KR20180061672A - Electrode for electrochemical device and method for manufacturing the same - Google Patents

Abstract

The present invention relates to an electrode for an electrochemical device and a method for manufacturing the same. The present invention provides the electrode for an electrochemical device, which comprises: a metal current collector; and an electrode active material layer formed on one surface or both surfaces of the metal current collector, wherein the electrode active material layer is immersed in a deposition solution containing phenol resin and a solvent and thus, coated with the phenol resin. In addition, the present invention provides a method for manufacturing the electrode, the method comprising: a first step of preparing a metal current collector and an electrode having the electrode active material layer formed on the one or both surfaces of the metal current collector; a second step of acquiring a deposition solution containing phenol resin and a solvent; and a third step of immersing the electrode in the plating solvent to coat the electrode. According to the present invention, it is possible to prevent damages to the electrode caused by volume expansion and to reduce internal resistance, and thus, the electrode has superior electrical properties while the electrode is able to secure reliability and longevity for a relatively long time.

Description

ELECTRODE FOR ELECTROCHEMICAL DEVICE AND METHOD FOR MANUFACTURING THE SAME

The present invention relates to an electrode for an electrochemical device and a method of manufacturing the same. More particularly, the present invention relates to an electrode for an electrochemical device, and more particularly to an electrode for an electrochemical device, (Long-life property) according to the present invention, and a method for manufacturing the same.

Electrochemical devices that store and discharge energy through charge and discharge are widely used in many technical fields. For example, electric double layer capacitors (EDLC) have high output and long life characteristics and are thus usefully applied as high output energy storage devices. However, electric double layer capacitors (EDLC) have a limited energy density, which is limited to other secondary batteries, especially lithium ion secondary batteries. Recently, a lithium ion capacitor (LiC), which satisfies the high output and long life characteristics of an electric double layer capacitor (EDLC) and a high energy density characteristic of a lithium ion secondary battery, has been developed and received a spotlight And the application field is further expanded, and the demand in the market is increasing rapidly.

The lithium ion capacitor (LiC) hybridizes two reactions of surface physical adsorption reaction in an electric double layer capacitor (EDLC) and energy storage by inserting and desorbing lithium ions in a lithium ion secondary battery. This is a conventional hybrid electric double layer capacitor (EDLC) has an asymmetric electrode structure and has a high energy density of more than twice that of electric double layer capacitors (EDLC), and about four times more.

Lithium ion capacitors (LiC) require a lithium (Li) source as in lithium ion secondary batteries, unlike electric double layer capacitors (EDLC). Generally, in the case of a lithium ion secondary battery, the electrode itself may be made of lithium oxide to provide a sufficient lithium source. However, in the case of a lithium ion capacitor (LiC), the anode is a carbonaceous material such as activated carbon. . Although a lithium source is supplied using an electrolyte solution in which a lithium salt is dissolved, it is difficult to realize a high energy density of a lithium ion capacitor (LiC).

Accordingly, the lithium ion capacitor (LiC) is capable of storing and discharging energy through the movement of lithium ions through charge and discharge through a separate lithium source. The most commonly used method is to pre-dope lithium before or after assembling the product by attaching a lithium metal foil to the cathode, and this is commonly referred to as " pre-doping. &Quot; In this way, when pre-doped, a high energy density can be obtained by maintaining the potential of the cathode at the same potential as the potential of the lithium metal during charging / discharging of the lithium ion capacitor (LiC). For example, Korean Patent Registration No. 10-1128654, Korean Patent Registration No. 10-1179629, and Korean Patent Laid-Open No. 10-2015-0059726 disclose techniques related to the above.

Further, in an electrochemical device using lithium, for example, an electrochemical device such as a lithium ion capacitor (LiC) or a lithium ion secondary battery, a negative electrode is very important in determining electrical characteristics. Particularly, in the negative electrode, a process of storing and releasing energy by repeating insertion and desorption processes of lithium ions is continuously performed. In this case, the volume change (volume expansion) of the negative electrode is essential in the process of inserting and removing lithium ions, which causes considerable stress and pressure on the electrode, thereby causing damage (deterioration or destruction) of the electrode. This volume change is larger as the amount of lithium ions used increases, that is, as the magnitude of the output increases. Generally, in the case of a high-output lithium-ion capacitor (LiC), the maximum discharge output has a high output power of 500 C-Rate or higher. In this case, the volume change occurring in the cathode is very severe. And ultimately can not function as an energy storage element.

