A full-solid high-temperature iron-air battery cell pair sharing a negative current collector and a preparation method thereof

Abstract

The application relates to a full-solid high-temperature iron-air battery cell pair sharing a negative electrode current collector and a preparation method thereof, which comprises a first battery cell containing a first electrolyte sheet and first positive electrode layers and first negative electrode active material layers arranged on opposite sides of the first electrolyte sheet; a second battery cell containing a second electrolyte sheet and second positive electrode layers and second negative electrode active material layers arranged on opposite sides of the second electrolyte sheet; a shared negative electrode current collector layer arranged between the two negative electrode active material layers and electrically connected; and a ceramic glaze sealing structure surrounding the periphery of the three to isolate air. The application precisely solves the problems of high cost, complex sealing and difficult stacking of the existing battery negative electrode current collector, greatly reduces the use amount of noble metals to reduce the cost, reduces the sealing area to improve the reliability, realizes the modularization of the unit pair and the easy stacking and integration, and completely retains the electrochemical performance, so that the low-cost, easy-to-seal and high-performance target is achieved.

Description

Technical Field

[0001] This invention relates to the field of electrochemical energy storage technology, and more specifically to an all-solid-state high-temperature iron-air battery cell pair with a shared negative electrode current collector and its preparation method. Background Technology

[0002] All-solid-state high-temperature iron-air batteries are widely recognized as one of the most promising large-scale energy storage technologies due to their significant advantages, including a wide availability of raw materials, high theoretical energy density, environmental friendliness, and no risk of electrolyte leakage. Under current technology, a typical single-cell structure of an all-solid-state high-temperature iron-air battery consists of a positive electrode, a solid electrolyte layer, a negative electrode active material layer, and a negative electrode current collector. These components work together to achieve the storage and release of electrical energy.

[0003] However, existing all-solid-state high-temperature iron-air batteries still face two major technical bottlenecks that urgently need to be addressed in the process of actual industrialization and large-scale application, which seriously restrict their cost control and performance stability: Firstly, the cost of negative electrode current collector materials is high. Since the operating temperature of all-solid-state high-temperature iron-air batteries typically reaches 600℃ to 900℃, and an oxidizing atmosphere exists in the negative electrode region, the negative electrode current collector must simultaneously meet the requirements of high-temperature stability, excellent electronic conductivity, and resistance to high-temperature oxidation. Currently, the industry commonly uses precious metals (such as silver and gold) as the core material for negative electrode current collectors. While these precious metals can meet the performance requirements under the aforementioned high-temperature conditions, the materials themselves are expensive, resulting in high manufacturing costs for a single cell. Especially when constructing large-capacity battery stacks, if each single cell is equipped with an independent negative electrode current collector, the total amount of precious metals used will increase linearly, further driving up the overall cost of the battery stack and greatly limiting the commercialization of this technology.

[0004] Secondly, the negative electrode sealing process is complex and has low reliability. The negative electrode active material (such as metallic iron) is highly susceptible to oxidation by oxygen in the air at high temperatures, leading to the failure of active components and significantly reducing battery capacity and cycle life. Therefore, current technologies require strict sealing of the negative electrode area to prevent contact between air and the negative electrode active material. The current mainstream sealing method involves coating the negative electrode area with ceramic glaze slurry and forming a dense ceramic glaze sealing layer through high-temperature sintering. However, this process has significant drawbacks: firstly, the sintering quality of the ceramic glaze greatly affects the sealing effect; cracking and porosity in the sealing layer are prone to occur during high-temperature sintering, leading to sealing failure; secondly, as the area of ​​a single cell increases, the coverage area of ​​the ceramic glaze seal increases accordingly, significantly increasing the operational difficulty of the sealing process. Simultaneously, the risk of sealing layer failure increases exponentially, which not only increases the difficulty of process control during production but also leads to premature battery failure due to sealing failure, reducing the long-term reliability of the battery system.

