KR101579578B1 - Preparation method of electrode, electrode formed therefrom, and electrochemical device having the same - Google Patents

Abstract

The present invention relates to a method for manufacturing an electrode, an electrode formed from the electrode, and an electrochemical device having the same. The method for manufacturing an electrode of the present invention comprises the steps of: (S1) dispersing first electrode active material particles in a first binder solution in which a first binder is dissolved in a solvent to prepare a first slurry; (S2) dispersing second electrode active material particles of a component different from the first electrode active material particles in a second binder solution in which the second binder is dissolved in a solvent to prepare a second slurry; (S3) sequentially coating the first slurry and the second slurry on the at least one surface of the current collector in the form of a layer, or (S3) applying the prepared first slurry and the second slurry to at least one surface of the current collector Independently applying each to the divided compartments; And (S4) removing the solvent from the result of (S3). According to the manufacturing method of the present invention, a plurality of active materials of different components can be applied to a current collector, and they can be applied to current collectors, which are incompatible with each other, Can be prepared.

Description

TECHNICAL FIELD The present invention relates to a method of manufacturing an electrode, an electrode formed from the electrode, and an electrochemical device having the same. BACKGROUND OF THE INVENTION [0002]

The present invention relates to a method for manufacturing an electrode, an electrode formed from the electrode, and an electrochemical device having the same.

Recently, interest in energy storage technology is increasing. As the application fields of cell phones, camcorders, notebook PCs and even electric vehicles are expanding, efforts for research and development of electrochemical devices are becoming more and more specified. The electrochemical device is one of the most attracting fields in this respect, and development of a rechargeable secondary battery is of particular interest.

The electrochemical device has been developed by various researches which have improved various performance of the positive electrode active material and the negative electrode active material as a result of continuous research. These various kinds of active materials are combined with the improved characteristics of each active material, Are usually used in the form of particles mixed with two or more kinds. However, in the mixing process of two or more kinds of active material particles, it is difficult to uniformly mix the active material particles due to their surface area, particle size, and the like.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a method of manufacturing an electrode which is applied to a current collector separately without mixing a plurality of desired electrode active materials, To provide a device.

According to one aspect of the present invention, there is provided a method of manufacturing an electrode, comprising: (S1) dispersing first electrode active material particles in a first binder solution in which a first binder is dissolved in a solvent to prepare a first slurry step; (S2) dispersing second electrode active material particles of a component different from the first electrode active material particles in a second binder solution in which the second binder is dissolved in a solvent to prepare a second slurry; (S3) sequentially coating the first slurry and the second slurry on the at least one surface of the current collector in the form of a layer; And (S4) removing the solvent from the result of (S3).

A method of manufacturing an electrode according to another aspect of the present invention includes the steps of: (S1) dispersing first electrode active material particles in a first binder solution in which a first binder is dissolved in a solvent to produce a first slurry; (S2) dispersing second electrode active material particles of a component different from the first electrode active material particles in a second binder solution in which the second binder is dissolved in a solvent to prepare a second slurry; (S3) applying the prepared first slurry and the second slurry independently from each other in at least one side of the current collector; And (S4) removing the solvent from the result of (S3).

An electrode according to an aspect of the present invention includes: (a) a current collector; (b) a first electrode active material layer coated on at least one surface of the current collector, the first electrode active material particles being bound by a first binder; And (c) a second electrode active material layer coated on the first electrode active material layer, wherein the second electrode active material particles having a component different from that of the first electrode active material particles are bound by a second binder.

According to another aspect of the present invention, there is provided an electrode comprising: (a) a current collector; (b) a first electrode active material layer coated on a first section of the current collector surface, the first electrode active material particles being bound by a first binder; And (c) a second electrode active material particle of a different composition from that of the first electrode active material particles is coated on a second section of the surface of the current collector separated from the first section, And an electrode active material layer.

According to the method of the present invention, a plurality of active materials having different characteristics can be applied to the current collector and the current collector can be efficiently complemented or complementary to the current collector in terms of battery performance although they are incompatible with each other.

1 is a process flow chart schematically showing a method of manufacturing an electrode according to an embodiment of the present invention.
2 is a process flow chart schematically showing a method of manufacturing an electrode according to another embodiment of the present invention.
3 is a cross-sectional view of a schematic electrode made in accordance with an embodiment of the present invention.
Figure 4 is a plan view of a schematic electrode made in accordance with another embodiment of the present invention.

