KR102415165B1 - Dispersant for carbon-based or graphite-based particles, slurry composition for an electrode fabrication comprising the same, electrode for a lithium secondary battery including the same, and lithium secondary battery including the electrode - Google Patents

Abstract

The present invention provides a carbon-based or graphite-based particle dispersant comprising a copolymer represented by the following formula (1); a slurry composition for manufacturing an electrode comprising the same; an electrode for a lithium secondary battery comprising the same; It provides a lithium secondary battery including the electrode:
[Formula 1]

Description

Dispersant for carbon-based or graphite-based particles, a slurry composition for producing an electrode comprising the same, an electrode for a lithium secondary battery comprising the same, and a lithium secondary battery including the electrode Dispersant for carbon-based or graphite-based particles, slurry composition for an electrode fabrication comprising the same, electrode for a lithium secondary battery including the same, and lithium secondary battery including the electrode}

The present invention relates to a carbon-based or graphite-based particle dispersant, a slurry composition for manufacturing an electrode comprising the same, an electrode for a lithium secondary battery comprising the same, and a lithium secondary battery including the electrode.

In recent years, interest in energy storage technology is increasing. Efforts for research and development of electrochemical devices are becoming more concrete as the field of application expands to cell phones, camcorders, notebook PCs, and even the energy of electric vehicles.

Electrochemical devices are receiving the most attention in this aspect, and among them, the development of rechargeable batteries capable of charging and discharging is the focus of interest. Recently, in developing such a battery, research and development on the design of a new electrode and battery in order to improve capacity density and specific energy is in progress.

Among the currently applied secondary batteries, lithium secondary batteries are attracting attention because of their high operating voltage and significantly higher energy density compared to conventional batteries such as Ni-MH, Ni-Cd, and sulfate-lead batteries that use aqueous electrolyte solutions.

Such an electrochemical device generally includes a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode. In this case, the positive electrode and the negative electrode are generally applied to the surface of the current collector by applying an electrode active material slurry containing an electrode active material, a polymer binder, and a solvent for dispersing the electrode active material and dissolving the polymer binder to form an electrode active material layer. is manufactured The electrode active material slurry may further include a conductive material to improve electrical conductivity of the electrode.

On the other hand, in order to form an excellent electrode, it is important to uniformly disperse the electrode active material and/or the conductive material. In particular, when the electrode active material and the conductive material include a carbon-based or graphite-based material, the carbon-based material or the graphite-based material is a material having very low polarity, and thus does not mix well with a binder or water having a high polarity in the aqueous slurry. Therefore, there is a problem in that it is not well dispersed and is easily aggregated and precipitated. Therefore, in order to solve this problem, CMC used as a thickener or binder was applied to pre-disperse the active material and/or the conductive material, and then added to the slurry, and a special mixer was used for this.

However, in the case of a thickener or binder that has no mutual attraction with the active material and/or the conductive material surface, it is simply physically mixed, and over time, the conductive material particles re-agglomerate again to form large particles and are precipitated by gravity. there was And, when the active material or the conductive materials aggregate or precipitate as described above, an uneven electrode was inevitably formed.

In addition, in order to modify the surface of the carbon-based or graphite-based material to be hydrophilic, a method of introducing -OH or -COOH groups to the aromatic carbon of the carbon/graphite surface by high-energy plasma treatment or UV/ozone treatment was also used. .

However, in this case, oxidation mainly occurs at the edge of carbon/graphite, so the efficiency of hydrophilic reforming is not high, and the conjugated network is damaged (double bond → single bond), and electrical conductivity is poor.

Therefore, when the electrode active material and the conductive material include a carbon-based or graphite-based material, development of a method capable of uniformly dispersing them is required.

Republic of Korea Patent Publication No. 10-2015-0095410

The present invention has been devised to solve the above problems of the prior art,

An object of the present invention is to provide a carbon-based or graphite-based particle dispersing agent capable of effectively dispersing an active material or a conductive material including a carbon-based or graphite-based material.

Another object of the present invention is to provide a slurry composition for manufacturing an electrode comprising the dispersant, an electrode for a lithium secondary battery prepared from the slurry composition, and a lithium secondary battery including the electrode.

In order to achieve the above object, the present invention

Provided is a carbon-based or graphite-based particle dispersing agent comprising a copolymer including a monomer including a catechol group and a polyethylene glycol methyl ether (meth)acrylate monomer.

