degradation rate of the prepared solid oxide cell was 0.023 V / kh, and the voltage after 1000 h was 1.2 V. Scanning electron microscopy (SEM) of the prepared solid oxide cell revealed no cracks in the Ni particles or 8YSZ in the fuel electrode.

[0081] Example 3

[0082] This embodiment provides a method for preparing a solid oxide battery, comprising:

[0083] S20 prepares a fuel electrode support layer.

[0084] NiO powder and 3YSZ powder were mixed in a mass ratio of 56:50, and dispersant, plasticizer and binder were added to prepare a fuel electrode support layer casting slurry. An appropriate amount of zirconium oxide ball milling beads were added and ball milled for 36 hours. Subsequently, a film belt casting machine was used to prepare the fuel electrode support layer.

[0085] S21 prepares the fuel electrode.

[0086] NiO powder was immersed in 2 mol / L ferric nitrate solution and stirred on a magnetic stirrer at 120°C and 500 r / min for 3 h. The solid product obtained after filtration was dried and heat-treated at 120°C and calcined at 900°C in a muffle furnace for 6 h to obtain NiFe alloy powder. It was then mixed with 8YSZ powder in a mass ratio of 66:40, and a dispersant, plasticizer and binder were added to make a fuel electrode casting slurry. An appropriate amount of zirconia ball milling beads was added and ball milled for 36 h. Subsequently, a film belt casting machine was used to prepare the fuel electrode.

[0087] S22 prepares an electrolyte layer.

[0088] The electrolyte layer is made of 8YSZ, and a dispersant, a plasticizer and a binder are added to prepare an electrolyte layer casting slurry, and then zirconium oxide ball milling beads are added and ball milled for 36 hours, and then a membrane belt casting machine is used to prepare the electrolyte layer.

[0089] S23 performs multi-step hot isostatic pressing treatment and sintering on the support layer, fuel electrode and electrolyte layer.

[0090] The three cast membrane layers are stacked in the order of support layer cast membrane, functional layer cast membrane, and electrolyte cast membrane. They are then hot-pressed in multiple steps at 85°C and 60 MPa using an isostatic press to produce solid oxide battery half-cell blanks. The hot-pressed half-cell is placed in a muffle furnace, slowly heated for debinding, and then sintered at 1500°C for 20 hours.

[0091] S24: Ethyl cellulose and terpineol were mixed in a mass ratio of 1:10 to obtain a carrier. 30 g of BSCF was weighed, and 40 wt% of the carrier based on the mass of BSCF was added to prepare an oxygen electrode slurry. The slurry was screen-printed on the surface of the electrolyte layer and then sintered at 1150 °C for 3 h to obtain a solid oxide battery.

[0092] After reduction in a reducing atmosphere, the prepared solid oxide cell had a Ni-Fe alloy layer thickness of 70 nm. During water electrolysis, the prepared solid oxide cell exhibited a degradation rate of 0.020 V / kh, with a voltage of 1.25 V after 1000 h. The Ni particles and 8YSZ in the fuel electrode of the prepared solid oxide cell exhibited no cracks.

[0093] Example 4

[0094] This embodiment provides a method for preparing a solid oxide battery, comprising:

[0095] S20 prepares a fuel electrode support layer.

[0096] NiO powder and 3YSZ powder were mixed in a mass ratio of 56:44, and dispersant, plasticizer and binder were added to prepare a fuel electrode support layer casting slurry. An appropriate amount of zirconium oxide ball milling beads were added and ball milled for 36 hours. Subsequently, a film belt casting machine was used to prepare the fuel electrode support layer.

[0097] S21 prepares the fuel electrode.

[0098] The NiO powder was immersed in a 1 mol / L ferric nitrate solution, stirred on a magnetic stirrer at 90°C and 400 r / min for 3 hours, the solid product obtained by filtration was dried and heat-treated at 150°C, and placed in a muffle furnace for calcination at 800°C for 5 hours to obtain a NiFe alloy powder intermediate. The following process was repeated three times: the NiFe alloy powder intermediate was immersed in a 1 mol / L ferric nitrate solution, stirred on a magnetic stirrer at 90°C and 400 r / min for 3 hours, the solid product obtained by filtration was dried and heat-treated at 150°C, and placed in a muffle furnace for calcination at 800°C for 5 hours to finally obtain a NiFe alloy powder, which was then mixed with 8YSZ powder in a mass ratio of 66:34, and a dispersant, plasticizer and binder were added to make a fuel electrode casting slurry. An appropriate amount of zirconia ball milling beads was added for ball milling for 36 hours, and then the fuel electrode was prepared using a membrane belt casting machine.

[0099] S22 prepares an electrolyte layer.

[0100] The electrolyte layer is made of 8YSZ, and a dispersant, a plasticizer and a binder are added to prepare an electrolyte layer casting slurry, and then zirconium oxide ball milling beads are added and ball milled for 36 hours, and then a membrane belt casting machine is used to prepare the electrolyte layer.

[0101] S23 performs multi-step hot isostatic pressing treatment and sintering on the support layer, fuel electrode and electrolyte layer.

