Barrier layer and method of making the same for solid oxide cells

Abstract

The application discloses a barrier layer, a preparation method thereof and a solid oxide battery, and belongs to the technical field of solid oxide batteries. The preparation method of the barrier layer comprises the following steps: uniformly mixing cerium-based oxide powder, a sintering aid and a solvent to obtain a slurry; and then spin coating the slurry on a substrate, and obtaining the barrier layer after sintering. The barrier layer is prepared by the preparation method. The solid oxide battery comprises at least the barrier layer. The barrier layer prepared by the application has the advantages of high compactness, high uniformity, high interface bonding strength and the like, and the preparation process and raw material system of the barrier layer are relatively simple. The barrier layer is suitable for large-area single cells.

Description

TECHNICAL FIELD

[0001] The application relates to a barrier layer and a preparation method thereof and a solid oxide cell, and belongs to the technical field of solid oxide cells. BACKGROUND

[0002] High-performance applications of solid oxide cells (SOCs) can be divided into two forms, one is SOFC, i.e. solid oxide fuel cell, which generates electric energy by oxidizing fuel; the other is SOEC, i.e. solid oxide electrolysis cell, which generates oxygen and hydrogen by electrolyzing water. In principle, SOEC can be regarded as the reverse process of the currently more studied SOFC. As a clean energy efficient utilization and conversion technology, solid oxide fuel cell / electrolysis cell (SOFC / SOEC) has become one of the important technical means to effectively solve the energy crisis and environmental pollution problems due to its good fuel flexibility, high energy conversion efficiency and other outstanding advantages.

[0003] The interface problem of yttrium stabilized zirconia (YSZ) electrolyte and active cathode during high-temperature preparation and operation leads to poor durability of cell stack and high maintenance cost and other obstacles, and adding a cerium-based oxide (for example, gadolinium-doped ceria, i.e. GDC) barrier layer between the electrolyte and the active cathode is an effective solution. Some studies use magnetron sputtering and pulsed laser deposition to prepare the barrier layer, but the low production efficiency and harsh use conditions limit the scale production development of this process. The conventional screen printing and spin coating are simple to operate, but the barrier layer prepared usually needs to be co-sintered with the adjacent YSZ electrolyte at >1400℃ to obtain relatively high density and interface strength, but the cerium-based oxide and YSZ will react to form a high-resistance Ce-Zr solid solution phase at >1250℃, so the application of conventional screen printing and spin coating is limited. It is found that the sintering temperature can be reduced to about 1250℃ by a multi-step dipping sintering method, but this greatly increases the complexity and time cost of the process, limiting the practical popularization and application of SOFC / SOEC technology.

[0004] CN111933980A discloses a preparation method of a solid oxide fuel cell. The preparation method mainly comprises the following steps: spin coating a barrier layer GDC slurry on a sintered dense electrolyte sheet to obtain a semi-finished cell; pressing the semi-finished cell on a to-be-prepared cell for sintering; the to-be-prepared cell comprises a cathode layer, a GDC barrier layer, an electrolyte layer, a GDC barrier layer and an anode layer in sequence. The preparation method of the solid oxide fuel cell is simple in process, low in equipment requirement and convenient to operate; the prepared solid oxide fuel cell is not easy to fall off the electrolyte, and the open circuit voltage of the cell is significantly improved. However, the preparation method of the solid oxide fuel cell has the following disadvantages: the cell needs to be pressed and sintered during sintering, the preparation process needs 1-2 times of sintering and more than 1 time of pre-annealing treatment, so the preparation conditions and process are complex, the process flow is time-consuming, and it is not easy to expand the process to prepare large-area single cells.

[0005] CN113929498B discloses a coating for preparing a barrier layer, a preparation method of the barrier layer and the barrier layer. The coating for preparing the barrier layer is an aqueous solution comprising a nitrate and a combustion-supporting agent, and the combustion-supporting agent is citric acid or glycine. The preparation method of the barrier layer comprises the following steps: coating the coating for preparing the barrier layer on an electrolyte sheet for pre-sintering, decomposing the nitrate to obtain GDC powder, and obtaining a barrier layer preform; coating a sintering aid on the barrier layer preform, the sintering aid being an aluminum nitrate solution; sintering the barrier layer preform to obtain the barrier layer. However, the preparation method of the barrier layer needs multiple steps of spin coating (4-6 times), pre-sintering and spin coating of a sintering aid for secondary sintering, and the process is complex, the process flow is time-consuming, and it is not suitable for preparing large-area single cells.

[0006] CN116364989A discloses a reversible solid oxide fuel cell and a preparation method thereof. The cell comprises an electrolyte intermediate layer and barrier layers and fuel electrodes on both sides of the electrolyte intermediate layer, wherein the barrier layers are prepared by introducing small particles into large particle powders and sintering, so that the densification of the barrier layers can be realized. The reversible solid oxide fuel cell as an energy storage device has the functions of generating electricity by hydrogen and generating hydrogen by electrolysis of water, the open circuit voltage is 1.15V or more, and the maximum power generation power is 0.45W / cm 2 The above has good industrialization prospects. However, the preparation method of the barrier layer needs to mix large particles and small particles of raw materials, the thickness of the barrier layer is 5-20μm, the raw material system of the method is complex, the thickness of the barrier layer is thick, and it is not easy to control the process to prepare large-area single cells.

[0007] CN111574244B discloses a method for densifying a solid oxide cell barrier layer. The method prepares a hydrothermal solution by mixing Ge(NO3)3·6H2O and Ce(NO3)3·6H2O at a molar ratio of 0.1:0.9 (Ce 0.9 Gd 0.1 O 2-m ) and then reacts a cell with a GDC barrier layer printed thereon by a hydrothermal method at 180°C for 24 hours. The cell thus prepared has higher conductivity and catalytic activity and lower ohmic resistance. However, this method uses screen printing to prepare the barrier layer and uses a hydrothermal reaction to improve the densification of the barrier layer. The method has the disadvantages of complex process, limited substrate material and size, and is not suitable for preparing large-area single cells.

