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CN-117098737-B - Glass composition for fuel cell stack sealing

CN117098737BCN 117098737 BCN117098737 BCN 117098737BCN-117098737-B

Abstract

The present invention relates to a glass composition and a sealing material comprising the same, which are suitable for use in electrochemical devices requiring hermetic sealing, such as Solid Oxide Fuel Cells (SOFC) and Solid Oxide Electrolysis Cell (SOEC) stacks.

Inventors

  • S. D.K. Amara Sinha
  • P. D.D. Rodrigo
  • B. Navak

Assignees

  • 固态动力澳大利亚私人有限公司

Dates

Publication Date
20260505
Application Date
20220204
Priority Date
20210820

Claims (20)

  1. 1. A glass composition comprising, in mole percent of the glass composition: -50 to 60 mol% SiO 2 ; -2 to 10 mol% of B 2 O 3 ; -0.5 to 3mol% Al 2 O 3 ; -4 to 6mol% TiO 2 ; -1 to 4mol% CeO 2 ; -2 to 30 mol% SrO, and -From 2 to 25 mol% of BaO, an Wherein the glass composition satisfies condition (a) and one or both of conditions (b) and (c): (a)mol% BaO > (2 x mol% TiO 2 + mol% B 2 O 3 ); (b)(mol% BaO + mol% SrO - 2 x mol% TiO 2 - mol% B 2 O 3 ) ≤ 0.5 x (mol% SiO 2 – 2 x mol% TiO 2 - 2/3 x mol% B 2 O 3 ); (c)(mol% BaO + mol% SrO - 2 x mol% TiO 2 ) / (mol% SiO 2 - 2 x mol% TiO 2 ) < 0.5.
  2. 2. the glass composition of claim 1, wherein the glass composition is substantially free of alkali oxides.
  3. 3. The glass composition of any one of claims 1 to 2, wherein the glass composition does not comprise CaO.
  4. 4. The glass composition of any one of claims 1 to 2, wherein the glass composition does not comprise ZrO 2 .
  5. 5. The glass composition of any of claims 1 to 2, wherein the glass composition comprises one or more of the following, in mol% of the glass composition: -52 to 59 mol% SiO 2 ; -3 to 10mol% of B 2 O 3 ; -0.5 to 2 mol% Al 2 O 3 ; -4 to 5.5 mol% TiO 2 ; -2 to 3 mol% CeO 2 ; -9 to 20 mol% SrO; 16 to 21 mol% BaO.
  6. 6. The glass composition of any of claims 1 to 2, wherein the glass composition comprises one or more of the following, in mol% of the glass composition: -54 to 58 mol% SiO 2 ; -5 to 7 mol% of B 2 O 3 ; -1 to 2 mol% Al 2 O 3 ; -4 to 5.5 mol% TiO 2 ; -2 to 3 mol% CeO 2 ; -10 to 12 mol% SrO; -17 to 19 mol% BaO.
  7. 7. A glass composition consisting of, in mole percent of the glass composition: -50 to 60 mol% SiO 2 ; -2 to 10 mol% of B 2 O 3 ; -0.5 to 3mol% Al 2 O 3 ; -4 to 6mol% TiO 2 ; -1 to 4mol% CeO 2 ; -2 to 30 mol% SrO, and -BaO 2 to 25 mol%.
  8. 8. The glass composition of claim 7, wherein condition (a) is satisfied and one or both of conditions (b) and (c) are satisfied: (a)mol% BaO > (2 x mol% TiO 2 + mol% B 2 O 3 ); (b)(mol% BaO + mol% SrO - 2 x mol% TiO 2 - mol% B 2 O 3 ) ≤ 0.5 x (mol% SiO 2 - 2 x mol% TiO 2 - 2/3 x mol% B 2 O 3 ); (c)(mol% BaO + mol% SrO - 2 x mol% TiO 2 ) / (mol% SiO 2 - 2 x mol% TiO 2 ) < 0.5.
  9. 9. a sealing material for an electrochemical device, comprising the glass composition according to any one of claims 1 to 8.
  10. 10. The sealing material of claim 9, wherein the sealing material further comprises one or more fillers.
  11. 11. The sealing material of claim 10, wherein the sealing material comprises 80 to 100% by volume of the glass composition and 0 to 20% by volume of the one or more fillers, based on the total amount of sealing material.
  12. 12. The sealing material of any one of claims 9 to 11, wherein the glass composition softens after undergoing a sintering thermal cycle to provide a sintered glass, and subsequently undergoes controlled crystallization to provide a glass-ceramic comprising one or more crystalline phases and a glass phase.
  13. 13. The sealing material of claim 12, wherein the sintering thermal cycle comprises: a first step carried out at a temperature higher than the glass transition temperature and lower than the glass crystallization onset temperature by 10 to 30 ℃ for a period of 30 to 120 minutes, and -A second step carried out at a temperature at least 50 ℃ higher than the intended operating temperature of the electrochemical device and at least 50 ℃ higher than the glass crystallization onset temperature for a period of time ranging from 2 to 5 hours.
  14. 14. The sealing material of claim 12, wherein the sintered glass forms a hermetic seal with the electrochemical device.
  15. 15. The sealing material of claim 12, wherein the glass-ceramic comprises 45 to 80 volume percent of one or more crystalline phases and 20 to 55 volume percent of a glass phase, based on the total amount of the glass-ceramic.
  16. 16. The sealing material of claim 15, wherein each of the one or more crystalline phases of the glass-ceramic comprises crystals ：2BaO.TiO 2 .2SiO 2 、2SrO.TiO 2 .2SiO 2 、3BaO.3B 2 O 3 .2SiO 2 、BaO.2SiO 2 、BaO.B 2 O 3 having a structure selected from the group consisting of and combinations thereof.
  17. 17. The sealing material of claim 15, wherein the glass ceramic has a thermal expansion and contraction mismatch of-0.04 to 0.10 with any other galvanic pile component to which it is bonded at any temperature up to the glass transition temperature of the glass phase, the thermal expansion and contraction mismatch being defined as: 。
  18. 18. the sealing material of claim 15, wherein the glass phase of the glass-ceramic is substantially free of BaO.
  19. 19. The sealing material of claim 15, wherein the glass phase of the glass-ceramic is substantially free of B 2 O 3 .
  20. 20. The sealing material of claim 15, wherein the glass-ceramic has a Coefficient of Thermal Expansion (CTE) of 10 x 10 -6 /°c to 13 x 10 -6 /°c.

