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CN-122000374-A - Asymmetric solid oxide fuel cell/electrolytic cell connector assembly, preparation method and solid oxide fuel cell/electrolytic cell

CN122000374ACN 122000374 ACN122000374 ACN 122000374ACN-122000374-A

Abstract

The invention provides an asymmetric solid oxide fuel cell/electrolytic cell connector assembly, a preparation method and a solid oxide fuel cell/electrolytic cell, wherein the connector assembly consists of an air side functional layer and a fuel side functional layer, the compositions of the air side functional layer and the fuel side functional layer are perovskite type rare earth chromates, the chemical compositions are represented by La 1‑x A x Cr 1‑y‑z B y C z O 3‑δ (0.2-0.4, 0-0.8 and 0-0.1), A is selected from Ca or Sr, B is selected from Co or Fe, C is selected from Zn, ti or Cu, the sum of the doping amounts of B and C in the air side functional layer is not lower than the sum of the doping amounts of B and C in the fuel side functional layer, and compared with the prior art, the asymmetric solid oxide fuel cell/electrolytic cell connector assembly provided by the invention has excellent thermo-mechanical matching property and structural reliability, high conductivity, low ohmic loss, good sintering activity and preparation process compatibility and good industrial application prospect.

Inventors

  • LIU CHANGQING
  • WANG WANTING
  • GAO YUAN
  • GAO JIUTAO
  • LI CHENGXIN

Assignees

  • 西安交通大学

Dates

Publication Date
20260508
Application Date
20260126

Claims (18)

