Flexible contact materials and their preparation methods, air electrode connection structures and their preparation methods

Abstract

This invention discloses a flexible contact material for use between the air electrode and the connector in a solid oxide battery. The material comprises a flexible metal framework and a deposited layer. The flexible metal framework is selected from one or more of Fe, Co, Ni, Cu, and Mn. The deposited layer coats the surface of the flexible metal framework and includes one or more of Fe, Co, Ni, Cu, and Mn. The compositions of the flexible metal framework and the deposited layer are not entirely the same. The deposited layer in the flexible contact material can undergo an oxidation reaction with the flexible metal framework under an oxygen-containing atmosphere and under heating conditions to produce a material with the general formula A. x B 3‑x The invention discloses a spinel-type structure of O4 (1≤x≤2), where A is the composition of the flexible metal framework and B is the composition of the deposited layer, 1≤x≤2. The invention also discloses a method for preparing flexible contact materials, an air electrode connection structure and its preparation method, a solid oxide battery, and a battery stack. The contact layer of this invention exhibits good high-temperature conductivity and long-term operational stability.

Description

Technical Field

[0001] This invention relates to the field of solid oxide batteries, and particularly to a flexible contact material and its preparation method, an air electrode connection structure and its preparation method, a solid oxide battery, and a battery stack. Background Technology

[0002] Solid oxide cells (SOCs) are generally classified into solid oxide fuel cells (SOFCs) and solid oxide electrolysis cells (SOECs) based on their operating modes. Both consist of three parts: a fuel electrode, an electrolyte, and an air electrode. SOFCs are all-solid-state energy conversion devices that can efficiently convert the chemical energy of fuels such as hydrogen, ammonia, or hydrocarbons directly into electrical energy, making them a highly promising power generation technology. In recent years, considering the increasingly severe environmental problems, countries around the world have also invested significant research funds and manpower in SOECs, the reverse operating mode of SOFCs. In this way, the same equipment can utilize renewable electricity to absorb carbon dioxide and produce syngas and carbon-containing chemicals.

[0003] Similar to electrochemical devices such as proton exchange membrane fuel cells and alkaline water electrolyzers, SOFC (Solar Charge Container) stacks require multiple cells to be connected in series using connectors to achieve higher voltage and power. Each connector is connected to the fuel electrode and air electrode of the adjacent two cells. For example, SOFC technology mainly uses a planar stack structure, with an operating temperature of approximately 600-900℃. To achieve good contact between the connectors and the electrodes on both sides and reduce electron conduction resistance, a contact material that can fit tightly to both sides and has good conductivity at high temperatures is usually added between the electrodes and the connectors. Currently, nickel mesh or nickel foam is often used as the contact layer on the fuel electrode side, but because the air electrode is in a high-temperature oxidizing atmosphere, it is not possible to directly use metal materials as the contact layer.

[0004] Currently, most contact materials are rigid bonding materials. For example, patent CN103427092A proposes a composite conductive ceramic material with a spinel-type structure phase coated with a perovskite structure phase. When used as a cathode contact layer, it can simultaneously exhibit the low-temperature sintering activity of spinel materials and the high conductivity of the perovskite phase. It can achieve good bonding with the cathode and connector at 900℃ or even lower, and maintain a conductivity below 20 mΩ·cm in SOFC operating environments. 2 The contact resistance is [not specified]. However, this method requires the preparation of two different ceramic powders using the sol-gel method, which involves multiple calcinations and ball millings, resulting in a complex manufacturing process and a long production cycle.

[0005] Patent CN116404188A proposes a LaNi 0.6 Fe 0.4 A method and application for controlling the particle size of O3 contact layer materials. Through simple high-temperature calcination and sieve separation, this invention enables controllable adjustment of LaNi particle size within the range of 1–10 μm. 0.6 Fe 0.4 The average particle size of the O3 contact layer material particles. Using this powder as the cathode contact layer via slurry coating results in a rigid connection with relatively high porosity and low powder sintering activity, which is beneficial for gas transport. However, the overall conductivity is relatively low, with resistivity mostly around 50 mΩ·cm. 2 above.

[0006] Patent CN117334943A proposes a method for forming a lanthanum-strontium-manganese oxide slurry on an SOFC cathode, followed by sintering during testing to form a lanthanum-strontium-manganese oxide contact layer. However, this method still requires control over the particle size of the lanthanum-strontium-manganese ceramic particles, as well as the proportions of the pore-forming agent, binder, and solvent. Furthermore, the thickness of the formed contact layer preform needs adjustment, and the contact layer pressed onto the cathode covers a large portion of the electrode area, affecting battery performance.

[0007] However, the thermal expansion coefficients of rigid connecting materials do not match those of the air electrode and the connector, resulting in poor adaptability to deformation of adjacent materials and a tendency to crack, leading to contact failure. Furthermore, the amount of rigid connecting material applied is difficult to control; too much can clog the porous structure of the electrode, while too little increases electron conduction resistance. Additionally, when using rigid connecting materials as contact layers, a balance must be struck between sintering activity and conductivity to ensure a firm sintering at SOFC operating temperatures while maintaining good conductivity. This limits the application range of rigid materials, and any change in the connector or battery material can significantly render the original contact material unsuitable.

[0008] Based on this, a new type of contact material has emerged. For example, patent CN103887533A provides a flexible connection component for solid oxide fuel cells with high electrical conductivity. This component is prepared by coating the surface of an alloy mesh or foam with one or more layers of coating material, resulting in a flexible connection component with high electrical conductivity under a high-temperature oxidizing atmosphere. The resulting connection component possesses high electrical conductivity, high-temperature oxidation resistance, and flexibility. The preparation method for this high-temperature connection component involves applying the coating material to the surface of the alloy mesh or foam component using methods such as brushing, spraying, or dipping, followed by sintering at a low temperature range of 700-900℃ to form the coating. However, most of these connection components are formed by using a slurry coating method to create the contact layer preform. After sintering, the bonding force between the coating material and the substrate in the contact layer is difficult to control, leading to poor stability of the contact layer after long-term operation. Summary of the Invention

[0009] To address the aforementioned technical problems, this invention provides a flexible contact material and its preparation method, an air electrode connection structure and its preparation method, a solid oxide battery, and a battery stack.

[0010] In a first aspect, embodiments of the present invention disclose a flexible contact material for use between the air electrode and the connector in a solid oxide battery, comprising a flexible metal framework and a deposited layer, wherein...

[0011] The flexible metal framework is selected from one or more of Fe, Co, Ni, Cu, and Mn. The deposited layer covers the surface of the flexible metal framework and includes one or more of Fe, Co, Ni, Cu, and Mn. The composition of the flexible metal framework and the composition of the deposited layer are not exactly the same. The deposited layer in the flexible contact material can undergo an oxidation reaction with the flexible metal framework under an oxygen-containing atmosphere and under heating conditions to generate a product with the general formula A. x B 3-x The O4 (1≤x≤2) spinel-type structure is coated on the surface of the flexible metal skeleton, wherein A is the composition of the flexible metal skeleton, B is the composition of the deposited layer, and 1≤x≤2.

[0012] Using the above technical solution, a spinel-type contact layer can be generated by oxidation reaction of the flexible metal skeleton and the deposited layer in an oxygen atmosphere during the reaction process of the air electrode, thereby giving the contact layer good high-temperature electrical conductivity and long-term operational stability.

[0013] According to another specific embodiment of the present invention, the deposited layer further includes one or more of La, Ce and Y.

[0014] According to another specific embodiment of the present invention, the thickness of the flexible metal skeleton is 50 to 500 μm.

[0015] According to another specific embodiment of the present invention, the pore size of the flexible metal skeleton is 40 to 1800 μm.

[0016] According to another specific embodiment of the present invention, the mass of the deposited layer accounts for 5 to 10 wt% of the total mass of the flexible contact material.

[0017] Secondly, embodiments of the present invention also disclose a method for preparing a flexible contact material, used to prepare the flexible contact material in any embodiment of the first aspect, comprising the following steps:

[0018] Electrodeposition: The flexible metal skeleton is immersed in an electrolyte to perform electrodeposition, thereby obtaining the flexible contact material;

[0019] The electrolyte comprises an acid salt and water, wherein the acid salt is the acid salt corresponding to the composition of the deposited layer.

[0020] By adopting the above technical solution, the deposition layer can be coated on the surface of the flexible metal skeleton through electrodeposition, which is beneficial to control the deposition amount and uniformity of the deposition layer, and can ensure strong bonding between the deposition layer and the flexible metal skeleton, thereby improving the overall stability of the flexible contact material.

[0021] According to another specific embodiment of the present invention, the acid salt includes an acid radical ion, wherein the acid radical ion is a sulfate ion or a chloride ion.

[0022] According to another specific embodiment of the present invention, the electrolyte further includes a second acid salt, the second acid salt having the same anion as the acid salt, and the cation in the second acid salt being an alkali metal ion.

[0023] According to another specific embodiment of the present invention, the electrolyte further includes an additive, which is one of pyrophosphate, citrate, ammonium sulfate or boric acid.

[0024] According to another specific embodiment of the present invention, the pH value of the electrolyte is 4 to 7.

[0025] According to another specific embodiment of the present invention, in the electrodeposition step, the electrodeposition is pulsed electrodeposition, and the pulse current density of the pulsed electrodeposition is 10 to 100 mA / cm². 2 The pulse frequency is 1–100 Hz, the deposition time is 1–60 min, and the working cycle is 20–80%.

[0026] Thirdly, embodiments of the present invention disclose an air electrode connection structure for a solid oxide battery, comprising an air electrode, a contact layer, and a connector arranged sequentially. The contact layer is obtained by an oxidation reaction of a flexible contact material as described in any embodiment of the first aspect. The oxidation reaction is performed by the deposited layer reacting with the flexible metal framework in an oxygen-containing atmosphere and under heating conditions to form a general formula A. x B 3-x The spinel-type structure of O4 (1≤x≤2) is coated on the surface of the flexible metal skeleton, wherein A is the composition of the flexible metal skeleton, B is the composition of the deposited layer, and 1≤x≤2.