[0008] CN114725461A discloses a low-temperature sintered and densified samarium-neodymium-doped ceria-based barrier layer and a preparation method thereof. The samarium-neodymium co-doped ceria-based barrier layer is a sintered and densified samarium-neodymium co-doped ceria-based barrier layer, and the density of the barrier layer is more than 90%. The preparation method of the barrier layer adds soluble iron salt and / or soluble manganese salt during the synthesis of the doped ceria-based powder, and uses a solid-liquid composite method to synthesize the powder, so that the SNDC can be obtained at a lower sintering temperature. However, this method needs to prepare a modified samarium-neodymium co-doped ceria-based powder first, which includes preparing a precursor solution by using soluble iron salt and / or soluble manganese salt and a complexing agent, and then needs to be heat treated. The formulation of the precursor is complex and the preparation process is tedious.

[0009] CN104269563A discloses a preparation method of a metal-supported solid oxide fuel cell cathode barrier layer. The method includes the following steps: adding cathode barrier layer material powder into an ethyl cellulose and pine oil solution in a certain proportion, and grinding to obtain a slurry; depositing the slurry on a half-cell of a porous metal support layer, a thick film / porous metal ceramic gradient transition layer film / porous anode layer film / dense electrolyte layer film by screen printing; sintering at 1000-1200°C for 2-4 hours in a vacuum atmosphere, controlling the heating and cooling rate to be 0.5-5°C / min, and cooling to room temperature to obtain the cathode barrier layer. The sintering of the cathode barrier layer in a high-temperature low-vacuum atmosphere can avoid excessive oxidation of the support and film peeling caused by the reduction of cerium valence in the cerium oxide barrier layer in a reducing atmosphere, and also avoids the loss of Ga in the LaGaO3-based barrier layer, thereby effectively blocking the reaction of high-performance cathode materials with zirconia-based solid electrolytes under the preparation conditions. However, the barrier layer prepared by the method has a thickness of 3-10 μm and needs to be sintered in a vacuum (0.1-10 Pa). The sintering conditions of the method are complex and the thickness of the prepared barrier layer is relatively thick.

[0010] CN220821635U discloses a bipolar plate assembly, which comprises two layers of graphite layers and at least one penetration barrier layer, the penetration barrier layer is sandwiched between the two layers of graphite layers, and the penetration rate of the penetration barrier layer is less than the penetration rate of the graphite layer. The bipolar plate assembly is used for a proton exchange membrane fuel cell. The penetration barrier layer can use any suitable transition metal, such as Ti (titanium), Ni (nickel), W (tungsten), Nb (niobium), etc., and suitable non-transition metals can also be used, such as Cu (copper), Al (aluminum), Zn (zinc), etc. Due to the arrangement of the penetration barrier layer, the penetration rate of the conductive structure to the reaction gas can be reduced, and the penetration barrier layer also has a certain conductivity to further increase the conductivity of the conductive structure. However, the bipolar plate assembly is not used for a solid oxide cell, and the material of the penetration barrier layer is a metal or an alloy, which functions to reduce gas penetration and increase conductivity, which is different from the material and function of the barrier layer in the solid oxide cell.

[0011] From the above prior art, it can be seen that the barrier layer of the current solid oxide cell mostly has problems such as complex raw material system and / or preparation process, or thick thickness, or poor density and / or uniformity, etc., which is not suitable for preparing a large-area single cell. SUMMARY

[0012] To solve at least one of the above technical problems, the purpose of the present application is to provide a barrier layer, a preparation method thereof and a solid oxide cell. The barrier layer prepared by the present application has the advantages of high density, and the preparation process and raw material system of the barrier layer are relatively simple, and the barrier layer is suitable for a large-area single cell.

[0013] To achieve the above purpose, the first aspect of the present application provides a preparation method of a barrier layer, which comprises the following steps:

[0014] S1, at least mixing cerium-based oxide powder, a sintering aid and a solvent uniformly to obtain a slurry;

[0015] S2, spin coating the slurry on a substrate, and obtaining the barrier layer after sintering;

[0016] The sintering aid comprises oxides and / or salt compounds of one or more metals of Co, Cu, Bi, Li, Zn, Al and Ni.

[0017] According to the specific embodiment of the present application, preferably, in step S1, the cerium-based oxide powder comprises a combination of one or more of gadolinium-doped cerium oxide (GDC) powder, samarium-doped cerium oxide (SDC) powder and lanthanum-doped cerium oxide (LDC) powder, etc.

[0018] According to the embodiment of the present application, preferably, in step S1, the average particle size of the cerium-based oxide powder is 0.01-1 μm, more preferably 0.05-0.5 μm.

[0019] According to the embodiment of the present application, preferably, in step S1, the content of the cerium-based oxide powder in the slurry is 20%-70%, more preferably 30%-40%, based on 100% of the mass of the slurry.

[0020] According to the embodiment of the present application, preferably, in step S1, the sintering aid comprises an oxide and / or a salt compound of one or more metals selected from Co, Cu and Bi.

[0021] According to the embodiment of the present application, preferably, in step S1, the mass ratio of the sintering aid to the cerium-based oxide powder is 0.5%-5%, more preferably 1%-3%.

[0022] According to the embodiment of the present application, preferably, in step S1, the slurry further comprises a binder. More preferably, the mass ratio of the binder to the cerium-based oxide powder is 0.5%-8%.