Description

Glass composition for fuel cell stack sealing Technical Field The present invention relates to a glass composition and a sealing material comprising the same, which are suitable for use in electrochemical devices requiring hermetic sealing, including solid oxide fuel cell stacks and the like, such as solid oxide electrolysis Chi Diandui (solid oxide electrolyser CELL STACKS). Related applications The present application claims priority from australian provisional patent application AU 2021900273 and australian patent application AU 2021218224, the entire contents of which are incorporated herein by reference. Background Electrochemical devices or electrochemical cells are devices capable of generating electrical energy from chemical reactions or using electrical energy to cause chemical reactions. One example of an electrochemical device is a Solid Oxide Fuel Cell (SOFC) device for converting chemical energy of a gaseous fuel (e.g., hydrogen) into electrical energy by electrochemical oxidation. A typical SOFC stack consists of a plurality of interconnected cells, each cell having a porous ceramic cathode and a porous ceramic anode separated by a dense ion conducting solid oxide electrolyte. The galvanic pile generally comprises a support structure consisting of one or more supports made of a suitable material, for example of a suitable metal. During operation of the SOFC stack, a fuel, such as natural gas, is supplied to the anode of each cell and an oxidant, such as air, is supplied to the cathode of each cell. The cell assemblies are assembled in such a way that fuel and oxidant can be supplied to the anode and cathode of each cell, respectively. Another example of an electrochemical device is a Solid Oxide Electrolytic Cell (SOEC) device, which is essentially a SOFC operating in a regenerative (reverse) mode, and implements electrolysis of water to produce hydrogen and oxygen. The cells of SOFCs and SOEC devices require airtight (hermetic) sealing to prevent mixing of fuel and oxidant and are therefore important for performance, durability and safe operation of the SOFC or SOEC stacks. Seals are typically used to separate the anode and cathode cavities of the SOFC or SOEC stacks from each other and from the surrounding environment, depending on the stack design requirements. The seal may also enable mechanical bonding of SOFC or SOEC stack components and electrical insulation between the bonded components. During operation, SOFCs and SOEC stacks reach elevated temperatures, typically in the range of about 500 ℃ to about 1000 ℃, and experience intentional and unintentional temperature fluctuations (thermal cycling), from as low as ambient temperature to operating temperatures with different heating and cooling rates. To ensure the commercial viability of SOFCs and SOEC stacks, the seals must maintain their integrity and meet all of the above requirements under thermal cycling conditions and at a constant temperature of thousands of hours of operation. For example, the mismatch between thermal expansion and contraction between each seal and other components of the SOFC or SOEC stack should be low enough to prevent the seal or any other component from failing under thermal stresses generated during thermal cycling. Furthermore, the seal should not interact adversely with other components of the SOFC or SOEC stack, whether by releasing unwanted volatile substances that alter the chemical or physical properties of the other components or by reacting with other components in contact with the seal. Various types of glass have been developed for use as seals in SOFCs and SOEC stacks. One type of glass is designed to retain a majority of the liquid glass phase. This provides the glass with the ability to flow (exhibit viscous relaxation) under the thermal stresses created as a primary means of reducing the amount of stress applied to other components and interfaces with other components at temperatures above the glass transition temperature (Tg). This type of glass has a number of drawbacks. For example, it generally tends to crack at temperatures below Tg where there is no tack-free temperature. In addition, glass typically contains significant amounts of components, such as alkali oxides and B2O3, that (a) render the seal an undesirable electrical insulator, (B) volatilize or leach out in the humid gas environment within the fuel cell stack, leading to continual changes in the chemical and physical properties of the seal, and (c) cause adverse reactions with other components. Another type of glass is designed to become a highly crystalline rigid glass ceramic at SOFC and SOEC operating temperatures. While this type of high-crystalline glass alleviates the disadvantages associated with the reactivity of the low-crystalline glass seals described above, it can be extremely difficult to densify seals made from this type of glass and eliminate large inherent defects. The presence of large intrinsic defects and the l