In one embodiment of the present invention, the copolymer may be represented by the following Chemical Formula 1:

[Formula 1]

In the above formula,

R1 and R2 are each independently hydrogen or a methyl group,

a and b represent the molar ratio of each monomer, a is 1-2, b is 1-5;

Said n is a natural number of 1-20.

Also, the present invention

It provides a slurry composition for manufacturing an electrode comprising the dispersant of the present invention.

Also, the present invention

An electrode for a lithium secondary battery prepared from the slurry composition for manufacturing an electrode and a lithium secondary battery including the electrode are provided.

The carbon-based or graphite-based particle dispersant of the present invention includes a hydrophilic copolymer containing a monomer containing a catechol group, which is a mussel-derived adhesive material, and a polyethylene glycol methyl ether (meth)acrylate monomer having excellent hydrophilicity. It provides excellent dispersibility to carbon-based or graphite-based particles such as ash.

In addition, since the slurry composition for manufacturing an electrode of the present invention uniformly disperses carbon-based or graphite-based particles such as an electrode active material and a conductive material, it is possible to provide an electrode for a lithium secondary battery having excellent physical properties.

In addition, the lithium secondary battery of the present invention by including the electrode, provides excellent charge and discharge characteristics and lifespan characteristics.

1 is a graph of NMR analysis of a copolymer included in a carbon-based or graphite-based particle dispersant of the present invention.
2 is a photograph taken of the experimental results (Test Example 1, Experiment 1) showing the dispersing performance of the carbon-based or graphite-based particle dispersant of the present invention.
3 is a graph showing the dispersion particle size and dispersion of carbon black particles as a test result of Experiment 2 of Test Example 1 of the present invention.
4 is a graph showing the dispersed particle size and dispersion of KS6 particles, which are graphite-based conductive materials, as a test result of Experiment 2 of Test Example 1 of the present invention.

Hereinafter, the present invention will be described in detail.

The present invention relates to a carbon-based or graphite-based particle dispersant comprising a copolymer comprising a monomer comprising a catechol group and a polyethylene glycol methyl ether (meth)acrylate monomer.

The carbon-based or graphite-based particles may be at least one selected from a conductive material and an active material, and the conductive material and the active material may be used in a lithium secondary battery.

In general, since carbon-based or graphite-based conductive materials are materials with very low polarity, they do not mix well with a binder or water having high polarity in an aqueous slurry. Therefore, there is a problem in that it is not well dispersed and is easily aggregated and precipitated. Therefore, solving these problems is recognized as a challenge in this field.

The present invention is characterized by providing a solution to the above problems. That is, the dispersant of the present invention provides excellent dispersibility by including a hydrophilic copolymer including a monomer containing a catechol group, which is an adhesive material derived from mussels. That is, the catechol group adheres well to any surface, and in particular, adheres well to the surface of carbon-based or graphite-based particles. In addition, the dispersing agent of the present invention provides excellent hydrophilicity by including a copolymer including a polyethylene glycol methyl ether (meth)acrylate monomer, so that the carbon-based or graphite-based particles are well dispersed.

When the dispersing agent of the present invention is used, the particles are well dispersed in the solution even if there is no external force in the process of the carbon-based or graphite-based particles falling to the floor by gravity.

In the dispersant of the present invention, the part described as “(meth)acrylate” should be interpreted as a concept including methacrylate and acrylate.

In the dispersant of the present invention, the molar ratio of the monomer containing the catechol group and the polyethylene glycol methyl ether (meth)acrylate monomer may be 1-2: 1-5, more preferably 1-1.5: 1.5-3 can be

Specifically, when the molar ratio of the monomer containing a catechol group is insufficient outside the above-mentioned range, a problem of insufficient adhesion to carbon-based or graphite-based particles may occur, and the molar ratio of the polyethylene glycol methyl ether (meth)acrylate monomer is described above. If it is insufficient outside one range, there may be a problem in that the dispersion ability is lowered due to insufficient hydrophilicity. When each component is included in excess outside the above-mentioned range, the opposite problem may occur, so it is not preferable.

The number of repeating units of the ethylene oxide group included in the polyethylene glycol methyl ether group included in the polyethylene glycol methyl ether (meth)acrylate monomer may be 1 to 20, more preferably 1 to 5.

When the ethylene oxide group repeating unit is less than the above range, a problem of insufficient hydrophilicity may occur, and if it exceeds the above range, a problem of increasing electrode resistance may occur.