[0023] According to the embodiment of the present application, preferably, in step S2, the substrate comprises at least one of a fuel electrode support type half cell, an electrolyte support type half cell, a metal support type half cell and an air electrode support type half cell.

[0024] According to the embodiment of the present application, preferably, in step S2, the spin-coating is performed at a rate of 500-5000 rpm, more preferably 1500-3000 rpm.

[0025] According to the embodiment of the present application, preferably, in step S2, the spin-coating is performed for 0.5-5 min, more preferably 1-2 min.

[0026] According to the embodiment of the present application, preferably, in step S2, the spin-coating is performed once.

[0027] According to the embodiment of the present application, preferably, in step S2, the sintering is performed at a temperature of 1200-1400 °C, more preferably 1225-1275 °C.

[0028] According to the embodiment of the present application, preferably, in step S2, the sintering is performed for 1-10 h.

[0029] According to the embodiment of the present application, preferably, in step S2, the thickness of the barrier layer is 0.5-8 μm, more preferably 1-3 μm.

[0030] The second aspect of the present application provides a barrier layer prepared by the above-mentioned method for preparing a barrier layer.

[0031] According to the embodiment of the present application, preferably, the barrier layer has a density > 73%.

[0032] According to the embodiment of the present application, preferably, the barrier layer has an interfacial bonding strength > 10 MPa.

[0033] According to the embodiment of the present application, preferably, the barrier layer has a thickness uniformity > 94%.

[0034] The third aspect of the present application provides a solid oxide cell comprising at least the above-mentioned barrier layer.

[0035] The technical solution of the present application at least achieves the following beneficial effects:

[0036] The present application uses cerium-based oxide powder as raw material, which produces a synergistic effect with the sintering aid. In the case of one-time spin coating and lower sintering temperature, a barrier layer with good density and uniformity and thin thickness can be prepared. Moreover, the barrier layer of the present application also has a high interfacial bonding strength. The preparation method of the barrier layer of the present application has the advantages of simple raw material system and preparation process. At the same time, since the preparation process of the present application is simple and the sintering temperature is low, the present application also has the advantages of saving time cost and reducing energy consumption. The barrier layer of the present application is suitable for large-area single cells. In the case of large area, the barrier layer of the present application still maintains high uniformity and flatness. In practical application, the barrier layer of the present application can avoid the reaction between YSZ electrolyte and LSCF cathode to generate La2Zr2O7 and SrZrO3 insulating phases. At the same time, since the sintering temperature of the present application is low, the generation of high impedance Ce-Zr solid solution phase is avoided. Therefore, the solid oxide cell (i.e. SOFC / SOEC single cell) of the present application has improved stability and chemical compatibility between components, which has very high practicality and commercial value. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 The flowchart of the preparation method of the barrier layer and single cell provided for Examples 1-5.

[0038] Figure 2 The structural diagram of the barrier layer and single cell provided for Examples 1-5.

[0039] Figure 3 The scanning electron microscope photo of the barrier layer 2 of Example 1.

[0040] Figure 4 The microstructure diagram of the single cell of Example 1.

[0041] Figure 5 Scanning electron micrograph of barrier layer 2 for Example 1.

[0042] Figure 6 Scanning electron micrograph of barrier layer 2 for Example 3.

[0043] Figure 7 Scanning electron micrograph of barrier layer 2 for Example 4.

[0044] Figure 8 Cell power-voltage-current graph for single cells of Examples 1-4.

[0045] Figure 9 Scanning electron micrograph of barrier layer 2 for Example 5.

[0046] Figure 10 Scanning electron micrograph of barrier layer 2 for Comparative Example 1.

[0047] Figure 11 Scanning electron micrograph of barrier layer 2 for Comparative Example 2.

[0048] Figure 12 Scanning electron micrograph of barrier layer 2 for Comparative Example 3.

[0049] Figure 13 Cell power-voltage-current graph for single cells of Comparative Examples 1-3.

[0050] BRIEF DESCRIPTION OF DRAWINGS

[0051] 1 - fuel electrode support type half cell; 2 - barrier layer; 3 - air electrode layer; 101 - support layer; 102 - fuel electrode layer; 103 - electrolyte layer. DETAILED DESCRIPTION

[0052] In order to make the objects, technical solutions and advantages of the present application clearer, the following will be combined with the embodiments of the present application to make a clear and complete description of the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application. It should be noted that the embodiments in the present application and the technical features in the embodiments can be combined with each other without conflict.

[0053] It should be noted that, unless otherwise specified, all the technical and scientific terms used in the present application have the same meanings as those generally understood by those of ordinary skill in the art to which the present application belongs.

[0054] The various raw materials, reagents, instruments and equipment used in the present application can be purchased or prepared by existing methods, unless otherwise specified.

[0055] According to the specific embodiments of the first aspect of the present application, the present application provides a preparation method of a barrier layer, comprising the following steps:

[0056] S1, at least mixing cerium-based oxide powder, a sintering aid and a solvent uniformly to obtain a slurry;

[0057] S2, spin coating the slurry on a substrate, and obtaining the barrier layer after sintering.

[0058] The sintering aid includes oxides and / or salt compounds of one or more metals selected from Co, Cu, Bi, Li, Zn, Al and Ni.

[0059] In some embodiments, in step S1, the cerium-based oxide powder includes, but is not limited to, a combination of one or more of gadolinium-doped ceria (GDC) powder, samarium-doped ceria (SDC) powder and lanthanum-doped ceria (LDC) powder, and preferably gadolinium-doped ceria (GDC).

[0060] In some embodiments, in step S1, the average particle size of the cerium-based oxide powder is 0.01-1 μm, for example but not limited to: 0.01 μm, 0.05 μm, 0.1 μm, 0.15 μm, 0.2 μm, 0.25 μm, 0.3 μm, 0.35 μm, 0.4 μm, 0.45 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm or 1 μm, and preferably 0.05-0.5 μm.

