Solid-state electrolyte, solid-state battery including the electrolyte, and method of making the same

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 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, or P; and

1≤a≤4, ≤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 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.

4. The solid-state ion conductor of claim 3 , 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.

5. 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.

6. The solid-state ion conductor of claim 1 , wherein X is 13Br.

7. The solid-state ion conductor of claim 1 , wherein c is 0<c≤2.

8. 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.

9. The component of claim 8 , wherein the current collector comprises at least one of nickel, copper, titanium, stainless steel, or amorphous carbon.

10. 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.

11. 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.

12. 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.

13. 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 is an anion having an average oxidation state of n, and is at least one of Br, I, F, O or P; and

1≤a≤4, 1≤b≤3, 0<c≤3; and 4.8≤(a+b+c)≤5.2.

14. The method according to claim 13 , wherein the treating the precursor mixture comprises mechanochemical milling of the precursor mixture to prepare the compound of Formula 1.

15. The method according to claim 13 , wherein the treating is heat-treating the precursor mixture at 25° C. to 800° C. to prepare the compound of Formula 1.

16. The method according to claim 15 , wherein the heat-treating comprises heating from 300° C. to 700° C. in an inert gas.

17. The method according to claim 15 , further comprising disposing the compound of Formula 1 on a substrate.