The copolymer may have a weight average molecular weight of 5,000 to 1,000,000, more preferably 5,000 to 300,000. If the weight average molecular weight is less than the above range, a problem of insufficient adhesion to the carbon-based or graphite-based particles may occur.

It may be preferable that the copolymer is a random copolymer. This is because, when the respective monomers are distributed as uniformly as possible, better dispersibility and adhesion can be exhibited.

The copolymer may be included in an amount of 10 to 100% by weight based on the total weight of the dispersant.

The method of claim 1,

The monomer including the catechol group may be a vinyl-based monomer, for example, a dopamine (meth)acrylamide monomer.

The carbon-based or graphite-based particles may be at least one selected from a conductive material and an active material.

The dispersant may further include known components commonly used in this field in addition to the copolymer. For example, a solvent and the like may be further included in a conventional composition ratio.

The copolymer may be specifically a copolymer represented by the following Chemical Formula 1:

[Formula 1]

In the above formula,

R1 and R2 are each independently hydrogen or a methyl group,

a and b represent the molar ratio of each monomer, a is 1-2, b is 1-5;

Said n is a natural number of 1-20.

It is more preferable that the molar ratio of a and b of the copolymer represented by Formula 1 is 1 to 1.5: 1.5 to 3.

When the molar ratio of a and b is out of the above range, specifically, when the molar ratio of the monomer containing a catechol group is insufficient outside the above range, a problem of insufficient adhesion to the conductive material may occur, and polyethylene glycol methyl ether When the molar ratio of the (meth)acrylate monomer is insufficient outside the above-mentioned range, there may be a problem in that the dispersibility is reduced due to insufficient hydrophilicity. When each component is included in excess outside the above-mentioned range, the opposite problem may occur, so it is not preferable.

The n is preferably a natural number of 1 to 20, more preferably 1 to 5.

When the value of n is less than the above range, a problem of insufficient hydrophilicity may occur, and when the value of n exceeds the above range, a problem of increasing electrode resistance may occur.

The copolymer may have a weight average molecular weight of 5,000 to 1,000,000, more preferably 5,000 to 300,000. When the weight average molecular weight is less than the above range, a problem of insufficient adhesion to carbon-based or graphite-based particles may occur.

The copolymer represented by Formula 1 may be prepared according to Scheme 1:

[Scheme 1]

Specifically, first, the inhibitor of the polyethylene glycol methyl ether (meth)acrylate monomer is removed using column chromatography filled with basic alumina. The inhibitor refers to an additive added at a level of 100 ppm to prevent self-photocuring or thermal curing of the polyethylene glycol methyl ether (meth)acrylate monomer, for example, BHT and MEHQ.

After adding a solvent such as DMF to the reactor, the purified polyethylene glycol methyl ether (meth)acrylate monomer, dopamine (meth)acrylamide monomer, and polymerization initiator are added.

Next, after degassing the reaction mixture with nitrogen gas, it is reacted for 10-25 hours while stirring at 40-80°C.

When the reaction is completed, the copolymer is obtained by precipitating the product using n-hexane or the like.

In addition, the present invention,

It relates to a slurry composition for manufacturing an electrode comprising the dispersant of the present invention.

The dispersant may be included in an amount of 1 to 10% by weight based on the total weight of the slurry composition.

The slurry composition may further include 10 to 90% by weight of the active material, 0.1 to 20% by weight of the conductive material, 1 to 20% by weight of the binder, and the remaining amount of the solvent based on the total weight of the composition.

At least one of the active material and the conductive material may be carbon-based or graphite-based particles. More specifically, the active material may be a Si-based active material, and the conductive material may be carbon-based or graphite-based particles.

In the slurry composition, a technique known in the art may be applied as it is, except for using the dispersant of the present invention.

Also, the present invention

It relates to an electrode for a lithium secondary battery prepared from the slurry composition for manufacturing an electrode of the present invention, and a lithium secondary battery including the electrode.

In the electrode and battery for a lithium secondary battery, a technique known in the art may be applied as it is, except for using the dispersant of the present invention.

The electrode for the lithium secondary battery may be a positive electrode or a negative electrode.

Hereinafter, the electrode for a lithium secondary battery and a lithium secondary battery will be described as an example.

