U.S. patent application number 15/196548 was filed with the patent office on 2017-11-23 for metal foil, metal foil manufacturing method and method for manufacturing electrode using the same.
The applicant listed for this patent is KOREA JCC CO., LTD.. Invention is credited to So Yeon HAN, Rae Cheol KANG, Mun Soo LEE, Ji Yoon PARK, Dal Woo SHIN, Jin Sik SHIN.
Application Number | 20170338493 15/196548 |
Document ID | / |
Family ID | 57485285 |
Filed Date | 2017-11-23 |
United States Patent
Application |
20170338493 |
Kind Code |
A1 |
SHIN; Dal Woo ; et
al. |
November 23, 2017 |
METAL FOIL, METAL FOIL MANUFACTURING METHOD AND METHOD FOR
MANUFACTURING ELECTRODE USING THE SAME
Abstract
Provided are a metal foil, a metal foil manufacturing method and
a method for manufacturing an electrode using the same, in which
the adhesion between the metal foil and a conductive resin layer
and the coating performance of the conductive resin layer can be
improved by treating the surface of the metal foil. The metal foil
comprises: a metal base substrate; a surface treatment layer formed
on at least one surface of the metal base substrate by treating the
surface of the metal base substrate; and a conductive resin layer
applied to the surface of the surface treatment layer, wherein the
surface treatment layer has a surface energy of 34-46 dyne/cm.
Inventors: |
SHIN; Dal Woo; (Cheongju-si,
KR) ; LEE; Mun Soo; (Cheongju-si, KR) ; SHIN;
Jin Sik; (Cheongju-si, KR) ; HAN; So Yeon;
(Cheongju-si, KR) ; KANG; Rae Cheol; (Cheongju-si,
KR) ; PARK; Ji Yoon; (Cheongju-si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KOREA JCC CO., LTD. |
Cheongwon-gun |
|
KR |
|
|
Family ID: |
57485285 |
Appl. No.: |
15/196548 |
Filed: |
June 29, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
Y02E 60/10 20130101;
H01M 4/663 20130101; C23C 22/66 20130101; H01M 4/583 20130101; H01M
10/052 20130101; H01M 4/661 20130101; H01M 4/668 20130101; Y02E
60/13 20130101; H01M 4/525 20130101; H01M 4/623 20130101; H01G
11/68 20130101; H01G 11/84 20130101; H01M 4/0404 20130101; H01M
4/667 20130101; H01M 10/0525 20130101; H01G 11/66 20130101; C23C
22/63 20130101 |
International
Class: |
H01M 4/66 20060101
H01M004/66; H01M 4/62 20060101 H01M004/62; H01M 4/583 20100101
H01M004/583; H01M 4/525 20100101 H01M004/525; H01M 10/0525 20100101
H01M010/0525; H01M 4/04 20060101 H01M004/04 |
Foreign Application Data
Date |
Code |
Application Number |
May 23, 2016 |
KR |
10-2016-0062864 |
Claims
1. A metal foil comprising: a metal base substrate; a surface
treatment layer formed on at least one surface of the metal base
substrate by treating the surface of the metal base substrate; and
a conductive resin layer applied to the surface of the surface
treatment layer, wherein the surface treatment layer is formed by
treating the surface of the metal base substrate with a surface
treatment solution, the surface treatment solution being prepared
by mixing 3-10 wt % of an alkaline metal oxide, 0.1-10 wt % of a
surfactant, 0.5-10 wt % of a reducing agent and 70-96.4 wt % of
deionized water to prepare an undiluted surface treatment solution,
and diluting 3-10 wt % of the undiluted surface treatment solution
with 90-97 wt % of deionized water, the surface treatment layer
having a surface energy of 34-46 dyne/cm.
2. The metal foil of claim 1, wherein the metal base substrate is
formed in a foil shape and made of aluminum or copper.
3. The metal foil of claim 1, wherein the surface treatment layer
is formed by treating the surface of the metal base substrate with
the surface treatment solution at a temperature of 60 to 85.degree.
C. for 3-20 seconds.
4. The metal foil of claim 1, wherein the conductive resin layer is
formed of one material selected from among acrylic resin,
nitrocellulose and chitosan.
5. A method for manufacturing a metal foil, comprising the steps
of: preparing a surface treatment solution; treating a surface of a
metal base substrate by dipping a metal base substrate in the
surface treatment solution while spraying the surface treatment
solution onto the surface of the metal base substrate, thereby
forming a surface treatment layer on the metal base substrate; and
applying a conductive resin to the surface of the surface treatment
layer to form a conductive resin layer, wherein the surface
treatment solution is prepared by mixing 3-10 wt % of an alkaline
metal oxide, 0.1-10 wt % of a surfactant, 0.5-10 wt % of a reducing
agent and 70-96.4 wt % of deionized water to prepare an undiluted
surface treatment solution, and diluting 3-10 wt % of the undiluted
surface treatment solution with 90-97 wt % of deionized water.
6. The method of claim 5, wherein the alkaline metal oxide that is
used in the step of preparing the surface treatment solution is one
selected from among sodium hydroxide, sodium carbonate, and sodium
metasilicate; the surfactant is selected from among sodium oleate,
polyoxyethylene alkylphenyl ether, and sodium myristate; and the
reducing agent is selected from among sodium metasilicate, sodium
silicate, benzthiazol, and benzimidazole.
7. The method of claim 5, wherein the surface treatment solution is
prepared using sodium hydroxide as the alkaline metal oxide, sodium
oleate as the surfactant, and sodium metasilicate as the reducing
agent; or the surface treatment solution is prepared using sodium
carbonate as the alkaline metal oxide, polyoxyethylene alkylphenyl
ether as the surfactant, and sodium silicate as the reducing agent;
or the surface treatment solution is prepared using sodium
metasilicate as the alkaline metal oxide, sodium myristate as the
surfactant, and benzthiazol or benzimidazole as the reducing
agent.
