Anode active material having high capacity and lithium secondary battery comprising the same

1. An anode active material comprising:

a lithium metal oxide; and

(a) a metal powder of Si reacting with lithium ions present in an electrolyte to form a lithium alloy, or

(b) a metal oxide,

the metal oxide having a content of not lower than 1% by weight and not higher than 30% by weight, based on the total weight of an anode mix,

wherein the content of the metal powder is not lower than 1% by weight and is not higher than 3% by weight, based on the total weight of the anode mix, and

wherein the metal oxide is at least one selected from the group consisting of PbO, PbO 2 , Pb 2 O 3 , Pb 3 O 4 , Sb 2 O 3 , Sb 2 O 4 , Sb 2 O 5 , GeO, GeO 2 , Bi 2 O 3 , Bi 2 O 4 , Bi 2 O 5 , V 2 O 5 , Nb 2 O 5 , TiO 2 , and WO 2 ,

wherein the lithium metal oxide is provided as a secondary particle formed of agglomerated primary particles, and the secondary particle has a particle diameter of 200 nm to 30 μm,

wherein the lithium metal oxide is represented by the following Formula 2:

Li a Ti b O 4   (2),

wherein 0.5≦a≦3 and 1≦b≦2.5.

2. The anode active material according to claim 1 , wherein the content of the metal oxide is not lower than 3% by weight and is not higher than 30% by weight, based on the total weight of the anode mix.

3. The anode active material according to claim 1 , wherein the lithium metal oxide is Li 1.33 Ti 1.67 O 4 or LiTi 2 O 4 .

4. An anode, comprising the anode active material according to claim 1 .

5. A lithium secondary battery comprising an electrode assembly inserted into a battery case, wherein the electrode assembly comprises an anode comprising the anode active material according to claim 1 , a cathode and a polymer membrane, and has a structure in which the polymer membrane is interposed between the cathode and the anode.

6. The lithium secondary battery according to claim 5 , wherein the lithium secondary battery is a lithium ion battery.

7. The lithium secondary battery according to claim 5 , wherein the lithium secondary battery is a lithium ion polymer battery.

8. A battery pack comprising the lithium secondary battery according to claim 5 .

9. A device comprising the battery pack according to claim 8 as a power source.