[0005] Furthermore, the two major technological bottlenecks mentioned above will be amplified when constructing all-solid-state high-temperature iron-air battery stacks (the core form for achieving large-scale energy storage). In existing technologies, battery stacks are mostly constructed using a "simple stacking of single cells": each single cell is independently configured with a negative electrode current collector, and the negative electrode area of ​​each single cell is completely edge-sealed before multiple single cells are stacked sequentially and electrically connected to form a battery stack. This stacking method directly leads to: ① the total amount of precious metal current collectors increases proportionally with the number of single cells, further exacerbating cost pressures; ② each single cell needs to independently complete a complex negative electrode sealing process, which not only makes the battery stack manufacturing process lengthy and inefficient, but also significantly reduces the overall sealing reliability of the battery stack due to the substantial increase in the number of sealing points; ③ independent current collectors and sealing structures increase the gap between single cells, resulting in low overall volume utilization of the battery stack, which is not conducive to the design of compact energy storage systems. Summary of the Invention

[0006] To address the problems of high cost of negative electrode current collector, complex and unreliable negative electrode sealing process, and poor stacking efficiency and volume utilization of battery stacks in the existing technologies, this invention aims to provide a pair of all-solid-state high-temperature iron-air battery cells with shared negative electrode current collector and its preparation method.

[0007] According to the present invention, a pair of all-solid-state high-temperature iron-air battery cells with a shared negative electrode current collector includes: a first battery cell including a first electrolyte sheet and a first positive electrode layer and a first negative electrode active material layer disposed on opposite sides of the first electrolyte sheet; a second battery cell including a second electrolyte sheet and a second positive electrode layer and a second negative electrode active material layer disposed on opposite sides of the second electrolyte sheet; a shared negative electrode current collector layer sandwiched between the first negative electrode active material layer and the second negative electrode active material layer, and electrically connected to both the first negative electrode active material layer and the second negative electrode active material layer; and a ceramic glaze sealing structure surrounding the shared negative electrode current collector layer, the first negative electrode active material layer and the second negative electrode active material layer, encapsulating the shared negative electrode current collector layer, the first negative electrode active material layer and the second negative electrode active material layer into one unit to isolate them from air.

[0008] In a preferred embodiment, both the first electrolyte sheet and the second electrolyte sheet are made of yttrium-stabilized zirconium oxide.

[0009] In a preferred embodiment, both the first negative electrode active material layer and the second negative electrode active material layer include Fe2O3 and oxygen ion conductor additives.

[0010] In a preferred embodiment, the material of the shared negative electrode current collector layer is conductive silver paste or silver-palladium alloy paste.

[0011] In a preferred embodiment, both the first positive electrode layer and the second positive electrode layer are porous silver layers; the first battery unit further includes a first positive electrode lead connected to the first positive electrode layer, and the second battery unit further includes a second positive electrode lead connected to the second positive electrode layer, wherein both the first positive electrode lead and the second positive electrode lead are silver wires.

[0012] In a preferred embodiment, the operating temperature of the all-solid-state high-temperature iron-air battery cell pair is 600°C to 900°C.

[0013] According to the present invention, the battery stack is composed of multiple all-solid-state high-temperature iron-air battery cells connected in series, in parallel, or in a series-parallel combination.

[0014] According to the above-described method for preparing an all-solid-state high-temperature iron-air battery cell pair, the method includes the following steps: S1, providing a first electrolyte sheet and a second electrolyte sheet; S2, preparing a first negative electrode active material layer on one side of the first electrolyte sheet and a second negative electrode active material layer on one side of the second electrolyte sheet; S3, disposing a shared negative electrode current collector layer between the first negative electrode active material layer and the second negative electrode active material layer, such that the first negative electrode active material layer, the shared negative electrode current collector layer, and the second negative electrode active material layer are in close contact to form a sandwich structure intermediate; S4, filling and surrounding the peripheral area of ​​the sandwich structure intermediate with ceramic glaze slurry, and then performing glaze firing to form a ceramic glaze sealing structure; S5, preparing a first positive electrode layer on the other side of the first electrolyte sheet and a second positive electrode layer on the other side of the second electrolyte sheet.

[0015] In a preferred embodiment, in step S3, the shared negative electrode current collector layer is formed by coating or printing conductive silver paste or silver-palladium alloy paste onto the first negative electrode active material layer or the second negative electrode active material layer, and then pressing the first negative electrode active material layer and the second negative electrode active material layer together.

