LITHIUM SECONDARY BATTERY
A lithium secondary battery according to an embodiment of the present disclosure includes a cathode, an anode and a non-aqueous electrolyte. The anode includes an anode active material which contains a mixture of an artificial graphite and a natural graphite. A sphericity of the natural graphite is 0.96 or more. The lithium secondary battery including the anode has improved life-span and power properties.
1 . A lithium secondary battery, comprising:
a cathode;
an anode comprising an anode active material comprised of a mixture of an artificial graphite and a natural graphite, wherein a sphericity of the natural graphite is 0.96 or more; and
a non-aqueous electrolyte.
2 . The lithium secondary battery of claim 1 , wherein the sphericity of the natural graphite is 0.98 or more.
3 . The lithium secondary battery of claim 1 , wherein an average particle diameter (D 50 ) of the natural graphite is in a range from 9 μm to 14 μm.
4 . The lithium secondary battery of claim 1 , wherein a half value width in a particle size distribution of the natural graphite is 10 μm or less.
5 . The lithium secondary battery of claim 1 , wherein a half value width in a particle size distribution of the natural graphite is 9 μm or less.
6 . The lithium secondary battery of claim 1 , wherein a mixing weight ratio of the natural graphite and the artificial graphite is in a range from 10:1 to 1:1.
7 . The lithium secondary battery of claim 1 , wherein an anode expansion rate represented by Equation 1 below is 20% or less:
Anode expansion rate (%)=100×( T 2 −T 1 )/( T 1 ) [Equation 1]
wherein, in the Equation 1, T 1 is a thickness of the anode at 0% SOC (State Of Charge), and T 2 is a thickness of the anode at 100% SOC.
8 . The lithium secondary battery of claim 1 , wherein an average particle diameter (D 50 ) of the natural graphite is in a range from 9 μm to 14 μm;
a half value width in a particle size distribution of the natural graphite is 10 μm or less;
a mixing weight ratio of the natural graphite and the artificial graphite is in a range from 10:1 to 1:1; and
an anode expansion rate represented by Equation 1 below is 20% or less:
Anode expansion rate (%)=100×( T 2 −T 1 )/( T 1 ) [Equation 1]
wherein, in the Equation 1, T 1 is a thickness of the anode at 0% SOC (State Of Charge), and T 2 is a thickness of the anode at 100% SOC.