8. The method of claim 5, wherein the surface treatment solution is
prepared by mixing 3-8 wt % sodium hydroxide as an alkaline metal
oxide, 0.1-1 wt % of sodium oleate as a surfactant, 0.5-3 wt %
sodium metasilicate of a reducing agent and 88-96.4 wt % of
deionized water to prepare an undiluted surface treatment solution,
and diluting 3-10 wt % of the undiluted surface treatment solution
with 90-97 wt % of deionized water, and treating the surface of the
metal base substrate with the surface treatment solution having the
above-described composition is performed by dipping the metal base
substrate in the surface treatment solution for 3-13 seconds in a
state in which the surface treatment solution is maintained at a
temperature of 60 to 70.degree. C.; the surface treatment solution
is prepared by mixing 4-10 wt % sodium carbonate as as an alkaline
metal oxide, 3-10 wt % of polyoxyethylene alkylphenyl ether as the
surfactant, 4-6 wt % sodium silicate of a reducing agent and 74-89
wt % of deionized water to prepare an undiluted surface treatment
solution, and diluting 3-10 wt % of the undiluted surface treatment
solution with 90-97 wt % of deionized water, and treating the
surface of the metal base substrate with the surface treatment
solution having the above-described composition is performed by
dipping the metal base substrate in the surface treatment solution
for 5-15 seconds in a state in which the surface treatment solution
is maintained at a temperature of 70 to 80.degree. C.; the surface
treatment solution is prepared by mixing 5-10 wt % sodium
metasilicate as an alkaline metal oxide, 0.1-8 wt % sodium
myristate of as the surfactant, 0.1-3 wt % benzthiazol or
benzimidazole of a reducing agent and 79-94.8 wt % of deionized
water to prepare an undiluted surface treatment solution, and
diluting 3-10 wt % of the undiluted surface treatment solution with
90-97 wt % of deionized water, and treating the surface of the
metal base substrate with the surface treatment solution having the
above-described composition is performed by dipping the metal base
substrate in the surface treatment solution for 10-20 seconds in a
state in which the surface treatment solution is maintained at a
temperature of 75 to 85.degree. C.
9. The method of claim 5, wherein the metal base substrate that is
used in the step of treating the surface of the metal base
substrate is formed in a foil shape and made of aluminum or copper,
and the step of forming the surface of the metal base substrate
comprises: storing the surface treatment solution in a surface
treatment bath; and dipping the metal base substrate in the surface
treatment solution for 3-20 seconds while spraying the surface
treatment solution onto the surface of the metal base substrate
through a nozzle disposed in the surface processing bath, in a
state in which the surface processing solution is maintained at a
temperature of 60 to 85.degree. C., thereby forming a surface
treatment layer having a surface energy of 34-46 dyne/cm on at
least one surface of the metal base substrate.
10. A method for manufacturing an electrode, comprising the steps
of: preparing a surface treatment solution; treating a surface of a
metal base substrate by dipping a metal base substrate in the
surface treatment solution while spraying the surface treatment
solution onto the surface of the metal base substrate, thereby
forming a surface treatment layer on the metal base substrate;
applying a conductive resin to the surface of the surface treatment
layer to form a conductive resin layer; and applying an electrode
material to the surface of the conductive resin layer to form an
electrode material layer, wherein the surface treatment solution is
prepared by mixing 3-10 wt % of an alkaline metal oxide, 0.1-10 wt
% of a surfactant, 0.5-10 wt % of a reducing agent and 70-96.4 wt %
of deionized water to prepare an undiluted surface treatment
solution, and diluting 3-10 wt % of the undiluted surface treatment
solution with 90-97 wt % of deionized water.
11. The method of claim 10, wherein the alkaline metal oxide that
is used in the step of preparing the surface treatment solution is
one selected from among sodium hydroxide, sodium carbonate, and
sodium metasilicate; the surfactant is selected from among sodium
oleate, polyoxyethylene alkylphenyl ether, and sodium myristate;
and the reducing agent is selected from among sodium metasilicate,
sodium silicate, benzthiazol, and benzimidazole.
12. The method of claim 10, wherein the metal base substrate that
is used in the step of treating the surface of the metal base
substrate is formed in a foil shape and made of aluminum or copper,
and the step of forming the surface of the metal base substrate
comprises dipping the metal base substrate in a surface processing
bath containing the surface treatment solution while spraying the
surface treatment solution onto the surface of the metal base
substrate through a nozzle disposed in the surface processing bath,
thereby forming a surface treatment layer having a surface energy
of 34-46 dyne/cm on at least one surface of the metal base
substrate.
13. The method of claim 10, wherein the electrode material layer
that is formed in the step of forming the electrode material layer
is formed of one of a cathode material and an anode material,
wherein the cathode material is one selected from among activated
carbon, LCO (lithium cobalt oxide), LMO (lithium manganese oxide),
and LFP (lithium iron phosphate), and the anode material is one
selected from among activated carbon, graphite, hard carbon, soft
carbon, silicone, and Li.sub.4Ti.sub.5O.sub.12, and wherein, when
activated carbon is selected as the cathode material, one of
activated carbon or Li.sub.4Ti.sub.5O.sub.12 is selected and used
as the anode material, and when one of LCO, LMO and LFP is selected
as the cathode material, one of graphite, hard carbon, soft carbon
and silicone is selected and used as the anode material.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of Korean Patent
Application No. 10-2016-0062864, filed on May 23, 2016 in the
Korean Intellectual Property Office, the disclosure of which is
incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The present invention relates to a metal foil, a metal foil
manufacturing method and a method for manufacturing an electrode
using the same, and more particularly, to metal foil, a metal foil
manufacturing method and a method for manufacturing an electrode
using the same, in which the adhesion between the metal foil and a
conductive resin layer and the coating performance of the
conductive resin layer can be improved by treating the surface of
the metal foil.
2. Description of the Related Art
[0003] Conventional lithium ion secondary batteries or electric
double layer capacitors have electrodes, and each of the electrodes
comprises an electrode material and a current collector to which
the electrode material is applied. The electrodes are required to
have high capacity per unit volume and low internal resistance so
that they can satisfy properties, including large current
charging/discharging capabilities, high energy density and high
output density. To satisfy such properties of the electrodes,
technology of reducing the interfacial resistance between the
electrode material and the current collector is required. A current
collector that is used in the cathode of a lithium ion secondary
battery or the electrode of an electrical double-layer capacitor is
formed of a metal foil such as an aluminum foil. The aluminum foil
is manufactured through a rolling process at high temperature and
high pressure, and rolling oil is used for cooling in this rolling
process. For these reasons, an aluminum oxide layer or an oil
layer, which is non-conductive, remains on the surface of the final
aluminum foil. The oxide layer or the oil layer has the problem of
increasing the interfacial resistance between the aluminum foil and
the electrode material. Particularly, the oil layer has the problem
of reducing the adhesion of the electrode material to cause the
peeling of the electrode material as charge/discharge cycles are
repeated, thereby reducing the output properties of the electrode
in charge/discharge cycles and reducing the calendar life of the
electrode.
