Lithium secondary battery including sulfone-based additive
A lithium secondary battery includes: a positive electrode; a negative electrode; and an electrolyte between the positive electrode and the negative electrode, wherein the positive electrode includes a positive active material represented by Formula 1, and the electrolyte includes a lithium salt, a non-aqueous solvent, and a sulfone compound represented by Formula 2. wherein, in Formula 1, 0.9≤x≤1.2, 0.7≤y≤0.98, 0≤z<0.2, M comprises Al, Mg, Mn, Co, Fe, Cr, V, Ti, Cu, B, Ca, Zn, Zr, Nb, Mo, Sr, Sb, W, Bi, or a combination thereof, and A is a monovalent anion, a divalent anion, or a combination thereof, and in Formula 2, R 1 and R 2 are each independently a halogen, an unsubstituted C 1 -C 10 alkyl group, or a C 1 -C 10 alkyl group substituted with a halogen, and a1 and a2 are each independently an integer from 0 to 5.
1. A lithium secondary battery comprising:
a positive electrode;
a negative electrode; and
an electrolyte between the positive electrode and the negative electrode,
wherein the positive electrode comprises a positive active material represented by Formula 1, and
the electrolyte comprises a lithium salt, a non-aqueous solvent, and a sulfone compound,
Li x Ni y M 1-y O 2-z A z Formula 1
wherein, in
9≤ x≤ 1.2,0.8≤ y≤ 0.98,0≤ z≤ 0.2 Formula 1
M comprises Al, Mg, Mn, Co, Fe, Cr, V, Ti, Cu, B, Ca, Zn, Zr, Nb, Mo, Sr, Sb, W, Bi, or a combination thereof, and
A is a monovalent anion, a divalent anion, a trivalent anion or a combination thereof, and
wherein the sulfone compound comprises a compound of Compounds 7 to 16, or a combination thereof,
2. The lithium secondary battery of claim 1 , wherein the non-aqueous solvent comprises vinylene carbonate.
3. The lithium secondary battery of claim 2 , wherein an amount of the vinylene carbonate is about 0.1 volume percent to about 3 volume percent, based on a total volume of the non-aqueous solvent.
4. The lithium secondary battery of claim 1 , wherein the non-aqueous solvent comprises fluoroethylene carbonate.
5. The lithium secondary battery of claim 4 , wherein an amount of the fluoroethylene carbonate is about 0.1 volume percent to about 10 volume percent, based on a total volume of the non-aqueous solvent.
6. The lithium secondary battery of claim 1 , wherein the positive active material is represented by Formula 3, Formula 4, or a combination thereof:
LiNi y′ Co 1-y′-z′ Al z′ O 2 , or Formula 3
LiNi y′ Co 1-y′-z′ Mn z′ O 2 , Formula 4
wherein, in Formulae 3 and 4, y′ and z′ are each independently 0.8≤y′≤0.98, 0≤z′≤0.1, and 0<1-y′-z′<0.2.
7. The lithium secondary battery of claim 6 , wherein the positive active material is represented by Formula 3 or Formula 4, and wherein 0.8<y′<0.9.
8. The lithium secondary battery of claim 1 , wherein the positive electrode comprises LiNi 0.80 Co 0.15 Mn 0.05 O 2 , LiNi 0.85 Co 0.1 Mn 0.05 O 2 , LiNi 0.88 Co 0.08 Mn 0.04 O 2 , LiNi 0.88 Co 0.08 Al 0.04 O 2 , Li 1.02 Ni 0.80 Co 0.15 Mn 0.05 O 2 , Li 1.02 Ni 0.85 Co 0.10 Mn 0.05 O 2 , Li 1.02 Ni 0.88 Co 0.08 Mn 0.04 O 2 , Li 1.02 Ni 0.88 Co 0.08 Al 0.04 O 2 , LiNi 0.8 Co 0.15 Al 0.05 O 2 , LiNi 0.88 Co 0.1 Al 0.02 O 2 , LiNi 0.85 Co 0.1 Al 0.05 O 2 , LiNi 0.88 Co 0.1 Mn 0.02 O 2 , or a combination thereof.
9. The lithium secondary battery of claim 1 , wherein the negative electrode comprises a negative active material comprising a metal that is alloyable with lithium, a carbonaceous negative active material, or a combination thereof.
10. The lithium secondary battery of claim 9 , wherein the negative active material comprises a metalloid that is alloyable with lithium, and
wherein the metalloid that is alloyable with lithium comprises Si, a Si—C composite material, SiO a′ wherein 0<a′<2, or a combination thereof.
11. The lithium secondary battery of claim 10 , wherein the Si—C composite material comprises Si particles having an average diameter of about 200 nanometers or less.
12. The lithium secondary battery of claim 1 , wherein the lithium secondary battery has a cell energy density of about 500 watt hours per liter or greater.
13. A method of preparing the lithium secondary battery of claim 1 , the method comprising:
disposing the electrolyte between the positive electrode and the negative electrode.
14. The lithium secondary battery of claim 1 , wherein the lithium salt comprises lithium difluoro(oxalato)borate, lithium bis(oxalato)borate, lithium difluoro bis(oxalato)phosphate, LiBF 4 , LiPF 6 , LiCF 3 SO 3 , (CF 3 SO 2 ) 2 NLi, (FSO 2 ) 2 NLi, or a combination thereof.
15. The lithium secondary battery of claim 1 , wherein the negative electrode comprises a negative active material comprising a metal that is alloyable with lithium, a carbonaceous negative active material, or a combination thereof.