A solid oxide battery containing a gradient layer and a preparation method thereof

Abstract

The present invention provides a solid oxide cell containing a gradient layer and a preparation method thereof, belonging to the technical field of solid oxide fuel cells. The functional layer of the solid oxide cell includes a proton conductor framework, a protective layer and a catalyst layer; the protective layer is attached to the surface of the proton conductor framework and includes a barrier layer and a gradient layer, and the gradient layer is formed by the reaction of the protective layer with the adjacent proton conductor framework; the catalyst layer is attached to the barrier layer. By optimizing the electrolyte material and the electrode structure, the present invention enhances its chemical stability at high temperatures. In addition, the above solid oxide cell is more flexible in fuel selection, can use various fuels such as hydrogen and natural gas, and can realize electrolysis of water and co-electrolysis to produce fuel, thereby further enhancing its application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid oxide fuel cells, and particularly relates to a solid oxide cell containing a gradient layer and a preparation method thereof. Background Art

[0002] A solid oxide fuel cell (SOFC) is a clean energy conversion device that can directly convert chemical energy into electrical energy. It can generate electricity in a fuel cell mode or prepare fuel in an electrolysis mode. According to the different ions conducted by the electrolyte material, SOFC can be divided into an oxygen ion conductor type (O-SOFC) and a proton conductor type (H-SOFC). Traditional high-temperature O-SOFCs have been developed for many years, with mature preparation technologies and excellent performance at high temperatures. However, as the battery operating conditions develop towards medium and low temperatures, proton conductor type SOFCs (H-SOFCs) have received extensive attention due to their lower operating temperatures, smaller activation energy values, and higher battery efficiencies. However, the current development of H-SOFCs is still immature, and the chemical stability and mechanical stability of proton conductor materials at high temperatures still need to be further improved to ensure no degradation during long-term operation.

[0003] The key technical problem restricting H-SOFC is that the proton conductor framework contains Ba element, which will decompose under the action of water partial pressure and CO2, resulting in serious performance degradation during the long-term operation of the battery. Summary of the Invention

[0004] Aiming at the above deficiencies in the prior art, the present invention provides a solid oxide cell containing a gradient layer and a preparation method thereof. By optimizing the electrolyte material and electrode structure, its chemical stability at high temperatures is enhanced. In addition, this solid oxide cell is more flexible in fuel selection, can use various fuels such as hydrogen and natural gas, and can be used for electrolyzing water and co-electrolysis, thereby further improving its application prospects.

[0005] To achieve the above object, the technical solutions adopted by the present invention are as follows:

[0006] On the one hand, the present invention provides a solid oxide cell, and the functional layers of the solid oxide cell include a proton conductor framework, a protective layer, and a catalyst layer; the protective layer is attached to the surface of the proton conductor framework and includes a barrier layer and a gradient layer, and the gradient layer is formed by the reaction of the protective layer with the adjacent proton conductor framework; the catalyst layer is attached to the barrier layer.

[0007] Further, the thickness of the gradient layer in the solid oxide cell is 1.0 - 4.5 μm.

[0008] Further, the material of the proton conductor framework includes: BaZr 1-x Y x O3-δ , BaZr 1-x , Yb x , O 3-δ , BaZr 1-x- y , Ce y , Y x , O 3-δ , BaZr 1-x-y-z , Ce z , Y y , Yb x , O 3-δ One or more of them, where 0 < x < 1, 0 < y < 1, 0 < z < 1, 0 < δ < 1.

[0009] Furthermore, the material of the protective layer includes: CeO2, Ce 1-x , Gd x , O 2-δ , Ce 1-x , La x , O 2-δ , Sm 1-x , Ce x , O 2-δ One or more of them, where 0 < x < 1, 0 < y < 1, 0 < δ < 1.

[0010] Furthermore, the porosity of the functional layer of the solid oxide cell is 10% - 60%.

[0011] On the other hand, the present invention discloses a preparation method of the above solid oxide cell, including:

[0012] Preparing a proton conductor framework of the functional layer; preparing a protective layer on the surface of the proton conductor framework; preparing a catalyst layer on the surface of the protective layer.

[0013] Furthermore, preparing a protective layer on the surface of the proton conductor framework includes: dissolving the material of the protective layer in an organic solvent and stirring to prepare an impregnation solution; dropping the impregnation solution onto the proton conductor framework by an impregnation method, then performing heat preservation treatment at a first preset temperature, and after the heat preservation ends, cooling and repeating the impregnation process until the impregnation quality no longer increases, and then performing a single sintering.

[0014] Furthermore, the particle size of the material powder of the protective layer is not greater than 60 nm, and the concentration of the impregnation solution is 0.5 - 3.0 mol / L.

[0015] Furthermore, the first preset temperature is 300 - 500 °C for heat preservation for 1 - 5 h; the single sintering process is: heating to 1100 - 1500 °C at a rate not greater than 5 °C / min for heat preservation for 4 - 10 h, and then cooling to room temperature.

[0016] Further, preparing a catalyst layer on the surface of the protective layer includes: preparing a catalyst material on the surface of the protective layer, and then performing secondary sintering. The secondary sintering process is as follows: heating to 600 - 1100°C at a rate not exceeding 3°C / min, holding for 2 - 20 h, and then cooling to room temperature.

