Positive active material for rechargeable lithium battery, method of preparing the same, and rechargeable lithium battery including the same
View Patent ↗A rechargeable lithium battery includes a positive electrode including a positive active material, a negative electrode including a negative active material and an electrolyte including a lithium salt and a non-aqueous organic solvent, wherein the positive active material includes a nickel-based composite oxide represented by the following Chemical Formula 1, the non-aqueous organic solvent includes ethylene carbonate, and the ethylene carbonate is included in an amount of 7.5 to 27.5 volume % based on the total amount of the non-aqueous organic solvent, LiNi x Co y Mn z O 2 [Chemical Formula 1] wherein in Chemical Formula 1, 0.63≤x≤0.85, 0.05<y<0.25, 0.03<z<0.02 and x+y+z=1.
1. A rechargeable lithium battery comprising:
a positive electrode comprising a positive active material, the positive active material consisting of a nickel-cobalt-manganese (NCM) composite oxide, wherein the nickel-cobalt-manganese (NCM) composite oxide comprises nickel in an amount of greater than or equal to 65 atomic % and less than or equal to 75 atomic % based on a total amount of nickel, cobalt, and manganese in the nickel-cobalt-manganese (NCM) composite oxide; and
an electrolyte comprising a lithium salt and a non-aqueous organic solvent, wherein the non-aqueous organic solvent consists of ethylene carbonate in an amount of 10 volume % to 25 volume % based on a total amount of the non-aqueous organic solvent, dimethyl carbonate in an amount of equal to or less than 55 volume % based on a total amount of the non-aqueous organic solvent, and
a remainder consisting of ethylmethyl carbonate.
2. The rechargeable lithium battery according to claim 1 , wherein the nickel-cobalt-manganese (NCM) composite oxide is represented by the following Chemical Formula 1,
LiNi x Co y Mn z O 2 [Chemical Formula 1];
wherein in Chemical Formula 1, 0.65≤x≤0.75, 0.05<y<0.25, 0.03<z<0.2, and x+y+z=1.
3. The rechargeable lithium battery according to claim 2 , wherein in Chemical Formula 1, x:y:z is 0.65:0.20:0.15.
4. The rechargeable lithium battery according to claim 2 , wherein in Chemical Formula 1, x:y:z is 0.75:0.10:0.15.
5. The rechargeable lithium battery according to claim 1 , wherein the nickel-cobalt-manganese (NCM) composite oxide is represented by the following Chemical Formula 1,
LiNi x Co y Mn z O 2 [Chemical Formula 1];
wherein 0.65≤x≤0.75, 0.1≤y≤0.2, 0.05≤z≤0.15, and x+y+z=1.
6. The rechargeable lithium battery according to claim 1 , wherein the nickel-cobalt-manganese (NCM) composite oxide has a specific capacity of 170 mAh/g or greater.
7. The rechargeable lithium battery according to claim 1 , wherein the nickel-cobalt-manganese (NCM) composite oxide has a specific capacity of 180 mAh/g or greater.
8. The rechargeable lithium battery according to claim 1 , wherein the nickel-cobalt-manganese (NCM) composite oxide has a specific capacity of 190 mAh/g or greater.