Therefore, techniques for preventing the change in the volume of the negative electrode are applied, and in the case of the lithium ion secondary battery, the volume change is prevented by using the mixed electrode in most cases. For example, Korean Patent Laid-Open Nos. 10-2013-0134241, 10-2015-0039555, and Japanese Laid-Open Patent Application No. 2011-90869 disclose a method of manufacturing a negative electrode by mixing a carbon material and SiOx as an anode active material, Technology is presented.

In the case of a lithium ion capacitor (LiC), there has been attempted to reduce the electrode density in manufacturing the negative electrode to set a certain space margin in the electrode and to suppress volume change using a mixed electrode such as a lithium ion secondary battery . However, when the electrode density is lowered, the energy density is decreased, and the high output characteristic, which is a main feature of the lithium ion capacitor (LiC), is degraded. Further, when a mixed electrode as in a lithium ion secondary battery is used, the performance as a high output can not be exhibited due to an increase in the inherent resistivity of the negative electrode active material. In addition, in this case, the electrostatic capacitance is reduced due to the mixing of different electrode materials, and the electrode is difficult to form in the process of forming the electrode.

In any case, if the lithium ion implantation and desorption process is continuously performed by long-term charge and discharge, degradation of the product progresses according to the use period, and the long-term reliability is accompanied with a decrease in the reliability of the lithium ion capacitor (LiC) It also has a negative effect on the semi-permanent charge / discharge life, which is a great advantage. Generally, the charge / discharge life of a lithium ion secondary battery is estimated to be about 1000 times in normal charge / discharge activities, whereas the charge / discharge life of an electric double layer capacitor (EDLC) and a lithium ion capacitor (LiC) exceeds several hundred thousand times It is difficult to have such unique characteristics. Accordingly, the output density of a lithium-ion capacitor (LiC) is significantly lower than that of a general electric double-layer capacitor (EDLC), and the internal resistance of the same standard product is less than that of a conventional electric double- , And the limit of applicability has appeared recently.

Therefore, lithium-ion capacitor (LiC) is a very important technology that can reduce the internal resistance of the cathode, which can be improved to a level comparable to that of general electric double layer capacitors (EDLC) There is a need for a technique capable of maintaining long-term reliability (long-life characteristics) and maintaining high output characteristics, which can be called intrinsic characteristics.

Korean Patent Registration No. 10-1128654 Korean Patent Registration No. 10-1179629 Korean Patent Publication No. 10-2015-0059726 Korean Patent Publication No. 10-2013-0134241 Korean Patent Publication No. 10-2015-0039555 Japanese Laid-Open Patent Application No. 2011-90869

Accordingly, it is an object of the present invention to provide an electrode for electrochemical devices and an electrode for electrochemical devices capable of securing a long-term reliability and a long-life characteristic due to repetitive charging and discharging while preventing damage to electrodes due to volume expansion and reducing internal resistance, There is a purpose in providing a method.

According to an aspect of the present invention,

A first step of preparing an electrode including a metal current collector and an electrode active material layer formed on one or both surfaces of the metal current collector;

A second step of obtaining a deposit liquid containing a phenol resin and a solvent; And

And a third step of immersing and coating the electrode on the immersion liquid.

According to a preferred embodiment, the immersion liquid comprises from 2% to 25% by weight of phenolic resin. In addition, the third step may include a step of obtaining an electrode body having an electrode fixed to a support, and a step of immersing and coating the electrode body with the immersion liquid.

The electrode active material layer is formed on one side or both sides of the metal current collector. The electrode active material layer is immersed in a plating solution containing a phenol resin and a solvent, An electrode for a chemical device is provided.

According to the present invention, by coating the phenolic resin through the deposition, damage of the electrode due to the volume expansion is prevented, and the internal resistance is reduced, thereby having excellent electrical characteristics. Further, according to the present invention, it has excellent long-term reliability and long-life characteristics.