[0017] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects: In the prior art, there are methods for preparing a protective layer, such as hydrothermal reaction, but there are corresponding problems. For example, it is relatively easy to prepare a protective layer by hydrothermal method in a roughly planar shape or in holes with relatively large sizes, and the protection effect is good. When the hole size is relatively small, due to factors such as hydrothermal reaction kinetics, the thickness of the protective layer inside the hole is uneven and the protection effect is poor. Moreover, due to the difference in physical properties between the protective layer and the conductor skeleton material, the tendency of interface splitting is large during use. In this application, the protective layer is set to two layers, including a barrier layer and a gradient layer. The gradient layer is formed by the reaction of the protective layer with the proton conductor skeleton. The gradient layer can coordinate the internal stress and interface stress caused by the different physical properties between the barrier layer and the surface of the proton conductor skeleton. Secondly, due to the setting of the gradient layer, the thickness of the barrier layer can be appropriately set thicker to avoid incomplete coverage of the local area by the protective layer. Finally, due to the presence of the barrier layer, and the preparation method of the protective layer in this application ensures that the barrier layer can completely cover the proton conductor skeleton, realizing the transfer of the electrochemically reactive interface from the catalyst - proton skeleton - gas three - phase interface to the catalyst - barrier layer - gas interface, reducing the reaction between the proton conductor skeleton and various adsorbed species. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0019] Figure 1 It is a schematic diagram of the solid oxide battery structure provided by the embodiment of the present invention;

[0020] Figure 2 It is the SEM image and elemental energy spectrum diagram of the solid oxide half - cell provided by Embodiment 1 of the present invention.

[0021] Reference numerals: 1, proton conductor skeleton; 2, protective layer; 3, oxygen electrode catalyst layer; 4, fuel electrode catalyst layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] To make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. The specific embodiments of the present invention are not limited to the specific embodiments given here. Those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the disclosed specific embodiments.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used are only for describing specific embodiments and do not limit the present invention.

[0024] An embodiment of the present invention discloses a solid oxide battery, such as Figure 1 shown, the functional layer of the solid oxide battery includes a proton conductor skeleton 1, a protective layer 2 and a catalyst layer; the protective layer 2 is attached to the surface of the proton conductor skeleton 1 and includes a barrier layer and a gradient layer (the thicknesses of the barrier layer and the gradient layer are small and not shown), and the gradient layer is formed by the reaction of the protective layer 2 with the adjacent proton conductor skeleton 1; the catalyst layer is attached to the barrier layer, and the catalyst layer includes an oxygen electrode catalyst layer 3 and a fuel electrode catalyst layer 4, Figure 1 The proton conductor skeleton 1 shown in is prepared from the same material as the electrolyte layer, that is, the oxygen electrode, the fuel electrode and the electrolyte are prepared from the same proton conductor material, which is a preferred structure. The integrated overall structure ensures the tight combination of the electrode and the electrolyte layer, effectively avoids the problem of cracks at the interface that may occur during operation, and enhances the stability and durability of the battery.

[0025] It can be understood that the proton conductor skeleton can also be made of different materials. For example, the oxygen electrode uses BZY, the fuel electrode uses BZCY, and the electrolyte layer can be the same as or different from any of the materials of the oxygen electrode or the fuel electrode in the proton conductor skeleton.

[0026] In the prior art, there are methods for preparing a protective layer, such as hydrothermal reaction, but there are corresponding problems. For example, it is relatively easy to implement the preparation of a protective layer by hydrothermal method in a roughly planar or relatively large-sized hole, and the protection effect is good. When the hole size is relatively small, due to factors such as hydrothermal reaction kinetics, the thickness of the internal protective layer is uneven and the protection effect is poor. Moreover, due to the difference in physical properties between the protective layer and the conductor skeleton, there is a large tendency for interface splitting during use. In this application, the protective layer is set to two layers, including a barrier layer and a gradient layer. The gradient layer is formed by the reaction of the protective layer with the proton conductor skeleton. The gradient layer can coordinate the internal stress and interface stress caused by the different physical properties between the barrier layer and the surface of the proton conductor skeleton. Secondly, due to the presence of the gradient layer, the thickness of the barrier layer can be appropriately set thicker to avoid incomplete coverage of the local area by the protective layer. Finally, due to the presence of the barrier layer, and the preparation method of the protective layer in this application ensures that the barrier layer can completely cover the proton conductor skeleton, realizing the transfer of the electrochemically reactive interface from the catalyst-proton skeleton-gas three-phase interface to the catalyst-barrier layer-gas interface, reducing the reaction between the proton conductor skeleton and various adsorbed species.

[0027] Specifically, the thickness of the gradient layer in the solid oxide cell is 1.0 - 4.5 μm. On the one hand, a smaller thickness of the gradient layer affects the coordination between the protective layer and the proton conductor skeleton. On the other hand, if the thickness of the gradient layer is larger, it affects the thickness of the barrier layer. That is, when the total thickness of the protective layer is certain, if the gradient layer is too thick, the barrier layer is too thin, and a too thin barrier layer will affect the service life of the solid oxide cell. Setting the thickness of the gradient layer to 1.0 - 4.5 μm can solve the above two technical problems. It should be noted that the thickness of the gradient layer of the present invention is obtained by measuring the thickness at at least 5 positions and taking the average value.