The lithium secondary battery of the present invention includes an anode; anode; a separator provided between the anode and the cathode; and electrolyte;

The negative electrode may include an anode active material, a binder, a conductive material, and the dispersant of the present invention. As the negative electrode active material, one known in the art may be used, and for example, an anode active material including a Si-based active material may be used. More specifically, for example, a mixture of Si, SiOx/C and graphite may be mentioned. The SiOx/C includes a carbon coating layer formed on the SiOx surface.

The negative electrode active material, the binder, the conductive material, and the dispersant of the present invention may form a negative electrode active material layer, wherein the negative electrode active material layer prepares a slurry including the components according to a conventional method, and applies the slurry to the current collector. It is included in the negative electrode by applying and drying. Here, as a non-limiting example of the current collector, a foil made of copper, gold, nickel, or a copper alloy, or a combination thereof, etc. may be mentioned.

Based on the total weight of the anode active material layer, the anode active material may be included in an amount of 70 to 97 wt%, the conductive material may be included in an amount of 1 to 20 wt%, and the binder may be included in an amount of 1 to 10 wt%, of the present invention The dispersant may be included in an amount of 1 to 10% by weight, but is not limited thereto.

The conductive material is not particularly limited, but a conductive material such as a graphite-based material such as KS6, a carbon-based material such as Super-P, Denka black, or carbon black, or a conductive polymer such as polyaniline, polythiophene, polyacetylene, polypyrrole, etc. may be used alone or in combination.

The negative electrode is not particularly limited except for the case where it is prepared by using the dispersant of the present invention, and may be prepared in a form in which the negative electrode active material is bound to the current collector according to a conventional method known in the art.

In the lithium secondary battery of the present invention, the positive electrode is not particularly limited except for including the dispersing agent of the present invention, and according to a conventional method known in the art, the positive electrode active material can be prepared in the form of binding to the current collector. .

As the cathode active material, a known cathode active material can be used, for example, lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron oxide, a three-component cathode material LiNi _x Mn _y Co _z O ₂ (NMC) or A lithium composite oxide or the like combining these can be used. And examples of the current collector may include a foil made of aluminum, nickel, or a combination thereof. The positive electrode may further include the dispersant of the present invention.

The separator positioned between the positive electrode and the negative electrode separates or insulates the positive electrode and the negative electrode from each other, and enables lithium ions to be transported between the positive electrode and the negative electrode. As the separator used in the present invention, any porous polymer substrate commonly used in this field may be used, for example, a polyolefin-based porous polymer membrane or a nonwoven fabric may be used, but is not particularly limited thereto.

Examples of the polyolefin-based porous polymer membrane include polyethylene, such as high-density polyethylene, linear low-density polyethylene, low-density polyethylene, and ultra-high molecular weight polyethylene, polyolefin-based polymers such as polypropylene, polybutylene, and polypentene, respectively, individually or as a mixture thereof. The formed membrane is mentioned.

As the nonwoven fabric, in addition to the polyolefin-based nonwoven fabric, for example, polyethyleneterephthalate, polybutyleneterephthalate, polyester, polyacetal, polyamide, polycarbonate ), polyimide, polyetheretherketone, polyethersulfone, polyphenyleneoxide, polyphenylenesulfide, polyethylenenaphthalene, etc. alone or and a nonwoven fabric formed of a polymer obtained by mixing them. The structure of the nonwoven fabric may be a spunbond nonwoven fabric composed of long fibers or a melt blown nonwoven fabric.

The thickness of the porous polymer substrate is not particularly limited, but may be 5 μm to 50 μm, and the pore size and pore size present in the porous polymer substrate are also not particularly limited, but may be 0.01 μm to 50 μm and 10 to 95%, respectively. have.

In addition, in order to improve the mechanical strength of the separator and the safety of the lithium secondary battery, at least one surface of the porous polymer substrate may further include a porous coating layer including inorganic particles and a polymer binder.

The polymer binder included in the porous coating layer is coated on some or all of the surfaces of the inorganic particles, and the inorganic particles are connected and fixed to each other by the polymer binder in a close contact state, and present between the inorganic particles. It is preferable that the pores are formed due to the interstitial volume. That is, the inorganic particles of the porous coating layer exist in a state in close contact with each other, and the interstitial volume generated in the state in which the inorganic particles are in close contact may become the pores of the porous coating layer.