1 is a cross-sectional view showing an example of a lithium ion capacitor as an electrochemical device.
2 is a photograph showing a state in which a negative electrode sheet is attached to a carbon plate according to an embodiment of the present invention.
FIG. 3 is a photograph showing a state in which an electrode body is put into an acupuncture bath according to an embodiment of the present invention.
4 is a photograph of an electrode after deposition coating according to an embodiment of the present invention.

The term "and / or" used in the present invention is used to mean at least one of the constituents listed before and after. The term "one or more" as used in the present invention means one or more than two. In the present invention, terms such as "first", "second", "one side (one side)" and "other side (another side)" are used to distinguish one element from another, But is not limited by the terms.

As described above, in the electrochemical device using lithium, volume change (volume expansion) of the electrode (negative electrode) is essentially caused by insertion and desorption of lithium ions due to charging and discharging. Such a change in volume causes damage (deterioration or destruction) of the electrode and deteriorates the electrical characteristics. In order to prevent this, conventionally, attempts have been made to reduce (prevent) the change in the volume of the electrode during the insertion and desorption of lithium ions through the use of a mixed electrode or a change in electrode density. However, such a method lowers the internal resistance and output characteristics of the electrode, and complicates the manufacturing process of the electrode. In addition, the long-term reliability of the electrochemical device deteriorates.

The present invention is based on the discovery that a new method of recovering from a reduction (prevention) of the above-described conventional volume change and having a corresponding response (recovery) to a volume change is applied so that even if a volume change due to insertion and desorption of lithium ions occurs The present invention relates to a novel technique capable of preventing damage (deterioration or destruction) of an electrode, improving internal resistance characteristics, output characteristics, and the like, thereby providing long-term reliability.

According to a first aspect of the present invention, there is provided an electrode for an electrochemical device into which a new technique is introduced. According to a second aspect of the present invention, there is also provided a method of manufacturing an electrode for an electrochemical device into which a new technique is introduced.

An electrode for an electrochemical device according to the present invention includes a metal current collector and an electrode active material layer formed on the surface of the metal current collector. At this time, the electrode active material layer is immersed in a plating solution containing a phenol resin and a solvent and coated with a phenol resin. An electrode for an electrochemical device (hereinafter abbreviated as "electrode") according to the present invention is preferably a method for producing an electrode for an electrochemical device according to the present invention Quot; abbreviated ").

A method of manufacturing an electrode according to the present invention includes a first step of preparing an electrode, a second step of obtaining a deposition solution containing a phenol resin and a solvent, and a third step of depositing and coating the electrode in the deposition solution . DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the electrode manufacturing method according to the present invention will be described, and embodiments of the electrode according to the present invention will be described together.

In the present invention, the electrochemical device is an energy storage device, as long as it uses lithium. In the present invention, the electrochemical device is selected from, for example, a lithium ion capacitor (LiC) and a rechargeable secondary battery, and the following description will be given taking a lithium ion capacitor (LiC) as an example. In addition, the electrode according to the present invention is applied to the cathode of the electrochemical device, and in some cases, it can be applied as a cathode. Hereinafter, a description will be made by taking the case where it is applied as a cathode.

[1] Preparation of Electrode (First Step)

First, an electrode is prepared according to the first step. As the electrode, for example, an electrode (cathode) manufactured by a conventional method can be used. The electrode includes a metal current collector and an electrode active material layer formed on the metal current collector. The electrode active material layer may be formed on one side of the metal current collector or on both sides of the metal current collector.

The metal current collector is not particularly limited, and for example, a metal foil selected from copper (Cu), aluminum (Al), nickel (Ni), lithium (Li) and / or an alloy thereof may be used. The metal current collector may be selected from a porous punched metal foil including a plurality of punching holes. The punching hole may have an average diameter of, for example, 0.05 mm to 0.5 mm. In addition, the metal current collector may have a thickness of, for example, 10 μm to 50 μm, and may have a thickness of 20 μm to 30 μm, for example. As the metal current collector, for example, a porous copper punching metal having a punching hole of 0.1 mm can be used.

The electrode active material layer is not particularly limited and may be configured as usual. The electrode active material layer may include an electrode active material capable of intercalating and deintercalating lithium ions, and the electrode active material may include a carbon material. The carbon material may be, for example, graphite (artificial graphite and / or natural graphite), graphitized carbon fiber, graphitized mesocarbon microbead, petroleum coke, hard carbon, soft carbon, carbon nanotube and / And the like. According to one embodiment, the electrode active material layer may include a carbon material such as graphite and / or polyacene (polyacene semiconductors) as an electrode active material.