[0027] By adopting the above technical solution, a good interface contact can be formed with the connector 3 and the air electrode 1, reducing the surface resistance and improving the current transmission efficiency of the battery.

[0028] According to another specific embodiment of the present invention, the air electrode connection structure is connected to the surface resistance testing device to form a circuit, and a current is passed through it with a constant current density of 500 mA / cm². 2 After 300 hours of isothermal operation at 850℃ in air atmosphere, and following 20 cooling-heating cycles, the surface resistivity of the air electrode connection structure was tested to be ≤50 mΩ·cm. 2 The cooling-heating process involves cooling from 850°C to 200°C, then heating from 200°C to 850°C and running at 850°C for 10 hours.

[0029] Fourthly, embodiments of the present invention disclose a method for preparing an air electrode connection structure, used to prepare an air electrode connection structure as described in any embodiment of the third aspect, comprising the following steps:

[0030] Electrodeposition: The flexible metal skeleton is immersed in an electrolyte to perform electrodeposition, thereby obtaining the flexible contact material;

[0031] Preparation of the air electrode connection structure: After assembling the air electrode, the flexible contact material and the connector, the deposited layer and the flexible metal skeleton undergo an oxidation reaction under an oxygen-containing atmosphere and under heating to obtain the contact layer, thus obtaining the air electrode connection structure;

[0032] The electrolyte comprises an acid salt and water, wherein the acid salt is the acid salt corresponding to the composition of the deposited layer.

[0033] The above technical solution can achieve good integration with adjacent components while exhibiting good high-temperature conductivity and long-term operational stability. The preparation method is simple and feasible.

[0034] According to another specific embodiment of the present invention, the heating temperature of the heating state is 800 to 1000°C.

[0035] According to another specific embodiment of the present invention, in the step of preparing the air electrode connection structure, after assembling the air electrode, the flexible contact material and the connector, sintering is performed to cause the deposited layer and the flexible metal skeleton to undergo an oxidation reaction to generate the contact layer, thereby obtaining the air electrode connection structure.

[0036] According to another specific embodiment of the present invention, in the step of preparing the air electrode connection structure, the air electrode, the flexible contact material and the connector are assembled into a solid oxide battery, the solid oxide battery is started and the solid oxide battery is brought to the operating temperature, so that the deposited layer and the flexible metal skeleton undergo an oxidation reaction to generate the contact layer, thereby obtaining the air electrode connection structure.

[0037] Fifthly, embodiments of the present invention disclose a solid oxide battery, including an air electrode connection structure as described in any embodiment of the third aspect, or including an air electrode connection structure obtained by a preparation method as described in any embodiment of the fourth aspect.

[0038] By adopting the above technical solution, the conductivity between the air electrode and the connector of the solid oxide battery can be increased, which is beneficial to improving the long-term stable operation and also allows more current to be transmitted under the same voltage, thereby improving the current collection efficiency of the solid oxide battery.

[0039] In a sixth aspect, embodiments of the present invention disclose a battery stack, including a solid oxide battery as described in any of the embodiments of the fifth aspect.

[0040] By adopting the above technical solution, the conductivity between adjacent solid oxide cells in the battery stack can be increased, allowing more current to be transmitted under the same voltage, thereby improving the current collection efficiency of the battery stack and improving its operating efficiency and long-term stable operation. Attached Figure Description

[0041] Figure 1 A schematic diagram of an air electrode connection structure according to an embodiment of the present invention is shown;

[0042] Figure 2 The ASR data of the air electrode connection structures prepared in the comparative examples and Examples 1-6 of the present invention are shown in comparison after being kept at 850°C for 100 hours in an air atmosphere.

[0043] Figure 3 This shows a microscope image of the flexible metal skeleton of Embodiment 2 of the present invention;

[0044] Figure 4 This image shows a microscopic photograph of the flexible contact material of Embodiment 2 of the present invention.

[0045] Figure 5 This shows a scanning electron microscope image of the flexible contact material of Embodiment 3 of the present invention;

[0046] Figure 6 This shows a scanning electron microscope image of the contact layer in Embodiment 3 of the present invention;

[0047] Figure 7 The ASR curves of the air electrode connection structures of Embodiments 4 and 5 of the present invention are shown after being kept at 850°C for 300 hours in an air atmosphere, and then undergoing 20 heating-cooling cycles between 200-850°C.

[0048] Figure 8 The XRD pattern of the flexible contact material of Embodiment 4 of the present invention after being kept at 850°C for 50 hours in an air atmosphere is shown.

[0049] Figure 9 The XRD pattern of the flexible contact material of Embodiment 6 of the present invention after being kept at 850°C for 50 hours in an air atmosphere is shown.

[0050] Figure 10 The performance of the battery stack in Embodiment 7 of the present invention is shown. Figure 1 ;

[0051] Figure 11 The performance of the battery stack in Embodiment 7 of the present invention is shown. Figure 2 .

[0052] 0. Air electrode connection structure, 1. Air electrode, 2. Contact layer, 3. Connector Detailed Implementation

[0053] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention is presented in conjunction with preferred embodiments, this does not mean that the features of the invention are limited to these embodiments. On the contrary, the purpose of describing the invention in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of the present invention. To provide a deep understanding of the invention, many specific details will be included in the following description. The invention may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of the invention, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0054] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0055] The terms “first”, “second”, etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0056] In the description of this embodiment, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment based on the specific circumstances.

[0057] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0058] In embodiments of the present invention, the air electrode is also the cathode. In SOFC, the air electrode is responsible for the reduction reaction of oxygen, where oxygen molecules gain electrons and are converted into oxygen ions. In SOEC, the air electrode is the site of oxygen evolution, where oxygen ions lose electrons to generate oxygen gas, undergoing an oxidation reaction.

[0059] In embodiments of the present invention, the connector refers to a component that ensures good contact between the electrodes of two adjacent batteries.

[0060] In an embodiment of the present invention, the air electrode, the contact layer, and the connector are sequentially bonded together to form a sandwich structure.

[0061] In a first aspect, embodiments of the present invention disclose a flexible contact material, combined with Figure 1 As shown, it is used between the air electrode 1 and the connector 3 in a solid oxide battery, that is, between the air electrode 1 and the connector 3 in a solid oxide fuel cell or solid oxide electrolyzer. The flexible contact material includes a flexible metal skeleton and a deposited layer. In embodiments of the present invention, the flexible metal skeleton refers to a metal material with a porosity greater than 0 and good deformability, and the structure of the flexible metal skeleton is, for example, cloth, mesh, felt, or foam.

[0062] The flexible metal framework is selected from one or more of Fe, Co, Ni, Cu, and Mn. In other words, it is selected from one or more of the metals iron, cobalt, nickel, copper, and manganese. Compared to traditional rigid connection materials, the flexible design significantly improves the reliability and lifespan of the battery. The flexible metal framework, selected from one or more of Fe, Co, Ni, Cu, and Mn, contains multiple valence states, which facilitates reactions to form different types of spinel structures.

[0063] A deposited layer coats the surface of the flexible metal skeleton. This deposited layer comprises one or more of Fe, Co, Ni, Cu, and Mn; that is, it comprises one or more of iron, cobalt, nickel, copper, and manganese. For example, the deposited layer may be iron, cobalt, nickel, copper, manganese, a combination of manganese and cobalt, or a cobalt-manganese alloy. This flexible metal skeleton design endows the flexible contact material with conductivity and excellent deformability, enabling it to effectively adapt to the differences in microscopic deformation and thermal expansion between the air electrode 1 and the connector 3. This helps prevent cracking of the contact layer 2, which could lead to contact failure with adjacent components, thus contributing to stability during long-term operation.

[0064] The composition of the flexible metal framework and the deposited layer are not entirely the same; that is, the composition of the flexible metal framework and the deposited layer are only partially the same, but not completely the same, or the composition of the flexible metal framework and the deposited layer are completely different. Specifically, for example, when the flexible metal framework is Fe, the deposited layer can be Fe and Co; when the flexible metal framework is Fe, Co, Ni, Cu, and Mn, the deposited layer can be an alloy or mixture of Fe, Co, Ni, and Cu. This facilitates the reaction between the flexible metal framework and the deposited layer to form a spinel-type structure. The spinel-type structure exhibits semiconductor properties at high temperatures, thus possessing good electronic conductivity and effectively conducting current. In addition, the spinel-type structure is not easily corroded or degraded in strongly acidic or alkaline environments, has good thermal stability at high temperatures, good interfacial compatibility, and high mechanical strength to withstand external forces and thermal stresses, thereby ensuring stable battery operation and improving the working efficiency of solid oxide batteries.

[0065] In the above embodiments, combined with Figure 1 As shown, the deposited layer in the flexible contact material can undergo an oxidation reaction with the flexible metal framework under an oxygen-containing atmosphere and under heating conditions, generating a product with the general formula A. x B 3-x A spinel-type structure of O4 (1≤x≤2) is coated on the surface of a flexible metal framework, thus serving as the contact layer 2 between the air electrode 1 and the connector 3 in a solid oxide battery. The heating state refers to the oxidation temperature required for the deposited layer to undergo an oxidation reaction with the flexible metal framework, for example, 800–1000°C. A represents the composition of the flexible metal framework, and B represents the composition of the deposited layer, 1≤x≤2. For example, when the flexible metal framework is metallic Fe, the deposited layer can be Ni and Co, and the deposited layer reacts with the flexible metal framework to form a product with the general formula Fe. x (NiCo) 3-x O4 spinel-type structure, 1≤x≤2.