Hereinafter, the present invention will be described in detail. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor may designate the concept of a term appropriately in order to describe its own invention in the best way possible. It should be interpreted as meaning and concept consistent with the technical idea of the present invention. Therefore, the constitutions described in the embodiments described herein are merely the most preferred embodiments of the present invention, and are not intended to represent all of the technical ideas of the present invention. Therefore, various equivalents which can be substituted at the time of application It should be understood that variations can be made.

According to an aspect of the present invention, an electrode can be manufactured as follows.

First, a first slurry is prepared by dispersing first electrode active material particles in a first binder solution in which a first binder is dissolved in a solvent (Step S1). That is, a binder suitable for a desired electrode active material is put in a solvent and dissolved to produce a binder solution. Then, the desired electrode active material particles are added to the resulting binder solution, and the mixture is further uniformly dispersed in the binder solution by stirring or the like using a mixer to prepare a slurry. The slurry thus prepared is referred to as a first slurry, which is distinct from the subsequently produced second slurry.

In the production method according to one aspect of the present invention, the electrode active material (i.e., the positive electrode active material and the negative electrode active material) and the current collector (i.e., the positive electrode collector and the negative electrode collector) of the present invention are not particularly limited, And can be prepared according to a conventional method or a modified method thereof.

The cathode active material may be a layered compound such as lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), or a compound substituted with at least one transition metal; A lithium manganese oxide (LiMnO ₂ ) such as LiMnO ₃ , LiMn ₂ O ₃ , LiMnO _2, etc. represented by the formula Li _{1 + x} Mn _{2 -x} O ₄ (where x is 0 to 0.33); Lithium copper oxide (Li ₂ CuO ₂ ); Vanadium oxides such as LiV ₃ O ₈ , LiFe ₃ O ₄ , V ₂ O ₅ and Cu ₂ V ₂ O ₇ ; A nickel-situ type lithium nickel oxide represented by the formula LiNi _1-x M _x O ₂ (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga and x = 0.01 to 0.3) oxide); Formula _{LiMn 2-x M x O 2} ( where, M = Co, Ni, Fe , Cr, and Zn, or Ta, x = 0.01 to 0.1 Im) or Li ₂ Mn ₃ MO ₈ (where, M = Fe, Co, Ni, Cu, or Zn); LiMn ₂ O _{4 in} which part of the lithium in the formula is substituted with an alkaline earth metal ion; Disulfide compounds; Fe ₂ (MoO ₄ ) _3, or a composite oxide formed of a combination of these materials, and the like, and are not limited thereto.

The cathode current collector has a thickness of 3 to 500 mu m, for example. Such a positive electrode current collector is not particularly limited as long as it has conductivity without causing chemical change in the battery. For example, the positive electrode current collector may be formed of a material such as carbon, stainless steel, aluminum, nickel, titanium, sintered carbon, , Nickel, titanium, silver, or the like may be used. The current collector may have fine irregularities on the surface thereof to increase the adhesive force of the cathode active material, and various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a nonwoven fabric are possible.

A conductive material may be further mixed with the positive electrode active material particles. Such a conductive material is added, for example, in an amount of 1 to 50% by weight based on the total weight of the mixture including the cathode active material. Such a conductive material is not particularly limited as long as it has high conductivity without causing a chemical change in the battery, for example, graphite such as natural graphite and artificial graphite; Carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and summer black; Conductive fibers such as carbon fiber and metal fiber; Metal powders such as carbon fluoride, aluminum, and nickel powder; Conductive whiskey such as zinc oxide and potassium titanate; Conductive oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used.

The binder is added to the binder in an amount of 1 to 50% by weight based on the total weight of the mixture containing the cathode active material, for example, as a component for bonding the cathode active material particles to the conductive material and bonding to the current collector. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene , Polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butylene rubber, fluorine rubber, various copolymers and the like.

Non-limiting examples of the solvent include acetone, tetrahydrofuran, methylene chloride, chloroform, dimethylformamide, N-methyl-2-pyrrolidone (N -methyl-2-pyrrolidone, NMP), cyclohexane, water, or a mixture thereof. These solvents provide an appropriate level of viscosity so that a slurry coating layer can be formed at a desired level on the collector surface.

The negative electrode is manufactured by coating and drying the negative electrode active material particles on the negative electrode collector, and may further include components such as the above-described conductive material, binder, solvent and the like, if necessary.

The negative electrode collector has a thickness of 3 to 500 mu m, for example. Such an anode current collector is not particularly limited as long as it has conductivity without causing chemical change in the battery, and may be formed of a material such as copper, stainless steel, aluminum, nickel, titanium, fired carbon, surface of copper or stainless steel A surface treated with carbon, nickel, titanium, silver or the like, an aluminum-cadmium alloy, or the like can be used. In addition, like the positive electrode collector, fine unevenness can be formed on the surface to enhance the bonding force of the negative electrode active material, and it can be used in various forms such as films, sheets, foils, nets, porous bodies, foams and nonwoven fabrics.