[0004] Korean Patent No. 1357464 (Patent Document 1) and U.S. Pat.
No. 8,663,845 (Patent Document 2) disclose technologies in which an
conductive resin layer is formed between an aluminum foil and an
electrode material to reduce the interfacial resistance between the
aluminum foil and the electrode material and increase the adhesion
therebetween, thereby solving the above-described problem.
[0005] Korean Patent No. 1357464 (Patent Document 1) will now be
briefly described.
[0006] Korean Patent No. 1357464 relates to a secondary-battery
current collector, a secondary battery cathode, a secondary battery
anode, a secondary battery, and a manufacturing method thereof, in
which the secondary-battery current collector comprises an aluminum
or copper foil having a coating layer containing a compound
obtained by cross-linking at least one polysaccharide polymer,
selected from the group consisting of chitin and chitosan, with an
acid anhydride, and fine carbon particles. Herein, the coating
layer has a thickness of 0.1-10 .mu.m, and the fine carbon
particles have a particle size of 10-100 nm.
[0007] In the case of the current collector disclosed in Korean
Patent No. 1357464, an conductive resin layer is applied to the
surface of the metal foil in order to improve the adhesion of the
electrode material to the surface. This metal foil has problems in
that, because an oxide layer or an oil layer remain on the metal
foil during the manufacturing process, the conductive resin layer
is not easily applied to the metal foil, and the applied conductive
resin layer is easily peeled, resulting in an increase in the
interfacial resistance between the metal foil and the electrode
material. In addition, it has a problem in that the electrode
material applied to the conductive resin layer is also peeled,
resulting in a decrease in the output and calendar
lifecharacteristics of the lithium ion secondary battery or the
electrical double-layer capacitor.
PATENT DOCUMENTS
[0008] Patent Document 1: Korean Patent No. 1357464 (registered on
Jan. 23, 2014);
[0009] Patent Document 2: U.S. Pat. No. 8,663,845 (registered on
Mar. 3, 2014);
SUMMARY OF THE INVENTION
[0010] Accordingly, the present invention has been made in order to
solve the above-described problems, and it is an object of the
present invention to provide a metal foil, a metal foil
manufacturing method and a method for manufacturing an electrode
using the same, in which the adhesion between the metal foil and a
conductive resin layer and the coating performance of the
conductive resin layer can be improved by treating the surface of
the metal foil.
[0011] Another object of the present invention is to provide a
metal foil, a metal foil manufacturing method and a method for
manufacturing an electrode using the same, in which the adhesion
between the metal foil and a conductive resin layer and the coating
performance of the conductive resin layer can be improved by
treating the surface of the metal foil, thereby alleviating the
peeling of an electrode material from the metal foil to thereby
reduce the interfacial resistance of the metal foil.
[0012] Still another object of the present invention is to provide
a metal foil, a metal foil manufacturing method and a method for
manufacturing an electrode using the same, in which the adhesion
between the metal foil and a conductive resin layer and the coating
performance of the conductive resin layer can be improved by
treating the surface of the metal foil, thereby alleviating the
peeling of an electrode material from the metal foil to thereby
reduce the interfacial resistance of the metal foil, thereby
improving the output and calendar lifecharacteristics of a lithium
ion secondary battery or an electrical double-layer capacitor when
the electrode of the present invention is applied to the lithium
ion secondary battery or the electrical double-layer capacitor.
[0013] To achieve the above objects, the present invention provides
a metal foil comprising: a metal base substrate; a surface
treatment layer formed on at least one surface of the metal base
substrate by treating the surface of the metal base substrate; and
a conductive resin layer applied to the surface of the surface
treatment layer, wherein the surface treatment layer has a surface
energy of 34-46 dyne/cm.
[0014] The present invention also provides a method for
manufacturing a metal foil, comprising the steps of: preparing a
surface treatment solution; treating the surface of a metal base
substrate by dipping the metal base substrate in the surface
treatment solution while spraying the surface treatment solution
onto the surface of the metal base substrate, thereby forming a
surface treatment layer on the metal base substrate; and applying a
conductive resin to the surface of the surface treatment layer to
form a conductive resin layer, wherein the surface treatment
solution is prepared by mixing 3-10 wt % of an alkaline metal
oxide, 0.1-10 wt % of a surfactant, 0.5-10 wt % of a reducing agent
and 70-96.4 wt % of deionized water to prepare an undiluted surface
treatment solution, and diluting 3-10 wt % of the undiluted surface
treatment solution with 90-97 wt % of deionized water.
[0015] The present invention also provides a method for
manufacturing an electrode, comprising the steps of: preparing a
surface treatment solution; treating the surface of a metal base
substrate by dipping the metal base substrate in the surface
treatment solution while spraying the surface treatment solution
onto the surface of the metal base substrate, thereby forming a
surface treatment layer on the metal base substrate; applying a
conductive resin to the surface of the surface treatment layer to
form a conductive resin layer; and applying an electrode material
to the surface of the conductive resin layer to form an electrode
material layer, wherein the surface treatment solution is prepared
by mixing 3-10 wt % of an alkaline metal oxide, 0.1-10 wt % of a
surfactant, 0.5-10 wt % of a reducing agent and 70-96.4 wt % of
deionized water to prepare an undiluted surface treatment solution,
and diluting 3-10 wt % of the undiluted surface treatment solution
with 90-97 wt % of deionized water.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The above and/or other aspects of the present invention will
become apparent and more readily appreciated from the following
description of the exemplary embodiments, taken in conjunction with
the accompanying drawings in which:
[0017] FIG. 1 is a cross-sectional view of an electrode having a
metal foil applied thereto according to the present invention.
[0018] FIG. 2 is a cross-sectional view showing another example of
the metal foil shown in FIG. 1.
[0019] FIG. 3 is a cross-sectional view showing still another
example of the metal foil shown in FIG. 1.
[0020] FIG. 4 is a process flow chart showing a method for
manufacturing an electrode using a metal foil manufacturing method
of the present invention.
[0021] FIG. 5 is a side view of an apparatus for forming the
surface treatment layer shown in FIG. 1.
[0022] FIGS. 6 and 7 are photographs showing a state in which a
conductive resin solution was applied to the surface of an aluminum
foil.
[0023] FIGS. 8 and 9 are photographs showing the results of a tape
peeling test and peeling test performed on conductive resin layers
formed in an electrode manufacturing method shown in FIG. 4.