[0028] Specifically, the materials of the proton conductor skeleton include: CeO2, BaZr 1-x Y x O 3-δ 、BaZr 1-x Yb x O 3-δ 、BaZr 1-x-y Ce y Y x O 3-δ 、BaZr 1-x-y-z Ce z Y y Yb x O 3-δ One or more of them, where 0 < x < 1, 0 < y < 1, 0 < z < 1, 0 < δ < 1.

[0029] Specifically, the materials of the protective layer include: Ce 1-x Gd x O2-δ , La 1-x , Gd x , O 2-δ , Sm 1-x , Gd x , O 2-δ One or more of them, where 0 < x < 1, 0 < y < 1, 0 < δ < 1.

[0030] Specifically, the porosity of the functional layer of the solid oxide battery is 10% - 60%.

[0031] The embodiment of the present invention also provides a preparation method of the above solid oxide battery, including:

[0032] S1 Prepare the proton conductor framework of the functional layer.

[0033] In the proton conductor framework, the oxygen electrode, the fuel electrode, and the electrolyte can be made of the same material or different materials. When the same material is used, due to the same thermal physical properties between the same materials, the stability is relatively high during heating, cooling, and operation. In the embodiment of the present invention, the oxygen electrode, the fuel electrode, and the electrolyte are all made of the same material.

[0034] Preparing the proton conductor framework includes: a) Preparing a three-layer structure including a proton conductor porous framework layer on the oxygen electrode side containing a pore-forming agent, a proton conductor dense electrolyte layer, and a proton conductor porous framework layer on the fuel electrode side containing a pore-forming agent. The preparation steps of each layer include, but are not limited to, one or more of the following methods: tape casting, screen printing, spin coating, spraying, chemical vapor deposition; b) Calcining the three-layer structure at a high temperature to obtain an integrated "porous layer | dense layer | porous layer" structure with proton conduction.

[0035] Specifically, the preparation steps include:

[0036] S10 Mix the proton conductor powder and the pore-forming agent powder at a mass ratio of 6:(3 - 5), add a dispersant, a plasticizer, and a binder to make the framework tape casting slurry for the oxygen electrode and the fuel electrode side, and add an appropriate amount of zirconia milling beads for ball milling for 36 h to ensure uniform mixing.

[0037] S11 Add a dispersant, a plasticizer, and a binder to the proton conductor powder to make the framework tape casting slurry for the oxygen electrode side, and add an appropriate amount of zirconia milling beads for ball milling for 36 h to ensure uniform mixing.

[0038] S12 Use a membrane tape casting machine to prepare the electrode and electrolyte tape casting film from the oxygen electrode, fuel electrode, and electrolyte slurries.

[0039] S13 Stack the three cast films in the order of the electrode cast film | electrolyte cast film | electrode cast film, and then perform multi-step hot pressing at 50 - 85 °C under a pressure of 10 - 60 Mpa. After sintering, an integrated "porous layer | dense layer | porous layer" structure framework with proton conduction is obtained. Multi-step hot pressing means stacking one side of the electrode cast film and the electrolyte cast film for hot pressing, and after completion, stacking the other side of the electrode cast film and the semi-finished product pressed in the previous step for hot pressing.

[0040] Sintering is carried out in an oxidizing atmosphere. Place the green body of the integrated proton conductor framework containing a pore-forming agent in a muffle furnace, first perform a debinding treatment, and then raise the temperature to 1300 - 1450 °C for sintering for 8 - 10 h to obtain an integrated proton conductor framework.

[0041] Preferably, the porosity of the prepared integrated proton conductor framework is 10 - 60%, and the average pore diameter is 10 - 100 μm.

[0042] S2 Prepare a protective layer on the surface of the proton conductor framework. It includes:

[0043] S20 Dissolve the material of the protective layer in an organic solvent and stir to prepare an impregnation solution; specifically, dissolve the powder of the protective layer material in an ethanol solution, add an appropriate amount of dispersant and surfactant to prepare a protective layer material impregnation solution with a concentration of 0.5 - 3.0 mol / L.

[0044] Preferably, the nano-powder particles of the protective layer are not larger than 60 nm. The organic solvent includes but is not limited to: ethanol, acetone, etc. The dispersant is triethanolamine (TEA), and the surfactant is polyether (P123).

[0045] S21 Use the impregnation method to drop the impregnation solution onto the proton conductor framework, and then perform a heat preservation treatment at a first preset temperature. After the heat preservation ends, cool down and repeat the impregnation process until the impregnation quality no longer increases, and then perform one sintering.

[0046] Absorb the impregnation solution and drop it into the integrated proton conductor framework, place it in a muffle furnace for heat preservation treatment at a high temperature, and repeat the above operation multiple times until the solution cannot penetrate.