[0061] In some embodiments, in step S1, the cerium-based oxide powder includes a combination of a first powder and a second powder, the average particle size of the first powder is 10-100 nm, and the average particle size of the second powder is greater than 100 nm to 500 nm; preferably, the average particle size of the first powder is 10-90 nm, and the average particle size of the second powder is 150 nm to 500 nm.

[0062] In some embodiments, in step S1, the mass ratio of the first powder to the second powder is 1:2-2:1, and preferably 1:1.

[0063] In some embodiments, in step S1, the content of the cerium-based oxide powder in the slurry is 20-70%, for example but not limited to 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, or the like, preferably 30-40%, based on 100% of the mass of the slurry.

[0064] In some embodiments, in step S1, the sintering aid includes an oxide and / or a salt compound of one or more of Co, Cu, and Bi, preferably an oxide of Co and / or Cu, more preferably an oxide of Co, for example a combination of one or more of CoO, Co2O3, and Co3O4.

[0065] In some embodiments, in step S1, the mass ratio of the sintering aid to the cerium-based oxide powder is 0.5-5%, for example but not limited to 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 4%, 5%, or the like, preferably 1-3%.

[0066] In some embodiments, in step S1, the solvent includes but is not limited to a combination of one or more of water, ethanol, ethylene glycol, and isopropyl alcohol, preferably ethanol.

[0067] In some embodiments, in step S1, the slurry further includes a binder.

[0068] In some embodiments, in step S1, the binder includes but is not limited to a combination of one or more of polyvinyl alcohol (PVA), polyvinyl butyral (PVB), and ethyl cellulose (EC).

[0069] In some embodiments, in step S1, the mass ratio of the binder to the cerium-based oxide powder is 0.5-8%, for example but not limited to 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 4%, 5%, 6%, 7%, 8%, or the like, preferably 1-3%.

[0070] In some embodiments, in step S1, the slurry further includes a dispersant. Preferably, the dispersant includes but is not limited to at least one of polyethylene glycol (PEG) and oleic acid (OA). More preferably, the mass ratio of the dispersant to the cerium-based oxide powder is 0.5-8%, for example but not limited to 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 4%, 5%, 6%, 7%, 8%, or the like.

[0071] In some embodiments, in step S1, the slurry further includes a plasticizer. Preferably, the plasticizer includes, but is not limited to, at least one of dibutyl phthalate (DBP) and acetyl trioctyl citrate (ATOC). More preferably, the mass ratio of the plasticizer to the cerium oxide powder is 0.5% to 5%, for example, but not limited to: 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 4%, or 5%.

[0072] In some embodiments, in step S2, the substrate includes, but is not limited to, at least one of a fuel electrode supported half-cell, an electrolyte supported half-cell, a metal supported half-cell, and an air electrode supported half-cell. These types of half-cells can all be half-cells disclosed in the prior art. The present invention does not impose any special limitations on the structure of these half-cells.

[0073] Specifically, taking the fuel electrode-supported half-cell as an example, it can be sequentially comprised from bottom to top a support layer, a fuel electrode layer, and an electrolyte layer. The materials of the support layer and the fuel electrode layer include, but are not limited to, at least one of Ni-YSZ, Ni-ScSZ (i.e., nickel-scandium-yttrium stabilized zirconium oxide), Ni-SDC, Ni-GDC, and Cu-GDC, with Ni-YSZ being preferred. The material of the electrolyte layer includes, but is not limited to, at least one of YSZ, GDC, SDC, LDC, and ScSZ, with YSZ being preferred. In a preferred embodiment, the material of the fuel electrode-supported half-cell is NiO-YSZ / YSZ, meaning that the materials of the support layer and the fuel electrode layer are Ni-YSZ, and the material of the electrolyte layer is YSZ.

[0074] In some embodiments, in step S2, the spin coating rate is 500 to 5000 rpm, for example, but not limited to: 500 rpm, 1000 rpm, 1500 rpm, 2000 rpm, 2500 rpm, 3000 rpm, 3500 rpm, 4000 rpm, 4500 rpm or 5000 rpm, etc., preferably 1500 to 3000 rpm.

[0075] In some embodiments, in step S2, the spin coating time is 0.5 to 5 minutes, for example, but not limited to: 0.5 minutes, 1 minute, 1.5 minutes, 2 minutes, 2.5 minutes, 3 minutes, 3.5 minutes, 4 minutes, 4.5 minutes or 5 minutes, preferably 1 to 2 minutes.

[0076] In some embodiments, the spin coating is performed once in step S2.

[0077] In some embodiments, in step S2, drying may be selectively performed after the spin coating is completed.

[0078] In some embodiments, in step S2, the sintering temperature is 1200 to 1400°C, for example but not limited to: 1200°C, 1225°C, 1250°C, 1275°C, 1300°C, 1325°C, 1350°C, 1375°C or 1400°C, preferably 1225 to 1275°C.

[0079] In some embodiments, the sintering time in step S2 is 1 to 10 hours, for example, but not limited to: 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours or 10 hours, preferably 3 to 5 hours.

[0080] In some embodiments, in step S2, the thickness of the barrier layer is 0.5 to 8 μm, such as, but not limited to: 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm or 8 μm, preferably 1 to 3 μm.

[0081] According to a specific embodiment of the second aspect of the present invention, the present invention provides a barrier layer, which is prepared by the above-described barrier layer preparation method.

[0082] In some embodiments, the density of the barrier layer is >73%. The method for testing this density includes the following steps: quantitatively evaluating the surface density of the barrier layer using ImageJ; importing a scanning electron microscope image of the barrier layer's surface into ImageJ; then identifying and quantifying pores; and calculating the density using the following formula: Density (%) = (Total area of ​​the barrier layer - Area of ​​pores in the barrier layer) / Total area of ​​the barrier layer × 100%. The barrier layer used for testing is a circular barrier layer with a diameter of 16 mm or an area of ​​10 × 10 cm². 2 A square barrier layer.