  1. 1. An asymmetric solid oxide fuel cell/electrolytic cell connector assembly is characterized by comprising an air side functional layer and a fuel side functional layer, wherein the air side functional layer and the fuel side functional layer are respectively perovskite type rare earth chromates, and the chemical composition is expressed as La 1-x A x Cr 1-y-z B y C z O 3-δ (x is more than or equal to 0.2 and less than or equal to 0.4, y is more than or equal to 0 and less than or equal to 0.8, and z is more than or equal to 0 and less than or equal to 0.1), wherein A is selected from Ca or Sr, B is selected from Co or Fe, and C is selected from Zn, ti or Cu; the sum of the doping amounts of B and C in the air-side functional layer is not lower than the sum of the doping amounts of B and C in the fuel-side functional layer.
  2. 2. The asymmetric solid oxide fuel cell/electrolyser connector assembly of claim 1, wherein the composition of the air side functional layer and the fuel side functional layer is La 1-x Sr x Cr 1-y-z Fe y Ti z O 3-δ (0.2 +.x +.0.4, 0 +.y +.0.8, 0 +.z +.0.1).
  3. 3. The asymmetric solid oxide fuel cell/electrolyser connector assembly of claim 2, wherein the amount of Fe doped in the air side functional layer is higher than the amount of Fe doped in the fuel side functional layer, and the amount of Ti doped in the air side functional layer is lower than the amount of Ti doped in the fuel side functional layer.
  4. 4. The asymmetric solid oxide fuel cell/electrolyser connector assembly of claim 1, wherein the composition of the air side functional layer and the fuel side functional layer is La 1-x Sr x Cr 1-y-z Co y Cu z O 3-δ (0.2 +.x +.0.4, 0 +.y +.0.1, 0 +.z < 0.05).
  5. 5. The asymmetric solid oxide fuel cell/electrolyser connector assembly of claim 4, wherein the doping level of Co in the air side functional layer is no less than the doping level of Co in the fuel side functional layer, and the doping level of Cu in the air side functional layer is greater than the doping level of Cu in the fuel side functional layer.
  6. 6. The asymmetric solid oxide fuel cell/electrolyser connector assembly of claim 1, wherein the composition of the air side functional layer and the fuel side functional layer is La 1-x Ca x Cr 1-y-z Co y Zn z O 3-δ (0.2 +.x +.0.4, 0 +.y +.0.1, 0 +.z < 0.05).
  7. 7. The asymmetric solid oxide fuel cell/electrolyser connector assembly of claim 6, wherein the doping level of Co in the air side functional layer is no less than the doping level of Co in the fuel side functional layer, and the doping level of Zn in the air side functional layer is greater than the doping level of Zn in the fuel side functional layer.
  8. 8. The asymmetric solid oxide fuel cell/electrolyser connector assembly of any of claims 1-7 wherein the electrical conductivity of the air side functional layer at 800 ℃ air atmosphere (σ AS ) and the electrical conductivity of the fuel side functional layer at 800 ℃ air atmosphere (σ FS ) satisfy σ AS ≥ 1.1σ FS .
  9. 9. The asymmetric solid oxide fuel cell/electrolyser connector assembly of any of claims 1-7 wherein the electrical conductivity of the fuel side functional layer at 800 ℃ hydrogen atmosphere (σ FS ) and the electrical conductivity of the air side functional layer at 800 ℃ hydrogen atmosphere (σ AS ) satisfy σ FS ≥ 1.1σ AS .
  10. 10. The asymmetric solid oxide fuel cell/electrolyser connector assembly of any of claims 1-7 wherein the coefficient of thermal expansion of the air side functional layer (CTE AS ) and the coefficient of thermal expansion of the fuel side functional layer (CTE FS ) meet that CTE AS differs from CTE FS by no more than 3 x 10 -6 K -1 .
  11. 11. A method of making an asymmetric solid oxide fuel cell/electrolyser connector assembly as claimed in any one of claims 1 to 10 wherein said connector assembly is obtained by the following method of making: Respectively weighing metal precursor salts required by the air side functional layer and the fuel side functional layer according to a preset stoichiometric ratio, and carrying out gelation, calcination and particle size homogenization treatment after dissolution to obtain target phase powder corresponding to each functional layer; layering the object phase powder corresponding to each functional layer by adopting a layer powder layering mode, preparing a laminated structure connector green body through dry pressing, and performing first high-temperature sintering on the laminated structure connector green body to obtain the connector assembly, or And mixing the target phase powder corresponding to each functional layer with an organic carrier to form slurry, performing layer-by-layer screen printing on two parts of the slurry by adopting a screen printing mode to obtain a layered structure connector green body, and performing second high-temperature sintering on the layered structure connector green body to obtain the connector assembly.
  12. 12. The method for preparing an asymmetric solid oxide fuel cell/electrolytic cell connector assembly according to claim 11, wherein the steps of weighing metal precursor salts required for composing the air side functional layer and the fuel side functional layer according to a predetermined stoichiometric ratio, respectively, and performing gelation, calcination and particle size homogenization treatment after dissolution, comprise: Dissolving metal precursor salt required by the air side functional layer and metal precursor salt required by the fuel side functional layer respectively to form AS mixed solution and FS mixed solution, adding citric acid and ethylene glycol into the two mixed solutions, continuously heating and stirring until gel substances are formed, and drying to obtain xerogel; and (3) grinding, calcining and ball milling the xerogel to finish the homogenization treatment process.
  13. 13. The method for preparing an asymmetric solid oxide fuel cell/electrolyzer connector assembly of claim 12 wherein the concentration ratio of citric acid, ethylene glycol to total metal ions in the mixed solution system is 1:1:1.
  14. 14. The method of making an asymmetric solid oxide fuel cell/electrolyser interconnect assembly of claim 12 wherein said calcining is at a temperature of 700-900 ℃ for a time of 5-10 h.
  15. 15. The method of producing an asymmetric solid oxide fuel cell/electrolyzer connector assembly of claim 12 characterized in that the particle size of the target phase powder is 0.05-5 μm.
  16. 16. The method of making an asymmetric solid oxide fuel cell/electrolyser connector assembly of claim 11 wherein said dry pressure is at a pressure of 100-300 MPa; The temperature of the first high-temperature sintering is 1300-1400 ℃ and the time is 2-4 h.
  17. 17. The method of making an asymmetric solid oxide fuel cell/electrolyser connector assembly of claim 11, wherein said organic carrier is selected from at least one of ethanol, ethyl acetate, alpha terpineol, ethylcellulose, castor oil, polyvinylpyrrolidone, triethanolamine, polyvinyl butyral, and polyethylene glycol; The mass ratio of the target phase powder to the organic carrier is 1:1-1.3; the temperature of the second high-temperature sintering is 1350-1450 ℃ and the time is 4-8 h.
  18. 18. An asymmetric solid oxide fuel cell/electrolyser comprising an asymmetric solid oxide fuel cell/electrolyser connector assembly as claimed in any of claims 1 to 10.