As the electrolyte, one known in the art may be used, for example, a non-aqueous electrolyte may be used. The non-aqueous electrolyte may include a lithium salt as an electrolyte salt. As the lithium salt, those commonly used in electrolytes for lithium secondary batteries may be used without limitation. For example, as an anion of the lithium salt, F ^- , Cl ^- , Br ^- , I ^- , NO ₃ ^- , N(CN) ₂ ^- , BF ₄ ^- , ClO ₄ ^- , PF ₆ ^- , (CF ₃ ) ₂ PF ₄ ^- , (CF ₃ ) ₃ PF ₃ ^- , (CF ₃ ) ₄ PF ₂ ^- , (CF ₃ ) ₅ PF ^- , (CF ₃ ) ₆ P ^- , CF ₃ SO ₃ ^- , CF ₃ CF ₂ SO ₃ ^- , (CF ₃ SO ₂ ) ₂ N ^- , (FSO ₂ ) ₂ N ^- _, CF ₃ CF ₂ (CF ₃ ) ₂ CO ^- , (CF ₃ SO ₂ ) ₂ CH ^- , (SF ₅ ) ₃ C ^- , (CF ₃ SO ₂ ) ₃ C ^- , CF ₃ (CF ₂ ) ₇ SO ₃ ^- , CF ₃ CO ₂ ^- , CH ₃ CO ₂ ^- , Any one or more selected from the group consisting of SCN ^- and (CF ₃ CF ₂ SO ₂ ) ₂ N ^- may be used.

As the organic solvent included in the non-aqueous electrolyte, organic solvents commonly used in electrolytes for lithium secondary batteries may be used without limitation, for example, ethers, esters, amides, linear carbonates, cyclic carbonates, etc. alone or 2 It can be used in combination of more than one species. Among them, a cyclic carbonate, a linear carbonate, or a carbonate compound that is a mixture thereof may be used.

Specific examples of the cyclic carbonate compound include ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, any one selected from the group consisting of 2,3-pentylene carbonate, vinylene carbonate, vinylethylene carbonate, and halides thereof, or a mixture of two or more thereof. Examples of these halides include, but are not limited to, fluoroethylene carbonate (FEC).

In addition, specific examples of the linear carbonate compound include any one selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, ethylmethyl carbonate (EMC), methylpropyl carbonate and ethylpropyl carbonate, or these A mixture of two or more of them may be typically used, but is not limited thereto.

In particular, among the carbonate-based organic solvents, ethylene carbonate and propylene carbonate, which are cyclic carbonates, are high-viscosity organic solvents and have a high dielectric constant, so that lithium salts in the electrolyte can be better dissociated. An electrolyte having higher electrical conductivity can be prepared by mixing and using a low-viscosity, low-dielectric constant linear carbonate in an appropriate ratio.

In addition, as the ether in the organic solvent, any one selected from the group consisting of dimethyl ether, diethyl ether, dipropyl ether, methylethyl ether, methylpropyl ether and ethylpropyl ether or a mixture of two or more thereof may be used. , but is not limited thereto.

In addition, as esters in the organic solvent, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, γ-butyrolactone, γ-valerolactone, γ-caprolactone, σ-valerolactone And any one selected from the group consisting of ε-caprolactone or a mixture of two or more thereof may be used, but the present invention is not limited thereto.

The injection of the non-aqueous electrolyte may be performed at an appropriate stage during the manufacturing process of the lithium secondary battery according to the manufacturing process and required physical properties of the final product. That is, it may be applied before assembling the lithium secondary battery or in the final stage of assembling the lithium secondary battery.

The lithium secondary battery may be configured by applying techniques known in the art except for the characteristic techniques of the present invention described above.

In the lithium secondary battery according to the present invention, a separator and an electrode stack (lamination), folding (folding), and stacking/folding processes are possible in addition to the general process of winding.

In addition, the external shape of the lithium secondary battery is not particularly limited, but may be a cylindrical shape, a square shape, a pouch type, or a coin type using a can.

Hereinafter, preferred examples are presented to help the understanding of the present invention, but the following examples are merely illustrative of the present invention, and it will be apparent to those skilled in the art that various changes and modifications are possible within the scope and spirit of the present invention, It goes without saying that such changes and modifications fall within the scope of the appended claims.

Example 1: Preparation of a copolymer represented by Formula 1 (carbon-based or graphite-based particle dispersant)

Inhibitors were removed by column chromatography filled with 12.5 ml of PEGMEA (polyethylene glycol methyl ether acrylate) with 30 g of basic alumina.