[0047] Dissolve the protective layer nano-powder in an organic solvent, add a dispersant and a surfactant, and add an appropriate amount of zirconia milling beads for ball milling for 36 h to ensure uniform mixing; drop the impregnation solution on the integrated proton conductor framework and place it in a furnace for high-temperature treatment. The high-temperature treatment process is as follows: heat up to 300 - 500 °C at a rate not exceeding 10 °C / min, hold for 1 - 5 h, and then cool down to room temperature at a rate not exceeding 10 °C / min; repeat the above impregnation steps multiple times until the impregnation mass no longer increases, and then perform a single sintering. In the present invention, a protective layer is prepared on the surface of the integrated proton conductor framework by an impregnation method, and the control difficulty of this application is relatively low. The reason is that when impregnating until the impregnation mass no longer increases, there is no need to consider the problem of controlling the number of impregnation times. After impregnation is completed, it is held at 300 - 500 °C for a certain period of time, which is the debinding process and no sintering is carried out, that is, the protective layer only physically adheres to the integrated proton conductor framework without high-temperature diffusion and reaction.

[0048] The single sintering process is as follows: heat up to 1100 - 1500 °C at a rate not exceeding 5 °C / min, hold for 4 - 10 h, and then cool down to room temperature. Further, during the cooling process, cool down to room temperature at a rate not exceeding 5 °C / min. The purpose of the single sintering process is, on the one hand, to promote the sintering and forming of the protective layer after debinding and increase its density, and on the other hand, part of the protective layer reacts with the proton conductor framework to generate a gradient layer for coordinating the thermal property differences between the barrier layer and the proton conductor framework to improve the interfacial coordinated deformation ability between the two. Secondly, the heating temperature and holding time are also quite important. Since secondary sintering is required when preparing the solid oxide battery blank subsequently, high-temperature sintering will affect the thickness of the gradient layer, and single sintering needs to ensure that the unreacted protective layer is sintered densely, so that the thickness of the barrier layer is 200 - 500 nm. In this application, the sintering temperature and holding time are controlled, which not only ensure that part of the protective layer reacts with the proton conductor framework to generate a gradient layer and can sinter the unreacted protective layer densely, but also combine with the subsequent secondary sintering to make the thickness of the prepared gradient layer 1.0 - 4.5 μm.

[0049] S3 Prepare a catalyst layer on the surface of the protective layer.

[0050] In the oxygen electrode catalyst layer of the embodiment of the present invention, it is composed of an electronic conductor or an ion and electron mixed conductor, etc. The specific materials include but are not limited to: Pr6O 11 、Ce 1-x Pr x O2、PrNi 1-x Co x O 3-δ (PNC)、Ba 1-x Sr x Co y Fe 1-y O 3-δ (BSCF)、La1-x Sr x Co y Fe 1-y O 3-δ (LSCF), BaCo y Fe 1-x-y-z Zr x Y z O 3-δ (BCFZY), where 0 < x < 1, 0 < y < 1, 0 < z < 1, 0 < δ < 1. The fuel electrode catalyst is composed of a metal or a cermet composite material or an electron-ion mixed conductor. The specific materials include, but are not limited to: Ni, NiFe, Ni / Ce 1-x Gd x O 2-δ 、Sr2Fe 2-x Mo x O 6-δ (SFM), where 0 < x < 1, 0 < y < 1, 0 < δ < 1.

[0051] Prepare the catalyst material on the surface of the protective layer, and then perform secondary sintering. The secondary sintering process is as follows: heat up to 600 - 1100 °C at a rate not exceeding 3 °C / min, hold for 2 - 20 h, and then cool to room temperature. Specifically, the sintering process of the present invention is as follows: heat up to 650 - 700 °C at a rate not exceeding 1 °C / min and hold for at least 30 min, heat up to 600 - 1100 °C at a rate not exceeding 3 °C / min and hold for 2 - 20 h, and then cool to room temperature at a rate not exceeding 5 °C / min. On the one hand, this sintering temperature and holding time are beneficial to sinter the catalyst material attached to the surface of the protective layer into a catalyst layer. On the other hand, this sintering temperature and holding time will affect the formation thickness of the gradient layer, so that the thickness of the finally prepared gradient layer is 1.0 - 4.5 μm.

[0052] Preferably, in the embodiment of the present invention, the oxygen electrode and fuel electrode materials are attached to the barrier layer by the impregnation method, and then prepared by secondary sintering.

[0053] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0054] Example 1

[0055] The embodiment of the present invention provides a method for preparing a solid oxide battery and a solid oxide battery prepared by this method. The method includes:

[0056] S1 Prepare the proton conductor framework of the functional layer.

[0057] Use BaZr 0.7Ce 0.2 Y 0.1 O 3-δ As an integrated proton conductor framework, specifically, the powder and the pore-forming agent powder are mixed at a mass ratio of 6:4, and a dispersant, a plasticizer, and a binder are added to prepare a casting slurry for the electrode-side framework. An appropriate amount of zirconia milling beads is added for ball milling for 36 h to ensure the mixing uniformity. BaZr 0.7 Ce 0.2 Y 0.1 O 3-δ powder is used to prepare the casting slurry for the electrolyte. The electrode and electrolyte slurries are cast using a tape casting machine to obtain the electrode and electrolyte cast films. The three-layer cast films are laminated in the order of electrode cast film|electrolyte cast film|electrode cast film, and then hot-pressed in multiple steps at 50 °C under a pressure of 10 Mpa. After sintering, an integrated "porous layer|dense layer|porous layer" structure framework with proton conduction is obtained, and it is kept at 1400 °C for 10 h during sintering. The porosity of the prepared BZCY conductor framework is 10%, and the average pore diameter is 10 μm.

