Method of manufacturing electrode for lithium secondary battery and electrode manufactured using the same

Abstract

Disclosed are a method of manufacturing an electrode for secondary batteries that includes surface-treating a current collector so as to have a morphology wherein a surface roughness R.sub.a of 0.001 μm to 10 μm is formed over the entire surface thereof to enhance adhesion between an electrode active material and the current collector and an electrode for secondary batteries that is manufactured using the method.

Claims

1. A method of manufacturing an electrode for secondary batteries that comprises an electrode active material coated on a current collector comprising: (i) surface-treating the current collector to provide a surface with irregularities having a morphology, wherein the surface-treating is performed so that the current collector is subjected to rolling using a roller having an embossed pattern at a surface thereof, wherein a vertical cross-section of the pattern is a polygonal, circular, oval, or slit shape, wherein a surface roughness R.sub.a of 0.001 μm to 10 μm is formed over an entire surface of the current collector to enhance adhesion between the electrode active material and the current collector, wherein an interval between the irregularities is from 0.001 μm to 10 μm, and a depth of a valley between the irregularities is 0.001 μm to 10 μm, and; (ii) coating a slurry obtained by mixing an electrode mixture comprising an electrode active material, a conductive material, and a binder with an organic solvent onto the current collector.

2. The method according to claim 1, wherein the surface roughness R.sub.a of the current collector is 0.1 μm to 1 μm is formed over the entire surface thereof.

3. An electrode for a secondary battery, manufactured using the method according to claim 1.

4. The electrode according to claim 3, wherein the electrode is at least one of a cathode and an anode.

5. The electrode according to claim 4, wherein the cathode comprises, as a cathode active material, a lithium metal oxide represented by Formula 1 below:
Li.sub.xM.sub.yMn.sub.2−yO.sub.4−zA.sub.z  (1) wherein 0.9≦x≦1.2, 0<y<2, and 0≦z<0.2; M is at least one element selected from the group consisting of Al, Mg, Ni, Co, Fe, Cr, V, Ti, Cu, B, Ca, Zn, Zr, Nb, Mo, Sr, Sb, W, Ti, and Bi; and A is at least one monovalent or divalent anion.

6. The electrode according to claim 5, wherein the oxide of Formula 1 is represented by Formula 2 below:
Li.sub.xNi.sub.yMn.sub.2−yO.sub.4  (2) wherein 0.9≦x≦1.2 and 0.4≦y≦0.5.

7. The electrode according to claim 6, wherein the oxide is LiNi.sub.0.5Mn.sub.1.5O.sub.4 or LiNi.sub.0.4Mn.sub.1.6O.sub.4.

8. The electrode according to claim 4, wherein the anode comprises, as an anode active material, a lithium metal oxide represented by Formula 3 below:
Li.sub.aM′.sub.bO.sub.4−cA.sub.c  (3) wherein M′ is at least one element selected from the group consisting of Ti, Sn, Cu, Pb, Sb, Zn, Fe, In, Al, and Zr; 0.1≦a≦4 and 0.2≦b≦4 in which a and b are determined according to oxidation number of M′; 0≦c<0.2 in which c is determined according to oxidation number of A; and A is at least one monovalent or divalent anion.

9. The electrode according to claim 8, wherein the lithium metal oxide is represented by Formula 4 below:
Li.sub.aTi.sub.bO.sub.4  (4) wherein 0.5≦a≦3 and 1≦b≦2.5.

10. The electrode according to claim 9, wherein the lithium metal oxide is Li.sub.1.33Ti.sub.1.67O.sub.4 or LiTi.sub.2O.sub.4.

11. A secondary battery comprising the electrode according to claim 3.

12. The secondary battery according to claim 11, wherein the secondary battery is a lithium secondary battery.

13. A battery module comprising the secondary battery according to claim 12 as a unit battery.

14. A battery pack comprising the battery module according to claim 13.

15. A device comprising the battery pack according to claim 14.

16. The device according to claim 15, wherein the device is an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a system for storing power.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

(2) FIGS. 1A to 1C are views illustrating current collectors having predetermined morphologies according to the present invention and surfaces of rollers for formation of morphologies of these current collectors.

MODE FOR INVENTION

Example 1

(3) To form a surface roughness R.sub.a of 0.5 μm on a surface of an Al current collector, the Al current collector was subjected to rolling using a roll provided at a surface thereof with an embossed tetragonal pattern. Subsequently, 95 wt % of Li.sub.1.33Ti.sub.1.67O.sub.4 as an anode active material, 2.5 wt % of Super-P as a conductive material, and 2.5 wt % of PVdF as a binder were added to NMP to prepare an anode mixture and the prepared anode mixture was coated onto the Al current collector, thereby completing fabrication of an anode for secondary batteries.

Comparative Example 1

(4) An anode for secondary batteries was manufactured in the same manner as in Example 1, except that an Al current collector was not surface-treated using a roller.

Experimental Example 1

(5) Adhesive strength of each of the anodes manufactured according to Example 1 and Comparative Example 1 was measured. Results are shown in Table 1 below.

(6) TABLE-US-00001 TABLE 1 Adhesive strength (gf/cm) Example 1 52 Comparative 36 Example 1

(7) As shown in Table 1 above, it can be confirmed that the anode of Example 1 manufactured using the current collector surface-treated using a roller having an embossed pattern exhibits enhanced adhesive strength as compared to the anode of Comparative Example 1 and, consequently, overall performance of a secondary battery including the anode of Example 1 is enhanced.

INDUSTRIAL APPLICABILITY

(8) As described above, a method of manufacturing an electrode for secondary batteries according to the present invention includes surface-treating a current collector so as to have a particular morphology over the entire surface thereof and thus may increase a surface area of the current collector and, accordingly, adhesion between a current collector and an electrode active material of the manufactured electrode is enhanced, whereby overall performance of a secondary battery, such as charging and discharging cycle characteristics and the like, may be enhanced.

(9) Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.