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

Abstract

Disclosed is a method of manufacturing an electrode for a secondary battery including an electrode mixture including an electrode active material, binder and conductive material coated on a current collector. Provided are a method including surface-treating the current collector such that an aluminum oxide (Al.sub.2O.sub.3) layer of 40 nm or less is formed on the current collector so as to enhance adhesion between the electrode mixture and the current collector, and an electrode for a secondary battery manufactured using the same.

Claims

1. A method of manufacturing an electrode for a secondary battery comprising an electrode mixture comprising an electrode active material, binder and conductive material coated on an aluminum current collector, the method comprising surface-treating the current collector via thermal treatment at 100 to 500 C. under an oxygen atmosphere of 1 to 150 mTorr to form an aluminum oxide (Al.sub.2O.sub.3) layer of 10 nm to 40 nm on the current collector wherein adhesion between the electrode mixture and the current collector is enhanced.

2. The method according to claim 1 comprising treating a surface of the current collector to form an aluminum oxide (Al.sub.2O.sub.3) layer of 20 to 30 nm on the current collector.

3. The method according to claim 1, wherein the thermal treatment is performed at 200 to 450 C. under an oxygen atmosphere of 30 to 100 mTorr.

4. The method according to claim 1, wherein an electrode is a cathode or anode, or a cathode and anode.

5. The method according to claim 4, wherein the cathode comprises, as a cathode active material, a spinel-structure lithium metal oxide represented by Formula 1 below:
Li.sub.xM.sub.yMn.sub.2-yO.sub.4-zA.sub.z(1) wherein 0.9x1.2, 0<y<2, and 0z<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 method according to claim 5, wherein the lithium metal oxide is represented by Formula 2 below:
Li.sub.xNi.sub.yMn.sub.2-yO.sub.4(2) wherein 0.9x1.2, and 0.4y0.5.

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

8. The method 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; 0.1a4 and 0.2b4 in which a and b is determined according to oxidation number of M; 0c<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 method according to claim 8, wherein the lithium metal oxide is represented by Formula 4 below:
Li.sub.aTi.sub.bO.sub.4(4) wherein 0.5a3 and 1b2.5.

10. The method 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. An electrode for a secondary battery comprising an electrode mixture comprising an electrode active material, binder and conductive material coated on an aluminum current collector wherein an aluminum oxide (Al.sub.2O.sub.3) layer of greater than or equal to 10 nm and less than 20 nm is formed on the current collector via thermal treatment at 100 to 500 C. under an oxygen atmosphere of 1 to 150 mTorr.

12. The electrode according to claim 11, wherein the electrode active material is a cathode active material or anode active material, or a cathode active material and anode active material wherein the cathode active material comprises a spinel-structure lithium metal oxide represented by Formula 1 below spinel and the anode active material comprises an oxide represented by Formula 3 below:
Li.sub.xM.sub.yMn.sub.2-yO.sub.4-zA.sub.z(1)
Li.sub.aM.sub.bO.sub.4-cA.sub.c(3) wherein 0.9x1.2, 0<y<2 and 0z<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; A is at least one monovalent or divalent anion; M is at least one element selected from the group consisting of Ti, Sn, Cu, Pb, Sb, Zn, Fe, In, Al and Zr; 0.1a4 and 0.2b4 in which a and b are determined according to oxidation number of M; 0c<0.2 in which c is determined according to oxidation number of A; and A is at least one monovalent or divalent anion.

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

14. The secondary battery according to claim 13, wherein the secondary battery is a lithium secondary battery.

15. A battery module comprising the secondary battery according to claim 14 as a unit battery.

16. A battery pack comprising the battery module according to claim 15.

17. A device comprising the battery pack according to claim 16.

18. The device according to claim 17, wherein the device is an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a system for storing power.

19. The method according to claim 1 comprising treating a surface of the current collector to form an aluminum oxide (Al.sub.2O.sub.3) layer of greater than or equal to 10 nm and less than 20 nm on the current collector.

Description

MODE FOR INVENTION

(1) Now, the present invention will be described in more detail with reference to the following examples. These examples are provided only for illustration of the present invention and should not be construed as limiting the scope and spirit of the present invention.

Example 1

(2) The Al current collector was heated to 200 C. under a 50 mTorr oxygen atmosphere for 2 hours to form an aluminum oxide (Al.sub.2O.sub.3) layer on a surface of the Al current collector A. Thereafter, 90 wt % of LiNi.sub.0.5Mn.sub.1.5O.sub.4 as a cathode active material), 5 wt % of Super-P as a conductive material and 5 wt % of PVdF as a binder were added to NMP to manufacture a cathode mixture. The cathode mixture was coated on the Al current collector and, as such, a cathode for secondary batteries was manufactured.

Example 2

(3) A cathode for secondary batteries was manufactured in the same manner as in Example 1, except that the Al current collector was heated to 400 C. under a 50 mTorr oxygen atmosphere for 2 hours to form an aluminum oxide (Al.sub.2O.sub.3) layer on a surface of the Al current collector A.

Example 3

(4) A cathode for secondary batteries was manufactured in the same manner as in Example 1, except that the Al current collector was heated to 200 C. under a 100 mTorr oxygen atmosphere for 2 hours to form an aluminum oxide (Al.sub.2O.sub.3) layer on a surface of the Al current collector A.

Example 4

(5) A cathode for secondary batteries was manufactured in the same manner as in Example 1, except that the Al current collector was heated to 400 C. under a 100 mTorr oxygen atmosphere for 2 hours to form an aluminum oxide (Al.sub.2O.sub.3) layer on a surface of the Al current collector A.

Example 5

(6) A cathode for secondary batteries was manufactured in the same manner as in Example 1, except that the Al current collector was heated to 100 C. under a 50 mTorr oxygen atmosphere for 2 hours to form an aluminum oxide (Al.sub.2O.sub.3) layer on a surface of the Al current collector A.

Example 6

(7) A cathode for secondary batteries was manufactured in the same manner as in Example 1, except that a surface of the Al current collector A was not heated.

Experimental Example 1

(8) Thicknesses and adhesive strengths of cathodes manufactured according to Examples 1 to 6 were measured. Results are shown in Table 1 below:

(9) TABLE-US-00001 TABLE 1 Thickness of Al.sub.2O.sub.3 (nm) Adhesive strength (gf/cm) Example 1 15 38 Example 2 20 42 Example 3 25 43 Example 4 30 49 Example 5 10 34 Example 6 5 32

(10) As shown in Table 1 above, it can be confirmed that in Examples 1 to 6, reactivity of aluminum and oxygen is high with increasing a temperature and pressure and thus the aluminum oxide layers thicken and, accordingly, adhesive strengths increases with increasing thickness of the aluminum oxide layers.

INDUSTRIAL APPLICABILITY

(11) As described above, a method of manufacturing an electrode for secondary batteries according to the present invention includes surface-treating an Al current collector to form an aluminum oxide (Al.sub.2O.sub.3) layer having a predetermined thickness and thus may increase a surface area of the current collector and, accordingly, adhesion between the current collector and an electrode active material is enhanced, whereby overall performance of a secondary battery, such as charging and discharging cycle characteristics and the like, may be enhanced.

(12) 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.