[0102] The three layers of cast membrane were stacked in the order of support layer cast membrane, functional layer cast membrane, and electrolyte cast membrane. The solid oxide battery half-cell blank was prepared using an isostatic press at 80°C and 30 MPa in a multi-step process. The hot-pressed half-cell was placed in a muffle furnace and slowly heated for debinding before being sintered at 1400°C for 10 hours.

[0103] S24: Ethyl cellulose and terpineol were mixed in a mass ratio of 1:10 to obtain a carrier. 30 g of BSCF was weighed, and 30 wt% of the carrier based on the mass of BSCF was added to prepare an oxygen electrode slurry. The slurry was screen-printed on the surface of the electrolyte layer and then sintered at 1100 °C for 2 h to obtain a solid oxide battery.

[0104] After reduction in a reducing atmosphere, the prepared solid oxide cell had a Ni-Fe alloy layer thickness of 195 nm. During water electrolysis, the prepared solid oxide cell exhibited a degradation rate of 0.020 V / kh, with a voltage of 1.28 V after 1000 h. The Ni particles and 8YSZ in the fuel electrode of the prepared solid oxide cell were free of cracks.

[0105] Example 5

[0106] This embodiment provides a method for preparing a solid oxide battery, comprising:

[0107] S20 prepares a fuel electrode support layer.

[0108] NiO powder and 3YSZ powder were mixed in a mass ratio of 56:50, and dispersant, plasticizer and binder were added to prepare a fuel electrode support layer casting slurry. An appropriate amount of zirconium oxide ball milling beads were added and ball milled for 36 hours. Subsequently, a film belt casting machine was used to prepare the fuel electrode support layer.

[0109] S21 prepares the fuel electrode.

[0110] NiO powder was immersed in 2 mol / L copper nitrate solution and stirred on a magnetic stirrer at 120°C and 500 r / min for 3 h. The solid product obtained after filtration was dried and heat-treated at 120°C and calcined at 900°C in a muffle furnace for 6 h to obtain NiCu alloy powder. It was then mixed with 8YSZ powder in a mass ratio of 66:40, and a dispersant, plasticizer and binder were added to make a fuel electrode casting slurry. An appropriate amount of zirconia ball milling beads was added and ball milled for 36 h. Subsequently, a film belt casting machine was used to prepare the fuel electrode.

[0111] S22 prepares an electrolyte layer.

[0112] The electrolyte layer is made of 8YSZ, and a dispersant, a plasticizer and a binder are added to prepare an electrolyte layer casting slurry, and then zirconium oxide ball milling beads are added and ball milled for 36 hours, and then a membrane belt casting machine is used to prepare the electrolyte layer.

[0113] S23 performs multi-step hot isostatic pressing treatment and sintering on the support layer, fuel electrode and electrolyte layer.

[0114] The three layers of cast membrane were stacked in the order of support layer cast membrane, functional layer cast membrane, and electrolyte cast membrane. The solid oxide battery half-cell blank was prepared using an isostatic press at 50°C and 60 MPa in multiple steps. The hot-pressed half-cell was placed in a muffle furnace and slowly heated for debinding before being sintered at 1500°C for 10 hours.

[0115] S24: Ethyl cellulose and terpineol were mixed in a mass ratio of 1:10 to obtain a carrier. 30 g of BSCF was weighed, and 30 wt% of the carrier based on the mass of BSCF was added to prepare an oxygen electrode slurry. The slurry was screen-printed on the surface of the electrolyte layer, and then sintered at 1100 °C for 3 h to obtain a solid oxide battery.

[0116] After the prepared solid oxide battery was reduced in a reducing atmosphere, the thickness of the Ni-Cu alloy layer was 150nm. The prepared solid oxide battery was used for water electrolysis at a current density of 1A / cm 2 , no cracks appeared after running at 750℃ for 1000h, and there were no cracks in the Ni particles and 8YSZ in the fuel electrode of the prepared solid oxide battery.

[0117] After reduction in a reducing atmosphere, the prepared solid oxide cell had a Ni-Cu alloy layer thickness of 150 nm. During water electrolysis, the prepared solid oxide cell exhibited a degradation rate of 0.020 V / kh, with a voltage of 1.21 V after 1000 h. The Ni particles and 8YSZ in the fuel electrode of the prepared solid oxide cell exhibited no cracks.

[0118] Comparative Example 1

[0119] Compared with Example 1, the difference is that in step S21, the NiO powder is immersed in a 0.4 mol / L ferric nitrate solution.

[0120] After reduction in a reducing atmosphere, the prepared solid oxide battery had a Ni-Fe alloy layer thickness of 9 nm. The prepared solid oxide battery was used for water electrolysis, with a degradation rate of 0.201 V / kh and a voltage of 1.45 V after 1000 h.

[0121] Comparative Example 2

[0122] Compared with Example 4, the difference is that in step S21, the following process is repeated four times: the NiFe alloy powder intermediate is immersed in a 1 mol / L ferric nitrate solution, stirred on a magnetic stirrer at 90°C and 400 r / min for 3 hours, and the solid product obtained after filtration is dried and heat-treated at 150°C and placed in a muffle furnace for calcination at 800°C for 5 hours.

