Solid ion conductor, solid electrolyte including the same, lithium battery including solid electrolyte, and method of manufacturing lithium battery
A solid ion conductor including a garnet oxide represented by Formula 1: L 5+x E 3 (Me z ,M 2-z )O d Formula 1 wherein L includes Li and is at least one of a monovalent cation and a divalent cation; E is a trivalent cation; Me and M are each independently one of a trivalent, tetravalent, pentavalent, and hexavalent cation; 0<x≤3, 0≤z<2, and 0<d≤12; and O is partially or totally substituted with at least one of a pentavalent anion, a hexavalent anion, and a heptavalent anion.
1. A solid ion conductor comprising:
a garnet oxide represented by Formula 4:
Li 5+x+2y (D y ,La 3-y )Zr 2 O 12 Formula 4
wherein D is K, Rb, or Cs, and
0<x+2y≤3 and 0<y≤0.5.
2. The solid ion conductor of claim 1 , further comprising a Group 1 element having an atomic weight of at least 80 Daltons.
3. The solid ion conductor of claim 2 , wherein an amount of the Group 1 element is in a range of about 0.25 to about 3.85 weight percent, based on a total weight of the solid ion conductor.
4. The solid ion conductor of claim 1 , wherein the Group 1 element is present at a grain boundary of the garnet oxide of Formula 1.
5. The solid ion conductor of claim 1 , wherein x and y satisfy the inequality 2<x+2y≤3.
6. The solid ion conductor of claim 3 , wherein the garnet oxide has an ionic conductivity of about 6.0×10 −4 Siemens per centimeter or more at 25° C.
7. The solid ion conductor of claim 6 , wherein the garnet oxide has an activation energy that is less than about 0.34 electron volts at a temperature from −10° C. to 100° C.
8. A solid electrolyte comprising the solid ion conductor according to claim 1 .
9. An all-solid-state lithium battery comprising the solid electrolyte according to claim 8 .
10. A lithium battery comprising:
a positive electrode comprising a positive active material;
a negative electrode comprising a negative active material; and
an organic electrolyte solution,
wherein at least one of the positive electrode, the negative electrode, and the organic electrolyte solution comprises the solid ion conductor according to claim 1 .
11. The lithium battery of claim 10 , wherein the solid ion conductor is present in the form of a coating layer disposed on a surface of at least one of the positive active material and the negative active material.
12. The lithium battery of claim 10 , wherein the solid ion conductor is present in the form of a solid ion conductor membrane which is disposed on a surface of at least one of the positive electrode and the negative electrode, wherein the surface is proximate to the organic electrolyte solution.
13. A lithium air battery comprising the solid ion conductor according to claim 1 .
14. The lithium air battery of claim 13 , wherein the battery comprises a positive electrode, a negative electrode, and a separator, and wherein an ion conductive membrane comprising the solid ion conductor is disposed on a surface of at least one of the positive electrode, the negative electrode, and the separator.
15. A method of preparing a solid ion conductor, the method comprising:
providing a precursor; and
sintering the precursor in an air atmosphere at a temperature from about 800° C. to about 1250° C. for about 2 to about 40 hours to prepare the solid ion conductor, wherein the solid ion conductor comprises a garnet oxide represented by Formula 4,
wherein the precursor is a precursor of the solid ion conductor:
Li 5+x+2y (D y ,La 3-y )Zr 2 O 12
wherein
D is K, Rb, or Cs, and
0<x+2y≤3 and 0<y≤0.5.
16. The method of claim 15 , wherein the sintering is performed at a temperature from about 900° C. to about 1200° C. for about 5 to about 30 hours.
17. A method of preparing a solid ion conductor, the method comprising:
contacting
a lithium compound,
a compound comprising a Group 1 element other than Li,
a compound comprising a trivalent cation, and
a compound comprising a metal element of Group 1 to Group 14 to form a mixture; and
sintering the mixture to preparing the solid ion conductor,
wherein the solid ion conductor has a cubic or pseudocubic structure, and
wherein the solid ion conductor comprises
a garnet oxide represented by Formula 4:
Li 5+x+2y (D y ,La 3-y )Zr 2 O 12 Formula 4
wherein
D is K, Rb, or Cs, and
0<x+2y≤3 and 0<y≤0.5.
18. The method of claim 17 , wherein the compound comprising a trivalent cation is lanthanum oxide.
19. The method of claim 18 , wherein the compound comprising a metal element of Group 1 to Group 14 is a zirconium compound.