Copper foil having improved workability and charge/discharge characteristics, electrode including the same, secondary battery including the same and method for manufacturing the same
Disclosed is a copper foil including a copper layer having a matte surface and a shiny surface, wherein the copper foil has a first surface of a direction of the matte surface of the copper layer and a second surface of a direction of the shiny surface of the copper layer, wherein a dynamic friction coefficient of the first surface is designated by μk1 and a dynamic friction coefficient of the second surface is designated by μk2. A ratio of three-dimensional surface area to two-dimensional surface area of the first surface is designated by Fs1, a ratio of three-dimensional surface area to two-dimensional surface area of the second surface is designated by Fs2.
1. A copper foil comprising a copper layer having a matte surface and a shiny surface,
wherein the copper foil has a first surface of a direction of the matte surface of the copper layer and a second surface of a direction of the shiny surface of the copper layer,
wherein a dynamic friction coefficient of the first surface is designated by μk1 and a dynamic friction coefficient of the second surface is designated by μk2, and μk1 and μk2 satisfy the following Equations 1 and 2:
0.4≤μ k 1≤0.5 [Equation 1]
|μ k 1−μ k 2|≤0.2, and [Equation 2]
wherein a ratio of three-dimensional surface area to two-dimensional surface area of the first surface is designated by Fs1, a ratio of three-dimensional surface area to two-dimensional surface area of the second surface is designated by Fs2, and Fs1 and Fs2 satisfy the following Equations 3 and 4:
4.0≤ Fs 1≤6.5 [Equation 3]
| Fs 1− Fs 21|≤2.0. [Equation 4]
2. The copper foil according to claim 1 , wherein the copper foil has a tensile strength of 40 kgf/mm 2 or more at room temperature.
3. The copper foil according to claim 1 , wherein the copper foil has a thickness of 4 μm to 35 μm.
4. The copper foil according to claim 1 , further comprising an anticorrosive film disposed on the copper layer.
5. The copper foil according to claim 1 , wherein the anticorrosive film comprises at least one of chromium (Cr), a silane compound or a nitrogen compound.
6. An electrode for secondary batteries comprising:
the copper foil according to claim 1 ; and
an active material layer disposed on the copper foil.
7. A secondary battery comprising:
a cathode;
an anode facing the cathode;
an electrolyte disposed between the cathode and the anode to provide an environment enabling lithium ions to move; and
a separator to electrically insulate (isolate) the cathode from the anode,
wherein the anode comprises:
the copper foil according to claim 1 ; and
an active material layer disposed on the copper foil.
8. A flexible copper foil laminate film comprising:
a polymer membrane; and
the copper foil according to claim 1 disposed on the polymer membrane.