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EP-4737394-A1 - SOLID ION CONDUCTOR, ELECTRODE AND SOLID OXIDE CELL EACH INCLUDING THE SOLID ION CONDUCTOR

EP4737394A1EP 4737394 A1EP4737394 A1EP 4737394A1EP-4737394-A1

Abstract

A solid ion conductor, an electrode, and a solid oxide cell. The solid ion conductor including a metal oxide having a perovskite structure. The metal oxide includes a first, a second, and a third element, each arranged in a cuboctahedral site of the perovskite structure, and includes a fourth and a fifth element, each arranged in an octahedral site of the perovskite structure, or includes a fourth, a fifth, and a sixth element, each arranged in an octahedral site of the perovskite structure, wherein the first element belongs to Group 3 of the Periodic Table, the second element and the third element each belong to Group 2 and have an atomic weight of 30 or more, the fourth and fifth element each belong to one of Groups 8 to 11, and the sixth element belongs to one of Groups 3, 4, or 7 to 12 of the Periodic Table.

Inventors

  • KIM, JUSIK
  • JUNG, DOH WON
  • LEE, SEUNGBOK
  • JI, SANG MIN
  • CHOI, BOKKYU

Assignees

  • Samsung Electronics Co., Ltd.

Dates

Publication Date
20260506
Application Date
20250923

Claims (15)