[0024] FIG. 10 is a table showing the results of electrical tests
performed on electrodes manufactured by an electrode manufacturing
method shown in FIG. 4.
[0025] FIGS. 11 and 12 are graphs showing the results of electrical
tests performed on electrodes manufactured by an electrode
manufacturing method shown in FIG. 4.
DETAILED DESCRIPTION OF THE INVENTION
[0026] Reference will now be made in detail to exemplary
embodiments of the present invention, examples of which are
illustrated in the accompanying drawings, wherein like reference
numerals refer to the like elements throughout. Exemplary
embodiments are described below to explain the present invention by
referring to the figures.
[0027] Hereinafter, examples of a metal foil according to the
present invention, a method for manufacturing the metal foil, and a
method for manufacturing an electrode using the same, will be
described with reference to the accompanying drawings.
[0028] As shown in FIGS. 1 to 3, a metal foil 10 according to the
present invention comprises a metal base substrate 11, a surface
treatment layer 12 and a conductive resin layer 13.
[0029] The metal base substrate 11 corresponds to the base portion
of the metal foil 10, and the surface treatment layer 12 is formed
on at least one surface of the metal base substrate 11 by treating
the surface of the metal base substrate 11. Namely, as shown in
FIG. 1, the surface treatment layer 12 is formed on the upper
surface of the metal base substrate 11, or as shown in FIGS. 2 and
3, the surface treatment layer 12 is formed on both the upper and
lower surfaces of the metal base substrate 11.
[0030] The surface treatment layer 12 is formed to have a surface
energy of 34-46 dyne/cm, and the conductive resin layer 13 is
formed on the surface of the surface treatment layer 12.
[0031] The configuration of the metal foil 10 according to the
present invention will now be described in detail.
[0032] As shown in FIGS. 1 to 5, the metal base substrate 11 is
formed in a foil shape and made of aluminum or copper.
[0033] As shown in FIGS. 1 to 3, the surface treatment layer 12 is
formed by treating the surface of the metal base substrate 11 with
a surface treatment solution so as to have a surface energy of
34-46 dyne/cm. Namely, the surface treatment layer 12 is formed
between the metal base substrate 11 and the conductive resin layer
13 so as to have a surface energy of 34-46 dyne/cm, thereby
increasing the adhesion of the conductive resin layer 13 to the
surface of the metal base substrate 11 and improving the coating
performance of the conductive resin layer 13 to exhibit the
reliability of coating work. As used herein, the term "coating
performance" refers to an extent to which the conductive resin
layer 13 is adhered uniformly and closely to the surface of the
metal base substrate 11 by the surface treatment layer 12 so as to
have a uniform thickness. The surface treatment solution is
prepared by mixing 3-10 wt % of an alkaline metal oxide, 0.1-10 wt
% of a surfactant, 0.5-10 wt % of a reducing agent and 70-96.4 wt %
of deionized water to prepare an undiluted surface treatment
solution, and diluting 3-10 wt % of the undiluted surface treatment
solution with 90-97 wt % of deionized water.
[0034] As shown in FIGS. 1 to 3, the conductive resin layer 13 is
formed by applying a conductive resin material to the surface of
the surface treatment layer 12 so as to be adhered closely to the
surface of the metal base substrate 11 by the surface energy of the
surface treatment layer 12.
[0035] As shown in FIG. 1, the conductive resin layer 13 is
disposed on the upper surface of the surface treatment layer 12, or
as shown in FIG. 2, the conductive resin layer 13 is disposed on
the upper surface of the surface treatment layer 12, on which the
electrode material layer 14 is to be formed, among the two surface
treatment layers 12. Alternatively, as shown in FIG. 3, the
conductive resin layer 13 is disposed on both the upper and lower
surfaces of the surface treatment layer 12.
[0036] This conductive resin layer 13 is formed of a conductive
resin material selected from among acrylic resin, nitrocellulose
and chitosan.
[0037] A method for manufacturing the above-described metal foil 10
of the present invention will now be described.
[0038] In the method for manufacturing the metal foil 10 of the
present invention, as shown in FIG. 4, a surface treatment solution
is first prepared (S11). In addition, the metal base substrate 11
is formed in a foil shape and is made of aluminum or copper. The
surface treatment solution for treating the surface of the metal
base substrate 11 is prepared by mixing 3-10 wt % of an alkaline
metal oxide, 0.1-10 wt % of a surfactant, 0.5-10 wt % of a reducing
agent and 70-96.4 wt % of deionized water to prepare an undiluted
surface treatment solution, and diluting 3-10 wt % of the undiluted
surface treatment solution with 90-97 wt % of deionized water.
[0039] The alkaline metal oxide that is used to prepare the surface
treatment solution is one selected from among sodium hydroxide,
sodium carbonate, and sodium metasilicate, and the surfactant that
is used to prepare the surface treatment solution is one selected
from among sodium oleate, polyoxyethylene alkylphenyl ether, and
sodium myristate. In addition, the reducing agent that is used to
prepare the surface treatment solution is one selected from among
sodium metasilicate, sodium silicate, benzthiazol, and
benzimidazole.
[0040] For preparation of the surface treatment solution, the
surfactant and the reducing agent are suitably selected depending
on the kind of alkaline metal oxide. For example, when sodium
hydroxide is used as the alkaline metal oxide, sodium oleate is
used as the surfactant, and sodium metasilicate is used as the
reducing agent. When sodium carbonate is used as the alkaline metal
oxide, polyoxyethylene alkylphenyl ether is used as the surfactant,
and sodium silicate is used as the reducing agent. When sodium
metasilicate is used as the alkaline metal oxide, sodium myristate
is used as the surfactant, and benzthiazol or benzimidazole is used
as the reducing agent.
[0041] After preparation of the surface treatment solution, as
shown in FIGS. 4 and 5, the metal base substrate 11 is dipped in
the surface treatment solution to treat the surface of the metal
base substrate 11 (S12).
[0042] Treatment of the surface of the metal base substrate 11 is
performed by storing the surface treatment solution in a surface
processing bath 110 in an apparatus for manufacturing the surface
treatment layer 12, that is, a roll-to-roll apparatus shown in FIG.