[0058] S2 Prepare a protective layer on the surface of the proton conductor framework.

[0059] Dissolve GDC powder (CeO2 stabilized with 40% mol of Gd2O3) in an ethanol solution, add an appropriate amount of dispersant and surfactant to prepare a GDC impregnation solution with a concentration of 0.5 mol / L. Absorb the impregnation solution and drop it into the BZCY conductor framework, place it in a muffle furnace for heat preservation treatment at high temperature, repeat the above operations multiple times until the solution cannot penetrate, and then keep it at 1100 °C for 4 h, and then cool it to room temperature.

[0060] S3 Prepare a catalyst layer on the surface of the protective layer.

[0061] Mix metal nitrates Pr(NO3)3, Ni(NO3)3, and Co(NO3)2 according to the molar ratio of Pr:Ni:Co = 2:1:1, and then add a surfactant according to 10% of the total mass of the added Pr, Ni, and Co elements, and add a certain amount of water to prepare a PNC oxygen electrode impregnation solution with a concentration of 0.7 mol / L.

[0062] Mix their metal nitrate solutions according to the molar ratio of Ni:Sm:Ce = 5:1:4, and then add a surfactant according to 10% of the total mass of Ni, Sm, and Ce elements, and add a certain amount of water to prepare a Ni / SDC fuel electrode impregnation solution with a concentration of 0.7 mol / L.

[0063] The above-mentioned impregnation solution was sucked and dropped into the electrode skeletons of the corresponding functional regions, and then placed in a muffle furnace for debinding treatment. The above operations were repeated multiple times until the solution could no longer penetrate. Finally, secondary sintering was carried out to obtain a complete solid oxide battery. The secondary sintering process was as follows: heat preservation at 600 °C for 2 h, and finally cooled to room temperature to obtain.

[0064] SEM was used to observe the microstructure of the prepared solid oxide battery, as Figure 2 shown. It can be seen that the protective layer completely covers the proton conductor skeleton. The thickness of the prepared gradient layer is 1.0 μm, and it can be seen from the elemental mapping that the gradient layer is a Y- and Ba-based intermediate phase.

[0065] The prepared solid oxide battery did not show a decay in power density when operating at 500 °C for 1000 h.

[0066] Example 2

[0067] An embodiment of the present invention provides a method for preparing a solid oxide battery, and a solid oxide battery prepared by using this method. The method includes:

[0068] S1 Prepare a proton conductor skeleton for the functional layer.

[0069] Using BaZr 0.7 Ce 0.2 Y 0.1 O 3-δ as an integrated proton conductor skeleton. Specifically, the powder and the pore-forming agent powder were mixed at a mass ratio of 6:4, and a dispersant, a plasticizer, and a binder were added to make a casting slurry for the electrode side skeleton. An appropriate amount of zirconia milling beads was added for ball milling for 36 h to ensure the mixing uniformity. Using BaZr 0.7 Ce 0.2 Y 0.1 O 3-δ powder to prepare an electrolyte casting slurry. The electrode and electrolyte slurries were used to prepare electrode and electrolyte casting membranes by a tape casting machine. The three casting membranes were laminated in the order of electrode casting membrane|electrolyte casting membrane|electrode casting membrane, and then multi-step hot pressing was carried out at 60 °C and a pressure of 30 Mpa. After sintering, an integrated "porous layer|dense layer|porous layer" structure skeleton with proton conduction was obtained, and heat preservation was carried out at a sintering temperature of 1400 °C for 10 h. The porosity of the prepared BZCY conductor skeleton was 30%, and the average pore diameter was 35 μm.

[0070] S2 Prepare a protective layer on the surface of the proton conductor skeleton.

[0071] Dissolve GDC powder (Gd2O3-stabilized CeO2 with a molar composition of 40%) in an ethanol solution, add an appropriate amount of dispersant and surfactant to prepare a GDC impregnation solution with a concentration of 1.5 mol / L. Absorb the impregnation solution and drop it into the BZCY conductor skeleton, place it in a muffle furnace for heat preservation treatment at high temperature, repeat the above operations multiple times until the solution can no longer penetrate, then keep it at 1250 °C for 5 h, and then cool it to room temperature.

[0072] S3 Prepare a catalyst layer on the surface of the protective layer.

[0073] Mix metal nitrates Pr(NO3)3, Ni(NO3)3, and Co(NO3)2 according to the molar ratio of Pr:Ni:Co = 2:1:1, add a surfactant according to 10% of the total mass of the added Pr, Ni, and Co elements, and add a certain amount of water to prepare a PNC oxygen electrode impregnation solution with a concentration of 0.7 mol / L.

[0074] Mix their metal nitrate solutions according to the molar ratio of Ni:Sm:Ce = 5:1:4, add a surfactant according to 10% of the total mass of the Ni, Sm, and Ce elements, and add a certain amount of water to prepare a Ni / SDC fuel electrode impregnation solution with a concentration of 0.7 mol / L.