  1. A solid ion conductor comprising a metal oxide having a perovskite structure, wherein the metal oxide comprises a first element, a second element and a third element, each arranged in a cuboctahedral site of the perovskite structure, and comprises a fourth element and a fifth element, each arranged in an octahedral site of the perovskite structure, or a fourth element, a fifth element and a sixth element, each arranged in an octahedral site of the perovskite structure, wherein the first element belongs to Group 3 of the Periodic Table, the second and third elements each belong to Group 2 of the Periodic Table and have an atomic weight of 30 or more, the fourth and fifth elements each belong to one of Groups 8 to 11 of the Periodic Table, the sixth element belongs to one of Groups 3, 4, or 7 to 12 of the Periodic Table, and wherein a content of each of the first element, the second element, and the third element is 0.5 or less relative to the total content of the first, second, and third elements.
  2. The solid ion conductor of claim 1, wherein a sum of the contents of the first element and the second element is greater than the content of the third element, a sum of the contents of the second element and the third element is equal to or greater than the content of the first element, or a sum of the contents of the first element and the third element is equal to or greater than the content of the second element.
  3. The solid ion conductor of claims 1 or 2, wherein the metal oxide comprises at least one of a cubic phase or a hexagonal phase, wherein a phase fraction of the cubic phase is 95 weight percent or more relative to the total of the cubic phase and the hexagonal phase, a phase fraction of the hexagonal phase is 5 weight percent or less relative to the total of the cubic phase and the hexagonal phase, and the metal oxide is free of a tetragonal phase.
  4. The solid ion conductor of any of claims 1-3, wherein the metal oxide is represented by Formula 1: Formula 1 M1 a1 M2 b1 M3 c1 M4 d1 M5 e1 M6 f1 O 3-δ wherein in Formula 1, 0.01≤a1≤0.5, 0.01≤b1≤0.5, 0.01≤c1≤0.5, 0.1≤d1≤0.9, 0.1≤e1≤0.9, 0≤f1<0.2, and 0≤δ<1, M1 is an element belonging to Group 3 of the Periodic Table, M2 and M3 are each independently an element belonging to Group 2 of the Periodic Table and having an atomic weight of 30 or more, M4 and M5 are each independently an element belonging to one of Groups 8 to 11 of the Periodic Table, M6 is an element belonging to one of Groups 3, 4, or 7 to 12 of the Periodic Table, and δ represents an oxygen vacancy.
  5. The solid ion conductor of any of claims 1-4, wherein M1 comprises a lanthanide element, Sc, Y or a combination thereof, and the lanthanide element comprises La, Pr, Nd or a combination thereof; and/or wherein M2 and M3 each independently comprise Ca, Sr, Ba or Ra.
  6. The solid ion conductor of any of claims 1-5, wherein a valence of M1 is greater than a valence of M2, and ionic radii of M1 are smaller than ionic radii of M2.
  7. The solid ion conductor of any of claims 1-6, wherein the metal oxide is represented by Formula 2: Formula 2 La a2 Sr b2 Ba c2 M4 d2 M5 e2 M6 f2 O 3-δ wherein in Formula 2, 0.01≤a2≤0.5, 0.01≤b2≤0.5, 0.01≤c2≤0.5, 0.1≤d2≤0.9, 0.1≤e2≤0.9, 0≤f2<0.2, and 0≤δ<1, M4 and M5 are each independently an element belonging to one of Groups 8 to 11 of the Periodic Table, M6 is an element belonging to one of Groups 3, 4, or 7 to 12 of the Periodic Table, and an atomic weight of the element belonging to Group 3 is 150 or more, and δ represents an oxygen vacancy.
  8. The solid ion conductor of any of claims 1-7, wherein M4 and M5 each independently comprise Ni, Co, Fe, Ru, Rh, or Pd, a valence of M4 is greater than a valence of M5, and the valence of M4 is +3 or higher, and the valence of M5 is less than +3.
  9. The solid ion conductor of any of claims 1-8, wherein M6 comprises Zn, Mn, Yb, Ni, Cu, Ti, Ho, or a combination thereof; and/or wherein a valence of M6 is +1, +2, +3, +4, +5, +6, or a combination thereof.
  10. The solid ion conductor of any of claims 1-10, wherein the metal oxide is represented by Formula 3: Formula 3 La a3 Sr b3 Ba c3 Co d3 Fe e3 O 3-δ wherein in Formula 3, ≤ a3 ≤ 0.5, 0.1 ≤ b3 ≤ 0.5, 0.1 ≤ c3 ≤ 0.45, 0.6 ≤ d3 ≤ 0.9, 0.1 ≤ e3 ≤ 0.4, 0 ≤ δ < 1, and d3 > e3, and δ represents an oxygen vacancy.
  11. The solid ion conductor of any of claims 1-10, wherein the metal oxide is represented by any one of Formulae 4A to 4G: Formula 4A La a4 Sr b4 Ba c4 Co d4 Fe e4 Zn f4 O 3-δ Formula 4B La a4 Sr b4 Ba c4 Co d4 Fe e4 Mn f4 O 3-δ Formula 4C La a4 Sr b4 Ba c4 Co d4 Fe e4 Yb f4 O 3-δ Formula 4D La a4 Sr b4 Ba c4 Co d4 Fe e4 Ni f4 O 3-δ Formula 4E La a4 Sr b4 Ba c4 Co d4 Fe e4 Cu f4 O 3-δ Formula 4F La a4 Sr b4 Ba c4 Co d4 Fe e4 Ti f4 O 3-δ Formula 4G La a4 Sr b4 Ba c4 Co d4 Fe e4 Ho f4 O 3-δ wherein in Formulae 4A to 4G, 0.1≤a4≤0.5, 0.1≤b4≤0.5, 0.1≤c4≤0.45, 0.6≤d4≤0.9, 0.1≤e4≤0.4, 0.1≤f4≤0.2, 0≤δ<1 and 4>e4+f4, and δ is an oxygen vacancy.
  12. The solid ion conductor of any of claims 1-11, wherein an area-specific resistance of the solid ion conductor, as measured by alternating current impedance method at 700 °C, is 0.5 ohms per square centimeter or less, and a thermal expansion coefficient of the solid ion conductor is 20 × 10 -6 inverse kelvin or less; and/or wherein the solid ion conductor further comprising a composite of: an ionconducting metal oxide, distinct from the metal oxide having the perovskite structure; and the metal oxide having the perovskite structure.
  13. A solid ion conductor comprising a first metal oxide having a perovskite structure, wherein the first metal oxide comprises a first element, a second element, and a third element, disposed at cuboctahedral sites of the perovskite structure, and comprises a fourth element and a fifth element, disposed at octahedral sites of the perovskite structure, or a fourth element, a fifth element, and a sixth element, disposed at octahedral sites of the perovskite structure, wherein the first element is an element belonging to Group 3 of the Periodic Table, the second element and the third element are each independently an element belonging to Group 2 of the Periodic Table and have an atomic weight of 30 or more, the fourth element and the fifth element are each independently an element belonging to one of Groups 8 to 11 of the Periodic Table, the sixth element is an element belonging to one of Groups 3, 4, or 7 to 12 of the Periodic Table, and wherein formation energy of the first metal oxide is -0.8 electronvolt to -10 electronvolt, compared to formation energy of a second metal oxide formed by excluding the first element from the first metal oxide.
  14. An electrode, comprising the solid ion conductor according to any of claims 1-13, preferably wherein the electrode is an air electrode.
  15. A solid oxide cell, comprising: an air electrode; a fuel electrode; and a solid electrolyte layer disposed between the air electrode and the fuel electrode, wherein one or more of the air electrode, the fuel electrode, and the solid electrolyte layer comprises a solid ion conductor according to any of claims 1-13; preferably wherein the solid oxide cell is a solid oxide fuel cell or a solid oxide electrolyzer cell.