5, and then dipping the metal base substrate 11 in the surface
treatment solution for 3-20 seconds in a state in which the surface
treatment solution is maintained at a temperature of 60 to
85.degree. C. For example, treatment of the surface is performed by
disposing the surface treatment solution-containing surface
processing bath 110 between a winding roller 120 and a withdrawal
roller 130, and then moving the metal base substrate 11 wound
around the winding roller 120 in the arrow direction in such a
manner as to be dipped in the surface processing bath 110 for 3-20
seconds.
[0043] An example of the surface treatment solution stored in the
surface processing bath 110 contains sodium hydroxide as the
alkaline metal oxide, sodium oleate as the surfactant, and sodium
metasilicate as the reducing, in which the alkaline metal oxide,
the surfactant and the reducing agent are used in amounts of 3-8 wt
%, 0.1-1 wt % and 0.5-3 wt %, respectively. If the sodium hydroxide
is used in an amount of more than 8 wt %, it can corrode the metal
base substrate 11, and if the sodium metasilicate is used in an
amount of more than 3 wt %, it will be excessively reduced to form
an oxide layer on the surface of the metal base substrate 11, and
thus can cause failure of the metal foil 10. That is, the surface
treatment solution is prepared by mixing 3-8 wt % sodium hydroxide
as an alkaline metal oxide, 0.1-1 wt % of sodium oleate as a
surfactant, 0.5-3 wt % sodium metasilicate of a reducing agent and
88-96.4 wt % of deionized water to prepare an undiluted surface
treatment solution, and diluting 3-10 wt % of the undiluted surface
treatment solution with 90-97 wt % of deionized water.
[0044] Treatment of the surface of the metal base substrate 11 with
the surface treatment solution having the above-described
composition is performed by dipping the metal base substrate 11 in
the surface treatment solution for 3-13 seconds in a state in which
the surface treatment solution is maintained at a temperature of 60
to 70.degree. C.
[0045] Another example of the surface treatment solution contains
sodium carbonate as the alkaline metal oxide, polyoxyethylene
alkylphenyl ether as the surfactant, and sodium silicate as the
reducing agent, in which the alkaline metal oxide, the surfactant
and the reducing agent are used in amounts of 4-10 wt %, 3-10 wt %
and 4-6 wt %, respectively. That is, the surface treatment solution
is prepared by mixing 4-10 wt % sodium carbonate as as an alkaline
metal oxide, 3-10 wt % of polyoxyethylene alkylphenyl ether as the
surfactant, 4-6 wt % sodium silicate of a reducing agent and 74-89
wt % of deionized water to prepare an undiluted surface treatment
solution, and diluting 3-10 wt % of the undiluted surface treatment
solution with 90-97 wt % of deionized water. Treatment of the
surface of the metal base substrate 11 with the surface treatment
solution having this composition is performed by dipping the metal
base substrate 11 in the surface treatment solution for 5-15
seconds in a state in which the surface treatment solution is
maintained at a temperature of 70 to 80.degree. C.
[0046] Still another example of the surface treatment solution
contains sodium metasilicate as the alkaline metal oxide, sodium
myristate as the surfactant, and benzthiazol or benzimidazole as
the reducing agent, in which the alkaline metal oxide, the
surfactant and the reducing agent are used in amounts of 5-10 wt %,
0.1-8 wt % and 0.1-3 wt %, respectively. That is, the surface
treatment solution is prepared by mixing 5-10 wt % sodium
metasilicate as an alkaline metal oxide, 0.1-8 wt % sodium
myristate of as the surfactant, 0.1-3 wt % benzthiazol or
benzimidazole of a reducing agent and 79-94.8 wt % of deionized
water to prepare an undiluted surface treatment solution, and
diluting 3-10 wt % of the undiluted surface treatment solution with
90-97 wt % of deionized water. Treatment of the surface of the
metal base substrate 11 with the surface treatment solution having
this composition is performed by dipping the metal base substrate
11 in the surface treatment solution for 10-20 seconds in a state
in which the surface treatment solution is maintained at a
temperature of 75 to 85.degree. C.
[0047] The surface treatment step (S12) in the present invention is
performed using dipping and nozzle spray methods. In the dipping
method in the surface treatment step (S12), the metal base
substrate 11 is dipped in the surface treatment solution so that
the surface treatment layer 12 is formed throughout at least one
surface of the metal base substrate 11. In the nozzle spray method
in the surface treatment step (S12), the surface treatment solution
is sprayed vertically onto the surface of the metal base substrate
11 so that a smooth surface treatment layer 12 is formed throughout
at least one surface of the metal base substrate 11.
[0048] As shown in FIG. 5, a nozzle 140 that is used in the nozzle
spray method is disposed at both sides of the surface processing
bath 110. The surface treatment solution that is sprayed through
the nozzle 140 is the same as the surface treatment solution stored
in the surface processing bath 110.
[0049] The surface treatment step (S12) is performed such that a
surface treatment layer 12 having a surface energy of 34-46 dyne/cm
is formed on the surface of the metal base substrate 11. The
surface energy range was determined by the applicant for the
following reasons. When the surface of the metal base substrate 11
was treated to have a surface energy of 34 dyne/cm or higher, the
adhesion between the metal base substrate 11 and the conductive
resin layer 13 was increased, and the uniform coating properties of
the conductive resin layer 13 were ensured. Such results were found
in many repeated experiments. In addition, although the surface
energy of the metal base substrate 11 is preferably as high as
possible, an additional cost is required to increase the surface
energy, and for this reason, the surface energy is limited to an
upper limit of 46 dyne/cm in the present invention. Thus, the upper
limit of the surface energy can further be increased according to
the user's needs.
[0050] As the surface energy of the surface treatment layer 12 is
closer to the surface tension of the conductive resin solution, the
wettability of the metal base substrate 11 with the conductive
resin solution increases and acts as a driving force for adhesion,
and thus the adhesion between the metal base substrate 11 and the
conductive resin layer 13 and the coating performance of the
conductive resin layer 13 increase.
[0051] Generally, the term "surface tension" refers to a tension
that acts to reduce the free surface area of liquid. A molecule
present near the surface of liquid has a potential energy greater
than a molecule present in the liquid, and thus has a surface
energy proportional to the surface area of the liquid.
[0052] To measure this surface energy, the dyne test is used. The a
dyne test is a method in which a solution having an already known
dyne value (i.e., characteristic surface tension value) is applied
to the surface of a material whose surface energy is to be
measured, and then the surface energy of the material is measured
based on the aggregation or spreading property of the solution. In
other words, the dyne test is a method of measuring surface energy
in comparison with a specific surface tension value, and the
waiting time for observation is 4 sec for 30-44 dyne/cm and 2 sec
for 45-60 dyne/cm. The surface energy is given in units of dyne/cm.