[0066] Preferably, when the flexible metal framework is metallic Mn, the deposited layer is Cu, and the general formula for the formation of the deposited layer and the flexible metal framework is Mn. x (Cu) 3-xO4 spinel-type structure, 1≤x≤2. The inventors discovered that the spinel-type structure exhibits good conductivity at higher temperatures, attributed to a "small polaron hopping" mechanism. Simply put, for this type of ionic crystal, electron-lattice coupling strengthens at high temperatures, forming small polarons. These small polarons participate in conduction through hopping between lattice cells, and their conductivity is influenced by factors such as mixed valence bands and oxygen vacancy concentration. Here, a small polaron refers to a polaron whose size is comparable to the lattice constant; the size of the polaron depends on the scale of the lattice polarization region where electron (or hole) coupling occurs. Among the elements Fe, Co, Ni, Cu, and Mn that can be used in flexible metallic frameworks, Mn, due to its abundant valence states (e.g., +2, +3, or +4), forms a spinel-type structure with more mixed valence bands, thus facilitating charge transfer and exhibiting higher conductivity. Because of its lower +1 valence state, Cu in the deposited layer can more easily introduce oxygen vacancies into the lattice, promoting charge transfer between oxygen and metal atoms, increasing electron density, accelerating carrier migration, and enhancing conductivity. Therefore, manganese copper spinel series composed of Mn and Cu in various valence states typically exhibits better conductivity, i.e., lower sheet resistivity.

[0067] The deposited layer in the flexible contact material can undergo an oxidation reaction with the flexible metal skeleton under an oxygen-containing atmosphere and under heating. This oxygen-containing atmosphere can be, for example, air or an oxygen atmosphere. Specifically, in SOFC, the deposited layer in the flexible contact material can undergo an oxidation reaction with the flexible metal skeleton under an oxygen-containing atmosphere and under heating to form a contact layer 2 with a spinel-type structure. In SOEC, the deposited layer in the flexible contact material can undergo an oxidation reaction with the flexible metal skeleton under an oxygen-containing atmosphere and under heating to form a contact layer 2 with a spinel-type structure. More specifically, the oxidation reaction between the flexible metal skeleton and the deposited layer occurs at a location where the flexible metal skeleton, the deposited layer, and oxygen in the air coexist. This location can be called a three-phase active site. The flexible metal skeleton and the deposited layer form the contact layer 2 through chemical bonding at the three-phase point, thereby effectively improving the bonding force between the flexible metal skeleton and the deposited layer. In addition, the in-situ oxidation reaction between the flexible metal skeleton and the deposited layer increases the bonding force between the contact layer 2 and the air electrode 1 and the connector 3, thereby achieving a good bond between the contact layer 2, the air electrode 1 and the connector 3, and further improving the stability of the overall structure.

[0068] Using the above technical solution, this invention generates a spinel-type structure by undergoing an oxidation reaction between the flexible metal skeleton and the deposited layer under an oxygen-containing atmosphere and heating conditions. Since the oxidation reaction between the flexible metal skeleton and the deposited layer occurs at the three-phase active sites, it is inevitable that part of the flexible metal skeleton itself will be exposed to air and oxidize. However, there is no need to worry about whether this oxidation will cause changes in the battery's internal resistance. This is because the deposited layer of this invention coats the surface of the flexible metal skeleton. Therefore, after the oxidation reaction between the flexible metal skeleton and the deposited layer generates a spinel-type structure on the surface of the flexible metal skeleton, the spinel-type structure in the contact layer 2 of this invention coats the oxidized surface of the flexible metal skeleton. Thus, the contact layer 2 of this invention contacts the air electrode 1 and the connector 3 respectively through the spinel-type structure for electron conduction, ensuring that even if part of the flexible metal skeleton in the contact layer 2 inevitably oxidizes, the contact layer 2 still maintains good electrical conductivity.

[0069] Compared to existing technologies that use physical adsorption to coat spinel-type structural materials onto the surface of a flexible metal skeleton to prepare the contact layer 2, the contact layer 2 of this invention is formed by chemical bonding between the flexible metal skeleton and the deposited layer. Therefore, the contact layer 2 obtained by this invention has a more stable bond between the flexible metal skeleton and the spinel-type structure, resulting in excellent stability. This also avoids the reduction in electrical conductivity and mechanical properties of the contact layer 2 due to the detachment of the coating deposit, and prevents further reactions between the flexible metal skeleton and the metal connector after the deposited layer detaches, such as catalyst Cr poisoning, which would significantly reduce the performance of the solid oxide battery.

[0070] Furthermore, the deposited layer in the flexible contact material can undergo an oxidation reaction with the flexible metal skeleton under an oxygen-containing atmosphere and under heating conditions. That is, the flexible contact material is bonded to the air electrode 1 and the connector 3 respectively, and directly assembled into the solid oxide battery. The deposited layer in the flexible contact material can undergo an in-situ oxidation reaction with the flexible metal skeleton under an oxygen-containing atmosphere and under heating conditions, generating a spinel-type structure coating the surface of the flexible metal skeleton. Therefore, it is unnecessary to first prepare a spinel-type structure and then assemble it into the solid oxide battery. Thus, without additional setup, the overall structure with a spinel-type structure can be obtained simply during the operation of the solid oxide battery, making the preparation process simple and cost-effective. Moreover, the in-situ generation of the spinel-type structure ensures closer contact between the spinel-type structure and the air electrode 1 and the connector 3, thereby achieving a good bond between the contact layer 2, the air electrode 1, and the connector 3. In other words, the overall structure of this invention, composed of the contact layer 2, the air electrode 1, and the connector 3, has good stability.

[0071] Therefore, compared to the method of coating to prepare contact layer 2, the present invention not only provides contact layer 2 with good stability, but also exhibits good overall structural stability. Thus, the contact layer 2 and overall structure obtained by the present invention possess good high-temperature conductivity while demonstrating better long-term operational stability; the surface resistivity of the overall structure after 20 cooling-heating cycles is ≤50 mΩ·cm. 2 .

[0072] In some possible embodiments provided by this invention, the deposited layer further includes one or more of La, Ce, and Y. That is, the deposited layer includes not only one or more of iron, cobalt, nickel, copper, and manganese, but also one or more of lanthanum, cerium, and yttrium. For example, when the flexible metal framework is metals Fe and Mn, the deposited layer can be Ni, Co, and Y, and the general formula for the formation of the deposited layer and the flexible metal framework is (FeMn). x (NiCoY) 3-x The O4 spinel-type structure has a value of 1 ≤ x ≤ 2. This allows the deposition layer to further include rare earth elements such as lanthanum, cerium, and yttrium. Lanthanum, cerium, and yttrium all possess strong chemical reactivity, which promotes oxidation reactions between the deposition layer and the flexible metal framework, resulting in a more stable spinel-type structure. Furthermore, it increases the bonding strength between the spinel-type structure and the flexible metal framework, enhancing the oxidation resistance of contact layer 2 and thus improving its stability.

[0073] In some possible embodiments provided by this invention, the thickness of the flexible metal skeleton is 50–500 μm. This further ensures good contact between the connector 3 and the air electrode 1, reducing electron conduction resistance. It avoids situations where the thickness is too small, resulting in insufficient mechanical strength of the flexible metal skeleton and a tendency to crack; and where the thickness is too large, causing the resistance of the flexible metal skeleton to increase with thickness.

[0074] In some possible embodiments provided by this invention, the pore size of the flexible metal framework is 40–1800 μm, which can also be understood as 10–300 mesh or 10–300 ppi. This pore size range is beneficial for increasing the three-phase active sites for the reaction between the flexible metal framework, oxygen, and the deposited layer, thereby promoting the oxidation reaction and obtaining a more structurally stable contact layer 2. Simultaneously, since the flexible metal framework serves as a template for the contact layer 2 to have a micro / nano scale, the deposited layer coats the surface of the flexible metal framework and undergoes an in-situ oxidation reaction, thus ensuring that the formed contact layer 2 has suitable porosity, thereby improving the mass transfer capacity of the contact layer 2.

[0075] In some possible embodiments provided by the present invention, the mass of the deposited layer accounts for 1.5 to 14.0 wt% of the total mass of the flexible contact material. That is, the mass of the deposited layer accounts for 1.5 to 14.0 wt% of the sum of the mass of the deposited layer and the mass of the flexible metal skeleton. In this case, the overall structure composed of the contact layer 2, the air electrode 1, and the connector 3 is connected to the surface resistance testing device to form a circuit, and a current is passed through it with a constant current density of 500 mA / cm². 2 After 300 hours of isothermal operation at 850℃ in air atmosphere, and following 20 cooling-heating cycles, the surface resistivity of the air electrode connection structure was tested to be ≤40 mΩ·cm. 2 The cooling-heating process involves cooling from 850℃ to 200℃, then heating from 200℃ to 850℃ and maintaining the temperature at 850℃ for 10 hours. If the mass content of the deposited layer is too low, the spinel-type structure formed by the reaction between the deposited layer and the flexible metal skeleton will be insufficient, resulting in poor conductivity. If the mass content of the deposited layer is too high, it may not be possible to form a complete spinel-type structure with the flexible metal skeleton, and the excess deposited layer oxidation will hinder electron conduction. Preferably, the mass of the deposited layer accounts for 5-10 wt% of the sum of the mass of the deposited layer and the flexible metal skeleton. This mass content further ensures the formation of sufficient spinel-type structures on the surface of the flexible metal skeleton, reduces internal resistance, and improves the conductivity of the contact layer 2; it also avoids excessive deposition, which facilitates air entry and the formation of more three-phase active sites in the deposited layer-flexible metal skeleton-oxygen phase. Thus, the overall structure composed of the contact layer 2, air electrode 1, and connector 3 is connected to the surface resistance testing device to form a circuit, through which current is passed, with a constant current density of 500 mA / cm². 2 After 300 hours of isothermal operation at 850℃ in air atmosphere, and following 20 cooling-heating cycles, the surface resistivity of the air electrode connection structure was tested to be ≤32mΩ·cm. 2 The cooling-heating process involves cooling from 850℃ to 200℃, then heating from 200℃ to 850℃ and running at 850℃ for 10 hours.