Examples of the negative electrode active material include carbon such as non-graphitized carbon and graphite carbon; _{Li x Fe 2 O 3 (0≤x≤1} ), Li x WO 2 (0≤x≤1), Sn x Me 1-x Me 'y O z (Me: Mn, Fe, Pb, Ge; Me' : Metal complex oxides of Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, halogen, 0 < x &lt; Lithium metal; Lithium alloy; Silicon-based alloys; Tin alloy; _{SnO, SnO 2, PbO, PbO} 2, Pb 2 O 3, Pb 3 O 4, Sb 2 O 3, Sb 2 O 4, Sb 2 O 5, GeO, GeO 2, Bi 2 O 3, Bi 2 O 4, Bi ₂ O ₅ and the like; Conductive polymers such as polyacetylene; Li-Co-Ni-based materials and the like can be used.

Also, the second electrode active material particles different from the first electrode active material particles are dispersed in a second binder solution in which the second binder is dissolved in a solvent to produce a second slurry (step S2). This step may use the same or similar process procedure as in step S1 except that the first electrode active material particles and other components are used, and the conductive material, binder and / or solvent exemplified in step S1 may be selected Can be used.

Thus, through this step, a second slurry of the second electrode active material particles having different characteristics from the first electrode active material particles (the first slurry containing the same) can be produced, and the two slurries of these different characteristics can be individually It is possible to incorporate the electrode active material having the specific properties required in the electrode into the electrode without any limitation without causing misalignment problems in the mixed slurries of two or more types as in the prior art do.

As described above, the first and second slurries may be prepared as the respective steps of preparing the separate slurry, and the order thereof is not important. That is, the order of steps S1 and S2 may be changed.

Then, the first slurry and the second slurry are individually applied to the current collector to produce a layer or a section of the electrode active material particles having the respective intrinsic properties (step S3).

For example, according to one embodiment of the present invention, the first slurry and the second slurry prepared in the step S2 are sequentially coated on at least one surface of the current collector in the form of a layer.

The application of the slurry can be carried out continuously or discontinuously by various methods such as slot die coating, slide coating, curtain coating and the like. In particular, in terms of productivity, it is preferable to perform the application continuously or simultaneously at the same time, an example of which is shown in FIG.

According to one embodiment with reference to Figure 1, a die 1 having two slots 3a, 3b may be used to effect the application of the slurry. The first slurry 7 is supplied through the first slot 3a and the second slurry 5 is supplied through the second slot 3b. When the current collector 9 is supplied to the rotating roller, the first slurry 7 is coated on the advancing current collector 9 and then the second slurry 5 is coated on the first slurry 7.

In another embodiment of this step S3, the first slurry and the second slurry prepared in the step S3 may be independently coated on at least one side of the current collector.

In this regard, referring to FIG. 2, the modified form of the die 1 of FIG. 1 is shown as a modified process of separating the surface of the current collector 9 through the two slots 3c, 3d of the deformed die 2 The first slurry 7 and the second slurry 5 can be independently applied to the compartments.

In other embodiments, a number of additional slots, such as a third slot, a fourth slot, etc., as well as the two aforementioned slots 3a, 3b or 3c, 3d, (Not shown in the drawing). Thus, in addition to the one kind of second slurry, a further second slurry (s) may be deposited on the current collector 9 sequentially through the additional slot (s) .

Finally, the step of removing the solvent from the result of (S3) above is included. The solvent may be removed by drying (step S4). The results of the first slurry and the second slurry (S3) applied on the current collector are simultaneously or individually dried by using a drier or the like to remove the solvent to obtain an electrode assembly. Specifically, the result of step (S3) is a structure in which the first slurry and the second slurry are sequentially laminated on the current collector, or a structure in which the first slurry and the second slurry are separately partitioned. If the slurry is passed through a drier or the like, in the former case, the second slurry coated on the first slurry is first affected by heat or hot air, so that the solvent in the second slurry coated on the outer portion is dried before the solvent in the first slurry will be. In the latter case, since the first slurry and the second slurry are coated on the same plane, they will be dried at substantially the same time.

An electrode according to an aspect of the present invention includes: (a) a current collector; (b) a first electrode active material layer coated on at least one surface of the current collector, the first electrode active material particles being bound by a first binder; And (c) a second electrode active material layer coated on the first electrode active material layer, wherein the second electrode active material particles having a component different from that of the first electrode active material particles are bound by a second binder.