As used herein, the term "dyne" refers to the force required to
give a mass of 1 g an acceleration of 1 cm/s.sup.2.
[0053] Examples of the method for forming the surface treatment
layer 12 having a surface energy of 34-46 dyne/cm are shown in
FIGS. 1 to 3. FIG. 1 shows an example in which the surface
treatment layer 12 is formed on the upper surface of the metal base
substrate 11 by using the surface treatment solution. In this
example, the surface treatment layer 12 is formed using the surface
treatment solution in a state in which the lower surface of the
metal base substrate is masked. Herein, the masking is performed by
bonding a known insulating film to the lower surface of the metal
base substrate 11 by an adhesive or applying a known insulating
material thereto. For example, when the roll-to-roll apparatus as
shown in FIG. 5 is used for formation of the surface treatment
layer 12, the masking is performed by bonding a known insulating
film to the lower surface of the metal base substrate 11 by an
adhesive. FIGS. 2 and 3 show examples in which the surface
treatment layer 12 is formed on both the upper and lower surfaces
of the metal base substrate 11 by treating the entire surface of
the metal base substrate 11 with the surface treatment solution
without masking.
[0054] The conductive resin layer 13 is formed using a conductive
resin solution. A method for preparing the conductive resin
solution using a conductive resin material is known, and thus the
description thereof is omitted herein. In addition, the surface
tension of the conductive resin solution is known, and thus the
description thereof is omitted herein. The conductive resin
solution is dried at a temperature of 150 to 200.degree. C. for
2-15 minutes to provide the conductive resin layer 13.
[0055] After completion of the surface treatment, as shown in FIGS.
1 to 5, a conductive resin is applied to the surface of the surface
treatment layer 12 to form the conductive resin layer 13 (S13),
thereby manufacturing the metal foil 10. FIG. 1 shows an example in
which one conductive resin layer 13 is formed on the upper surface
of the surface treatment layer 12 formed on the upper surface of
the metal base substrate 11. FIG. 2 shows another example in which
one conductive resin layer 13 is formed in the same manner as the
example shown in FIG. 1, except that the surface treatment layer 12
is formed on both the upper and lower surfaces of the metal base
substrate 11, after which the conductive resin layer 13 is formed
on the upper surface of the surface treatment layer 12 formed on
the upper surface of the metal base substrate 11. FIG. 3 shows
still another example two surface treatment layers 12 and two
conductive resin layers 13 are formed by forming the surface
treatment layer 12 on both the upper and lower surfaces of the
metal base substrate 11, and then forming the conductive resin
layer 13 not only on the upper surface of the surface treatment
layer 12 formed on the upper surface of the metal base substrate
11, but also on the lower surface of the surface treatment layer 12
formed on the lower surface of the metal base substrate 11.
[0056] The conductive resin layer 13 is formed by applying a
conductive resin solution, and a method for preparing the
conductive resin solution using a conductive resin material is
known, and thus the description thereof is omitted herein. The
conductive resin material that is used in the present invention is
one selected from among acrylic resin, nitrocellulose and
chitosan.
[0057] A method for manufacturing an electrode of the present
invention using the metal foil 10 as described above will now be
described.
[0058] As shown in FIGS. 1 to 5, a method for manufacturing an
electrode according to the present invention comprises the steps
of: (S11) preparing a surface treatment solution; (S12) dipping a
metal base substrate 11 in the prepared surface treatment solution
while spraying the surface treatment solution onto the surface of
the metal base substrate 11, thereby treating the surface of the
metal base substrate 11; (S13) applying a conductive resin to the
treated surface of the surface treatment layer 12 to form a
conductive resin layer 13; and (S14) forming an electrode material
layer 14 on the conductive resin layer 13.
[0059] The metal foil manufacturing steps (S11 to S13) in the
electrode manufacturing method according to the present invention
are similar to the method for manufacturing the metal foil 10 as
described above, and thus the detailed description thereof is
omitted herein.
[0060] After completion of the metal foil 10, as shown in FIGS. 1
to 4, an electrode material is applied to the surface of the
conductive resin layer 13 to form an electrode material layer 14
(S14).
[0061] As shown in FIG. 1, when one electrode material layer 14 is
to be formed, it is formed on the upper surface of the conductive
resin layer 13 after the surface treatment layer 12 and the
conductive resin layer 13 are sequentially formed on the upper
surface of the metal base substrate 11.
[0062] In another example shown in FIG. 2, one electrode material
layer 14 is formed. In this example, the surface treatment layer 12
is formed on both the upper and lower surfaces of the metal base
substrate 11, and then the conductive resin layer 13 and the
electrode material layer 14 are sequentially formed on the upper
surface of the surface treatment layer 12 formed on the upper
surface of the metal base substrate 11.
[0063] In still another example shown in FIG. 3, two electrode
material layers 14 are formed. In this example, the surface
treatment layer 12 and the conductive resin layer 13 are
sequentially formed on both the upper and lower surfaces of the
metal base substrate 11, and then the electrode material layer 14
is formed not only on the upper surface of the conductive resin
layer 13 disposed on the metal base substrate 11, but also on the
lower surface of the conductive resin layer 13 disposed under the
metal base substrate 11.
[0064] The electrode material layer 14 is formed of one of a
cathode (positive electrode) material and an anode (negative
electrode) material, and each of the cathode material and the anode
material is applied using a silk printing method or a roll-to-roll
method. The cathode material that is applied using the silk
printing method or the roll-to-roll method is one selected from
activated carbon and metal oxides, including LCO (lithium cobalt
oxide), LMO (lithium manganese oxide) and LFP (lithium iron
phosphate), and the anode material is one selected from among
activated carbon, graphite, hard carbon, soft carbon, silicone, and
Li.sub.4Ti.sub.5O.sub.12.
[0065] Regarding the selection of the cathode material and the
anode material, when the electrode that is manufactured by the
electrode manufacturing method of the present invention is applied
to an electrical double-layer capacitor or a hybrid capacitor,
activated carbon is selected as the cathode material, and one of
activated carbon and Li.sub.4Ti.sub.5O.sub.12 is selected as the
anode material. Specifically, when the electrode that is
manufactured by the electrode manufacturing method of the present
invention is applied to an electrical double-layer capacitor,
activated carbon is selected as the cathode material, and activated
carbon is used as the anode material, and when the electrode is
applied to a hybrid capacitor, activated carbon is used as the
cathode material, and one selected from among activated carbon and
Li.sub.4Ti.sub.5O.sub.12 is used as the anode material. When the
electrode that is manufactured by the electrode manufacturing
method of the present invention is applied to a lithium ion
secondary battery, one selected from among LCO, LMO and LFP is used
as the cathode material, and one selected from among graphite, hard
carbon, soft carbon, and silicone is used as the anode
material.