[0016] In a preferred embodiment, in step S4, the temperature of the glazing treatment is 850°C to 950°C.

[0017] This invention addresses the technical challenges of high negative electrode current collector cost, complex sealing processes, and difficult stacking in existing all-solid-state high-temperature iron-air batteries by having two battery cells share a single negative electrode current collector layer and encapsulating the shared negative electrode current collector layer and two negative electrode active material layers using a ceramic glaze sealing structure. The shared negative electrode current collector layer significantly reduces the amount of precious metal materials used, thus substantially lowering the battery's material cost. The ceramic glaze sealing structure integrates the two negative electrode areas, which previously required separate large-area sealing, into a single ring seal, significantly reducing the sealing area and perimeter, lowering the sealing process difficulty while improving sealing reliability and yield. Furthermore, the battery cell formed by this design has a compact modular structure with higher volumetric energy density and area utilization, making it easier to integrate into subsequent battery stacks and further simplifying the stacking structure. In achieving these advantages, the electrochemical performance of each battery cell is fully preserved, ultimately achieving the design goals of a low-cost, easily sealed, efficiently stackable, and stable all-solid-state high-temperature iron-air battery cell. Attached Figure Description

[0018] Figure 1 This is a schematic cross-sectional view of a pair of all-solid-state high-temperature iron-air battery cells with a shared negative electrode current collector according to the present invention.

[0019] Figure 2 This is a charge-discharge curve of the battery cell prepared in Example 1 at 800°C.

[0020] Figure 3 This is a charge-discharge curve of the battery cell prepared in Example 2 at 750°C.

[0021] Figure 4 This is a charge-discharge curve of the battery cell prepared in Example 3 at 850°C. Detailed Implementation

[0022] The following detailed description, in conjunction with the accompanying drawings, provides a specific embodiment of the all-solid-state high-temperature iron-air battery cell pair with shared negative electrode current collector, its battery stack, and its preparation method according to the present invention.

[0023] like Figure 1 As shown, the all-solid-state high-temperature iron-air battery cell pair with shared negative electrode current collector according to the present invention includes a first battery cell (first positive electrode lead 101, first positive electrode layer 102, first electrolyte sheet 103 and first negative electrode active material layer 104), a second battery cell (second positive electrode lead 109, second positive electrode layer 108, second electrolyte sheet 107, second negative electrode active material layer 106), a shared negative electrode current collector layer 105 sandwiched between the first negative electrode active material layer 104 and the second negative electrode active material layer 106, and a ceramic glaze sealing structure 110 surrounding the above three components.

[0024] In this configuration, the first positive electrode layer 102 and the second positive electrode layer 108 serve as air electrodes, responsible for catalyzing the reduction reaction of oxygen in the air under high-temperature conditions. The first positive electrode lead 101 is connected to the first positive electrode layer 102 to conduct current from the first battery cell, and the second positive electrode lead 109 is connected to the second positive electrode layer 108 to conduct current from the second battery cell. In a preferred embodiment, the first positive electrode layer 102 and the second positive electrode layer 108 are porous silver layers, and the first positive electrode lead 101 and the second positive electrode lead 109 are silver wires.

[0025] The first electrolyte sheet 103 and the second electrolyte sheet 107 respectively perform the function of oxygen ion conduction and isolate the positive and negative electrode reactants, forming the core isolation and conduction components to ensure the electrochemical performance of the battery. In a preferred embodiment, the first electrolyte sheet 103 and the second electrolyte sheet 107 are made of yttrium-stabilized zirconium oxide (YSZ). In another preferred embodiment, the first electrolyte sheet 103 and the second electrolyte sheet 107 are made of 8 mol% yttrium oxide (Y2O3)-doped zirconium oxide (ZrO2), abbreviated as 8YSZ. 8YSZ is preferred because it has the highest oxygen ion conductivity at 600-900℃; other concentrations of yttrium-stabilized zirconium oxide (such as 3YSZ, 10YSZ) can also be used, but their performance will differ slightly.