[0123] After reduction in a reducing atmosphere, the prepared solid oxide battery had a Ni-Fe alloy layer thickness of 210 nm. The prepared solid oxide battery was used for water electrolysis, with a degradation rate of 0.020 V / kh and a voltage of 1.5 V after 1000 h.

[0124] Comparative Example 3

[0125] Compared with Example 1, the difference is that in step S23, the temperature is first slowly increased to perform binder removal treatment, and then the temperature is increased to 1500° C. and sintered for 22 hours.

[0126] After reduction in a reducing atmosphere, the prepared solid oxide battery had a Ni-Fe alloy layer thickness of 210 nm. The prepared solid oxide battery was used for water electrolysis, with a degradation rate of 0.021 V / kh and a voltage of 1.48 V after 1000 h.

[0127] Comparative Example 4

[0128] Compared with Example 1, the difference is that in step S23, the temperature is first slowly increased to perform debinding treatment, and then the temperature is increased to 1150° C. and sintered for 22 hours.

[0129] The prepared solid oxide battery was used to electrolyze water, with a degradation rate of 0.221 V / kh and a voltage of 1.51 V at 1000 h.

[0130] As shown in Examples 1 and 4 and Comparative Examples 1 and 2, both too small or too large a Ni-Fe alloy layer thickness results in a higher voltage at 1000 h. This is because a smaller thickness reduces the bonding strength between the Ni particles and the ceramic substrate, causing cracks during electrolysis, increasing internal resistance, and leading to a voltage increase. On the other hand, a larger thickness results in lower electrochemical activity in the solid oxide battery, resulting in a lower degradation rate but a higher voltage. As shown in Example 1 and Comparative Examples 3 and 4, sintering temperature and time are critical, controlling the diffusion distance between the Ni-Fe elements, thereby reducing the Ni content in the Ni-Fe alloy layer close to the ceramic substrate and improving the wettability of the Ni particles with the ceramic substrate.

[0131] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a solid oxide battery fuel electrode, characterized in that: The solid oxide cell fuel electrode is used in an electrolysis mode under a reducing atmosphere, wherein the fuel electrode of the solid oxide cell comprises Ni particles and an oxygen ion conductor oxide, wherein the surface of the Ni particles has a Ni-Fe or Ni-Cu alloy layer; The thickness of the Ni-Fe or Ni-Cu alloy layer is 10-200 nm; The preparation method comprises: preparing alloy powder; Mixing the alloy powder with oxygen ion conductor oxide powder to prepare a fuel electrode membrane; Sintering the fuel electrode membrane to obtain; The fuel electrode can be obtained under a reducing atmosphere; The preparation method of the alloy powder comprises: Mixing NiO powder with a nitrate solution of Fe or Cu, separating the solid, drying it, and calcining it after drying to obtain an alloy powder intermediate; repeating the following process no more than three times: mixing the alloy powder intermediate with a nitrate solution of Fe or Cu, separating the solid, drying it, and calcining it; finally obtaining an alloy powder; The calcination is carried out in an air atmosphere or an oxygen atmosphere; The NiO powder is immersed in a 0.5-2.0 mol / L Fe or Cu nitrate solution, stirred at 70-120° C. and a stirring speed of 300-500 r / min for at least 3 hours; and then dried and calcined at 700-900° C. for 5-6 hours.

2. The preparation method according to claim 1, characterized in that The oxygen ion conductor oxide is YSZ or GDC.

3. The preparation method according to claim 1, characterized in that The preparation of a fuel electrode membrane by mixing alloy powder with oxygen ion conductor oxide powder includes: The alloy powder and the oxygen ion conductor oxide powder are added in a mass ratio of 66: (30-40), and a binder, a plasticizer and a dispersant are added to obtain a fuel electrode slurry and a fuel electrode membrane.

4. The preparation method according to claim 1, characterized in that The fuel electrode membrane sintering process is: heating to 1200-1500° C. at a rate of no more than 20° C. / min and maintaining the temperature for 5-20 hours.

5. A method for preparing a solid oxide half-cell, characterized in that: include: preparing a fuel electrode support layer; Prepare a fuel electrode, wherein the fuel electrode is prepared by the preparation method according to any one of claims 1 to 4; preparing an electrolyte layer; The fuel electrode support layer, the fuel electrode and the electrolyte layer are subjected to a multi-step hot isostatic pressing treatment and sintered to obtain the fuel electrode support layer.

6. The preparation method according to claim 5, characterized in that The hot isostatic pressing process is: maintaining the temperature at 50-85° C. and a pressure of 10-60 MPa for at least 30 minutes.

7. A method for preparing a solid oxide battery, characterized in that: include: A solid oxide half-cell prepared by the preparation method according to claim 5 or 6; An oxygen electrode functional layer is prepared on the surface of the electrolyte layer of the solid oxide half-cell by screen printing, and then sintered at a temperature of 1000-1150° C. for 1.5-3.0 hours.

Images