Lithium battery having higher performance
View Patent ↗Disclosed is a lithium secondary battery including an electrode assembly including a cathode, an anode, and a separator disposed between the cathode and the anode and an electrolyte, wherein the anode includes a lithium titanium oxide (LTO) as an anode active material, and the lithium secondary battery has a charge cut-off voltage of 3.3 to 4 V and, when the charge cut-off voltage is reached, the anode has a potential of 0.75 to 1.545 V within a range within which a potential of the cathode does not exceed 4.95 V.
1. A lithium secondary battery comprising: an electrode assembly comprising a cathode, an anode, and a separator disposed between the cathode and the anode; and an electrolyte,
wherein the anode comprises a lithium titanium oxide as an anode active material, and
the lithium secondary battery has a charge cut-off voltage of 3.3 to 4 V and, when the charge cut-off voltage is reached, the anode has a potential of 0.75 to 1.545 V within a range within which a potential of the cathode does not exceed 4.95 V,
wherein the cathode is a high-voltage cathode,
wherein the cathode comprises, as a cathode active material, a spinel-structure lithium nickel manganese composite oxide represented by Formula 3 below:
Li x Ni y Mn 2−y O 4 (3),
wherein 0.9≦x≦1.2 and 0.4≦y≦0.5, and
wherein the capacity of the anode is 80 to 100% the capacity of the cathode.
2. The lithium secondary battery according to claim 1 , wherein the charge cut-off voltage of the lithium secondary battery is in a range of 3.3 to 3.5 V and, when the cut-off voltage is reached, the anode has a potential of 1.2 to 1.545 V within a range within which the potential of the cathode does not exceed 4.95 V.
3. The lithium secondary battery according to claim 1 , wherein the lithium nickel manganese composite oxide is LiNi 0.5 Mn 1.5 O 4 or LiNi 0.4 Mn 1.6 O 4 .
4. The lithium secondary battery according to claim 1 , wherein the lithium titanium oxide (LTO) is represented by Formula 1 below:
Li a Ti b O 4 (1)
wherein 0.5≦a≦3, and 1≦b≦2.5.
5. The lithium secondary battery according to claim 4 , wherein the lithium titanium oxide is Li 1.33 Ti 1.67 O 4 or LiTi 2 O 4 .
6. The lithium secondary battery according to claim 1 , wherein the capacity of the anode is 90 to 100% the capacity of the cathode.
7. A battery module comprising the lithium secondary battery according to claim 1 as a unit battery.
8. A battery pack comprising the battery module according to claim 7 .
9. A device comprising the battery pack according to claim 8 .
10. The device according to claim 9 , wherein the device is an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a system for storing power.