[0076] Secondly, embodiments of the present invention also disclose a method for preparing a flexible contact material, used to prepare the flexible contact material in any embodiment of the first aspect, comprising the following steps:

[0077] Electrodeposition: A flexible metal framework is immersed in an electrolyte to perform electrodeposition, thereby obtaining a flexible contact material. In embodiments of this invention, electrodeposition refers to the process of electrochemically depositing a metal or alloy from an aqueous solution, non-aqueous solution, or molten salt of its compound.

[0078] The electrolyte consists of acid salts and water. The acid salts are the acid salts corresponding to the components of the deposited layer, meaning that the deposited layer is dissolved in water in the form of acid salts to form the electrolyte. For example, acid salts formed by manganese and acid radicals, or acid salts formed by cobalt, lanthanum, and acid radicals.

[0079] The above-mentioned scheme, employing electrodeposition to coat the surface of the flexible metal skeleton, facilitates the control of the deposition amount and uniformity, promotes the formation of three-phase active sites, and consequently fosters the formation of a uniform and appropriate amount of spinel-type structure on the flexible metal skeleton surface. It also ensures strong adhesion between the deposition layer and the flexible metal skeleton, improving the overall stability of the flexible contact material. By having the deposition layer exist in the form of an acidic salt, the components of the deposition layer are encouraged to exist in ionic form in the electrolyte, ensuring smooth electrodeposition. This method is simple, requiring only the preparation of the electrolyte, and is easy to operate. It has low equipment requirements, low raw material costs, and high utilization rates, facilitating streamlined operations and mass production. It can also prepare contact layer reserves in advance for large-scale commercial SOFC stack production, demonstrating broad application prospects.

[0080] Acidic salts may include acid radicals, such as sulfate or chloride ions, which are dissolved in water to form an electrolyte in the form of sulfate or chloride salts. Acidic salts formed from sulfate or chloride ions can provide a stable ionic environment during electrodeposition, facilitating the uniform deposition of metal or alloy ions onto the flexible metal framework and ensuring a tight bond between the deposited layer and the flexible metal framework.

[0081] Furthermore, the electrolyte also includes a second acid salt, which has the same anion as the first acid salt, and the cation in the second acid salt is an alkali metal ion. Having the same anion as the first acid salt also avoids the introduction of other impurities. The second acid salt can be, for example, sodium sulfate, sodium chloride, potassium sulfate, or potassium chloride, which increases the conductivity of the electrolyte, thereby accelerating the electrodeposition process. High conductivity also means a more uniform ion distribution, which helps to form a more uniform and dense deposition layer, thus ensuring long-term stable operation.

[0082] Furthermore, the electrolyte also includes additives, which are one of pyrophosphate, citrate, ammonium sulfate or boric acid, and can complex with cations to improve deposition quality.

[0083] Preferably, the electrolyte is an acidic solution with a pH value of 4 to 7. Specifically, this pH value can be adjusted by adding acid to the electrolyte, such as dilute sulfuric acid and dilute hydrochloric acid. This avoids introducing other impurities, and the neutral to slightly acidic electrolyte is conducive to the metal in the deposited layer existing better in the electrolyte in ionic form.

[0084] In some possible embodiments provided by this invention, the preparation method of the flexible contact material involves growing a deposition layer on the surface of a flexible metal skeleton by electrodeposition, including: preparing an electrolyte; selecting a platinum sheet, graphite, glassy carbon, or a soluble metal electrode as the anode; selecting the flexible metal skeleton as the cathode; and using a constant voltage, constant current, pulse voltage, or pulse current charging mode in an electrolytic cell to obtain the flexible contact material; removing the flexible contact material from the electrolytic cell; cleaning; and drying. Specifically, before using the flexible metal skeleton as the cathode, it can be ultrasonically cleaned sequentially with ethanol and acetone for 1–10 minutes to remove contaminants from the surface of the raw material; cleaning is performed by multiple immersions in deionized water, 3–10 times, with each cleaning lasting 1–10 minutes; drying can be done by setting an oven drying temperature of 60–200°C for 1–24 hours.

[0085] Furthermore, in the electrodeposition step, the electrodeposition is pulsed electrodeposition, and the pulse current density of pulsed electrodeposition is 10–100 mA / cm². 2 The pulse frequency ranges from 1 to 100 Hz, the deposition time from 1 to 60 minutes, and the duty cycle from 20% to 80%. The pulse frequency reflects the sum of the pulse on-time and pulse off-time, i.e., the total time. For example, a pulse frequency of 1 to 100 Hz corresponds to a total time of 10 ms to 1000 ms. The duty cycle refers to the proportion of pulse on-time to the total time. Therefore, using pulsed current electrodeposition within the above range allows for the formation of a more uniform deposition layer on the flexible metal skeleton surface. Preferably, the pulse off-time is 10 to 60 ms. If the pulse current density is too low or the pulse off-time is too long, the deposition layer will redissolve into the electrolyte when there is no current at the cathode, resulting in insufficient deposition layer mass. Therefore, by setting the pulse current mode and controlling the pulse off-time within the above range, a uniform deposition layer with appropriate deposition amount can be obtained, further enhancing the long-term operational stability of the flexible contact material and enabling it to withstand the thermal and mechanical stresses during battery operation.

[0086] Thirdly, combining Figure 1 As shown, an embodiment of the present invention discloses an air electrode connection structure 0 for a solid oxide battery, comprising an air electrode 1, a contact layer 2, and a connector 3 arranged sequentially. The contact layer 2 is obtained by an oxidation reaction of a flexible contact material as described in any embodiment of the first aspect. The oxidation reaction is the formation of a deposited layer with a flexible metal skeleton under an oxygen-containing atmosphere and under heating conditions, with the general formula A. x B 3-x The spinel-type structure of O4 (1≤x≤2) is coated on the surface of a flexible metal framework, where A is the composition of the flexible metal framework and B is the composition of the deposited layer, and 1≤x≤2.

[0087] Using the above technical solution, a contact layer 2 can be obtained by directly sandwiching a flexible contact material between the connector 3 and the air electrode 1, and the flexible metal skeleton and the deposited layer undergo an in-situ oxidation reaction. This results in an air electrode connection structure 0. The contact layer 2 can form a tighter and better interface contact with the connector 3 and the air electrode 1, reducing the surface resistance and improving the conductivity of the battery.

[0088] In any of the above embodiments, the area specific resistance (ASR) of the air electrode connection structure 0 remains below 31 mΩ·cm. 2 Even after multiple cooling-heating cycles, the resistance remains below 50 mΩ·cm. 2 Furthermore, the surface resistivity after 20 cooling-heating cycles increases by less than 13%, demonstrating good performance stability. In some embodiments of the present invention, the surface resistivity of the air electrode connection structure 0 decreases after long-term operation, meaning that the conductivity of the air electrode connection structure 0 is further improved after long-term operation. Specifically, the reduction rate of the surface resistivity of the air electrode connection structure 0 after 20 cooling-heating cycles is 10% to 20%. The reduction rate is calculated as (surface resistivity before the start of the cycle - surface resistivity after the end of the cycle) / surface resistivity before the start of the cycle.

[0089] Fourthly, embodiments of the present invention disclose a method for preparing an air electrode connection structure 0, used to prepare an air electrode connection structure 0 as described in any embodiment of the third aspect, comprising the following steps:

[0090] Electrodeposition: A flexible metal framework is immersed in an electrolyte for electrodeposition to obtain a flexible contact material; wherein the electrolyte includes an acid salt and water, and the acid salt is the acid salt corresponding to the composition of the deposited layer. Specifically, the electrolyte and acid salt are the same as in the second aspect above, and will not be repeated.

[0091] Fabrication of the air electrode connection structure 0: After assembling the air electrode 1, flexible contact material, and connector 3, the deposited layer and flexible metal skeleton undergo an oxidation reaction under an oxygen-containing atmosphere and under heating conditions to obtain the contact layer 2, thus obtaining the air electrode connection structure 0. The heating temperature is 800–1000℃. Specifically, the heating state refers to the oxidation temperature required for the deposited layer and flexible metal skeleton to undergo an oxidation reaction, i.e., an oxidation temperature of 800–1000℃.

[0092] Using the above technical solution, flexible contact materials can be prepared by electrodeposition. The flexible contact materials prepared by this method are different from rigid contact materials that are coated with slurry and then sintered. Before use, they retain the flexibility of metallic materials and can be directly sandwiched between connector 3 and air electrode 1. After assembling air electrode 1, flexible contact materials and connector 3, the flexible metal skeleton and the deposited layer undergo an in-situ oxidation reaction to obtain contact layer 2, thus obtaining air electrode connection structure 0. This achieves good bonding with adjacent components while exhibiting good high-temperature conductivity and long-term operational stability. The preparation method is simple and feasible.

[0093] In this embodiment, in the step of preparing the air electrode connection structure 0, the air electrode, flexible contact material, and connector are assembled and then sintered. This causes an oxidation reaction between the deposited layer and the flexible metal skeleton to form the contact layer 2, thus obtaining the air electrode connection structure 0. Specifically, sintering is carried out in an oxygen-containing atmosphere at a temperature of 800–1000°C for 2–50 hours, ensuring the full progress of the oxidation reaction and obtaining an air electrode connection structure 0 with good chemical and mechanical stability.

[0094] Specifically, in the embodiment of the present invention, the preparation process of the air electrode connection structure 0 is specifically achieved by setting it to... Figure 1 The sandwich structure shown consists of a contact layer 2 in the middle, and air electrodes 1 and connectors 3 on both sides. Typically, a current collector with a sintered thin air electrode layer is used as the air electrode 1. The thin air electrode layer and the current collector are common SOFC air electrode materials (such as LSM, LSC, and LSCF). A coated metal connector is used as the connector 3. The coating can be a spinel coating or a perovskite coating. Specifically, the sandwich structure is fixed using a high-temperature resistant clamp and a certain external pressure is applied to ensure tight contact between the layers. Four leads are fixed in pairs to the air electrodes 1 and connectors 3 as current and voltage lines, respectively. Then, sintering is performed in an oxygen atmosphere. The metal skeleton and deposited layer in the flexible contact material undergo an oxidation reaction to form a spinel-type structure, resulting in the air electrode connection structure 0.