The electrode active material layer may be formed by coating an electrode active material composition (paste or slurry) including an electrode active material (carbon material), a binder and a conductive material on the surface of the metal current collector. The binder and the conductive material are not particularly limited and may be selected from conventionally used ones. The binder may be, for example, polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), polyvinylidene fluoride (PVDF), and / Copolymers and the like. The conductive material may be selected from, for example, Ketchen black, Denka black, carbon black, acetylene black and / or metal powder and the like.

[2] Dipping solution preparation (second step)

According to the second step, a deposition liquid containing a phenol resin and a solvent is obtained. The solvent may be any one capable of dissolving the phenolic resin. The solvent may be selected from hydrocarbon-based organic solvents, and may be selected from, for example, alcohols and / or ketones. Specific examples of the solvent may be selected from methyl alcohol, ethyl alcohol, isopropyl alcohol and / or methyl ethyl ketone and the like.

Electrodes are immersed in the immersion liquid for coating. By such deposition coating, the electrode is coated with a phenolic resin. At this time, the phenolic resin is coated and dispersed on the electrode active material layer of the electrode, and is dispersed among the electrode active material constituting the electrode active material layer, specifically, the carbon material as described above. The phenolic resin functions as a crosslinking material connecting the electrode active material, which also imparts elasticity between the electrode active materials.

As described above, the present invention has been developed in a manner of reducing the volume change of the electrode, so that it has a response (volume recovery) to the volume change through the coating of phenol resin by immersion. Specifically, according to the present invention, even if a phenol resin coated or dispersed in an electrode active material imparts elasticity between electrode active materials, thereby causing volume expansion, relaxation of the expansion and restoration of the original state can be performed to damage the electrode, .

In general, a binder for binding an electrode active material is used for manufacturing the electrode. Examples of the binder include polytetrafluoroethylene (PTFE), styrene rubber, cellulosic and polyvinylidene fluoride Has been used. However, this type of binder has the characteristics of an insulating material, and when the content of the binder is increased for the rigidity of the electrode, the internal resistance of the electrode is increased and the capacitance is reduced.

According to the present invention, when a phenolic resin other than the above-mentioned kind of resin used as a binder is deposited and coated, in particular, the phenolic resin penetrates between the binder and the electrode active material as described above, It is found that it improves. In addition, it was found that the phenolic resin plays a role of crosslinking between the binder and the electrode active material and provides elasticity to prevent electrode damage due to volume expansion. As a result, it was found that the increase in the internal resistance of the electrode and the decrease in the electrostatic capacity due to the volume expansion were suppressed. In particular, despite repeated charge and discharge, high capacity retention ratio And it has long-term reliability and long-life characteristics.

Further, according to the present invention, it was found that the concentration of the immersion liquid (content of the phenolic resin) acts as an important technical factor for improving the above characteristics. According to a preferred embodiment of the present invention, the concentration of the immersion liquid is preferably 2 to 25% by weight. That is, the content (solid content) of the phenol resin based on the total weight of the immersion liquid is preferably 2 to 25% by weight. The phenol resin is commercially available, and a high concentration phenol resin solution having a solid content of 30 wt% or more can be used. At this time, when such a high-concentration phenol resin solution is used, it is preferable to use a solvent (isopropyl alcohol or the like) to dilute it and titrate it to a concentration of 2 to 25% by weight (based on solid content).

When the content of the phenol resin is too low as less than 2% by weight in the concentration of the immersion liquid, the effect as described above due to the immersion coating of the phenol resin may be insignificant. Specifically, when the content of the phenol resin is less than 2% by weight, the ability to impart crosslinkability and stretchability upon immersion coating of the phenolic resin is weak, so that the effect of preventing damage to the electrode and improving the electrical characteristics may be insignificant. If the content of the phenol resin is more than 25% by weight, the internal resistance may be increased, and the long-term reliability such as the capacity retention rate may not be preferable. Considering this point, the concentration of the immersion liquid is preferably 5 to 20% by weight, more preferably 5 to 15% by weight. This can be confirmed by the following examples. The immersion liquid is not particularly limited, but may have a viscosity of, for example, about 400 to 1,000 mPa · s.

