Secondary battery including electrolyte additive
View Patent ↗Disclosed is a secondary battery including a cathode, an anode, and an electrolyte including a lithium salt and a non-aqueous organic solvent, wherein the electrolyte includes an electrolyte additive to be decomposed at 4.5 V or higher to less than 5.5 V vs. reduction voltage of Li + .
1. A secondary battery comprising a cathode, an anode, and an electrolyte consisting of a lithium salt, a non-aqueous organic solvent, and an electrolyte additive, wherein the electrolyte additive decomposes at 4.5 V or higher to less than 5.5 V vs. reduction voltage of Li + ,
wherein an amount of the electrolyte additive is in a range of 0.1 to 1 wt % based on a total weight of the electrolyte and the electrolyte additive consists of diacetoxy biphenyl or cyclohexyl benzene,
wherein at least one of the cathode and the anode has a surface layer formed by decomposition of the electrolyte additive, and
wherein the cathode comprises a spinel-structure lithium metal oxide as a cathode active material is represented by Formula 2 below,
Li x Ni y Mn 2−y O 4 (2)
wherein 0.9≦x≦1.2 and 0.4≦y≦0.5, and
the anode comprises an anode active material represented by Formula 4 below:
Li a Ti b O 4 (4)
wherein 0.1≦a≦4 and 0.2≦b≦4.
2. The secondary battery according to claim 1 , wherein an amount of the electrolyte additive is in a range of 0.1 to 0.6 wt % based on a total weight of the electrolyte.
3. The secondary battery according to claim 1 , wherein the lithium metal oxide is LiNi 0.5 Mn 1.5 O 4 or LiNi 0.4 Mn 1.6 O 4 .
4. A battery module comprising the secondary battery according to claim 1 , as a unit cell.
5. A battery pack comprising the battery module according to claim 4 .
6. A device comprising the battery pack according to claim 5 .
7. The device according to claim 6 , wherein the device is an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a system for storing power.