[0095] In another embodiment of the present invention, in step 0 of preparing the air electrode connection structure, the air electrode, flexible contact material, and connector are assembled into a solid oxide battery. The solid oxide battery is then started and brought to its operating temperature, causing the deposited layer and flexible metal skeleton to undergo an oxidation reaction to form contact layer 2, thus obtaining the air electrode connection structure. Here, the operating temperature refers to the temperature required for the solid oxide battery to operate normally. For SOEC, it is the operating temperature required for the SOEC to undergo an electrolysis reaction. For SOFC, it is the operating temperature required for the SOFC to convert the chemical energy in the fuel into electrical energy. The operation process of the solid oxide battery includes: starting the solid oxide battery and activating the temperature control device to heat the solid oxide battery to its operating temperature. Specifically, the battery operating temperature will be greater than or equal to the oxidation temperature required for the deposited layer and flexible metal skeleton in the flexible contact material to undergo an oxidation reaction. That is, during the heating process of the solid oxide battery, the conditions required for the oxidation reaction to occur will be reached first, and then, during the process of the solid oxide battery reaching its operating temperature, the deposited layer and flexible metal skeleton will undergo an oxidation reaction to form contact layer 2. More specifically, the oxidation temperature is, for example, 800–1000°C, and the operating temperature is, for example, 800–1000°C.

[0096] Both the method of directly assembling into a solid oxide battery, obtaining an air electrode connection structure through battery preparation, and the method of first sintering to obtain an air electrode connection structure and then assembling into a solid oxide battery, can obtain a contact layer with a high degree of integration between the spinel structure and the flexible metal skeleton. Both can obtain an air electrode connection structure with a tight bond between the contact layer and the air electrode and the connector, and thus can obtain a solid oxide battery with excellent conductivity and long-term operational stability.

[0097] Furthermore, the aforementioned method of directly assembling a solid oxide battery and obtaining the air electrode connection structure by turning on the battery directly utilizes the process of heating the solid oxide battery to its operating temperature to obtain the air electrode connection structure 0 with a spinel-type structure. This method is simple and cost-effective. In addition, the flexible contact material before the oxidation reaction is more flexible than after the oxidation reaction, thus assembling the air electrode, flexible contact material, and connector into the solid oxide battery before the oxidation reaction makes installation easier and more convenient. Simultaneously, this direct assembly method facilitates better bonding between the contact layer 2, the air electrode 1, and the connector 3, thereby further improving the stability and conductivity of the entire air electrode connection structure 0.

[0098] In other embodiments of the present invention, in step 0 of preparing the air electrode connection structure, the flexible contact material, connector, and solid oxide battery are assembled into a battery stack. The battery stack is started and brought to its operating temperature, causing the deposited layer and flexible metal skeleton to undergo an oxidation reaction to form a contact layer, thus obtaining the air electrode connection structure. Here, the operating temperature refers to the temperature required for the solid oxide battery to operate normally. For SOEC, it is the operating temperature required for SOEC to perform the electrolysis reaction. For SOFC, it is the operating temperature required for SOFC to convert the chemical energy in the fuel into electrical energy. This reduces the internal resistance of the battery stack, improves the energy conversion efficiency, and the preparation method is simple, with low production cost and high production efficiency.

[0099] It should be noted that, in the embodiments of the present invention, the test method for the high-temperature conductivity of the air electrode connection structure 0 is specifically as follows:

[0100] Sheet resistance testing: A constant current four-electrode method was used. At 850℃ and in an air atmosphere, the air electrode connection structure 0 was connected to the sheet resistance testing device to form a circuit, and a constant current density of 500 mA / cm² was applied. 2 .

[0101] Isothermal operation: Under a fixed temperature of 850℃ and in an air atmosphere, a constant current density of 500mA / cm² is maintained. 2 It runs continuously for 100 hours.

[0102] Twenty-cycle cooling-heating test: The ambient temperature was cooled from 850℃ to 200℃, then heated from 200℃ to 850℃, and then operated continuously at 850℃ for 10 hours; subsequently, the temperature was cooled again to 200℃, then heated from 200℃ to 850℃, and then operated continuously at 850℃ for 10 hours; this cycle was repeated 20 times. "Operation" refers to the sheet resistance testing device maintaining a constant current density of 500mA / cm². 2 The work status.

[0103] Fifthly, embodiments of the present invention disclose a solid oxide battery, including an air electrode connection structure as described in any embodiment of the third aspect, or including an air electrode connection structure obtained by the preparation method as described in any embodiment of the fourth aspect. Specifically, the solid oxide battery includes a solid oxide fuel cell and a solid oxide electrolyzer.

[0104] By adopting the above technical solution, the conductivity between the air electrode and the connector of the solid oxide battery can be increased, which is beneficial to improving the long-term stable operation and also allows more current to be transmitted under the same voltage, thereby improving the current collection efficiency of the solid oxide battery.

[0105] In a sixth aspect, embodiments of the present invention disclose a battery stack, including a solid oxide battery as described in any embodiment of the fifth aspect. The battery stack is formed by stacking multiple solid oxide batteries.

[0106] By adopting the above technical solution, the conductivity of adjacent solid oxide cells can be increased, thereby enabling the transmission of more current at the same voltage. This improves the current collection efficiency of the battery stack and is beneficial to improving the operating efficiency and long-term stable operation of the battery stack.

[0107] The following will describe a more specific implementation method.

[0108] The air electrode connection structure 0 in Examples 1-6 is prepared by the following steps:

[0109] Preparation of electrolyte: Dissolve the sulfate or chloride salts corresponding to the components of the deposited layer in deionized water at a concentration not exceeding their room temperature solubility. Then add potassium or sodium salts of the same anion (e.g., potassium sulfate, potassium chloride, sodium sulfate, or sodium chloride). Add additives (e.g., pyrophosphate, citrate, ammonium sulfate, or boric acid). Adjust the pH of the solution to 4–7 with dilute hydrochloric acid or dilute sulfuric acid. Stir continuously for 2–24 hours at a speed of 100–500 rpm until the solution is clear and transparent.

[0110] Electrodeposition: The flexible metal skeleton is ultrasonically cleaned with ethanol and acetone in sequence and then used as the cathode. Platinum sheet, graphite, glassy carbon or soluble metal electrode is selected as the anode. The reaction area of ​​the electrode is immersed in the electrolyte in the electrolytic cell, so that the deposition layer elements in the electrolyte are deposited on the flexible metal skeleton to form a deposition layer. After electrodeposition, the flexible contact material is repeatedly soaked and cleaned with deionized water to remove solution residues, and then dried to obtain the flexible contact material.

[0111] Preparation of the air electrode connection structure 0: A flexible contact material is cut to a suitable size and placed between the air electrode 1 and the connector 3. The air electrode 1 has a sintered thin air electrode layer, and the connector 3 is a coated alloy (SUS411) with a spinel coating. The preparation method of the spinel coating is described in Chinese patent document CN112323065A. Platinum or silver wires are attached to the outside of the air electrode 1 and the connector 3 as voltage and current lines, respectively. Pre-tightening pressure is applied by an external clamp to ensure close contact between the parts. The entire pre-tightened clamp, air electrode 1, flexible contact material, and connector 3 are sintered in air at a temperature of 800–1000℃ for 2–50 hours to obtain the air electrode connection structure 0.

[0112] The composition of the flexible contact materials in the embodiments and comparative examples of the present invention is shown in Table 1.

[0113] Table 1

[0114] Flexible metal skeleton mass content sedimentary layer mass content Example 1 Co 99.0 Mn 1.0 Example 2 Cu 98.3 Mn 1.7 Example 3 Cu 93.7 Mn 6.3 Example 4 Cu 91.9 Mn 8.1 Example 5 Cu 87.2 Mn 12.8 Example 6 Cu 85.0 Mn 15.0 Comparative Example Cu 100 / /

[0115] The following will provide more specific preparation and testing methods for examples and comparative examples:

[0116] Example 1

[0117] Preparation of electrolyte: Weigh 6.29 g of manganese chloride and 14.92 g of potassium chloride into a clean beaker, then add 80 mL of deionized water and stir until the solids are completely dissolved. Then add 2.47 g of boric acid and stir until dissolved. Adjust the volume of the solution to 100 mL with deionized water. At this point, the molar concentrations of manganese chloride, potassium chloride and boric acid in the solution are 0.5 M, 2 M and 0.4 M, respectively. Then adjust the pH of the solution to 5 with 1 M dilute hydrochloric acid and stir magnetically for 24 h at 300 rpm to obtain the electrolyte.

[0118] Electrodeposition: Cobalt foam with a pore size of 150 ppi and a thickness of 100 μm was sequentially ultrasonically cleaned with ethanol and acetone for 5 min each, and then air-dried. The cleaned cobalt foam was then fixed with electrode clamps as the cathode, and a 0.5 mm thick manganese sheet was selected as the anode. Electrolyte was poured into the electrolytic cell, and the two electrodes were then immersed face-to-face in the electrolyte, with an immersion area of ​​1.5 cm². 2 The pulsed current mode was adopted, with a saturated calomel electrode selected as the reference electrode. The cathode current was set to 90 mA, the pulse on-time to 40 ms, the pulse off-time to 80 ms, and the pulse current density to 20 mA / cm². 2 The pulse frequency was 8.3 Hz, and the deposition time was 10 min. The electrodeposited cobalt foam was rinsed with deionized water 5 times, 2 min each time, to remove electrolyte residue. Then it was dried in an oven at 80 ℃ for 6 h to obtain the flexible contact material with the composition shown in Table 1.