[0026] In this embodiment, the first negative electrode active material layer 104 and the second negative electrode active material layer 106 respectively achieve charge storage through the redox reaction of iron. In a preferred embodiment, the materials of the first negative electrode active material layer 104 and the second negative electrode active material layer 106 respectively include Fe2O3 and oxygen ion conductor additive. In a preferred embodiment, the mass ratio of Fe2O3 to oxygen ion conductor additive is (6-8):(2-4). In a preferred embodiment, the mass ratio of Fe2O3 to oxygen ion conductor additive is 7:3. In a preferred embodiment, the oxygen ion conductor additive is 8YSZ and GDC (Ce 0.8 Gd 0.2 O 1.9 At least one of gadolinium-doped cerium dioxide.

[0027] The shared negative electrode current collector layer 105, serving as a key channel for electron conduction, is electrically connected between the first negative electrode active material layer 104 and the second negative electrode active material layer 106. This ensures the efficient discharge of electrons generated by the first and second negative electrode active material layers 104 and 106, enabling the battery to discharge externally. In a preferred embodiment, the shared negative electrode current collector layer 105 is made of conductive silver paste or silver-palladium alloy paste. After coating, it undergoes a glazing treatment at 900°C along with the two negative electrode active material layers. The organic carrier in the silver paste is removed, and the silver particles are sintered to form a porous conductive network, forming good mechanical interlocking and electronic contact with the oxygen ion conductor particles in the negative electrode active material layer.

[0028] The ceramic glaze sealing structure 110 acts like a frame, enclosing and sealing the active core composed of the first negative electrode active material layer 104, the shared negative electrode current collector layer 105, and the second negative electrode active material layer 106, thus completely isolating it from the air.

[0029] The method for preparing a pair of all-solid-state high-temperature iron-air battery cells with a shared negative electrode current collector according to the present invention first includes step S1, providing a first electrolyte sheet and a second electrolyte sheet.

[0030] The method for preparing the all-solid-state high-temperature iron-air battery cell pair with shared negative electrode current collector of the present invention includes step S2, in which a first negative electrode active material layer is prepared on one side of the first electrolyte sheet and a second negative electrode active material layer is prepared on one side of the second electrolyte sheet.

[0031] The method for preparing an all-solid-state high-temperature iron-air battery cell pair with a shared negative electrode current collector according to the present invention includes step S3, which involves providing a shared negative electrode current collector layer and bonding it with a first negative electrode active material layer and a second negative electrode active material layer, so that the three layers are in close contact to form a sandwich structure intermediate. In a preferred embodiment, the shared negative electrode current collector layer is a coated or printed conductive silver paste layer. In a preferred embodiment, the shared negative electrode current collector layer is formed by coating the first negative electrode active material layer or the second negative electrode active material layer with conductive silver paste and then bonding the two layers together by pressure bonding.

[0032] The method for preparing a pair of all-solid-state high-temperature iron-air battery cells with a shared negative electrode current collector according to the present invention includes step S4, which involves filling and surrounding the outer region of the sandwich structure intermediate with a ceramic glaze slurry, followed by glazing to form the ceramic glaze sealing structure. In a preferred embodiment, the glazing temperature is between 850°C and 950°C. Generally, a ceramic glaze with a coefficient of thermal expansion close to that of the YSZ electrolyte is selected to avoid cracking during cooling.

[0033] The method for preparing a pair of all-solid-state high-temperature iron-air battery cells with a shared negative electrode current collector according to the present invention finally includes step S5, which involves preparing a first positive electrode layer and a first positive electrode lead on the other side of the first electrolyte sheet, and preparing a second positive electrode layer and a second positive electrode lead on the other side of the second electrolyte sheet.

[0034] The all-solid-state high-temperature iron-air battery cell pair obtained by the above preparation method of the present invention preferably operates at a temperature of 600°C to 900°C. In a preferred embodiment, the operating temperature is 750°C to 850°C.

[0035] The all-solid-state high-temperature iron-air battery cell pairs obtained according to the present invention can be used to construct battery stacks through series, parallel, or a combination of series and parallel connections to meet the voltage and capacity requirements of different energy storage scenarios. The core purpose of series connection is to increase the total voltage of the battery stack (the voltage of a single cell pair is added together), and the core purpose of parallel connection is to increase the total capacity of the battery stack (the capacity of a single cell pair is added together). Combining the two can simultaneously achieve high voltage and high capacity.