[0075] Absorb the above impregnation solutions and drop them into the electrode skeletons of the corresponding functional areas respectively, place them in a muffle furnace for debinding treatment, repeat the above operations multiple times until the solution can no longer penetrate, and finally perform secondary sintering to obtain a complete solid oxide battery. The secondary sintering process is: keep it at 800 °C for 2 h, and finally cool it to room temperature to obtain.

[0076] The protective layer of the prepared solid oxide battery completely covers the proton conductor skeleton. The prepared gradient layer has a thickness of 2 μm, and the gradient layer is a Y- and Ba-based intermediate phase.

[0077] The prepared solid oxide battery operates at 500 °C for 1000 h without power density decay.

[0078] Example 3

[0079] The embodiment of the present invention provides a method for preparing a solid oxide battery and a solid oxide battery prepared by using this method. The method includes:

[0080] S1 Prepare a proton conductor skeleton of the functional layer.

[0081] Use BaZr 0.7 Ce 0.2 Y 0.1 O 3-δAs an integrated proton conductor framework, specifically, the powder and the pore-forming agent powder are mixed at a mass ratio of 6:4, and a dispersant, a plasticizer, and a binder are added to prepare a casting slurry for the electrode-side framework. An appropriate amount of zirconia milling beads is added for ball milling for 36 h to ensure uniform mixing. BaZr 0.7 Ce 0.2 Y 0.1 O 3-δ powder is used to prepare a casting slurry for the electrolyte. The electrode and electrolyte slurries are cast using a tape casting machine to obtain electrode and electrolyte cast films. The three cast films are laminated in the order of electrode cast film|electrolyte cast film|electrode cast film, and then hot-pressed in multiple steps at 85 °C and a pressure of 60 Mpa. After sintering, an integrated "porous layer|dense layer|porous layer" structure framework with proton conduction is obtained, and it is kept at 1400 °C for 10 h. The porosity of the prepared BZCY conductor framework is 70%, and the average pore diameter is 98 μm.

[0082] S2 A protective layer is prepared on the surface of the proton conductor framework.

[0083] GDC powder (CeO2 stabilized with 40% mol of Gd2O3) is dissolved in an ethanol solution, and an appropriate amount of dispersant and surfactant are added to prepare a GDC impregnation solution with a concentration of 3 mol / L. The impregnation solution is sucked and dropped onto the BZCY conductor framework, and it is placed in a muffle furnace for heat preservation treatment at high temperature. The above operations are repeated multiple times until the solution cannot penetrate, and then it is kept at 1500 °C for 10 h, and then cooled to room temperature.

[0084] S3 A catalyst layer is prepared on the surface of the protective layer.

[0085] According to the molar ratio of Pr:Ni:Co = 2:1:1, the metal nitrates Pr(NO3)3, Ni(NO3)3, and Co(NO3)2 are mixed, and a surfactant is added according to 10% of the total mass of the added Pr, Ni, and Co elements, and a certain amount of water is added to prepare a PNC oxygen electrode impregnation solution with a concentration of 0.7 mol / L.

[0086] According to the molar ratio of Ni:Sm:Ce = 5:1:4, their metal nitrate solutions are mixed, and a surfactant is added according to 10% of the total mass of the Ni, Sm, and Ce elements, and a certain amount of water is added to prepare a Ni / SDC fuel electrode impregnation solution with a concentration of 0.7 mol / L.

[0087] The above impregnation solutions are sucked and dropped onto the electrode frameworks in the corresponding functional areas respectively, and they are placed in a muffle furnace for debinding treatment. The above operations are repeated multiple times until the solution cannot penetrate, and finally, a secondary sintering is carried out to obtain a complete solid oxide battery. The secondary sintering process is: keep it at 1100 °C for 20 h, and finally cool it to room temperature to obtain.

[0088] The prepared protective layer of the solid oxide battery completely covers the proton conductor skeleton. The prepared gradient layer has a thickness of 4.5 μm, and the gradient layer is an intermediate phase of Y and Ba.

[0089] The prepared solid oxide battery operates at 500 °C for 1000 h without any attenuation of power density.

[0090] Example 4

[0091] The embodiment of the present invention provides a preparation method of a solid oxide battery and a solid oxide battery prepared by using this method. The method includes:

[0092] S1 Prepare the proton conductor skeleton of the functional layer.

[0093] Use BaZr 0.7 Ce 0.2 Y 0.1 O 3-δ As an integrated proton conductor skeleton. Specifically, the powder and the pore-forming agent powder are mixed at a mass ratio of 6:4, and a dispersant, a plasticizer, and a binder are added to make a casting slurry for the electrode-side skeleton. An appropriate amount of zirconia milling beads are added for ball milling for 36 h to ensure uniform mixing. Use BaZr 0.7 Ce 0.2 Y 0.1 O 3-δ Powder to prepare the electrolyte casting slurry. The electrode and electrolyte slurries are prepared into electrode and electrolyte casting membranes using a tape casting machine. The three casting membranes are stacked in the order of electrode casting membrane | electrolyte casting membrane | electrode casting membrane, and then hot-pressed in multiple steps at 85 °C and a pressure of 60 Mpa. After sintering, an integrated "porous layer | dense layer | porous layer" structure skeleton with proton conduction is obtained, and it is kept at 1400 °C for 10 h. The porosity of the prepared BZCY conductor skeleton is 70%, and the average pore diameter is 98 μm.