Description

FIELD OF THE INVENTION The disclosure relates to a solid ion conductor, and an electrode and a solid oxide cell each including the solid ion conductor. BACKGROUND OF THE INVENTION Solid oxide cells may operate in fuel cell mode, where they generate electricity by oxidizing fuel and reducing air. Solid oxide cells may operate in electrolysis cell mode, where they produce hydrogen by electrolyzing water. While a solid oxide cell is operating in electrolysis cell mode, the air electrode of the solid oxide cell may deteriorate. SUMMARY OF THE INVENTION During the operation of a solid oxide cell in electrolysis mode, high oxygen partial pressure may occur in localized regions within the air electrode, leading to the formation of pores and/or changes in the stoichiometry of the air electrode. Such pore formation and/or stoichiometric changes within the air electrode may reduce active reaction sites in the air electrode, thereby increasing the overpotential in solid oxide cells. An increase in overpotential may further elevate the local oxygen partial pressure within the air electrode, potentially causing delamination between the air electrode and the solid electrolyte layer. During operation of the solid oxide cell in electrolysis mode, metals on the surface of the air electrode may vaporize, and the vaporized metals may diffuse into the solid electrolyte layer, forming an insulating metal oxide phase between the air electrode and the solid electrolyte layer. There is a demand for a solid ion conductor with enhanced structural stability that may suppress delamination between the air electrode and the solid electrolyte layer and inhibit the formation of an insulating phase between them, thereby suppressing deterioration of the air electrode. Provided is a novel solid ion conductor with improved structural stability. Provided is an electrode including the solid ion conductor. Provided is a metal oxide cell including the solid ion conductor. Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments of the disclosure. According to an aspect of the disclosure, a solid ion conductor includes a metal oxide having a perovskite structure,wherein the metal oxide includes a first element, a second element, and a third element, each arranged in a cuboctahedral site of the perovskite structure,and further includes a fourth element and a fifth element, each arranged in an octahedral site of the perovskite structure, or a fourth element, a fifth element and a sixth element, each arranged in an octahedral site of the perovskite structure,wherein the first element belongs to Group 3 of the Periodic Table,the second and third elements each belong to Group 2 of the Periodic Table and have an atomic weight of 30 or more,the fourth and fifth elements each belong to one of Groups 8 to 11 of the Periodic Table,the sixth element belongs to one of Groups 3, 4, or 7 to 12 of the Periodic Table, andwherein a content of each of the first element, the second element, and the third element is 0.5 or less relative to the total content of the first, second, and third elements. According to another aspect of the disclosure, a solid ion conductor includes a first metal oxide having a perovskite structure,wherein the first metal oxide includes a first element, a second element, and a third element, each arranged in a cuboctahedral site of the perovskite structure,and includes a fourth element and a fifth element, each arranged in an octahedral site of the perovskite structure, or a fourth element, a fifth element and a sixth element arranged in an octahedral site of the perovskite structure,wherein the first element belongs to Group 3 of the Periodic Table,the second element and the third element each belong to Group 2 of the Periodic Table and have an atomic weight of 30 or more,the fourth element and the fifth element each independently belong to one of Groups 8 to 11 of the Periodic Table,the sixth element belongs to one of Group 3, 4, or 7 to 12 of the Periodic Table, andwherein the formation energy of the first metal oxide is about -0.8 electronvolt (eV) to about -10 eV relative to the formation energy of a second metal oxide formed by excluding the first element from the first metal oxide. According to another aspect of the disclosure, an electrode includes a solid ion conductor according to the aspect. According to another aspect of the disclosure, a solid oxide cell includes an air electrode, a fuel electrode, anda solid electrolyte layer disposed between the air electrode and the fuel electrode,wherein one or more of the air electrode, the fuel electrode, and the solid electrolyte layer include the solid ion conductor described above. BRIEF DESCRIPTION OF THE DRAWINGS The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following descrip