Solid-state electrolyte, solid-state battery including the electrolyte, and method of making the same
A solid-state ion conductor includes a compound of Formula 1: Li 3a+b−(c*n) N a Cl b X c Formula 1 wherein, in Formula 1, X is an anion having an average oxidation state of n and is −3≤n≤−1, and is at least one of Br, I, F, O, S, or P; and 1≤a≤4, 1≤b≤3, 0<c≤3, and 4.8≤(a+b+c)≤5.2.
1. A solid-state ion conductor comprising a compound of Formula 1:
Li 3a+b-(c*n) N a Cl b X c Formula 1
wherein, in Formula 1,
X comprises an anion having an average oxidation state of n and is −2, and comprises S; and
1≤a≤4, 1≤b≤3, 0<c≤3, and 4.8≤(a+b+c)≤5.2.
2. The solid-state ion conductor of claim 1 , wherein the compound of Formula 1 has an antifluorite structure, and wherein N, Cl, and X form a face-centered cubic structure.
3. The solid-state ion conductor of claim 2 , wherein the antifluorite structure comprises a vacancy on a lithium site in the antifluorite structure.
4. The solid-state ion conductor of claim 1 , wherein the solid-state ion conductor has an ionic conductivity equal to or greater than of 1×10 −6 siemens per centimeter, at 25° C.
5. The solid-state ion conductor of claim 4 , wherein the solid-state ion conductor has an ionic conductivity of 1×10 −4 siemens per centimeter to 1×10 −2 siemens per centimeter, at 25° C.
6. The solid-state ion conductor of claim 1 , wherein the solid-state ion conductor does not form an alloy or a compound when contacted with lithium metal.
7. The solid-state ion conductor of claim 1 , wherein c is 0<c≤2.
8. The solid-state ion conductor of claim 1 , wherein c is 0.1≤c<2.
9. The solid-state ion conductor of claim 1 , wherein c is 0.5≤c≤2.
10. The solid-state ion conductor of claim 1 , wherein a is 1 or 2.
11. The solid-state ion conductor of claim 1 , wherein b is 0.5≤b≤2.5.
12. The solid-state ion conductor of claim 1 , wherein a is 1 or 2, b is 0.5≤b≤2.5, and c is 0.5≤c≤2.
13. The solid-state ion conductor of claim 1 , wherein X is an anion having an average oxidation state of n and is −2, and is S.
14. The solid-state ion conductor of claim 1 , wherein X further comprises at least one of Br, I, F, O, or P.
15. The solid-state ion conductor of claim 1 , wherein the compound of Formula 1 is Li 9 NCl 2 S 2 .
16. The solid-state ion conductor of claim 1 , wherein the solid-state ion conductor has a porosity of 0 to less than 25 volume percent, based on a total volume of the solid-state ion conductor.
17. A component for a lithium battery comprising:
a current collector; and
the solid-state ion conductor of claim 1 on a surface of the current collector.
18. The component of claim 17 , wherein the current collector comprises at least one of nickel, copper, titanium, stainless steel, or amorphous carbon.
19. A negative electrode comprising:
a negative active material; and
the solid-state ion conductor of claim 1 disposed on a surface of the negative active material.
20. A separator for a lithium battery comprising:
a substrate; and
the solid-state ion conductor of claim 1 disposed on a surface of the substrate.
21. A lithium battery comprising:
a positive electrode;
a negative electrode comprising lithium, a lithium alloy, or a combination thereof; and
the solid-state ion conductor of claim 1 between the positive electrode and the negative electrode.
22. A method of preparing a solid-state ion conductor, the method comprising:
providing a precursor mixture comprising a lithium precursor, a nitrogen precursor, a chlorine precursor, and an X precursor; and
treating the precursor mixture to prepare a compound of Formula 1,
wherein the solid-state ion conductor comprises a compound represented by Formula 1,
Li 3a+b-(c*n) N a Cl b X c Formula 1
wherein, in Formula 1,
X comprises an anion having an average oxidation state of n; where −3≤n≤−1, and comprises S; and
1≤a≤4, 1≤b≤3, 0<c≤3; and 4.8≤(a+b+c)≤5.2.
23. The method according to claim 22 , wherein the treating the precursor mixture comprises
mechanochemical milling of the precursor mixture; or
heat-treating the precursor mixture at 25° C. to 800° C.,
to prepare the compound of Formula 1.
24. The method according to claim 23 , wherein the heat-treating comprises heating from 300° C. to 700° C. in an inert gas.
25. The method according to claim 23 , further comprising disposing the compound of Formula 1 on a substrate.