[0119] Preparation of air electrode connection structure 0: A flexible contact material with a diameter of 10 mm was cut and placed between air electrode 1 and connector 3. Two platinum wires were sintered onto the outer sides of air electrode 1 and connector 3 respectively using platinum paste. The entire test sample was subjected to pre-tightening pressure through an external clamp to ensure that all parts were in contact. The entire pre-tightened clamp and sample were sintered at 1000℃ for 5 hours in an air atmosphere, thereby causing an oxidation reaction between the flexible metal skeleton and the deposited layer to form contact layer 2, thus obtaining air electrode connection structure 0.

[0120] Performance testing: The surface resistance of contact layer 2 was tested using the constant current four-electrode method under the following conditions: 850℃ air atmosphere, constant current density of 500mA / cm². 2 After 100 hours of isothermal operation, the test results are shown in Table 2 and... Figure 2 As shown.

[0121] Example 2

[0122] Preparation of electrolyte: Weigh 16.9g of manganese sulfate monohydrate and 26.15g of potassium sulfate into a clean beaker, then add 80mL of deionized water and stir until the solids are completely dissolved. Then add 5.28g of ammonium sulfate and stir until dissolved. Adjust the volume of the solution to 100mL with deionized water. At this point, the molar concentrations of manganese sulfate, potassium sulfate and ammonium sulfate in the solution are 1M, 1.5M and 0.4M, respectively. Then adjust the pH of the solution to 4 with 1M dilute sulfuric acid. Stir magnetically for 12 hours at 200rpm to obtain the electrolyte.

[0123] Electrodeposition: Copper foam with a pore size of 110 ppi and a thickness of 100 μm was sequentially ultrasonically cleaned with ethanol and acetone for 10 min each, and then air-dried. The cleaned copper foam was then fixed with electrode clamps as the cathode, and a 0.3 mm thick graphite sheet was selected as the anode. Electrolyte was poured into the electrolytic cell, and the two electrodes were then immersed face-to-face in the electrolyte, with an immersion area of ​​1.5 cm². 2 A constant voltage mode was adopted, with a saturated calomel electrode selected as the reference electrode, a cathode voltage set to 1.64V, and a deposition time of 5min. The electrodeposited copper foam was rinsed five times with deionized water for 2min each time to remove electrolyte residue, and then dried in an oven at 100℃ for 1h to obtain the flexible contact material with the composition shown in Table 1.

[0124] Preparation of air electrode connection structure 0: A flexible contact material with a diameter of 10 mm was cut and placed between air electrode 1 and connector 3. Two platinum wires were sintered onto the outer sides of air electrode 1 and connector 3 respectively using platinum paste. The entire test sample was subjected to pre-tightening pressure through an external clamp to ensure that all parts were in contact. The entire pre-tightened clamp and sample were sintered at 900℃ for 10 hours in an air atmosphere, thereby causing an oxidation reaction between the flexible metal skeleton and the deposited layer to form contact layer 2, thus obtaining air electrode connection structure 0.

[0125] Performance testing: The surface resistance of the air electrode connection structure 0 was tested using the constant current four-electrode method under the following conditions: 850℃ air atmosphere, constant current density of 500mA / cm². 2 After 100 hours of isothermal operation, the test results are shown in Table 2 and... Figure 2 As shown.

[0126] like Figures 3-4 As shown, a black manganese deposit layer is uniformly coated on the surface of the copper foam.

[0127] Example 3

[0128] Preparation of electrolyte: Weigh 16.9 g of manganese sulfate monohydrate and 26.15 g of potassium sulfate into a clean beaker, then add 80 mL of deionized water and stir until the solids are completely dissolved. Then add 2.64 g of ammonium sulfate and stir until dissolved. Adjust the volume of the solution to 100 mL with deionized water. At this point, the molar concentrations of manganese sulfate, potassium sulfate and ammonium sulfate in the solution are 1 M, 1.5 M and 0.2 M, respectively. Then adjust the pH of the solution to 4.5 with 1 M dilute sulfuric acid. Stir magnetically for 24 h at 300 rpm to obtain the electrolyte.

[0129] Electrodeposition: A 300-mesh, 90 μm thick oxygen-free copper mesh was sequentially ultrasonically cleaned with ethanol and acetone for 5 min each, and then air-dried. The cleaned copper mesh was then fixed with electrode clamps as the cathode, and a 0.5 mm thick manganese sheet was selected as the anode. Electrolyte was poured into the electrolytic cell, and the two electrodes were then immersed face-to-face in the electrolyte, with an immersion area of ​​1.5 cm². 2 The pulsed current mode was adopted, with a saturated calomel electrode selected as the reference electrode. The cathode current was set to 100mA, the pulse on-time to 36ms, the pulse off-time to 24ms, and the pulse current density to 40mA / cm². 2 The pulse frequency was 16.7 Hz, and the deposition time was 10 min. The electrodeposited copper mesh was rinsed three times with deionized water for 1 min each time to remove electrolyte residue, and then dried in an oven at 60 ℃ for 12 h to obtain the flexible contact material with the composition shown in Table 1.

[0130] Preparation of air electrode connection structure 0: A flexible contact material with a diameter of 10 mm was cut and placed between air electrode 1 and connector 3. Two platinum wires were sintered onto the outer sides of air electrode 1 and connector 3 respectively using platinum paste. The entire test sample was subjected to pre-tightening pressure through an external clamp to ensure that all parts were in contact. The entire pre-tightened clamp and sample were sintered at 950°C for 5 hours in an air atmosphere, thereby causing an oxidation reaction between the flexible metal skeleton and the deposited layer to form contact layer 2, thus obtaining air electrode connection structure 0.

[0131] Performance testing: The surface resistance of the air electrode connection structure 0 was tested using the constant current four-electrode method under the following conditions: 850℃ air atmosphere, constant current density of 500mA / cm². 2 After 100 hours of isothermal operation, the test results are shown in Table 2 and... Figure 2 As shown.

[0132] like Figures 5-6 As shown, after the manganese layer deposited on the copper mesh surface is sintered in an air atmosphere, the resulting octahedral spinel structure is clearly coated on the skeleton surface, improving the conductivity of the contact layer 2.

[0133] Example 4

[0134] Preparation of electrolyte: Weigh 12.58g of manganese chloride and 14.92g of potassium chloride into a clean beaker, then add 80mL of deionized water and stir until the solids are completely dissolved. Then add 2.47g of boric acid and stir until dissolved. Adjust the volume of the solution to 100mL with deionized water. At this point, the molar concentrations of manganese chloride, potassium chloride and boric acid in the solution are 1M, 2M and 0.4M, respectively. Then adjust the pH of the solution to 4.5 with 1M dilute hydrochloric acid. Stir magnetically for 24 hours at 300rpm to obtain the electrolyte.

[0135] Electrodeposition: A 300-mesh, 90 μm thick oxygen-free copper mesh was sequentially ultrasonically cleaned with ethanol and acetone for 5 min each, and then air-dried. The cleaned copper mesh was then fixed with electrode clamps as the cathode, and a 0.5 mm thick manganese sheet was selected as the anode. Electrolyte was poured into the electrolytic cell, and the two electrodes were then immersed face-to-face in the electrolyte, with an immersion area of ​​1.5 cm². 2 The pulsed current mode was adopted, with a saturated calomel electrode selected as the reference electrode. The cathode current was set to 100mA, the pulse on-time to 18ms, the pulse off-time to 12ms, and the pulse current density to 40mA / cm². 2 The pulse frequency was 33.3 Hz, and the deposition time was 15 min. The electrodeposited copper mesh was rinsed three times with deionized water for 1 min each time to remove electrolyte residue, and then dried in an oven at 80 ℃ for 6 h to obtain the flexible contact material with the composition shown in Table 1.

[0136] Preparation of air electrode connection structure 0: A flexible contact material with a diameter of 10 mm was cut and placed between air electrode 1 and connector 3. Two platinum wires were sintered onto the outer sides of air electrode 1 and connector 3 respectively using platinum paste. The entire test sample was subjected to pre-tightening pressure through an external clamp to ensure that all parts were in contact. The entire pre-tightened clamp and sample were sintered at 950°C for 5 hours in an air atmosphere, thereby causing an oxidation reaction between the flexible metal skeleton and the deposited layer to form contact layer 2, thus obtaining air electrode connection structure 0.

[0137] Performance testing: The surface resistance of the air electrode connection structure 0 was tested using the constant current four-electrode method under the following conditions: 850℃ air atmosphere, constant current density of 500mA / cm². 2 The system was run isothermally for 300 hours, then the ambient temperature was lowered from 850℃ to 200℃, then raised back to 850℃, and maintained at 850℃ for 10 hours. This cycle was repeated 20 times, with a total runtime exceeding 700 hours. Test results are shown in Tables 2 and 3. Figure 2 and Figure 7 As shown.

[0138] Example 5

[0139] Preparation of electrolyte: Weigh 12.58g of manganese chloride and 14.92g of potassium chloride into a clean beaker, then add 80mL of deionized water and stir until the solids are completely dissolved. Then add 3.71g of boric acid and stir until dissolved. Adjust the volume of the solution to 100mL with deionized water. At this point, the molar concentrations of manganese chloride, potassium chloride and boric acid in the solution are 1M, 2M and 0.6M, respectively. Then adjust the pH of the solution to 5.5 with 1M dilute hydrochloric acid. Stir magnetically for 24 hours at 500rpm to obtain the electrolyte.