One embodiment of such an electrode is schematically shown in the cross-sectional view of Figures 3a and 3b. The first electrode active material particle layer 37 and the second electrode active material particle layer 35 in which the first slurry 7 and the second slurry 5a are laminated and dried and formed on the current collector 9 are sequentially layered (Fig. 3A). The first electrode active material particle layer 37 and one or more second electrode active material particle layers 35 and 35a may be sequentially stacked on the current collector 9 to form an electrode assembly (FIG. 3B).

According to another aspect of the present invention, there is provided an electrode comprising: (a) a current collector; (b) a first electrode active material layer coated on a first section of the current collector surface, the first electrode active material particles being bound by a first binder; And (c) a second electrode active material particle of a different composition from that of the first electrode active material particles is coated on a second section of the surface of the current collector separated from the first section, And an electrode active material layer.

Other embodiments of such electrodes are schematically illustrated in the plan view of Figures 4a and 4b. The first electrode active material particle layer 47 and the second electrode active material particle layer 45 in which the first slurry 7 and the second slurry 5a are dried and formed on the current collector 9, To form an electrode assembly (Fig. 4A). The first electrode active material particle layer 47 and the one or more second electrode active material particle layers 45 and 45a may be applied to the compartments that are independently divided on the current collector 9 to form an electrode assembly (Fig. 4B) .

Thus, layers of active material particles having respective properties can be formed by the application of the first slurry sequentially deposited and the subsequent application of the second slurry. In addition, the application of the first slurry and the application of the second slurry, which are carried out in the independently divided sections, can be performed by applying the active material particles having the respective properties to each of the compartments, thereby expressing each unique function of the active material.

The electrochemical device can be manufactured by winding or laminating the electrodes of different kinds manufactured according to the manufacturing method of the present invention, that is, the positive electrode and the negative electrode with a separator interposed therebetween.

As the porous substrate of the separator for insulating the electrodes between the anode and the cathode, any porous substrate used for electrochemical devices such as a porous membrane or nonwoven fabric formed of various polymers can be used. For example, a polyolefin-based porous film used as an electrochemical device, particularly a separator of a lithium secondary battery, or a nonwoven fabric made of polyethylene terephthalate fiber may be used, and the material and shape thereof may be variously selected depending on the purpose. For example, the polyolefin-based porous membrane may be formed of a polymer such as polyethylene, polypropylene, polybutylene, or polypentene, such as high-density polyethylene, linear low-density polyethylene, low-density polyethylene, ultra-high molecular weight polyethylene, And the nonwoven fabric may also be made of a polyolefin-based polymer or a fiber using a polymer having higher heat resistance. The thickness of the porous substrate is not particularly limited, but is preferably 1 to 100 占 퐉, more preferably 5 to 50 占 퐉, and the pore size and porosity present in the porous substrate are also not particularly limited, but 0.001 to 50 占 퐉 and 10 To 95%.

The electrolytic solution which can be used in the electrochemical device of the present invention is a salt having a structure such as A ⁺ B ^- , wherein A ⁺ includes an alkali metal cation such as Li ⁺ , Na ⁺ , K ^{+ -} it is _{^{PF 6 -, BF 4 -,}} Cl -, Br -, I -, ClO 4 -, AsF 6 -, CH 3 CO 2 -, CF 3 SO 3 -, N (CF 3 SO 2) 2 -, C (CF ₂ SO _{2) 3} ^- anion, or a salt containing an ion composed of a combination of propylene carbonate (PC) such as, ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl (DMP), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethylmethyl carbonate (EMC), gamma butyrolactone -Butyrolactone), or a mixture thereof, but the present invention is not limited thereto.

The electrolyte may be injected at an appropriate stage of the battery manufacturing process, depending on the manufacturing process and required properties of the final product. That is, it can be applied before assembling the cell or at the final stage of assembling the cell.

In addition, the electrochemical device of the present invention includes all devices that perform an electrochemical reaction, and specific examples thereof include capacitors such as all kinds of primary cells, secondary cells, fuel cells, solar cells, or super capacitor devices, And so on. Particularly, a lithium secondary battery including a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, or a lithium ion polymer secondary battery among the above secondary batteries is preferable.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not to be limited to the details thereof and that various changes and modifications will be apparent to those skilled in the art. And various modifications and variations are possible within the scope of the appended claims.