[0083] In some embodiments, the interfacial bonding strength of the barrier layer is >10 MPa. The method for testing this interfacial bonding strength includes the following steps: fixing one side of a substrate with the barrier layer formed thereon, and adhering the other side (i.e., one side of the barrier layer) to a tensile gauge; applying a tensile force per unit area in a direction perpendicular to the substrate with the barrier layer formed thereon; the tensile stress applied when the barrier layer detaches from the substrate is the interfacial bonding strength. The barrier layer used in the test is a circular barrier layer with a diameter of 16 mm.

[0084] In some embodiments, the thickness uniformity of the barrier layer is >94%. The method for testing this thickness uniformity includes the following steps: scanning electron microscopy (SEM) is used to examine cross-sectional images of the substrate with the barrier layer at its center and 5-6 mm from the edge; then, the barrier layer is identified and its thickness is quantified. The formula for calculating the thickness uniformity is: Thickness uniformity (%) = [1 - (thickness of the barrier layer at the center - thickness of the barrier layer 5-6 mm from the edge) / thickness of the barrier layer at the center] × 100%. The barrier layer used for testing has an area of ​​10 × 10 cm². 2 A square barrier layer.

[0085] This invention uses cerium-based oxide powder with a specific particle size and a specific sintering aid as raw materials, especially GDC powder with a specific particle size and Co oxide as raw materials. By combining the specific content of cerium-based oxide powder in the slurry and the specific mass ratio of sintering aid to cerium-based oxide powder, the optimal synergistic effect is achieved. Combined with the specific spin coating rate and spin coating time of this invention, a barrier layer with excellent density and uniformity, high interfacial strength and thin thickness can be prepared in one spin coating at a relatively low sintering temperature.

[0086] According to a specific embodiment of a third aspect of the present invention, the present invention provides a solid oxide battery, which includes at least the barrier layer described above.

[0087] In some embodiments, as described above, the substrate includes, but is not limited to, at least one of a fuel electrode supported half-cell, an electrolyte supported half-cell, a metal supported half-cell, and an air electrode supported half-cell, and the barrier layer is formed on the substrate. Based on this, those skilled in the art can select the functional layers further included on the barrier layer of the solid oxide battery according to the substrate specifically used in this invention.

[0088] Specifically, in some embodiments, the solid oxide battery further includes an air electrode layer disposed on the barrier layer.

[0089] In some embodiments, the material of the air electrode layer includes, but is not limited to, at least one of LSC-GDC (i.e., lanthanum strontium cobalt oxide-gadolinium doped cerium oxide), LSCF-GDC (i.e., lanthanum strontium cobalt iron oxide-gadolinium doped cerium oxide), LSTF-GDC (i.e., lanthanum strontium titanium iron oxide-gadolinium doped cerium oxide), LNO-GDC (lanthanum nickel oxide-gadolinium doped cerium oxide), preferably LSCF-GDC.

[0090] In some embodiments, the air electrode layer is formed on the barrier layer by coating an air electrode layer slurry onto the barrier layer and then sintering it to obtain the air electrode layer. Specifically, the method of coating the air electrode layer slurry onto the barrier layer may include, but is not limited to, at least one of screen printing, spin coating, etc. Drying may be selectively performed after coating. Furthermore, the sintering temperature may be 900–1200°C, preferably 1000–1100°C; the sintering time may be 1–5 hours, preferably 1–3 hours.

[0091] In some embodiments, the thickness of the air electrode layer is 5–50 μm.

[0092] In some embodiments, specifically, the solid oxide battery comprises, from bottom to top, the fuel electrode supported half-cell, the barrier layer, and the air electrode layer.

[0093] The solid oxide battery of the present invention has improved stability and chemical compatibility between components, and can be used as a large-area single cell.

[0094] The technical solutions of the present invention are specifically illustrated by the following embodiments, but the present invention is not limited to these embodiments. Of course, various modifications can be made within the scope of the key points of the present invention.

[0095] Example 1

[0096] like Figure 1 and Figure 2 As shown, 2.0 g of GDC powder with an average particle size of 200 nm, 0.04 g of PVB binder, 0.02 g of Co3O4 sintering aid, and 4 g of ethanol solvent were mixed evenly to obtain a slurry (the content of GDC powder in the slurry was approximately 33% by mass). Using a fuel electrode supported half-cell 1 as the substrate, the substrate was fixed in a spin coater, and an appropriate amount of slurry was dropped onto the substrate surface. After spin coating at 1500 rpm for 2 min, the slurry was dried and then sintered in a muffle furnace at 1250 °C for 5 h to obtain barrier layer 2. Scanning electron microscopy showed that the thickness of barrier layer 2 was 1.1 μm. Figure 3 This is a scanning electron microscope image of the barrier layer 2 in this embodiment. The barrier layer 2 has a planar dimension and shape of a circle with a diameter of 16 mm.

[0097] Subsequently, LSCF-GDC slurry was screen-printed onto barrier layer 2, dried, and then sintered in a muffle furnace at 1050℃ for 2 hours to obtain air electrode layer 3, thus yielding a solid oxide single-cell battery. The LSCF-GDC slurry composition was 50 wt% LSCF and 50 wt% GDC. Scanning electron microscopy (SEM) analysis showed that the thickness of air electrode layer 3 was 28 μm.