After putting 20 ml of DMF in a 500 ml two neck round bottom flask, 7.5 g of purified PEGMEA (Mn=480), 1.7 g of DMA (dopamine methacrylamide), and 106 mg of azobisisobutyronitrile were added to DMF. melted After degassing the reaction mixture with N ₂ (g) for 10 minutes, the reaction mixture was stirred at 60° C. for 17 hours. After completion of the reaction, the reaction product was precipitated using 800 ml of n-haxane in a 1000 ml beaker to obtain P(DMA-co-PEGMEA) having a weight average molecular weight of 250,000.

Example 2: Preparation of slurry composition for negative electrode

A slurry composition for a negative electrode was prepared using Si as an active material, KS6 as a graphite-based conductive agent, polyacrylic acid (molecular weight 450,000 manufactured by Sigma Aldrich) as a binder, and the copolymer prepared in Example 1 as a dispersant. The weight ratio of the active material: the conductive material: the binder; the dispersant based on the solid content was 70:20:7:3.

Specifically, 1 g of the copolymer prepared in Example 1 was dissolved in 9 g of distilled water to prepare a solution of 10% concentration, and then 1.2 g of this solution was mixed with 0.8 g of KS6, a graphite-based conductive agent, and thoroughly mixed. Next, 2.8 g of Si and 2.8 g of a binder (0.28 g of solid content) were added to uniformly prepare a slurry composition (a total of 4 g of solid content).

Example 3: Preparation of a negative electrode for a lithium secondary battery

A negative electrode was prepared by applying the slurry composition prepared in Example 2 on a copper foil using a doctor blade.

The slurry prepared above was coated on a Cu foil with a thickness of 20 μm using a doctor blade to a thickness of 10 to 40 μm, and primary drying was performed at 70° C. for 30 minutes using a convection oven. A negative electrode (design capacity 3500 mAh/g) was prepared by taking a portion with a constant loading and performing secondary drying at 130° C. for 3 hours in a vacuum oven.

Example 4: Preparation of a lithium secondary battery

Lithium metal was used as a reference and counter electrode for the negative electrode prepared in Example 3 (rolling to adjust the porosity to about 30%), and as an electrolyte, EC: DEC = 3: 7, 10wt% FEC, 1.3M LiPF ₆ The composition was A coin cell was prepared using a polyethylene (PE) film with a thickness of 20 microns as a separator.

Test Example 1: Performance evaluation of carbon-based or graphite-based particle dispersants

<Experiment 1>

As a dispersing agent, an aqueous solution of the copolymer of Formula 1 prepared in Example 1 was dissolved in distilled water to prepare an aqueous solution having a concentration of 1 wt% (used in Example 1-1). In addition, as a dispersant, Li-PAA was dissolved in distilled water to prepare an aqueous solution having a concentration of 1% by weight, which was used as Comparative Example 1-1, and only distilled water without a dispersant was used as Comparative Example 2-1.

4 ml each of the copolymer aqueous solution of Formula 1, Li-PAA aqueous solution, and distilled water were put into three vials, respectively, and then 0.05 g of KS6, a graphite-based conductive agent, was added. Thereafter, in a state left at room temperature, the deposition form of the conductive material over time was observed, and the results are shown in FIG. 2 below.

2, in the case of Comparative Example 2-1 (distilled water ONLY) and Comparative Example 1-1 (Li-PAA used as a dispersant), the conductive material sank to the floor by gravity immediately after adding the conductive material. After 1.5 minutes, a significant amount of conductive material was deposited on the floor. On the other hand, in the case of Example 1-1 (using the copolymer of Formula 1 as a dispersant), it was confirmed that the conductive material particles fell to the floor while being dispersed.

<Experiment 2>

As shown in Table 1 below, 0.1 g of the copolymer of Formula 1 prepared in Example 1 as a dispersing agent and 0.2 g of carbon black or graphite-based conductive agent KS6 as a conductive material were dissolved in distilled water to prepare a slurry of a total of 5 g , The slurry was mixed twice for 30 seconds at a speed of 3,000 rpm in a vortexmixer to prepare a slurry.

In addition, 5 g of a slurry was prepared in the same manner as above, except that Li-PAA was used instead of the copolymer of Formula 1 prepared in Example 1 as a dispersant.

In addition, 0.2 g of carbon black or graphite-based conductive agent KS6 was dispersed in distilled water without using a dispersant to prepare a total of 5 g of slurry.

Thereafter, a portion of the slurry was aliquoted to measure the average particle size and particle size distribution in a particle size analyzer, and the results are shown in Table 1, FIGS. 3 and 4 below.