[0140] Electrodeposition: Copper foam with a pore size of 110 ppi and a thickness of 100 μm was sequentially ultrasonically cleaned with ethanol and acetone for 5 min each, and then air-dried. The cleaned copper foam was then fixed with electrode clamps as the cathode, and a 0.1 mm thick platinum sheet was selected as the anode. Electrolyte was poured into the electrolytic cell, and the two electrodes were then immersed face-to-face in the electrolyte, with an immersion area of ​​1.5 cm². 2 The pulsed current mode was adopted, with a saturated calomel electrode selected as the reference electrode. The cathode current was set to 90 mA, with an on cycle of 40 ms and an off cycle of 20 ms, and a current density of 40 mA / cm². 2 The pulse frequency was 16.7 Hz, and the deposition time was 20 min. The electrodeposited copper foam was rinsed with deionized water 5 times, 3 min each time, to remove electrolyte residue. Then it was dried in an oven at 80 ℃ for 24 h to obtain the flexible contact material with the composition shown in Table 1.

[0141] Preparation of air electrode connection structure 0: A flexible contact material with a diameter of 10 mm was cut and placed between air electrode 1 and connector 3. Two platinum wires were sintered onto the outer sides of air electrode 1 and connector 3 respectively using platinum paste. The entire test sample was subjected to pre-tightening pressure through an external clamp to ensure that all parts were in contact. The entire pre-tightened clamp and sample were sintered at 950°C for 10 hours in an air atmosphere, thereby causing an oxidation reaction between the flexible metal skeleton and the deposited layer to form contact layer 2, thus obtaining air electrode connection structure 0.

[0142] Performance testing: The surface resistance of the air electrode connection structure 0 was tested using the constant current four-electrode method under the following conditions: 850℃ air atmosphere, constant current density of 500mA / cm². 2 The system was operated isothermally for 300 hours. Then, the ambient temperature was lowered from 850℃ to 200℃, then raised back to 850℃ and maintained at 850℃ for 10 hours. This process was repeated 20 times, with a total runtime exceeding 700 hours. The test results are shown in Tables 2 and 3. Figure 2 and Figure 7 As shown.

[0143] Example 6

[0144] Preparation of electrolyte: Weigh 12.58g of manganese chloride and 14.92g of potassium chloride into a clean beaker, then add 80mL of deionized water and stir until the solids are completely dissolved. Then add 3.09g of boric acid and stir until dissolved. Adjust the volume of the solution to 100mL with deionized water. At this point, the molar concentrations of manganese chloride, potassium chloride and boric acid in the solution are 1M, 2M and 0.5M, respectively. Then adjust the pH of the solution to 5 with 1M dilute hydrochloric acid and stir magnetically for 12h at 300rpm to obtain the electrolyte.

[0145] Electrodeposition: A 300-mesh, 90 μm thick oxygen-free copper mesh was sequentially ultrasonically cleaned with ethanol and acetone for 5 min each, and then air-dried. The cleaned copper mesh was then fixed with electrode clamps as the cathode, and a 0.5 mm thick manganese sheet was selected as the anode. Electrolyte was poured into the electrolytic cell, and the two electrodes were then immersed face-to-face in the electrolyte, with an immersion area of ​​1.5 cm². 2 A constant current mode was used, with a saturated calomel electrode selected as the reference electrode, and the cathode current set to 75 mA and the current density to 50 mA / cm². 2 The deposition time was 30 min. The electrodeposited copper mesh was rinsed three times with deionized water for 2 min each time to remove electrolyte residue, and then dried in an oven at 80℃ for 12 h to obtain the flexible contact material with the composition shown in Table 1.

[0146] Preparation of air electrode connection structure 0: A flexible contact material with a diameter of 10 mm was cut and placed between air electrode 1 and connector 3. Two platinum wires were sintered onto the outer sides of air electrode 1 and connector 3 respectively using platinum paste. The entire test sample was subjected to pre-tightening pressure through an external clamp to ensure that all parts were in contact. The entire pre-tightened clamp and sample were sintered at 900℃ for 20 hours in an air atmosphere, thereby causing an oxidation reaction between the flexible metal skeleton and the deposited layer to form contact layer 2, thus obtaining air electrode connection structure 0.

[0147] Performance testing: The surface resistance of the air electrode connection structure 0 was tested using the constant current four-electrode method under the following conditions: 850℃ air atmosphere, constant current density of 500mA / cm². 2 After 100 hours of isothermal operation, the test results are shown in Table 2 and... Figure 2 As shown.

[0148] Example 7

[0149] Preparation of electrolyte: Weigh 12.58g of manganese chloride and 14.92g of potassium chloride into a clean beaker, then add 80mL of deionized water and stir until the solids are completely dissolved. Then add 2.47g of boric acid and stir until dissolved. Adjust the volume of the solution to 100mL with deionized water. At this point, the molar concentrations of manganese chloride, potassium chloride and boric acid in the solution are 1M, 2M and 0.4M, respectively. Then adjust the pH of the solution to 4.5 with 1M dilute hydrochloric acid. Stir magnetically for 24 hours at 300rpm to obtain the electrolyte.

[0150] Electrodeposition: A 300-mesh, 90 μm thick oxygen-free copper mesh was sequentially ultrasonically cleaned with ethanol and acetone for 5 min each, and then air-dried. The cleaned copper mesh was then fixed with electrode clamps as the cathode, and a 0.5 mm thick manganese sheet was selected as the anode. Electrolyte was poured into the electrolytic cell, and the two electrodes were then immersed face-to-face in the electrolyte, with an immersion area of ​​20 cm². 2 The pulsed current mode was adopted, with a saturated calomel electrode selected as the reference electrode. The cathode current was set to 500mA, the pulse on-time was 18ms, the pulse off-time was 12ms, and the pulse current density was 15mA / cm². 2 The pulse frequency was 33.3 Hz, and the deposition time was 40 min. The electrodeposited copper mesh was rinsed three times with deionized water for 1 min each time to remove electrolyte residue, and then dried in an oven at 80 ℃ for 6 h to obtain the flexible contact material with the composition shown in Table 1.

[0151] Preparation of air electrode connection structure 0: Cut a flexible contact material with an area of ​​4cm×4cm and place it between the air electrode and the connector of an adjacent electrolyte-supported solid oxide battery. Assemble the battery stack, start the battery stack and bring it to the working temperature of 850℃. As a result, the flexible metal skeleton and the deposited layer undergo an oxidation reaction to generate contact layer 2, thus obtaining air electrode connection structure 0.

[0152] Performance testing: Ohmic resistance and peak power density tests were performed on the battery stack. The test results are as follows: Figure 10 and Figure 11 As shown.

[0153] like Figure 10 As shown, in Example 7, during the battery stack heating process, the deposited layer and the flexible metal skeleton undergo an oxidation reaction in an air atmosphere to generate contact layer 2. The overall ohmic resistance, including the connector, contact layer, and battery, is less than 500 mΩ·cm. 2 ( Figure 10 The intersection of neutralization and Z” = 0). From Figure 11 As shown in the figure, "Current Density" represents current density, "Voltage" refers to voltage, and "Power Density" represents power density. The peak power density can reach 400 mW / cm².2 The overall ohmic resistance and peak power density are at an industry-leading level.

[0154] Comparative Example

[0155] Copper foam with a pore size of 110 ppi and a thickness of 100 μm was ultrasonically cleaned with ethanol and acetone for 10 min each, and then air-dried. A 10 mm diameter piece of copper foam was cut and placed between air electrode 1 and connector 3. Two platinum wires were sintered onto the outer sides of air electrode 1 and connector 3 respectively using platinum paste. The entire test sample was subjected to pre-tightening pressure through an external clamp to ensure contact between all parts. The entire pre-tightened clamp and sample were sintered at 900 °C for 2 h in an oxygen atmosphere to obtain a comparative example.

[0156] Performance testing: The surface resistance of the comparative sample was tested using the constant current four-electrode method under the following conditions: 850℃ air atmosphere, constant current density of 500mA / cm². 2 After 100 hours of isothermal operation, the test results are shown in Table 2 and... Figure 2 As shown.

[0157] Table 2. ASR changes in the examples and comparative examples over 100 hours.

[0158] 0h 100h rate of change Example 1 30.2 27.2 -9.9％ Example 2 27.1 25.2 -7.0％ Example 3 24.1 23.5 -2.5％ Example 4 23.2 22.6 -2.6％ Example 5 23.4 24.3 3.8％ Example 6 26.2 30.1 14.9％ Comparative Example 41.9 45.4 8.4％

[0159] Table 3. ASR changes in Examples 4 and 5

[0160] 0h 300h Loop start Loop ends Example 4 23.2 21.0 23.3 19.4 Example 5 23.4 26.5 28.8 32.4

[0161] From Table 2, Table 3, Figure 2 , Figure 7 and Figure 8 The following can be known:

[0162] The comparative example's ASR increased from 41.9 mΩ·cm over 100 h. 2 Increased to 45.4 mΩ·cm 2 This indicates that the conductivity of pure copper metal is not particularly good in a high-temperature oxidizing atmosphere, and it may continue to degrade over a longer period of time. The embodiments of this invention have a lower sheet resistivity compared to the comparative examples.

[0163] Example 1: ASR decreased from 30.2 mΩ·cm over 100 h. 2 Reduced to 27.2 mΩ·cm 2 As shown in Table 1, compared to other embodiments, the manganese deposited on the surface of cobalt foam in Example 1 has a smaller mass, with a relative mass ratio of manganese to cobalt of 1%.

[0164] Example 2: ASR increased from 27.1 mΩ·cm over 100 h. 2 It slowly decreased to 25.2 mΩ·cm2 In Example 2, the conductivity of the contact layer obtained by sintering the flexible contact material of foamed copper with deposited manganese under a high-temperature oxidizing atmosphere was significantly better than that of the contact layer obtained by oxidizing pure copper material.

[0165] Example 3: ASR increased from 24.1 mΩ·cm over 100 h. 2 It slowly decreased to 23.5 mΩ·cm 2 Combining Figure 5 and Figure 6 As shown, Example 3 uses pulse electrodeposition, and Example 3 further satisfies the pulse off time of 10-60ms, so that the manganese deposition layer deposited on the copper mesh surface is uniform and dense, and the contact layer 2 after sintering has a complete structure, and the reaction of copper and manganese to form an octahedral spinel structure can be observed on the surface.