Claims (12)

(S1) preparing a first slurry by dispersing first electrode active material particles in a first binder solution in which a first binder is dissolved in a solvent;
(S2) dispersing second electrode active material particles of a component different from the first electrode active material particles in a second binder solution in which the second binder is dissolved in a solvent to prepare a second slurry;
(S3) applying the prepared first slurry and the second slurry independently from each other in at least one side of the current collector; And
(S4) removing the solvent from the result of (S3)
In the step (S3), the divided compartments are divided into at least one surface of the current collector, and the first compartments to which the first slurry is applied and the second compartments to which the second slurry is applied.
The method according to claim 1,
Wherein the electrode active material particle is a cathode active material particle and the current collector is a current collector for a positive electrode.
3. The method of claim 2,
Wherein the cathode active material particle is a layered compound of lithium cobalt oxide (LiCoO ₂ ) or lithium nickel oxide (LiNiO ₂ ) or a compound in which at least one transition metal is substituted; A lithium manganese oxide (LiMnO ₂ ) of LiMnO ₃ , LiMn ₂ O ₃ or LiMnO _{2 with} the formula Li _{1 + x} Mn _{2 -x} O ₄ where x is 0 to 0.33; Lithium copper oxide (Li ₂ CuO ₂ ); Vanadium oxides of LiV ₃ O ₈ , LiFe ₃ O ₄ , V ₂ O ₅ or Cu ₂ V ₂ O ₇ ; A nickel-situ type lithium nickel oxide represented by the formula LiNi _1-x M _x O ₂ (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga and x = 0.01 to 0.3) oxide); Formula _{LiMn 2-x M x O 2} ( where, M = Co, Ni, Fe , Cr, and Zn, or Ta, x = 0.01 to 0.1 Im) or Li ₂ Mn ₃ MO ₈ (where, M = Fe, Co, Ni, Cu, or Zn); LiMn ₂ O _{4 in} which part of the lithium in the formula is substituted with an alkaline earth metal ion; Disulfide compounds; Fe ₂ (MoO ₄ ) _3, or a combination thereof.
The method according to claim 1,
A conductive material is added to the first slurry and the second slurry independently of each other,
The method according to claim 1,
Wherein the electrode active material particle is a negative electrode active material particle, and the current collector is a current collector for a negative electrode.
6. The method of claim 5,
Carbon of the non-graphitized carbon or graphite carbon; _{Li x Fe 2 O 3 (0} = x = 1), Li x WO 2 (0 = x = 1), Sn x Me 1-x Me 'y O z (Me: Mn, Fe, Pb, Ge; Me' : A metal complex oxide of Al, B, P, Si, group 1, group 2, group 3 elements of the periodic table, halogen, 0? X = 1; y = 3; Lithium metal; Lithium alloy; Silicon-based alloys; Tin alloy; _{SnO, SnO 2, PbO, PbO} 2, Pb 2 O 3, Pb 3 O 4, Sb 2 O 3, Sb 2 O 4, Sb 2 O 5, GeO, GeO 2, Bi 2 O 3, Bi 2 O 4 , or An oxide of Bi ₂ O ₅ ; A conductive polymer of polyacetylene; Li-Co-Ni based material.
The method of claim 1,
Wherein the first binder and the second binder are selected from the group consisting of polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, (EPDM), sulfonated EPDM, styrene butadiene rubber, and fluorine rubber. The method for producing an electrode according to claim 1, wherein the fluorine-containing polymer is selected from the group consisting of ethylene-propylene-diene terpolymer, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM)
(a) a current collector;
(b) a first electrode active material layer coated on a first section of the current collector surface, the first electrode active material particles being bound by a first binder; And
(c) a second electrode active material particles of a different composition from the first electrode active material particles are coated on a second section of the surface of the current collector divided from the first section, And an active material layer,
Here, the first and second compartments are divided into a first compartment where the first electrode active material layer is formed and a second compartment where the second electrode active material layer is formed, by surface-dividing the surface of the current collector.
9. The method of claim 8,
Wherein the electrode active material particle is a cathode active material particle and the current collector is a current collector for a positive electrode.
9. The method of claim 8,
Wherein the electrode active material particle is a negative electrode active material particle, and the current collector is a current collector for a negative electrode. The method according to claim 1,
In the step (S3), at least one surface of the current collector is divided into two sections and divided into a first section and a second section. The first section is coated with the first slurry, and the second section is coated with the second slurry Wherein the first slurry application area and the second slurry application area are separated by a boundary between the first and second compartments.
9. The method of claim 8,
The first and second compartments are divided into two sections by dividing the surface of the current collector into two sections. The first electrode active material layer is formed in the first section and the second electrode active material layer is formed in the second section. Wherein the first electrode active material layer and the second electrode active material layer are separated by a boundary between the first and second sections.

Images