Electrode and lithium secondary battery comprising same
An electrode and a lithium secondary battery including the same. By preparing an electrode including an electrode active layer formed using a structure capable of supporting an electrode active material, safety and charge and discharge properties of a battery are improved due to morphological characteristics of the electrode active material being supported inside the structure.
1. An electrode comprising:
a current collector; and
an electrode active layer comprising a structure for supporting an electrode active material, formed on the current collector,
wherein the structure comprises a tube having one side surface or both side surfaces open; and a metal comprised on an inner surface of the tube,
wherein the electrode active material is lithium metal as a negative electrode active material,
wherein the lithium metal is formed inside the tube having the metal formed on the inner surface of the tube,
wherein the tube comprises carbon,
wherein the tube has a length, an inner diameter (D in ) and outer diameter (D ex ), and
wherein the inner diameter (D in ) of the tube ranges from 0.1 μm to 1.8 μm, the length of the tube ranges from 2 μm to 25 μm, and the outer diameter (D ex ) of the tube ranges from 0.2 μm to 2 μm, and
wherein the tube has a longitudinal section aspect ratio (a) of greater than 1 by the following Equation 1:
a=L/D ex [Equation 1]
in Equation 1, L is the length of the tube and D ex is the outer diameter of the tube.
2. The electrode of claim 1 , wherein the current collector is one or more selected from the group consisting of copper, stainless steel, aluminum, nickel, titanium and baked carbon.
3. The electrode of claim 1 , wherein the electrode active layer further comprises a binder and a conductor.
4. The electrode of claim 3 , wherein the electrode active layer comprises the structure in 80% by weight to 99.5% by weight, the binder in 0.3% by weight to 19.8% by weight and the conductor in 0.2% by weight to 19.7% by weight.
5. The electrode of claim 3 , wherein the binder is one or more aqueous binder selected from the group consisting of acrylate-based rubber and styrene-based rubber.
6. The electrode of claim 3 , wherein the conductor is one or more selected from the group consisting of carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black and carbon fiber.
7. The electrode of claim 1 , wherein the carbon of the tube is porous.
8. The electrode of claim 1 , wherein the metal is present in 0.1% by weight to 25% by weight with respect to a total weight of the structure.
9. The electrode of claim 1 , wherein the metal has a particle diameter of 1 nm to 50 nm.
10. The electrode of claim 1 , wherein the metal is a metal having a lower overvoltage with an electrode active material compared to an electrode current collector; or a metal having a multiphase with an electrode active material.
11. The electrode of claim 1 , wherein the metal is one or more metal selected from the group consisting of Au, Zn, Mg, Ag, Al, Pt, In, Co, Ni, Mn, Si and Ca.
12. The electrode of claim 1 , wherein a volume ratio (a) of the lithium metal with respect to a free volume of the tube is 0≤α≤1 by the following Equation 2:
α= V Li /V F [Equation 2]
in Equation 2, V F is a free volume of the tube and V Li is a volume of the lithium metal, and the V F is calculated by the following Equation 3:
V F =π( D in /2) 2 L [Equation 3]
in Equation 3, D in is the inner diameter of the tube and L is the length of the tube.
13. A lithium secondary battery comprising:
the electrode of claim 1 ;
an opposing electrode; and
an electrolyte disposed between the electrode and opposing electrode.
14. The electrode of claim 1 , wherein the lithium metal is prepared by electroplating.