阅读说明：本技术 正极浆料组合物、使用所述正极浆料组合物制造的正极和包含所述正极的电池 (Positive electrode slurry composition, positive electrode manufactured using the same, and battery including the same ) 是由 李载佶 梁斗景 金有美 金伦耕 赵恩京 于 2019-01-11 设计创作，主要内容包括：本发明提供正极浆料组合物、使用所述正极浆料组合物制造的正极、和包含所述正极的电池,其中所述正极浆料组合物包含正极活性材料、粘结剂、醇和水,并且基于所述组合物的总重量,所述醇的含量在0.1重量％至10重量％的范围内。根据本发明的用于制造正极的浆料组合物具有以下效果,即大幅改善正极活性材料和导电材料的分散性、降低电极的表面粗糙度并且显著减少电极中的卷曲现象。此外,本发明的所述浆料组合物在经济上所具有的优势为：不使用分散剂或可以显著减少分散剂的量。(The present invention provides a positive electrode slurry composition, a positive electrode manufactured using the same, and a battery including the positive electrode, wherein the positive electrode slurry composition includes a positive electrode active material, a binder, alcohol, and water, and the alcohol is contained in an amount ranging from 0.1 wt% to 10 wt%, based on the total weight of the composition. The slurry composition for manufacturing a positive electrode according to the present invention has the effects of greatly improving the dispersibility of a positive electrode active material and a conductive material, reducing the surface roughness of an electrode, and significantly reducing a curling phenomenon in the electrode. Furthermore, the slurry composition of the present invention has the economic advantages of: no dispersant is used or the amount of dispersant can be significantly reduced.)

1. A positive electrode slurry composition comprising a positive electrode active material, a binder, an alcohol and water, wherein

The alcohol is present in an amount ranging from 0.1 to 10 wt.%, based on the total weight of the composition.

2. The cathode slurry composition according to claim 1, wherein the composition comprises 0.1 to 15 wt.% of the alcohol and 85 to 99.9 wt.% of water, based on the total weight of the alcohol and the water.

3. The cathode slurry composition according to claim 1, wherein the alcohol is a lower alcohol of C1 to C5.

4. The cathode slurry composition according to claim 3, wherein the C1-C5 lower alcohol is propanol.

5. The cathode slurry composition according to claim 1, wherein the composition comprises 10 to 78 wt% of the cathode active material, 1 to 50 wt% of the binder, 0.1 to 10 wt% of the alcohol, and the balance water.

6. The cathode slurry composition according to claim 5, wherein the composition further comprises 0.1 to 10 wt% of a conductive material.

7. The cathode slurry composition according to claim 6, wherein the composition comprises 2 to 45 parts by weight of the alcohol, based on 100 parts by weight of the cathode active material and the conductive material in total.

8. The cathode slurry composition according to claim 1, wherein the composition is used to manufacture a cathode for a lithium sulfur battery.

9. The cathode slurry composition according to claim 8, wherein the cathode active material is a sulfur-carbon composite.

10. A positive electrode manufactured by coating the positive electrode slurry composition according to claim 1 on a current collector.

11. A battery, the battery comprising:

the positive electrode according to claim 10;

a negative electrode containing lithium metal or a lithium alloy as a negative electrode active material;

a separator disposed between the positive electrode and the negative electrode; and

an electrolyte.

12. The battery of claim 11, wherein the lithium alloy is an alloy of lithium with a metal selected from the group consisting of Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, Ra, Al, and Sn.

Technical Field

This application claims priority to korean patent application No. 10-2018-0003656 filed on 11.1.2018 to the Korean Intellectual Property Office (KIPO) and korean patent application No. 10-2019-0003703 filed on 11.1.2019 to the korean intellectual property office, the entire contents of which are incorporated herein by reference.

The present invention relates to a positive electrode slurry composition, a positive electrode manufactured using the same, and a battery including the same.

Background

As the application field of energy storage technology extends not only to mobile phones, tablet and laptop computers, and camcorders, but also to Electric Vehicles (EV) and Hybrid Electric Vehicles (HEV), demands for research and development of electrochemical devices for energy storage are increasing.

In particular, attention has been paid to the development of secondary batteries such as chargeable/dischargeable lithium sulfur batteries and the like. In recent years, research and development to design new electrodes and batteries have been actively conducted to improve the capacity density and specific energy of secondary batteries.

Since lithium-sulfur (Li-S) batteries have a high energy density, the Li-S batteries are receiving attention as next-generation secondary batteries that can replace lithium ion batteries. In general, a lithium sulfur battery has a structure in which a lithium electrolyte is impregnated into an electrode assembly including: a positive electrode comprising a sulfur-carbon composite as an electrode active material, a negative electrode comprising lithium metal or a lithium alloy, and a separator.

The positive electrode of such a lithium sulfur battery is generally manufactured by coating a positive electrode slurry on a metal foil. In this case, the cathode slurry is prepared by mixing an electrode mixture including a cathode active material for storing energy, a conductive material for imparting conductivity, and a binder (PVdF) for adhering them to an electrode foil in a solvent such as water and N-methylpyrrolidone (NMP).

In the above-described cathode slurry, the dispersibility of the cathode active material and/or the conductive material has an important influence on the workability in manufacturing the electrode and the characteristics of the electrode formed therefrom. Therefore, various methods have been studied to improve the dispersibility of the positive electrode active material and/or the conductive material in the positive electrode slurry.

For example, korean patent laid-open publication No. 10-2015-0025665 discloses "a positive electrode slurry for a secondary battery, characterized by comprising a positive electrode active material, a conductive material, a binder, a dispersant, and an aqueous solvent, wherein the dispersant is a copolymer comprising a main chain having ionic characteristics and a side chain having nonionic surfactant characteristics".