[0098] like Figure 2 As shown, the single-cell battery in this embodiment comprises, from bottom to top, a fuel electrode-supported half-cell 1, a barrier layer 2, and an air electrode layer 3. The fuel electrode-supported half-cell 1 comprises, from bottom to top, a support layer 101, a fuel electrode layer 102, and an electrolyte layer 103. The material of the fuel electrode-supported half-cell 1 is NiO-YSZ / YSZ, wherein the materials of the support layer 101 and the fuel electrode layer 102 are Ni-YSZ, and the material of the electrolyte layer 103 is YSZ.

[0099] The density and interfacial bonding strength of the barrier layer 2 were tested using the method described above. The results were: density 79.1% and interfacial bonding strength 15 MPa.

[0100] A large-area single-cell battery was prepared using the method described in this embodiment, and its microstructure is as follows: Figure 4 As shown. In the case of scaled-up fabrication, the area of ​​the large-area single cell in this embodiment is 10 × 10 cm. 2 The density of the barrier layer 2 in this battery is 78.3%, which is almost negligible compared to the smaller area barrier layer 2 mentioned above. Furthermore, the thickness uniformity of the barrier layer 2 is 97%, exhibiting high uniformity. Simultaneously, confocal microscopy analysis of the barrier layer 2 and the substrate revealed that the flatness of the barrier layer 2 is essentially consistent with that of the substrate.

[0101] The single cell (active area 0.785 cm²) of this embodiment was tested. 2 The battery uses a circular barrier layer with a diameter of 16 mm (the active area is calculated based on the diameter of the air electrode layer 3 being 10 mm). Its peak power density at 800°C is 805 mW / cm². 2 The test conditions were as follows: a four-electrode method was used, with silver wires serving as current and voltage leads, hydrogen as fuel, and air as the oxidant.

[0102] Example 2

[0103] like Figure 1 and Figure 2 As shown, 2.0 g of GDC powder with an average particle size of 200 nm, 0.04 g of PVB binder, 0.02 g of Bi2O3 sintering aid, and 4 g of ethanol solvent were mixed evenly to obtain a slurry (the content of GDC powder in the slurry was approximately 33% by mass). Using a fuel electrode supported half-cell 1 as the substrate, the substrate was fixed in a spin coater, and an appropriate amount of slurry was dropped onto the substrate surface. After spin coating at 1500 rpm for 2 min, the slurry was dried and then sintered in a muffle furnace at 1250 °C for 5 h to obtain barrier layer 2. Scanning electron microscopy showed that the thickness of barrier layer 2 was 1.2 μm.Figure 5 This is a scanning electron microscope image of the barrier layer 2 in this embodiment. The barrier layer 2 has a planar dimension and shape of a circle with a diameter of 16 mm.

[0104] Subsequently, LSCF-GDC slurry was screen-printed onto barrier layer 2, dried, and then sintered in a muffle furnace at 1050°C for 2 hours to obtain air electrode layer 3, thereby obtaining a solid oxide single-cell battery. The composition and content of the LSCF-GDC slurry were the same as in Example 1. Scanning electron microscopy (SEM) analysis showed that the thickness of air electrode layer 3 was 26 μm.

[0105] like Figure 2 As shown, the structure of the single cell in this embodiment is the same as that in Embodiment 1.

[0106] The density and interfacial bonding strength of the barrier layer 2 were tested using the method described above. The results were: density 73.2% and interfacial bonding strength 12 MPa.

[0107] The single cell (active area 0.785 cm²) of this embodiment was tested. 2 The peak power density at 800℃ is 734 mW / cm³. 2 The test conditions were the same as in Example 1.

[0108] Example 3

[0109] like Figure 1 and Figure 2 As shown, 2.5 g of GDC powder with an average particle size of 200 nm, 0.05 g of PVB binder, 0.025 g of Co3O4 sintering aid, and 4 g of ethanol solvent were mixed evenly to obtain a slurry (the content of GDC powder in the slurry was approximately 38% by mass). Using a fuel electrode supported half-cell 1 as the substrate, the substrate was fixed in a spin coater, and an appropriate amount of slurry was dropped onto the substrate surface. After spin coating at 1500 rpm for 2 min, the slurry was dried and then sintered in a muffle furnace at 1250 °C for 5 h to obtain barrier layer 2. Scanning electron microscopy showed that the thickness of barrier layer 2 was 1.7 μm. Figure 6 This is a scanning electron microscope image of the barrier layer 2 in this embodiment. The barrier layer 2 has a planar dimension and shape of a circle with a diameter of 16 mm.

[0110] Subsequently, LSCF-GDC slurry was screen-printed onto barrier layer 2, dried, and then sintered in a muffle furnace at 1050°C for 2 hours to obtain air electrode layer 3, thereby obtaining a solid oxide single-cell battery. The composition and content of the LSCF-GDC slurry were the same as in Example 1. Scanning electron microscopy (SEM) analysis showed that the thickness of air electrode layer 3 was 27 μm.

[0111] like Figure 2 As shown, the structure of the single cell in this embodiment is the same as that in Embodiment 1.

[0112] The density and interfacial bonding strength of the barrier layer 2 were tested using the method described above. The results were: density 79.6% and interfacial bonding strength 16 MPa.

[0113] The single cell (active area 0.785 cm²) of this embodiment was tested. 2 The peak power density at 800℃ is 692 mW / cm³. 2 The test conditions were the same as in Example 1.

[0114] Example 4

[0115] like Figure 1 and Figure 2 As shown, 2.0 g of GDC powder with an average particle size of 200 nm, 0.04 g of PVB binder, 0.02 g of CuO sintering aid, 0.05 g of PEG dispersant, and 4 g of ethanol solvent were mixed evenly to obtain a slurry (the content of GDC powder in the slurry was approximately 32.7% by mass). Using a fuel electrode supported half-cell 1 as the substrate, the substrate was fixed in a spin coater, and an appropriate amount of slurry was dropped onto the substrate surface. After spin coating at 1500 rpm for 2 min, the substrate was dried and then sintered in a muffle furnace at 1250 °C for 5 h to obtain barrier layer 2. Scanning electron microscopy showed that the thickness of barrier layer 2 was 1.4 μm. Figure 7 This is a scanning electron microscope image of the barrier layer 2 in this embodiment. The barrier layer 2 has a planar dimension and shape of a circle with a diameter of 16 mm.