[0036] Example 1 Two 8YSZ electrolyte sheets with a diameter of 20mm are provided, namely the first electrolyte sheet 103 and the second electrolyte sheet 107.

[0037] Fe2O3 powder and 8YSZ powder are mixed at a mass ratio of 7:3, and an organic binder (e.g., polyvinyl alcohol) and a solvent (e.g., water) are added to form a negative electrode slurry. The negative electrode slurry is sprayed onto one side of the first electrolyte sheet 103 and the second electrolyte sheet 107 using a spraying process. The two electrolyte sheets after spraying are placed in a muffle furnace and pre-sintered at 800°C for 1 hour to allow the negative electrode active material layer to initially solidify and tightly bond with the electrolyte sheet. The organic binder is then removed to form a first negative electrode active material layer 104 with a diameter of about 15 mm and a thickness of about 30 μm, and a second negative electrode active material layer 106.

[0038] Take a first electrolyte sheet 103 with a first negative electrode active material layer 104, and uniformly coat a layer of conductive silver paste on the surface of the first negative electrode active material layer 104 (the side away from the first electrolyte sheet 103). This silver paste layer is the shared negative electrode current collector layer 105. Flip the second electrolyte sheet 107 with a second negative electrode active material layer 106 so that the second negative electrode active material layer 106 faces the shared negative electrode current collector layer 105. After alignment, gently press them together to ensure that the first negative electrode active material layer 104, the shared negative electrode current collector layer 105, and the second negative electrode active material layer 106 are in close contact, forming a sandwich structure intermediate of "negative electrode layer-current collector-negative electrode layer".

[0039] The ceramic glaze slurry is carefully filled into the outer area of ​​the sandwich structure intermediate to form a closed glaze ring around the intermediate, ensuring that the glaze completely covers the edge gaps of the intermediate to prevent air from seeping in during subsequent use. The glaze-coated intermediate is first dried at 60°C to remove the solvent from the glaze; then, the temperature is increased to 900°C at a rate of 3°C / min and held for 1 hour for glaze firing, which melts and densifies the ceramic glaze, ultimately forming the ceramic glaze sealing structure 110.

[0040] On the other side of the sealed first electrolyte sheet 103 (the side away from the first negative electrode active material layer 104), a porous silver paste is coated and sintered to form a first positive electrode layer 102; a first positive electrode lead 101 is then connected to the surface of the first positive electrode layer 102. Similarly, on the other side of the second electrolyte sheet 107 (the side away from the second negative electrode active material layer 106), a porous silver paste is coated and sintered to form a second positive electrode layer 108, and then a second positive electrode lead 109 is connected. This completes the fabrication of the all-solid-state high-temperature iron-air battery cell pair with a shared negative electrode current collector as described in this embodiment.

[0041] The prepared battery cells were placed in a high-temperature furnace, and the furnace temperature was controlled at 800℃. A battery tester was used to perform charge-discharge tests on both battery cells. The test results are as follows: Figure 2 As shown, the battery cell exhibits a clear charge-discharge plateau at 800°C with no abnormal fluctuations in charging voltage. Its electrochemical performance is comparable to that of a traditional independent all-solid-state high-temperature iron-air battery, demonstrating that the shared current collector design of this invention does not adversely affect the core performance of the battery, while simultaneously reducing the amount of precious metals used and simplifying the sealing process.

[0042] Example 2 Fe2O3 powder and 8YSZ powder were mixed at a mass ratio of 7:3. A binder (e.g., polymethyl methacrylate PMMA), a plasticizer (e.g., dibutyl phthalate), and a solvent (e.g., ethanol) were added to prepare a negative electrode slurry. The slurry was then cast into a negative electrode green body with a thickness of approximately 100 μm using a casting machine, and then punched into a circular green body. Two 8YSZ electrolyte green bodies were provided, and the above-mentioned negative electrode green bodies were respectively bonded to one side of the two YSZ electrolyte green bodies to form a composite green body of YSZ green body-negative electrode green body. The composite green body was co-sintered at 1400℃ for 3 hours to simultaneously densify and tightly bond the YSZ electrolyte and the negative electrode layer, resulting in a first electrolyte sheet 103 with a first negative electrode active material layer 104 and a second electrolyte sheet 107 with a second negative electrode active material layer 106.

