Lithium ion conductor, and solid electrolyte, active material, and lithium battery each including the lithium ion conductor

1. A solid electrolyte comprising a lithium ion conductor represented by Formula 1:

Li 1+x+2y Al x Mg y M 2−x−y (PO 4 ) 3   Formula 1

wherein, in Formula 1,

M comprises at least one of titanium (Ti), germanium (Ge), zirconium (Zr), hafnium (Hf), and tin (Sn), and

0<x≦0.3, and 0<y≦0.1, and

wherein the aluminum (Al) and the magnesium (Mg) of Formula 1 are substituted at a plurality of M sites of the lithium ion conductor of Formula 1, and

wherein M has an oxidation number of 4, which is constant during migration of lithium ions.

2. The solid electrolyte of claim 1 , wherein M comprises at least one of titanium (Ti) and germanium (Ge).

3. The solid electrolyte of claim 2 , wherein M is titanium (Ti).

4. The solid electrolyte of claim 1 , wherein 0<y≦0.05.

5. The solid electrolyte of claim 1 , wherein the lithium ion conductor is Li 1.2 Al 0.1 Mg 0.05 Ti 1.85 (PO 4 ) 3 , Li 1.3 Al 0.2 Mg 0.05 Ti 1.75 (PO 4 ) 3 , Li 1.4 Al 0.3 Mg 0.05 Ti 1.65 (PO 4 ) 3 , or Li 1.4 Al 0.2 Mg 0.1 Ti 1.7 (PO 4 ) 3 .

6. An electrode active material for a lithium battery, the electrode active material comprising:

a core comprising a material capable of intercalating and deintercalating lithium ions; and

a shell disposed on at least a portion of a surface of the core,

wherein the shell comprises the solid electrolyte comprising the lithium ion conductor of claim 1 .

7. The electrode active material for a lithium battery of claim 6 , wherein the lithium ion conductor is Li 1.2 Al 0.1 Mg 0.05 Ti 1.85 (PO 4 ) 3 , Li 1.3 Al 0.2 Mg 0.05 Ti 1.75 (PO 4 ) 3 , Li 1.4 Al 0.3 Mg 0.05 Ti 1.65 (PO 4 ) 3 , or Li 1.4 Al 0.2 Mg 0.1 Ti 1.7 (PO 4 ) 3 .

8. An all-solid-state lithium battery comprising:

a cathode including a cathode active material;

an anode including an anode active material; and

the solid electrolyte including the lithium ion conductor of claim 1 .

9. The all-solid-state lithium battery of claim 8 , wherein at least one of the cathode and the anode further comprises the solid electrolyte comprising the lithium ion conductor of claim 1 .

10. The all-solid-state lithium battery of claim 8 , wherein the lithium ion conductor is Li 1.2 Al 0.1 Mg 0.05 Ti 1.85 (PO 4 ) 3 , Li 1.3 Al 0.2 Mg 0.05 Ti 1.75 (PO 4 ) 3 , Li 1.4 Al 0.3 Mg 0.05 Ti 1.65 (PO 4 ) 3 , or Li 1.4 Al 0.2 Mg 0.1 Ti 1.7 (PO 4 ) 3 .

11. A lithium battery comprising:

a cathode including a cathode active material;

an anode including an anode active material; and

an organic electrolyte solution,

wherein at least one of the cathode, the anode, and the organic electrolyte solution further comprises the lithium ion conductor of claim 1 .

12. The lithium battery of claim 11 , wherein the lithium ion conductor is disposed in the cathode, and

the cathode has a layered structure including

a cathode current collector,

a cathode active material layer including the cathode active material, and

a protective layer comprising the lithium ion conductor,

wherein the cathode current collector, the cathode active material layer, and the protective layer are disposed sequentially upon one another.

13. The lithium battery of claim 11 , wherein the lithium ion conductor is disposed in the cathode, and

wherein the cathode active material comprises:

a core including a material capable of intercalating and deintercalating lithium ions; and

a shell disposed on at least a portion of a surface of the core, wherein the shell comprises the lithium ion conductor.

14. The lithium battery of claim 11 , wherein the lithium ion conductor is disposed in the anode, and

the anode has a layered structure including

an anode current collector,

an anode active material layer including the anode active material, and

a protective layer comprising the lithium ion conductor, wherein the anode current collector, the anode active material layer, and the protective layer are disposed sequentially upon one another.

15. The lithium battery of claim 11 , wherein the lithium ion conductor is disposed in the anode, and

wherein the anode active material comprises:

a core including a material capable of intercalating and deintercalating lithium ions; and

a shell disposed on at least a portion of a surface of the core, wherein the shell comprises the lithium ion conductor.

16. A lithium air battery comprising:

a cathode comprising at least one of an oxygen-oxidation catalyst and an oxygen-reduction catalyst;

an anode including lithium;

an electrolyte disposed between the cathode and the anode; and

an ion conductive membrane disposed between the anode and the electrolyte,

wherein the ion conductive membrane comprises the lithium ion conductor of claim 1 .