[0116] Subsequently, LSCF-GDC slurry was screen-printed onto barrier layer 2, dried, and then sintered in a muffle furnace at 1050°C for 2 hours to obtain air electrode layer 3, thereby obtaining a solid oxide single-cell battery. The composition and content of the LSCF-GDC slurry were the same as in Example 1. Scanning electron microscopy (SEM) analysis showed that the thickness of air electrode layer 3 was 28 μm.

[0117] like Figure 2 As shown, the structure of the single cell in this embodiment is the same as that in Embodiment 1.

[0118] The density and interfacial bonding strength of the barrier layer 2 were tested using the method described above. The results were: density 78.9% and interfacial bonding strength 14 MPa.

[0119] The single cell (active area 0.785 cm²) of this embodiment was tested. 2 The peak power density at 800℃ is 826 mW / cm³. 2The test conditions were the same as in Example 1.

[0120] Figure 8 The diagram shows the battery power-voltage-current of the individual cells in Examples 1-4.

[0121] Example 5

[0122] like Figure 1 and Figure 2 As shown, 1.0 g each of GDC powder with average particle sizes of 200 nm and 50 nm, 0.04 g of binder PVB, 0.02 g of sintering aid Co3O4, and 4 g of solvent ethanol were mixed evenly to obtain a slurry (the content of GDC powder in the slurry was approximately 33% by mass). Using a fuel electrode supported half-cell 1 as the substrate, the substrate was fixed in a spin coater, and an appropriate amount of slurry was dropped onto the substrate surface. After spin coating at a speed of 1500 rpm for 2 min, the substrate was dried and then sintered in a muffle furnace at 1250 °C for 5 h to obtain barrier layer 2. The thickness of barrier layer 2 was found to be 1.9 μm by scanning electron microscopy. Figure 9 This is a scanning electron microscope image of the barrier layer 2 in this embodiment. The barrier layer 2 has a planar dimension and shape of a circle with a diameter of 16 mm.

[0123] Subsequently, LSCF-GDC slurry was screen-printed onto barrier layer 2, dried, and then sintered in a muffle furnace at 1050℃ for 2 hours to obtain air electrode layer 3, thus yielding a solid oxide single-cell battery. The LSCF-GDC slurry composition was 50 wt% LSCF and 50 wt% GDC. Scanning electron microscopy (SEM) analysis showed that the thickness of air electrode layer 3 was 27 μm.

[0124] like Figure 2 As shown, the structure of the single cell in this embodiment is the same as that in Embodiment 1.

[0125] The density and interfacial bonding strength of the barrier layer 2 were tested using the method described above. The results were: density 81.9% and interfacial bonding strength 17 MPa.

[0126] The single cell (active area 0.785 cm²) of this embodiment was tested. 2 The peak power density at 800℃ is 761 mW / cm³. 2 The test conditions were the same as in Example 1.

[0127] Comparative Example 1

[0128] 2.0 g of GDC powder with an average particle size of 200 nm, 0.04 g of PVB binder, and 4 g of ethanol solvent were mixed evenly to obtain a slurry. Using a fuel electrode supported half-cell 1 as the substrate, the substrate was fixed in a spin coater, and an appropriate amount of slurry was dropped onto the substrate surface. After spin coating at 1500 rpm for 2 min, the slurry was dried and then sintered in a muffle furnace at 1250 °C for 5 h to obtain barrier layer 2. Scanning electron microscopy showed that the thickness of barrier layer 2 was 2.3 μm. Figure 10 This is a scanning electron microscope image of the barrier layer 2 in this comparative example. The planar dimensions and shape of the barrier layer 2 are a circle with a diameter of 16 mm.

[0129] Subsequently, LSCF-GDC slurry was screen-printed onto barrier layer 2, dried, and then sintered in a muffle furnace at 1050°C for 2 hours to obtain air electrode layer 3, thereby obtaining a solid oxide single-cell battery. The composition and content of the LSCF-GDC slurry were the same as in Example 1. Scanning electron microscopy (SEM) analysis showed that the thickness of air electrode layer 3 was 26 μm.

[0130] The structure of the single cell in this comparative example is the same as that in Example 1.

[0131] The density and interfacial bonding strength of barrier layer 2 were tested using the method described above. The results were: density 72.8% and interfacial bonding strength 14 MPa.

[0132] The peak power density of the single cell in this comparative example was tested at 800℃, and the result was 686 mW / cm². 2 The test conditions were the same as in Example 1.

[0133] Comparative Example 2

[0134] 2.0 g of GDC powder with an average particle size of 200 nm, 0.04 g of PVB binder, 0.02 g of Fe3O4 sintering aid, and 4 g of ethanol solvent were mixed evenly to obtain a slurry. A fuel electrode supported half-cell 1 was used as the substrate. The substrate was fixed in a spin coater, and an appropriate amount of slurry was dropped onto the substrate surface. After spin coating at 1500 rpm for 2 min, the slurry was dried and then sintered in a muffle furnace at 1250 °C for 5 h to obtain the barrier layer 2. Scanning electron microscopy showed that the thickness of the barrier layer 2 was 1.2 μm. Figure 11 This is a scanning electron microscope image of the barrier layer 2 in this comparative example. The planar dimensions and shape of the barrier layer 2 are a circle with a diameter of 16 mm.