[0043] A layer of conductive silver paste (sharing the negative electrode current collector layer 105) is printed on the surface of the first negative electrode active material layer 104. The second negative electrode active material layer 106 is aligned with the silver paste layer and a slight (e.g., 0.5 MPa) pressure is applied to press it together to form a sandwich structure intermediate.

[0044] Low-melting-point glass glaze powder is mixed with binder to form a glaze, which is then coated onto the periphery of the intermediate. The intermediate is sintered at 850°C to form a ceramic glaze sealing structure 110.

[0045] Porous silver paste is printed on the other side of the two YSZ electrolyte sheets, and after sintering, a first positive electrode layer 102 and a second positive electrode layer 108 are formed. Silver wires are connected as the first positive electrode lead 101 and the second positive electrode lead 109.

[0046] The battery cells were tested in a high-temperature furnace at 750°C, and the results were as follows: Figure 3 As shown, due to the increased thickness of the negative electrode layer, the battery capacity is significantly higher than that of Example 1 (capacity reaches more than 14mAh), and the charge and discharge platform is stable, proving that the structural design of the present invention is applicable to negative electrode layers of different thicknesses, and capacity optimization can be achieved by adjusting the thickness of the negative electrode layer.

[0047] Example 3 Fe2O3 powder and GDC powder were mixed at a mass ratio of 7:3, and an organic binder was added to prepare a negative electrode slurry. A first negative electrode active material layer 104 and a second negative electrode active material layer 106 were prepared on two 8YSZ electrolyte sheets by spraying.

[0048] A silver-palladium alloy paste (e.g., Ag:Pd=95:5 by mass) is coated on the surface of the first negative electrode active material layer 104 to serve as a shared negative electrode current collector layer 105; after the second negative electrode active material layer 106 is aligned and pressed together, a ceramic glaze paste is coated around the intermediate body and sintered at 950°C to form a ceramic glaze sealing structure 110.

[0049] A porous silver first positive electrode layer 102 and a second positive electrode layer 108 were prepared, and silver wires were connected as the first positive electrode lead 101 and the second positive electrode lead 109. The battery cell was tested in a high-temperature furnace at 850°C, and the results are as follows. Figure 4 As shown, at a relatively high operating temperature of 850℃, the battery still maintains stable charge and discharge performance without voltage sudden change or capacity drop, proving that the silver-palladium alloy current collector has excellent high-temperature oxidation resistance, and the GDC additive can effectively improve the oxygen ion conduction efficiency of the negative electrode layer. The structural design of this invention is suitable for higher temperature operating conditions.

[0050] In summary, this invention precisely overcomes the technical shortcomings of existing all-solid-state high-temperature iron-air batteries in stacked applications, namely high cost of negative electrode current collectors and complex sealing processes, by sharing a negative electrode current collector and uniformly sealing the periphery. Ultimately, it provides a compact, lower-cost, and easier-to-seal and stackable battery cell pair and its fabrication method. Specifically, it simplifies the original two independent negative electrode regions, each requiring large-area sealing, into a compact structure that only needs to seal its outer edge. This directly reduces the amount of precious metals (such as silver) used by approximately 50%, significantly lowering material costs. Furthermore, by merging the two separately sealed negative electrode regions, the sealing perimeter and area are significantly reduced, effectively reducing sealing difficulty, improving sealing reliability, and increasing yield. Simultaneously, the battery cell pair formed based on this design is itself a compact modular unit with higher volumetric energy density and area utilization, making it easier to integrate into subsequent battery stacks. This significantly simplifies the stacking structure and, while simplifying the structure and controlling costs, fully preserves the electrochemical performance of each battery cell. It truly achieves a solution to the cost and sealing challenges of existing all-solid-state high-temperature iron-air batteries without sacrificing battery performance.