The average particle size after dispersion in Table 1 and the dispersion degree of FIGS. 3 and 4 were measured using a particle size analyzer.

dispersant dispersed particles dispersion solvent Average particle size after dispersion (㎛) Example 1-2
Prepare 5 g of slurry Example 1 Preparation Using 0.1 g of the copolymer of Formula 1 0.2 g of carbon black
(average size: 32 nm) Distilled water 11.07 Comparative Example 1-2 Preparation of 5 g of slurry Using 0.1 g of Li-PAA 0.2 g of carbon black
(average size: 32 nm) Distilled water 19.67 Comparative Example 2-2 Preparation of 5 g of slurry not used 0.2 g of carbon black
(average size: 32 nm) Distilled water 18.08 Examples 1-3
Prepare 5 g of slurry Example 1 Preparation Using 0.1 g of the copolymer of Formula 1 Graphite KS6 0.2 g
(average size: 3.4 μm) Distilled water 4.85 Comparative Example 1-3 Preparation of 5 g of slurry Using 0.1 g of Li-PAA Graphite KS6 0.2 g
(average size: 3.4 μm) Distilled water 5.61 Comparative Example 2-3 Preparation of 5 g of slurry not used Graphite KS6 0.2 g
(average size: 3.4 μm) Distilled water 14.73

As can be seen from Table 1, it can be seen that the average particle size after dispersion of the dispersed particles of Examples 1-2 and 1-3 of the present invention is significantly smaller than the average particle size of Comparative Examples.

Furthermore, as shown in FIGS. 3 and 4 , in the case of Examples 1-2 and 1-3 of the present invention, it can be seen that the particle size distribution is much better than that of Comparative Examples.

Therefore, it can be confirmed from the above experiment that the dispersant of the present invention including the copolymer of Formula 1 has excellent dispersion performance for carbon-based particles such as CNTs or graphite-based particles such as artificial graphite.

Claims (15)

A slurry composition for manufacturing an electrode comprising a carbon-based or graphite-based particle dispersant comprising a copolymer including a monomer containing a catechol group and a polyethylene glycol methyl ether (meth)acrylate monomer. According to claim 1,
The molar ratio of the monomer containing the catechol group and the polyethylene glycol methyl ether (meth)acrylate monomer is 1-2: 1-5. According to claim 1,
The weight average molecular weight of the copolymer is a slurry composition for manufacturing an electrode, characterized in that 5,000 to 1,000,000. According to claim 1,
The copolymer is a slurry composition for manufacturing an electrode, characterized in that it is a random copolymer. According to claim 1,
The copolymer is a slurry composition for manufacturing an electrode, characterized in that it is contained in an amount of 10 to 100% by weight based on the total weight of the dispersant. According to claim 1,
The slurry composition for manufacturing an electrode, characterized in that the monomer containing the catechol group is a vinyl-based monomer. According to claim 1,
The carbon-based or graphite-based particles are a slurry composition for manufacturing an electrode, characterized in that at least one selected from a conductive material and an active material. According to claim 1,
The copolymer is a slurry composition for manufacturing an electrode, characterized in that it is represented by the following Chemical Formula 1:
[Formula 1]

In the above formula,
R1 and R2 are each independently hydrogen or a methyl group,
a and b represent the molar ratio of each monomer, a is 1-2, b is 1-5;
Said n is a natural number of 1-20. 9. The method of claim 8,
A slurry composition for manufacturing an electrode, characterized in that the molar ratio of a and b of the copolymer represented by Formula 1 is 1 to 1.5: 1.5 to 3. delete According to claim 1,
The dispersant is a slurry composition for manufacturing an electrode, characterized in that it is included in an amount of 1 to 10% by weight based on the total weight of the slurry composition. 12. The method of claim 11,
The slurry composition is a slurry composition for manufacturing an electrode, characterized in that it further comprises 10 to 90% by weight of the active material, 0.1 to 20% by weight of the conductive material, 1 to 20% by weight of the binder, and the remaining amount of the solvent based on the total weight of the composition. 13. The method of claim 12,
At least one of the active material and the conductive material is a slurry composition for manufacturing an electrode, characterized in that carbon-based or graphite-based particles. An electrode for a lithium secondary battery prepared from the slurry composition for manufacturing an electrode of claim 1. A lithium secondary battery comprising the electrode of claim 14 .

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