[0135] Subsequently, LSCF-GDC slurry was screen-printed onto barrier layer 2, dried, and then sintered in a muffle furnace at 1050°C for 2 hours to obtain air electrode layer 3, thereby obtaining a solid oxide single-cell battery. The composition and content of the LSCF-GDC slurry were the same as in Example 1. Scanning electron microscopy (SEM) analysis showed that the thickness of air electrode layer 3 was 28 μm.

[0136] The structure of the single cell in this comparative example is the same as that in Example 1.

[0137] The density and interfacial bonding strength of the barrier layer 2 were tested using the method described above. The results were: density 76.4% and interfacial bonding strength 15 MPa.

[0138] The peak power density of the single cell in this comparative example was tested at 800℃, and the result was 627 mW / cm². 2 The test conditions were the same as in Example 1.

[0139] Comparative Example 3

[0140] 2.0 g of GDC powder with an average particle size of 200 nm, 0.04 g of PVB binder, 20.02 g of Fe(NO3)2 sintering aid, and 4 g of ethanol solvent were mixed evenly to obtain a slurry. A fuel electrode supported half-cell 1 was used as the substrate. The substrate was fixed in a spin coater, and an appropriate amount of slurry was dropped onto the substrate surface. After spin coating at 1500 rpm for 2 min, the slurry was dried and then sintered in a muffle furnace at 1250 °C for 5 h to obtain the barrier layer 2. Scanning electron microscopy showed that the thickness of the barrier layer 2 was 1.8 μm. Figure 12 This is a scanning electron microscope image of the barrier layer 2 in this comparative example. The planar dimensions and shape of the barrier layer 2 are a circle with a diameter of 16 mm.

[0141] Subsequently, LSCF-GDC slurry was screen-printed onto barrier layer 2, dried, and then sintered in a muffle furnace at 1050°C for 2 hours to obtain air electrode layer 3, thereby obtaining a solid oxide single-cell battery. The composition and content of the LSCF-GDC slurry were the same as in Example 1. Scanning electron microscopy (SEM) analysis showed that the thickness of air electrode layer 3 was 25 μm.

[0142] The structure of the single cell in this comparative example is the same as that in Example 1.

[0143] The density and interfacial bonding strength of the barrier layer 2 were tested using the method described above. The results were: density 63.9% and interfacial bonding strength 11 MPa.

[0144] The peak power density of the single cell in this comparative example was tested at 800℃, and the result was 639 mW / cm². 2The test conditions were the same as in Example 1.

[0145] Figure 13 The diagram shows the power-voltage-current of individual cells in Comparative Examples 1-3.

Claims

1. A method for preparing a barrier layer, comprising the following steps: S1. At least the cerium-based oxide powder, sintering aid and solvent are mixed evenly to obtain a slurry; S2. Spin-coating the slurry onto the substrate and sintering it to obtain the barrier layer. The average particle size of the cerium-based oxide powder is 0.01–1 μm. The sintering aid is an oxide of Cu and / or Bi; Based on the mass of the slurry, the content of the cerium-based oxide powder therein is 20% to 50%. The mass ratio of the sintering aid to the cerium-based oxide powder is 0.5% to 5%. The spin coating rate is 500-5000 rpm, the spin coating time is 0.5-5 min, and the spin coating is performed once. The thickness of the barrier layer is 0.5–5 μm.

2. The method for preparing the barrier layer according to claim 1, wherein, In step S1, the cerium-based oxide powder includes one or a combination of gadolinium-doped cerium oxide powder, samarium-doped cerium oxide powder, and lanthanum-doped cerium oxide powder.

3. The method for preparing the barrier layer according to claim 1, wherein, In step S1, the average particle size of the cerium-based oxide powder is 0.05 to 0.5 μm.

4. The method for preparing the barrier layer according to claim 1, wherein, In step S1, the content of the cerium-based oxide powder in the slurry is 30% to 40% based on the mass of the slurry (100%).

5. The method for preparing the barrier layer according to claim 1, wherein, In step S1, the mass ratio of the sintering aid to the cerium-based oxide powder is 1% to 3%.

6. The method for preparing the barrier layer according to claim 1, wherein, In step S1, the slurry further includes a binder.

7. The method for preparing the barrier layer according to claim 6, wherein, In step S1, the mass ratio of the binder to the cerium-based oxide powder is 0.5% to 8%.

8. The method for preparing the barrier layer according to claim 1, wherein, In step S2, the substrate includes at least one of a fuel electrode supported half-cell, an electrolyte supported half-cell, a metal supported half-cell, and an air electrode supported half-cell.

9. The method for preparing the barrier layer according to claim 1, wherein, In step S2, the spin coating rate is 1500-3000 rpm.

10. The method for preparing the barrier layer according to claim 9, wherein, In step S2, the spin coating time is 1 to 2 minutes.

11. The method for preparing the barrier layer according to claim 1, wherein, In step S2, the sintering temperature is 1200–1400°C.

12. The method for preparing the barrier layer according to claim 1 or 11, wherein, In step S2, the sintering temperature is 1225–1275°C.

13. The method for preparing the barrier layer according to claim 11, wherein, In step S2, the sintering time is 1 to 10 hours.

14. The method for preparing the barrier layer according to claim 1, wherein, In step S2, the thickness of the barrier layer is 1 to 3 μm.

15. A barrier layer, which is prepared by the method for preparing a barrier layer according to any one of claims 1-14.

16. The barrier layer according to claim 15, wherein, The density of the barrier layer is >73%.

17. The barrier layer according to claim 15, wherein, The interfacial bonding strength of the barrier layer is >10MPa.

18. The barrier layer according to claim 15, wherein, The thickness uniformity of the barrier layer is >94%.

19. A solid oxide battery comprising at least the barrier layer according to any one of claims 15-18.

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