[3] Deposition coating (third step)

An electrode is immersed in the immersion liquid. For example, a phenol resin and a solvent may be mixed in an immersion bath to obtain an immersion liquid having an appropriate concentration, and then an electrode may be immersed in the immersion liquid. At this time, the immersion coating can be performed while stirring the immersion liquid in the immersion tank. Further, the deposition can be carried out at room temperature for 5 to 24 hours, for example.

According to an embodiment of the present invention, in consideration of handling property of the electrode, the third step may include a step of obtaining an electrode body having an electrode fixed to a support, and a step of immersing and coating the electrode body with the immersion liquid . Most of the electrodes are thin and flexible, so that handling may be inconvenient when immersed. However, when the electrode is immobilized on the support member as described above, handling of the electrode can be facilitated in the process of being introduced into the acupuncture water tank and in the process of taking out after immersion.

The support may be any one capable of supporting the electrode, and may have a plate-like shape corresponding to the shape of the electrode. The electrode can be attached and fixed to the support via the coupling means. The bonding means may be, for example, an adhesive and / or an adhesive tape.

The support preferably includes a carbon material which is the same as the carbon material constituting the electrode active material layer. Specifically, when the electrode active material layer constituting the electrode contains a carbon material as the electrode active material, it is preferable that the support uses a carbon material containing a carbon material having the same material as the carbon material as the electrode active material. For example, when the electrode active material of the electrode active material layer is graphite, it is preferable to use a graphite plate having graphite as its main material. Thus, the addition reaction can be suppressed (prevented). For example, when the electrode active material of the electrode active material layer is graphite and the support is made of a material other than graphite, the material constituting the support and the phenol resin of the deposit may react with each other to adversely affect the electrode.

After performing the above-described deposition, the electrode body (electrode + support) is taken out from the needle-applied water bath and dried (solvent volatilization). The drying can be carried out, for example, at a temperature of 100 to 200 DEG C under a nitrogen atmosphere. The third step may be repeated a plurality of times at least once, or twice or more, by performing the above-mentioned deposition and drying in one cycle. In one example, two to five runs may be performed. Thereafter, when the support is separated and removed from the electrode body, it is possible to complete the manufacture of the electrode coated with the phenolic resin through the deposition according to the present invention.

The electrode manufactured through the above process can be used as a negative electrode of a lithium ion capacitor (LiC) or a lithium ion secondary battery. According to a specific embodiment, it can be usefully used as a cathode of a lithium ion capacitor (LiC). In the present invention, the lithium ion capacitor (LiC) may be selected from, for example, a coin type, a winding type, a prismatic type, and a pouch type.

1 is a cross-sectional view showing an example of a coin type lithium ion capacitor (LiC). 5, a lithium ion capacitor LiC includes an anode can A, an anode can C, an anode can C, and an anode can C, And may include a cathode 10A and an anode 10C as elements. A separator S may be interposed between the cathode 10A and the anode 10C and a gasket G may be provided on the side surfaces of the separator S and the cathode 10A and the anode 10C. Further, a lithium metal foil L for supplying lithium may be attached to the cathode 10A. At this time, the cathode 10A may be composed of the electrode of the present invention as described above. The anode 10C is the same as usual.

According to the present invention described above, the coating of the phenolic resin through the deposition as described above prevents the electrode from being damaged due to the volume expansion and improves the electrical characteristics such as the internal resistance and the capacitance. In addition, it has a high capacity retention rate even after 10,000 repetitive charge / discharge cycles, for example, and has long-term reliability and long-life characteristics.

In addition, according to the present invention, as compared with a conventional method of using a mixed electrode or a method of changing the density of electrodes to reduce the volume expansion, it is possible to prevent the damage of the electrode due to the volume expansion by a simple method through deposition coating, It is also advantageous in terms of economic efficiency.

Hereinafter, examples and comparative examples of the present invention will be exemplified. The following examples are provided to illustrate the present invention only and the technical scope of the present invention is not limited thereto.