[0166] Example 4: ASR decreased from 23.2 mΩ·cm over 100 h. 2 It slowly decreased to 22.6 mΩ·cm 2 Combining Figure 7 As shown, the long-term ASR curve indicates that each thermal cycle has a certain impact on the surface resistance, but by stabilizing at 850°C for 10 hours, the overall resistance level can be reduced. Over an operating time exceeding 700 hours, the ASR of Example 4 decreased from the initial 23.2 mΩ·cm. 2 Reduced to 19.4 mΩ·cm 2 That is, in Example 4, the surface resistivity after 20 cooling-heating cycles over a 700-hour operating time is ≤20 mΩ·cm. 2 This is the preferred embodiment of this patent. The tested sample is then photographed with an X-ray diffraction (XRD) pattern, such as... Figure 8 As shown in the figure, "Intensity" represents intensity, and "2-Theta" refers to the 2θ diffraction angle, which is the angle between the extension of the incident X-ray and the reflected X-ray. The copper portion of the flexible metal framework in the inner layer is oxidized to copper oxide, while the manganese in the outer deposited layer reacts completely with the copper in the flexible metal framework to form a copper-manganese spinel phase with higher conductivity.

[0167] Example 5: ASR increased from 23.4 mΩ·cm over 100 h. 2 It increased slightly to 24.3 mΩ·cm 2 As shown in Table 1, the manganese deposited on the surface of the copper foam has a relatively high mass, with a relative mass ratio of manganese to copper exceeding 10%. (Combined) Figure 7 As shown, over an operating time exceeding 700 hours, the ASR of Example 5 decreased from the initial 23.4 mΩ·cm. 2 Increased to 32.4 mΩ·cm 2That is, in Example 5, the surface resistivity after 20 cooling-heating cycles over a 700-hour operating time is ≤40 mΩ·cm. 2 It still meets the requirements for use as a contact layer between the air electrode and the connector.

[0168] Example 6: ASR decreased from 26.2 mΩ·cm over 100 h. 2 Increased to 30.1 mΩ·cm 2 (like Figure 2 As shown in Table 1, the manganese deposited on the copper mesh surface has a relatively large mass, with a relative mass ratio of manganese to copper reaching 15%. Figure 9 As shown, the XRD results indicate that the manganese in the outer deposit layer not only reacts with the copper in the flexible metal framework to form a copper-manganese spinel phase, but also that the excess manganese generates manganese oxide with higher electrical resistance. This suggests that a high mass fraction of the deposit layer is not conducive to the complete reaction and formation of the spinel phase.

[0169] Furthermore, since Examples 3 and 4 further satisfy the requirement that the mass of the deposited layer accounts for 5-10 wt% of the sum of the mass of the deposited layer and the mass of the flexible metal skeleton, they exhibit lower sheet resistivity. As can be seen from the above, in Example 4 of the present invention, the ASR decreases within 100 hours of isothermal operation at 850°C, and after 300 hours of isothermal operation at 850°C, and further undergoing 20 cooling-heating cycles, the sheet resistivity is ≤20 mΩ·cm. 2 That is, over a total operating time of more than 700 hours, the sheet resistance decreased by more than 15% compared to the sheet resistance at 0 hours. In other words, compared to 0 hours, the conductivity of Example 4 was further improved after operating for more than 700 hours.

[0170] In summary, the flexible contact material of this invention possesses excellent electrical conductivity, good chemical stability, resistance to high-temperature oxidizing atmospheres, good chemical compatibility with adjacent materials, suitable contact area with the connector and air electrode, and low contact resistance. Furthermore, the flexible contact material's coefficient of thermal expansion matches that of adjacent materials, exhibits a certain degree of flexibility, can adjust for minute strains, is inexpensive, and uses readily available raw materials. In particular, the preparation process of the flexible contact material of this invention is also simple. Moreover, the contact layer 2 and the overall structure obtained by this invention possess both good high-temperature electrical conductivity and better long-term operational stability.

[0171] While the present invention has been illustrated and described with reference to certain preferred embodiments, those skilled in the art should understand that the above description is a further detailed explanation of the invention in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of the invention to these descriptions. Various changes in form and detail can be made by those skilled in the art, including several simple deductions or substitutions, without departing from the spirit and scope of the invention.

Claims

1. A flexible contact material for use between the air electrode and the connector in a solid oxide battery, characterized in that, Includes a flexible metal framework and a deposited layer, wherein, The flexible metal framework is selected from one or more of Fe, Co, Ni, Cu, and Mn. The deposited layer covers the surface of the flexible metal framework and includes one or more of Fe, Co, Ni, Cu, and Mn. The composition of the flexible metal framework and the composition of the deposited layer are not exactly the same. The deposited layer in the flexible contact material can undergo an oxidation reaction with the flexible metal framework under an oxygen-containing atmosphere and under heating conditions to generate a product with the general formula A. x B 3-x The spinel-type structure of O4 (1≤x≤2) is coated on the surface of the flexible metal skeleton, wherein A is the composition of the flexible metal skeleton, B is the composition of the deposited layer, and 1≤x≤2.

2. The flexible contact material as described in claim 1, characterized in that, The deposited layer also includes one or more of La, Ce and Y.

3. The flexible contact material as described in claim 1, characterized in that, The thickness of the flexible metal skeleton is 50–500 μm.

4. The flexible contact material as described in claim 3, characterized in that, The pore size of the flexible metal skeleton is 40–1800 μm.

5. The flexible contact material as described in claim 1, characterized in that, The mass of the deposited layer accounts for 5 to 10 wt% of the total mass of the flexible contact material.

6. A method for preparing a flexible contact material, characterized in that, The method for preparing the flexible contact material as described in any one of claims 1 to 5 comprises the following steps: Electrodeposition: The flexible metal skeleton is immersed in an electrolyte to perform electrodeposition, thereby obtaining the flexible contact material; The electrolyte comprises an acid salt and water, wherein the acid salt is the acid salt corresponding to the composition of the deposited layer.

7. The method for preparing the flexible contact material as described in claim 6, characterized in that, The acid salt includes an acid radical ion, which is a sulfate ion or a chloride ion.

8. The method for preparing the flexible contact material as described in claim 7, characterized in that, The electrolyte also includes a second acid salt, which has the same anion as the acid salt, and the cation in the second acid salt is an alkali metal ion.

9. The method for preparing the flexible contact material as described in claim 6, characterized in that, The electrolyte also includes additives, which are one of pyrophosphate, citrate, ammonium sulfate or boric acid.

10. The method for preparing the flexible contact material as described in claim 6, characterized in that, The electrolyte has a pH value of 4 to 7.

11. The method for preparing the flexible contact material as described in claim 6, characterized in that, In the electrodeposition step, the electrodeposition is pulsed electrodeposition, and the pulse current density of the pulsed electrodeposition is 10–100 mA / cm². 2 The pulse frequency is 1–100 Hz, the deposition time is 1–60 min, and the working cycle is 20–80%.

12. An air electrode connection structure for a solid oxide battery, characterized in that, It includes an air electrode, a contact layer, and a connector arranged sequentially. The contact layer is obtained by an oxidation reaction of the flexible contact material as described in any one of claims 1 to 5. The oxidation reaction is performed by the deposited layer reacting with the flexible metal skeleton in an oxygen-containing atmosphere and under heating conditions to form a general formula A. x B 3-x The spinel-type structure of O4 (1≤x≤2) is coated on the surface of the flexible metal skeleton, wherein A is the composition of the flexible metal skeleton, B is the composition of the deposited layer, and 1≤x≤2.

13. The air electrode connection structure as described in claim 12, characterized in that, The air electrode connection structure is connected to the surface resistance testing device to form a circuit, and a current is passed through it at a constant current density of 500 mA / cm². 2 After 300 hours of isothermal operation at 850℃ in air atmosphere, and following 20 cooling-heating cycles, the surface resistivity of the air electrode connection structure was tested to be ≤50 mΩ·cm. 2 The cooling-heating process involves cooling from 850°C to 200°C, then heating from 200°C to 850°C and running at 850°C for 10 hours.

14. A method for preparing an air electrode connection structure, characterized in that, The method for preparing the air electrode connection structure as described in claim 12 comprises the following steps: Electrodeposition: The flexible metal skeleton is immersed in an electrolyte to perform electrodeposition, thereby obtaining the flexible contact material; Preparation of the air electrode connection structure: After assembling the air electrode, the flexible contact material and the connector, the deposited layer and the flexible metal skeleton undergo an oxidation reaction under an oxygen-containing atmosphere and under heating to obtain the contact layer, thus obtaining the air electrode connection structure; The electrolyte comprises an acid salt and water, wherein the acid salt is the acid salt corresponding to the composition of the deposited layer.

15. The method for preparing the air electrode connection structure as described in claim 14, characterized in that, The heating temperature in the heating state is 800-1000℃.

16. The method for preparing the air electrode connection structure as described in claim 14, characterized in that, In the step of preparing the air electrode connection structure, the air electrode, the flexible contact material and the connector are assembled and then sintered, so that the deposited layer and the flexible metal skeleton undergo an oxidation reaction to generate the contact layer, thereby obtaining the air electrode connection structure.

17. The method for preparing the air electrode connection structure as described in claim 14, characterized in that, In the step of preparing the air electrode connection structure, the air electrode, the flexible contact material, and the connector are assembled into a solid oxide battery. The solid oxide battery is then started and brought to its operating temperature, causing the deposited layer and the flexible metal skeleton to undergo an oxidation reaction to generate the contact layer, thereby obtaining the air electrode connection structure.

18. A solid oxide battery, characterized in that, It includes the air electrode connection structure as described in any one of claims 12-13, or the air electrode connection structure obtained by any one of the preparation methods as described in claims 14 to 17.

19. A battery stack, characterized in that, Including the solid oxide battery as described in claim 18.

Images