Positive electrode active material and lithium secondary battery including the same
View Patent ↗Disclosed herein are a positive electrode active material including at least one selected from among compounds represented by Formula 1 below and a lithium secondary battery including the same that is capable of improving lifetime characteristics and rate characteristics while exhibiting excellent safety: xLi 2 M y Mn (1-y) O 3-z A z *(1−x)LiM′O 2-z′ A′ z′ (1), where M is at least one element selected from a group consisting of Ru, Mo, Nb, Te, Re, Ir, Pt, Cr, S, W, Os, and Po, M′ is at least one element selected from a group consisting of Ni, Ti, Co, Al, Mn, Fe, Mg, B, Cr, Zr, Zn, and second row transition metals, A and A′ are each independently a negative monovalent or divalent anion, and 0<x<1, 0.3<y<1, 0≤z<0.5, and 0≤z′<0.5.
1. A positive electrode active material comprising at least one selected from among compounds represented by Formula 1 below:
x Li 2 M y Mn (1-y) O 3-z A z *(1 −x )LiM′O 2-z′ A′ z′ (1),
where
M is at least one element selected from a group consisting of Ru, Mo, Nb, Te, Re, Ir, Pt, Cr, S, W, Os, and Po,
M′ is at least one element selected from a group consisting of Ni, Ti, Co, Al, Mn, Fe, Mg, B, Cr, Zr, Zn, and second row transition metals,
A and A′ are each independently a negative monovalent or divalent anion, wherein A and A′ are each at least one element selected from a group consisting of halogen elements, sulfur, and nitrogen, and
0<x<1, 0.3<y<1, 0<z≤0.5, and 0≤z′≤0.5.
2. The positive electrode active material according to claim 1 , wherein M is at least one element selected from a group consisting of Ru, Mo, S, W, Os, and Po.
3. The positive electrode active material according to claim 1 , wherein M is Ru.
4. The positive electrode active material according to claim 1 , wherein M′ is Mn a M″ 1-a (where M″ is at least one element selected from a group consisting of Ni, Ti, Co, Al, Fe, Mg, B, Cr, Zr, Zn, and second row transition metals, and 0<a<1).
5. The positive electrode active material according to claim 4 , wherein M″ is at least two elements selected from a group consisting of Ni, Ti, Co, Al, Fe, Mg, B, Cr, Zr, and Zn.
6. The positive electrode active material according to claim 1 , wherein M′ is Mn a Ni b Co c (where 0<a<1, 0<b<1, 0<c<1, and a+b+c=1).
7. The positive electrode active material according to claim 4 , wherein 0<a<0.5.
8. The positive electrode active material according to claim 1 , wherein 0<x≤0.7.
9. The positive electrode active material according to claim 1 , wherein 0.4<y<1.
10. The positive electrode active material according to claim 1 , wherein 0<z≤0.2 and 0≤z′≤0.2.
11. The positive electrode active material according to claim 1 , wherein the compounds represented by Formula 1 above are layered composites or solid solutions.
12. A positive electrode formed by applying a positive electrode active material according to claim 1 to a current collector.
13. A lithium secondary battery comprising a positive electrode according to claim 12 .
14. A battery module comprising a lithium secondary battery according to claim 13 as a unit battery.
15. A battery pack comprising a battery module according to claim 14 .
16. A device using a battery pack according to claim 15 as a power source.
17. The device according to claim 15 , wherein the device is an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a power storage apparatus.
18. The positive electrode active material according to claim 6 , wherein 0<a<0.5.