[Example]

≪ Preparation of positive electrode &

A positive electrode was prepared by applying a slurried polyacene cathode active material to an aluminum porous metal current collector having a thickness of 20 탆. At this time, the positive electrode active material is formed by mixing a polytetrafluoroethylene (PTFE) powder as a conductive material, a black graphite material of Ketjenblack and denka black as a conductive material in a polyacene semiconducting powder (PAS) A slurry to which isopropyl alcohol was added was used. This slurry was coated on an aluminum metal current collector and then dried in a nitrogen atmosphere at 180 캜 for about 12 hours.

≪ Preparation of negative electrode &

(1) Negative electrode sheet

A porous copper punching metal having a punching hole of 0.1 mm formed in a copper foil (Cu) having a thickness of 30 탆 was used as a metal collector, and the negative electrode active material composition was applied thereto. At this time, the negative electrode active material composition is prepared by mixing, as a negative electrode active material, a polytetrafluoroethylene (PTFE) powder as a conductive material, a black graphite material of Ketjenblack and denka black as a conductive material in a polyacene semiconducting powder (PAS) And a slurry to which isopropyl alcohol (isopropyl alcohol) was added as a solvent was used. This slurry was coated on a copper punching metal and dried in a nitrogen atmosphere at 180 캜 for about 12 hours to prepare a negative electrode sheet having a negative electrode active material layer on both sides of a copper punching metal.

(2) Manufacture of immersion liquid

A phenolic resin adhesive (solid content: about 40% by weight) used as an adhesive between metals was purchased in the market, and it was mixed with isopropyl alcohol (solvent) in a dip application bath and titrated to an appropriate concentration. As shown in Table 1 below, the content of the phenol resin (concentration of the immersion liquid) was varied depending on the amounts of the phenol resin adhesive and the isopropyl alcohol used, Respectively. In Table 1 below, the content of the phenolic resin (concentration of the immersion liquid) is the solid content of the phenolic resin based on the total weight of the immersion liquid. After the addition of isopropyl alcohol, the mixture was stirred at about 500 rpm for about 24 hours in an immersion bath to smoothly disperse the phenolic resin, thereby completing the immersion liquid.

(3) Immersion coating

The negative electrode sheet prepared above was adhered and fixed to a plate-like support through taping to form an electrode body. These electrode bodies were put into the dip coating bath, and the dip coating was performed while stirring the dip coating liquid for 12 hours. At this time, in order to prevent a side reaction, the support was made of a carbon material having the same carbon material as that of the anode active material layer, that is, a polyacene semiconducting conductor (PAS) as a main material. FIG. 2 is a photograph showing a state in which a negative electrode sheet is attached to a carbon plate, and FIG. 3 is a photograph showing a state in which an electrode body is put in a needle applying tank.

Thereafter, the immersed electrode body was taken out from the water bath, and then dried in a nitrogen atmosphere at 180 캜 to volatilize the solvent. This deposition process and drying process were repeated 3 times in total. At the time of the repeated deposition, the concentration of the immersion liquid was measured from time to time, and the initial concentration was maintained by supplementing with isopropyl alcohol or phenol resin. Through this, the cross - linkability of the negative electrode active material was established by coating the negative electrode with phenol resin. 4 is a photograph showing a state after deposition coating.

(4) Pre-doping

Next, after separating and removing the carbon plate, a lithium metal foil was attached to one side of the anode coated with phenol resin, then impregnated with the electrolytic solution and pre-doped at 80 ° C for about 24 hours to complete the cathode. The electrolytic solution was prepared by dissolving hexafluoride lithium salt in propylene carbonate solvent at 1.0M.

<LiC cell fabrication and evaluation of electrical characteristics>

The negative electrode and the positive electrode thus prepared were cut to a predetermined size and then impregnated with an electrolyte (1.0 M lithium hexafluoride) through a separator to form a coin-type Φ6.8 mm x 1.4 mm LiC coin Cells were assembled and assembled. The voltage (V), the electrostatic capacity (F) and the internal resistance (m?) Of the LiC coin cell specimen according to each of the manufactured embodiments were evaluated in the initial cycle. The results are shown in Table 1 below. .

The LiC cell specimens according to the respective examples were subjected to charge and discharge 10,000 times, and the voltage (V), the electrostatic capacity (F) and the internal resistance (m?) Of the last cycle (10,000 cycles) Are shown in Table 2 below. (Charging / discharging test: Charging 3.8V 5mA 30sec, discharging 3.8 ~ 2.2V 100μA 30sec)

[Comparative Example 1]

A LiC coin cell specimen was prepared in the same manner as in Example 1 except that the coating (deposition) of the phenol resin was not carried out in the preparation of the negative electrode. The electrical characteristics of the LiC coin cell specimen according to this comparative example were evaluated in the initial (1 cycle) and the latter (10,000 cycles) in the same manner as in Example 1. The results are shown in Table 1 and Table 2 below. .