[0094] S2 Prepare a protective layer on the surface of the proton conductor skeleton.

[0095] Dissolve LDC (Ce 0.6 La 0.4 O2) powder in an ethanol solution, add an appropriate amount of dispersant and surfactant to prepare an LDC impregnation solution with a concentration of 3 mol / L. Absorb the impregnation solution and drop it into the BZCY conductor skeleton, place it in a muffle furnace for heat preservation at high temperature, repeat the above operation multiple times until the solution cannot penetrate, and then keep it at 1450 °C for 10 h, and then cool it to room temperature.

[0096] S3 Prepare a catalyst layer on the surface of the protective layer.

[0097] Mix metal nitrates Pr(NO3)3, Ni(NO3)3, and Co(NO3)2 according to the molar ratio of Pr:Ni:Co = 2:1:1, then add a surfactant at 10% of the total mass of the added Pr, Ni, and Co elements, and add a certain amount of water to prepare a PNC oxygen electrode impregnation solution with a concentration of 0.7 mol / L.

[0098] Mix their metal nitrate solutions according to the molar ratio of Ni:Sm:Ce = 5:1:4, then add a surfactant at 10% of the total mass of the Ni, Sm, and Ce elements, and add a certain amount of water to prepare a Ni / SDC fuel electrode impregnation solution with a concentration of 0.7 mol / L.

[0099] Absorb the above impregnation solution and drop it into the electrode skeletons of the corresponding functional areas, put it into a muffle furnace for debinding treatment, repeat the above operation multiple times until the solution cannot penetrate, and finally perform secondary sintering to obtain a complete solid oxide battery. The secondary sintering process is: keep it at 1100 °C for 20 h and finally cool it to room temperature.

[0100] The protective layer of the prepared solid oxide battery completely covers the proton conductor skeleton. The prepared gradient layer has a thickness of 4.4 μm, and the gradient layer is a Y- and Ba-based intermediate phase.

[0101] The prepared solid oxide battery operates at 500 °C for 1000 h without power density decay.

[0102] Example 5

[0103] The embodiment of the present invention provides a method for preparing a solid oxide battery and a solid oxide battery prepared by using this method. The method includes:

[0104] S1 Prepare a proton conductor skeleton for the functional layer.

[0105] Use BaZr 0.7 Ce 0.2 Y 0.1 O 3-δ As an integrated proton conductor skeleton, specifically, mix the powder and the pore-forming agent powder according to a mass ratio of 6:4, add a dispersant, a plasticizer, and a binder to make a casting slurry for the electrode-side skeleton, and add an appropriate amount of zirconia milling beads for ball milling for 36 h to ensure uniform mixing. Use BaZr 0.7 Ce 0.2 Y 0.1 O 3-δThe electrolyte tape-casting slurry for powder preparation, the electrode and the electrolyte slurry are used to prepare the electrode and the electrolyte tape-cast film by a film tape-casting machine. Stack the three tape-cast films in the order of electrode tape-cast film|electrolyte tape-cast film|electrode tape-cast film, and then perform multi-step hot pressing at 85°C and 60 Mpa pressure. After sintering, an integrated "porous layer|dense layer|porous layer" structure framework with proton conduction is obtained, and keep it at 1400°C for 10 h. The porosity of the prepared BZCY conductor framework is 70%, and the average pore diameter is 98 μm.

[0106] S2 Prepare a protective layer on the surface of the proton conductor framework.

[0107] Dissolve SDC (Sm 0.2 Ce 0.8 O 2) powder in an ethanol solution, add an appropriate amount of dispersant and surfactant to prepare an LDC impregnation solution with a concentration of 3 mol / L. Absorb the impregnation solution and drop it into the BZCY conductor framework, put it into a muffle furnace and keep it at a high temperature for heat treatment. Repeat the above operations multiple times until the solution cannot penetrate, and then keep it at 1450°C for 10 h, and then cool it to room temperature.

[0108] S3 Prepare a catalyst layer on the surface of the protective layer.

[0109] Mix metal nitrates Pr(NO3)3, Ni(NO3)3, and Co(NO3)2 according to the molar ratio of Pr:Ni:Co = 2:1:1, and then add a surfactant according to 10% of the total mass of the added Pr, Ni, and Co elements, and add a certain amount of water to prepare a PNC oxygen electrode impregnation solution with a concentration of 0.7 mol / L.

[0110] Mix their metal nitrate solutions according to the molar ratio of Ni:Sm:Ce = 5:1:4, and then add a surfactant according to 10% of the total mass of Ni, Sm, and Ce elements, and add a certain amount of water to prepare a Ni / SDC fuel electrode impregnation solution with a concentration of 0.7 mol / L.