[0051] The above embodiments are merely specific application examples. Any implementation methods that adjust the electrolyte type (such as other stabilized zirconium oxides), the proportion of negative electrode active material, the current collector material (such as other high-temperature resistant precious metal alloys), and the composition of the sealing glaze based on the technical solution of this invention are all within the protection scope of this invention. All aspects not described in detail in this invention are conventional technical content.

Claims

1. A pair of all-solid-state high-temperature iron-air battery cells with a shared negative electrode current collector, characterized in that, This all-solid-state high-temperature iron-air battery cell pair includes: The first battery cell includes a first electrolyte sheet and a first positive electrode layer and a first negative electrode active material layer disposed on opposite sides of the first electrolyte sheet. The second battery cell includes a second electrolyte sheet and a second positive electrode layer and a second negative electrode active material layer disposed on opposite sides of the second electrolyte sheet. A shared negative electrode current collector layer is sandwiched between the first negative electrode active material layer and the second negative electrode active material layer, and is electrically connected to the first negative electrode active material layer and the second negative electrode active material layer respectively. A ceramic glaze sealing structure is arranged around the periphery of the shared negative electrode current collector layer, the first negative electrode active material layer and the second negative electrode active material layer, and is respectively sealed and connected to the first electrolyte sheet and the second electrolyte sheet, thus encapsulating the shared negative electrode current collector layer, the first negative electrode active material layer and the second negative electrode active material layer into one unit to isolate them from air.

2. The all-solid-state high-temperature iron-air battery cell pair according to claim 1, characterized in that, Both the first electrolyte sheet and the second electrolyte sheet are made of yttrium-stabilized zirconium oxide.

3. The all-solid-state high-temperature iron-air battery cell pair according to claim 1, characterized in that, Both the first negative electrode active material layer and the second negative electrode active material layer include Fe2O3 and oxygen ion conductor additive, wherein the mass ratio of Fe2O3 to oxygen ion conductor additive is 6:4 to 8:

2.

4. The all-solid-state high-temperature iron-air battery cell pair according to claim 1, characterized in that, The material of the shared negative electrode current collector layer is conductive silver paste or silver-palladium alloy paste.

5. The all-solid-state high-temperature iron-air battery cell pair according to claim 1, characterized in that, Both the first positive electrode layer and the second positive electrode layer are porous silver layers; the first battery cell further includes a first positive electrode lead connected to the first positive electrode layer, and the second battery cell further includes a second positive electrode lead connected to the second positive electrode layer; Both the first positive lead and the second positive lead are silver wires.

6. The all-solid-state high-temperature iron-air battery cell pair according to claim 1, characterized in that, The operating temperature of the all-solid-state high-temperature iron-air battery cell pair is 600℃~900℃.

7. The all-solid-state high-temperature iron-air battery cell pair according to claims 1-6, characterized in that, The all-solid-state high-temperature iron-air battery units are connected in series, parallel, or a combination of series and parallel to form a battery stack.

8. A method for preparing an all-solid-state high-temperature iron-air battery cell pair according to any one of claims 1-6, characterized in that, Includes the following steps: S1, providing a first electrolyte sheet and a second electrolyte sheet; S2, a first negative electrode active material layer is prepared on one side of the first electrolyte sheet, and a second negative electrode active material layer is prepared on one side of the second electrolyte sheet; S3, a shared negative electrode current collector layer is disposed between the first negative electrode active material layer and the second negative electrode active material layer, so that the first negative electrode active material layer, the shared negative electrode current collector layer and the second negative electrode active material layer are in close contact to form a sandwich structure intermediate. S4, fill and surround the outer area of ​​the sandwich structure intermediate with ceramic glaze slurry, and then perform glazing treatment to form a ceramic glaze sealed structure; S5, a first positive electrode layer is prepared on the other side of the first electrolyte sheet, and a second positive electrode layer is prepared on the other side of the second electrolyte sheet.

9. The preparation method according to claim 8, characterized in that, In step S3, the shared negative electrode current collector layer is formed by coating or printing conductive silver paste or silver-palladium alloy paste onto the first negative electrode active material layer or the second negative electrode active material layer, and then pressing the first negative electrode active material layer and the second negative electrode active material layer together.

10. The preparation method according to claim 8, characterized in that, In step S4, the glazing temperature is 850℃~950℃.

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