[0066] In order to test the above-described metal foil and
electrode of the present invention, a metal foil, an electrode and
a lithium ion secondary battery comprising the electrode were
manufactured according to the metal foil manufacturing method and
electrode manufacturing method of the present invention.
Example 1
[0067] In Example 1 of the present invention, a physical test was
performed to examine the state of application of a conductive resin
solution used to form the conductive resin layer 13, based on
whether the surface treatment layer 12 (shown in FIG. 1) was formed
on the surface of the metal base substrate 11 (shown in FIG. 1) of
the metal foil 10 (shown in FIG. 1). In Example 1 of the present
invention, an aluminum foil (Al235) was used as the metal base
substrate 11.
[0068] The aluminum foil (Al235) used had a thickness of 20 .mu.m,
and a surface treatment layer 12 was formed on the surface of the
aluminum foil. The surface treatment layer 12 was formed to have a
surface energy value of 44 dyne/cm by dipping the aluminum foil in
a surface treatment solution (stored in a surface processing bath
110 (shown in FIG. 5)) at a temperature of 60.degree. C. for 8
seconds while spraying the surface treatment solution onto the
surface of the aluminum foil through a nozzle 140 (see FIG. 5).
Herein, the surface treatment solution was prepared by mixing 4 wt
% of sodium hydroxide as an alkaline metal oxide, 0.5 wt % of
sodium oleate as a surfactant, 2 wt % of sodium metasilicate as a
reducing agent, and 93.5 wt % of deionized water, and diluting 5 wt
% of the mixture with 95 wt % of deionized water. As the surface
treatment solution sprayed through the nozzle 140, the same
solution as the surface treatment solution stored in the surface
processing bath 110 was used.
[0069] To each of the surface of the aluminum foil having the
surface treatment layer 12 formed thereon according to Example 1 of
the present invention and the surface of an aluminum foil having no
surface treatment layer 12 formed thereon, a conductive resin
solution for forming the conductive resin layer 13 was applied. The
results of application of the conductive resin solution are shown
in FIGS. 6 and 7. FIGS. 6 and 7 show the result of testing the
application of the conductive resin solution in the present
invention. The application of the conductive resin layer 13 (shown
in FIG. 1) could be tested based on the state of application of the
conductive resin solution after drying of the applied conductive
resin solution.
[0070] FIG. 6 shows a state in which the conductive resin solution
for forming the conductive resin layer 13 was applied to the
surface of the aluminum foil having no surface treatment layer 13
formed thereon. In FIG. 6, the region indicated by gray indicates
the aluminum foil, and the region indicated by black indicates a
region applied with the conductive resin solution. FIG. 7 shows a
state in which the conductive resin solution for forming the
conductive resin layer 13 was applied to the surface of the surface
treatment layer 12 formed by treating the surface of the aluminum
foil in the present invention. In FIG. 7, the portion indicated by
black indicates a region applied with the conductive resin
solution. Herein, the conductive resin solution was prepared by
adding fine carbon particles and water to a chitosan compound
cross-linked with a conductive resin material, in which the
cross-linked chitosan compound, the fine carbon particles, and
water were used at a weight ratio of 30:20:50 (wt %). The
conductive resin solution was applied to the surface of the
aluminum foil by an automatic applicator (not shown).
[0071] The results of testing the application of the conductive
resin solution are as follows. As shown in FIG. 6, in the case in
which the surface treatment layer 12 was not formed, the adhesion
of the conductive resin solution to the surface of the aluminum
foil was poor, and the conductive resin solution aggregated so that
it would not be uniformly distributed on the surface of the
aluminum foil. On the contrary, as shown in FIG. 7, in the case in
which the surface treatment layer 12 was formed on the aluminum
foil, the black portion (i.e., the conductive resin solution) was
uniformly distributed throughout the surface of the aluminum foil
by the surface treatment layer 12, indicating that the conductive
resin solution was applied to the aluminum foil with high
adhesion.
Example 2
[0072] In Example 2 of the present invention, a conductive resin
layer 13 was prepared in order to perform a physical test (i.e.,
tape peeling test). Herein, the conductive resin layer 13 was
prepared by drying the conductive resin solution (shown in each of
FIGS. 6 and 7) in a drying furnace (not shown) at 180.degree. C.
for 8 minutes.
[0073] In the tape peeling test, to the surface of the conductive
resin layer 13 formed by drying the conductive resin solution shown
each of FIGS. 6 and 7, a polypropylene adhesive tape 150 (shown in
each of FIGS. 8 and 9) having a width of 10 mm and a length of 150
mm was adhered by applying an uniform load of 20.+-.0.4 N (Newton)
with the reciprocating movement of a press roller. After the
adhesive tape was adhered to the surface of the conductive resin
layer 13, the adhesive tape 150 was peeled off at a speed of 10
mm/s and an angle of 90.degree. by use of an automatic adhesion
tester (not shown), and whether the conductive resin layer 13 was
peeled off was observed.
[0074] As a result, as can be seen in FIG. 8, the conductive resin
layer 13 prepared by drying the conductive resin solution shown in
FIG. 6 was easily peeled off so that the surface of the aluminum
foil (i.e., metal base substrate 11) would be exposed. However, as
shown in FIG. 9, the conductive resin layer 13 prepared by drying
the conductive resin solution shown in FIG. 7 was adhered strongly.
In FIGS. 8 and 9, the black region indicates the conductive resin
layer 13, and the white region indicates the surface of the
aluminum foil (i.e., metal base substrate 11).
[0075] In a peeling test, the surface of the conductive resin
solution formed by drying the conductive resin solution shown each
of FIGS. 6 and 7 was rubbed with each of a cotton swab (not shown)
soaked with deionized water (aqueous solvent) and a cotton swab
(not shown) soaked with NMP (N-methyl-2-pyrrolidone) (organic
solvent), and the number of rubbings when the conductive resin
layer 13 started to be peeled off was measured.