Description

Asymmetric solid oxide fuel cell/electrolytic cell connector assembly, preparation method and solid oxide fuel cell/electrolytic cell Technical Field The invention relates to the technical field of solid oxide fuel cells/electrolytic cells, in particular to an asymmetric solid oxide fuel cell/electrolytic cell connector assembly, a preparation method and a solid oxide fuel cell/electrolytic cell. Background The solid oxide fuel cell (Solid Oxide Fuel Cell, SOFC for short) has the advantages of high energy conversion efficiency, high power density, low pollution and the like, and has obvious advantages in the aspect of flexibly and effectively utilizing hydrocarbon fuel. Therefore, the device is regarded as a power generation device with great application prospect. The voltage of the SOFC single cell is only 1.2V in theory, and if the power range of the SOFC single cell reaches the kW level or the MW level of engineering application, a plurality of single cells need to be connected in series or in parallel through a connector to form a cell stack. Solid Oxide Fuel Cells (SOFCs) and Solid Oxide Electrolysis Cells (SOECs) are reversible applications of the same device in different modes of operation, collectively referred to as Solid Oxide Cells (SOCs). The connector is one of the key core components in the solid oxide fuel cell/electrolytic cell, and is used for transmitting electrons between adjacent cathodes and anodes and isolating fuel gas and oxygen, so that the connector is a key factor for ensuring long-term stable operation of the electric pile. The chemical potential gradient caused by the obvious oxygen partial pressure difference between the oxidant and the fuel gas severely limits the selection range of the connector materials when the connector is exposed to the high-temperature oxidation and reduction dual atmosphere in the actual service environment, and the performance requirements of the connector materials are the most severe in the SOC component, (i) high electronic conductivity and negligible ionic conductivity, (ii) excellent chemical and structural stability under the oxidation and reduction dual atmosphere, (iii) extremely low oxygen and hydrogen permeability, (iv) thermal expansion coefficient matched with adjacent components and good compatibility, and (v) higher mechanical strength and thermal conductivity. Up to now, the connectors developed can be divided into two main categories, metal connectors and ceramic connectors. The metal connectors such as chromium-based alloy, nickel-based alloy, ferrite stainless steel and the like have remarkable advantages in the middle-low temperature flat plate type galvanic pile due to lower cost and excellent electric conductivity and thermal conductivity under the middle-low temperature condition. However, the metal connector is difficult to be applied to the high-temperature segmented tandem tube type galvanic pile, and the reason is that the metal connector has a plurality of problems in a high-temperature environment, including insufficient oxidation resistance at high temperature, severe interface reaction and cathode poisoning caused by volatilization of Cr (VI) species. Ceramic connectors are the preferred type of connector materials in high temperature segmented tandem SOC stacks due to their excellent electronic conductivity and good thermal stability under oxidizing/reducing atmospheres, and their good compatibility with other battery components in terms of phase, microstructure and thermal expansion. The ceramic connectors which are widely used at present mainly comprise La-doped SrTiO 3 (abbreviated as LST) and Sr-or Ca-doped LaCrO 3 (abbreviated as LSC or LCC). However, limited by the intrinsic conductivity properties of these two types of materials, the conductivities of both on both sides of the cathode/anode exhibit orders of magnitude differences when in actual service. The LST has extremely low conductivity in the cathode atmosphere, and the LSC or LCC has low conductivity in the anode atmosphere. Therefore, when a single ceramic connector is used, the output performance of the entire cell stack is severely limited by the low conductivity of the connector in an atmosphere on one side. In addition, laCrO 3 -based materials have poor sintering activity, LSC usually needs densification temperature exceeding 1700 ℃, LCC is improved, but LCC still needs to be sintered at about 1600 ℃ to reach the density requirement, the sintering temperature is higher when the LaCrO 3 -based materials are sintered in a film form, and the severe sintering condition further increases the construction difficulty of batteries and galvanic piles. Therefore, the development of a novel ceramic connector material with good sintering performance, high conductivity and stability in oxidation/reduction dual-atmosphere and the structural design thereof are important to the output performance and long-term operation stability of the high-temperature tubular segme