              <Evaluation results of electrical characteristics of cell specimen (initial / 1 cycle)> Remarks Concentration of immersion liquid
(Content of phenolic resin) Voltage
[V] Capacitance
[F] Internal resistance
[mΩ] Example 1
2 wt% 3.8 0.28 45.2 Example 2
5 wt% 3.8 0.32 30.3 Example 3
10 wt% 3.8 0.36 28.4 Example 4
15 wt% 3.8 0.30 42.5 Example 5
20 wt% 3.8 0.25 48.6 Example 6
25 wt% 3.8 0.21 51.8 Comparative Example 1
Uncoated 3.8 0.20 64.3

            <Evaluation results of electrical characteristics of cell specimen (late / 10,000 cycle)> Remarks Phenolic
Coating (deposition) conditions Voltage
[V] Capacitance
[F] Internal resistance
[mΩ] Example 1
2 wt% 3.8 0.11 65.2 Example 2
5 wt% 3.8 0.28 32.3 Example 3
10 wt% 3.8 0.35 29.7 Example 4
15 wt% 3.8 0.22 67.5 Example 5
20 wt% 3.8 0.18 88.6 Example 6
25 wt% 3.8 0.07 120.4 Comparative Example 1
Uncoated 3.8 0.002 -

As shown in [Table 1] and [Table 2], according to the examples of the present invention, the cell specimens (Examples 1 to 6) to which the anode coated with the phenol resin through the deposition were applied It was found that the electrical characteristics were superior to those of the cell specimen (Comparative Example 1), and the internal resistance was remarkably improved, in particular.

In addition, the cell specimen (Comparative Example 1) which did not undergo the deposit coating exhibited the function as an energy storage device due to the change of the structure of the electrode due to the insertion and desorption of lithium and the destruction of the electrode in the long term charge-discharge test (10,000 cycles) I could not see that I could not.

Also, in comparison with Examples 1 to 6, it was found that the electrical characteristics were varied depending on the concentration of the immersion liquid (the content of the waste resin). In these examples, excellent electrical characteristics were exhibited not only in the initial characteristics but also after 10,000 charge / discharge cycles when the concentration of the immersion liquid was 5 to 20 wt% (Examples 2 to 5). In particular, when the concentration of the immersion liquid was 5 to 15% by weight (Examples 2 to 4), there was no significant change in capacitance and internal resistance even after 10,000 cycles of charging and discharging. In addition, in this embodiment, the optimum optimum characteristics were obtained at a concentration of 10 wt% of the immersion liquid.

A: anode can C: anode can
10A: cathode 10C: anode
L: lithium metal foil S: separator
G: Gasket

Claims (7)

A first step of preparing an electrode including a metal current collector and an electrode active material layer formed on one or both surfaces of the metal current collector;
A second step of obtaining a deposit liquid containing a phenol resin and a solvent; And
And a third step of immersing and coating the electrode on the immersion liquid.
The method according to claim 1,
Wherein the immersion liquid comprises 2 wt% to 25 wt% of a phenolic resin.
The method according to claim 1,
Wherein the immersion liquid comprises 5 wt% to 15 wt% of a phenolic resin.
The method according to claim 1,
In the third step,
Obtaining an electrode body having the electrode fixed to a support,
And immersing and coating the electrode body in the immersion liquid.
5. The method of claim 4,
Wherein the electrode active material layer includes a carbon material as an electrode active material, a binder, and a conductive material,
Wherein the support comprises a carbon material which is the same as the carbon material constituting the electrode active material layer.
The metal housing,
And an electrode active material layer formed on one or both surfaces of the metal current collector,
Wherein the electrode active material layer is immersed in a plating solution containing a phenol resin and a solvent and coated with a phenol resin.
The method according to claim 6,
Wherein the electrode for an electrochemical device is manufactured by the method for manufacturing an electrode for an electrochemical device according to any one of claims 1 to 5.

Images