[0076] As a result, the conductive resin layer 13 prepared by
drying the conductive resin solution shown in FIG. 6 was peeled
when it was rubbed 10 times with the aqueous solvent and when it
was rubbed 12 times with the organic solvent. However, the
conductive resin layer 13 prepared by drying the conductive resin
solution shown in FIG. 7 was not peeled off even when it was rubbed
50 times (standard value) with either of the aqueous solvent and
the organic solvent.
Example 3
[0077] In Example 3 of the present invention, an electrode 20
(shown in FIG. 1) and a lithium ion secondary battery (not shown)
comprising the electrode 20 were manufactured in order to test
electrical properties, including capacity retention rate,
impedance, and battery life span.
[0078] In Example 3 of the present invention, the electrode 20 was
manufactured by applying an electrode material layer 14 (shown in
FIG. 1) to the conductive resin layer 13 formed in Example 2 of the
present invention, that is, the conductive resin layer 13 formed by
drying the conductive resin solution shown in each of FIGS. 6 and
7.
[0079] The electrode material layer 14 was manufactured as a
cathode and an anode. For example, a cathode electrode 20 and an
anode electrode 20 were manufactured by applying each of a cathode
electrode and an anode material on the surface of the conductive
resin layer 13 formed by drying the conductive resin solution shown
in FIG. 6. In addition, using the conductive resin layer 13 formed
by drying the conductive resin solution shown in FIG. 7, a cathode
electrode 20 and an anode electrode 20 were manufactured in the
same manner as described above.
[0080] Among the electrodes 20 for manufacturing a lithium ion
secondary battery, the cathode was manufactured using lithium
cobalt oxide (LCO) as a cathode active material, carbon black as a
conductive material, and polyvinylidene difluoride (PVDF) as a
binder, which were mixed at a weight ratio of 92:3:5 (wt %). The
anode was manufactured using crystalline graphite as an anode
active material and PVDF as a binder, which were mixed at a weight
ratio of 90:10 (wt %).
[0081] After the cathode and the anode for a lithium ion secondary
battery were manufactured, a separator made of porous polyethylene
was interposed between the cathode and the anode, and an
electrolyte prepared by dissolving lithium hexafluorophosphate
(LiPF.sub.6) in a 5:5 solvent mixture of ethylene carbonate (EC)
and diethylene carbonate (DEC) at a concentration of 1 mol/L was
introduced into the resulting structure, thereby manufacturing a
lithium ion secondary battery. Specifically, a cathode electrode 20
and an anode electrode 20 were manufactured by applying a cathode
material and an anode material to the surface of the conductive
resin layer 13 formed by drying the conductive resin solution shown
in FIG. 6, and a lithium ion secondary battery (hereinafter
referred to as the "battery1") was manufactured using the
manufactured cathode electrode and anode electrode. In the same
manner, a cathode electrode 20 and an anode electrode 20 were
manufactured by applying a cathode material and an anode material
to the surface of the conductive resin layer 13 formed by drying
the conductive resin solution shown in FIG. 7, and a lithium ion
secondary battery (hereinafter referred to as the "battery 2") was
manufactured using the manufactured cathode electrode and anode
electrode.
[0082] To test the capacity retention rates of battery 1 and
battery 2 manufactured in Example 3 of the present invention, each
of the batteries was cycled for 200 cycles using a charge/discharge
tester (manufactured by TOYO SYSTEM) at a voltage ranging from 2.7
to 4.0 V, a temperature of 25.degree. C. and C-rates (current
rates) of 1C, 5C, 10C and 20C, and the ratio of the initial
capacity to the capacity after 200 cycles of each battery was
measured, thereby determining the capacity retention rate (%) of
each battery. As a result, as shown in FIG. 10, as the C-rate
increased, battery 2 comprising the electrode 20 of the present
invention showed a capacity retention rate higher than that of
battery 1.
[0083] To test the impedances of battery 1 and battery 2
manufactured in Example 3 of the present invention, the impedance
of each of the batteries was measured five times at a frequency of
1 kHz using an AC impedance tester (manufactured by HIOKI), and the
measurements were averaged for comparison. As a result, as shown in
FIG. 10, battery 2 comprising the electrode 20 of the present
invention showed an impedance value which was about 5 times lower
than that of battery 1.
[0084] To test the life spans of battery 1 and battery 2
manufactured in Example 3 of the present invention, each of the
batteries was charged/discharged for 800 cycles using a
charge/discharge tester (manufactured by TOYO SYSTEM) under the
conditions of constant current and constant voltage charge and
constant current discharge at 2C-rate, a voltage ranging from 2.7V
to 4.0V and a temperature of 45.degree. C., and the capacity and
resistance change rates over time (cycle) were measured. The
results of the measurement are shown in FIGS. 11 and 12. As shown
in FIGS. 11 and 12, it can be seen that the calendar life of
battery 2 comprising the electrode 20 of the present invention
significantly increased compared to that of battery 1. In the
graphs shown in FIGS. 11 and 12, the curve indicated by the dotted
line represents the characteristics of battery 1, and the curve
indicated by the solid line represents the characteristics of
battery 2.
[0085] As described above, according to the metal foil of the
present invention, the method for manufacturing the metal foil, and
the method for manufacturing an electrode using the same, the
adhesion between the metal foil and the conductive resin layer and
the coating performance of the conductive resin layer can be
improved by treating the surface of the metal foil, thereby
alleviating the peeling of the electrode material from the metal
foil to thereby reduce the interfacial resistance of the metal
foil. In addition, as a result of improving the adhesion between
the metal foil and the conductive resin layer and the coating
performance of the conductive resin layer to thereby alleviate the
peeling of the electrode material from the metal foil to thereby
reduce the interfacial resistance of the metal foil, the output and
calendar lifecharacteristics of a lithium ion secondary battery or
an electrical double-layer capacitor can be improved when the
electrode of the present invention is applied to the lithium ion
secondary battery or the electrical double-layer capacitor.
[0086] The metal foil of the present invention, the method for
manufacturing the metal foil, and the method for manufacturing an
electrode using the same, can be applied in the manufacture of
metal foils or electrodes and the manufacture of lithium ion
secondary batteries or electric double layer capacitors.
[0087] Although a few exemplary embodiments of the present
invention have been shown and described, the present invention is
not limited to the described exemplary embodiments. Instead, it
would be appreciated by those skilled in the art that changes may
be made to these exemplary embodiments without departing from the
principles and spirit of the invention, the scope of which is
defined by the claims and their equivalents.
* * * * *