[0111] Absorb the above impregnation solutions and drop them into the electrode frameworks of the corresponding functional areas respectively, put them into a muffle furnace for debinding treatment, repeat the above operations multiple times until the solution cannot penetrate, and finally perform secondary sintering to obtain a complete solid oxide battery. The secondary sintering process is: keep it at 1100°C for 20 h, and finally cool it to room temperature to obtain.

[0112] The protective layer of the prepared solid oxide battery completely covers the proton conductor framework, the prepared gradient layer has a thickness of 4.3 μm, and the gradient layer is a Y and Ba type intermediate phase.

[0113] The prepared solid oxide cell operated at 500 °C for 1000 h without power density decay.

[0114] Comparative Example 1

[0115] Compared with Example 1, in step S2 of this comparative example, it was held at 1100 °C for 3 h and then cooled to room temperature.

[0116] The prepared solid oxide cell had a gradient layer thickness of 0.7 μm, and the power density of the solid oxide cell decayed by 10% when operated at 400 °C for 1000 h.

[0117] Comparative Example 2

[0118] Compared with Comparative Example 3, in step S2 of this comparative example, it was held at 1500 °C for 12 h and then cooled to room temperature.

[0119] The prepared solid oxide cell had a gradient layer thickness of 4.8 μm, and the power density of the solid oxide cell decayed by 12% when operated at 500 °C for 1000 h.

[0120] Comparative Example 3

[0121] Compared with Example 1, in step S2 of this comparative example, a GDC impregnation solution with a concentration of 0.4 mol / L was prepared.

[0122] The prepared solid oxide cell had a gradient layer thickness of 0.8 μm, and the power density of the solid oxide cell decayed by 5% when operated at 500 °C for 1000 h.

[0123] Comparative Example 4

[0124] Compared with Example 3, in step S2 of this comparative example, a GDC impregnation solution with a concentration of 3.2 mol / L was prepared.

[0125] The prepared solid oxide cell had a gradient layer thickness of 4.7 μm, and the solid oxide cell did not show power density decay when operated at 500 °C for 1000 h, but the power density was 3% lower than that of Example 3.

[0126] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A solid oxide battery containing a gradient layer, characterized in that, The functional layer of the solid oxide battery includes a proton conductor framework, a protective layer, and a catalyst layer; The protective layer adheres to the surface of the proton conductor framework and includes a barrier layer and a gradient layer, and the gradient layer is formed by the reaction of the protective layer with the adjacent proton conductor framework; The catalyst layer adheres to the barrier layer; The preparation of the proton conductor framework includes: a) preparing a three-layer structure including a porous framework layer of the oxygen electrode side proton conductor containing a pore-forming agent, a dense electrolyte layer of the proton conductor, and a porous framework layer of the fuel electrode side proton conductor containing a pore-forming agent; b) subjecting the three-layer structure to high-temperature calcination to obtain an integrated "porous layer | dense layer | porous layer" structure with proton conduction. The porosity of the prepared integrated proton conductor framework is 10% - 60%, and the average pore diameter is 10μm - 100μm; The thickness of the gradient layer in the solid oxide battery is 1.0µm - 4.5µm; The materials of the proton conductor framework include: BaZr 1-x Y x O 3−δ 、BaZr 1-x-y Ce y Y x O 3−δ 、BaZr 1-x-y-z Ce z Y y Yb x O 3−δ one or more of them, where 0 < x < 1, 0 < y < 1, 0 < z < 1, 0 < δ < 1.

2. The solid oxide battery according to claim 1, wherein The materials of the protective layer include: CeO2, Ce 1-x Gd x O 2-δ 、Ce 1-x La x O 2-δ 、Sm 1-x Ce x O 2-δ one or more of them, where 0 < x < 1, 0 < y < 1, 0 < δ < 1.

3. A method for preparing a solid oxide battery according to any one of claims 1-2, characterized in that, it includes: preparing the proton conductor framework of the functional layer; preparing a protective layer on the surface of the proton conductor framework; preparing a catalyst layer on the surface of the protective layer.

4. The preparation method according to claim 3, wherein preparing a protective layer on the surface of the proton conductor framework includes: dissolving the material of the protective layer in an organic solvent and stirring to prepare an impregnation solution; using the impregnation method to drop the impregnation solution onto the proton conductor framework, then performing a heat preservation treatment at a first preset temperature. After the heat preservation ends, cool down and repeat the impregnation process until the impregnation quality no longer increases, and then perform a single sintering.

5. The preparation method according to claim 4, wherein the particle size of the material powder of the protective layer is not greater than 60nm, and the concentration of the impregnation solution is 0.5 - 3.0mol / L.

6. The preparation method according to claim 4, wherein the first preset temperature is 300 - 500℃ for heat preservation for 1 - 5h; the single sintering process is: heating at a rate not greater than 5℃ / min to 1100 - 1500℃ for heat preservation for 4 - 10h, and then cooling to room temperature.

7. The preparation method according to claim 3 or 5, wherein preparing a catalyst layer on the surface of the protective layer includes: preparing a catalyst material on the surface of the protective layer, and then performing a secondary sintering. The secondary sintering process is: heating at a rate not greater than 3℃ / min to 600 - 1100℃ for heat preservation for 2 - 20h, and then cooling to room temperature.

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