However, as disclosed in the patent document, when an additional dispersant is used, the manufacturing process of the electrode becomes complicated and the manufacturing cost of the electrode is increased, which is economically undesirable.

Therefore, there is a need to study a method capable of improving the dispersibility of the positive electrode active material and/or the conductive material without using any additional dispersant.

[ Prior art documents ]

[ patent document ]

Korean patent laid-open publication No. 10-2015-0025665

Disclosure of Invention

[ problem ] to provide a method for producing a semiconductor device

The present invention has been made to solve the problems of the prior art, and an object of the present invention is to provide a slurry composition for manufacturing a positive electrode, which can greatly improve the dispersibility of a positive electrode active material and a conductive material, reduce the surface roughness of an electrode, and significantly reduce a curling phenomenon in the electrode.

Another object of the present invention is to provide a slurry composition for manufacturing a positive electrode, which exhibits excellent dispersibility without using any additional dispersant, suppresses a curling phenomenon in an electrode, and has advantages in a manufacturing process of a battery.

It is still another object of the present invention to provide a positive electrode for a battery manufactured using the slurry composition for manufacturing a positive electrode and a battery including the positive electrode.

[ technical solution ] A

In order to solve the above-mentioned problems, according to an aspect of the present invention, there is provided a cathode slurry composition comprising a cathode active material, a binder, an alcohol and water, wherein the alcohol is contained in an amount ranging from 0.1 wt% to 10 wt%, based on the total weight of the composition.

According to another aspect of the present invention, there is provided a positive electrode manufactured by coating the positive electrode slurry composition of the present invention on a current collector.

According to still another aspect of the present invention, there is provided a battery including:

the positive electrode of the invention;

a negative electrode containing lithium metal or a lithium alloy as a negative electrode active material;

a separator disposed between the positive electrode and the negative electrode; and

an electrolyte.

[ PROBLEMS ] the present invention

The slurry composition for manufacturing a positive electrode according to the present invention has the effects of greatly improving the dispersibility of a positive electrode active material and a conductive material, reducing the surface roughness of an electrode, and significantly reducing a curling phenomenon in the electrode. Furthermore, the slurry composition of the present invention has the economic advantages of: no dispersant is used or the amount of dispersant can be significantly reduced.

The battery including the positive electrode manufactured using the slurry composition for manufacturing a positive electrode has the effect of greatly improving capacity, life characteristics, and economic feasibility.

Drawings

Fig. 1 is a photograph observed in experimental example 1, which is obtained by photographing the rolled state of the electrodes manufactured in examples 5 to 8 and comparative examples 4 and 5.

Detailed Description

Hereinafter, the present invention will be described in more detail.

The present invention relates to a positive electrode slurry composition comprising a positive electrode active material, a binder, an alcohol, and water, characterized in that the alcohol is contained in an amount ranging from 0.1 wt% to 10 wt%, based on the total weight of the composition.

The present inventors have paid attention to the fact that the positive active material and the conductive material of the battery are not easily mixed with a strongly polar binder or water in an aqueous slurry. That is, since materials of very weak polarity are used as the positive electrode active material and the conductive material, these materials of very weak polarity are not easily mixed with a binder of strong polarity or water in an aqueous slurry. It is therefore a feature of the present invention to provide a solution to the above-mentioned problems. That is, the present invention has a technical feature that an alcohol solvent having amphiphilicity is added to improve the dispersibility of the carbon and sulfur particles exhibiting weak polarity. Since the above alcohol solvent is evaporated during the drying process so that it does not remain in the electrode, the weight of the electrode is not increased. In addition, since the alcohol solvent does not increase the resistance, the energy density of the electrode is not decreased.

As the alcohol aqueous solution, a lower alcohol aqueous solution of C1 to C5 may be used. Alcohols having a very high vapor pressure have the disadvantage that the content of solids in the slurry may decrease during slurry preparation, because the alcohol has a high evaporation rate. In addition, the alcohol having a very low vapor pressure has a disadvantage in that it is necessary to increase the drying temperature or to extend the drying time because the alcohol has a low drying rate. Among the aqueous solutions of lower alcohols of C1 to C5, an aqueous solution of propanol may be more preferably used. This is because the aqueous propanol solution has a similar vapor pressure to water in the temperature range of 20 ℃ to 80 ℃ for preparing the slurry and drying the electrode, so it has a low possibility of reducing the dispersion effect due to evaporation of alcohol and causing variation in the solid content in the slurry during the slurry preparation, and is suitable for a conventional drying electrode process without great change. The aqueous propanol solution comprises an aqueous 1-propanol solution.

In the present invention, the alcohol may be included in an amount of 0.1 to 10% by weight, more preferably 1 to 7% by weight, based on the total weight of the composition.

When the aqueous alcohol solution included in the positive electrode slurry composition is included within the above content range, the dispersibility of the positive electrode active material and/or the conductive material is greatly improved, the surface roughness of the electrode is reduced, and the curling phenomenon in the electrode is significantly reduced. In particular, when the electrode is curled during the manufacture of the electrode, cracks may occur on the electrode when the electrode is planarized in the manufacturing process of the battery, or the electrode may be separated from the current collector, which may cause processing difficulty and increased cost. Thus, the improvement of these problems provides great advantages in manufacturing the electrode.

When the alcohol is contained at a content of less than 0.1 wt%, it may be difficult to expect the desired effect as described above. On the other hand, when the content of the alcohol is more than 10% by weight, the solubility of the binder in the alcohol may be reduced, which makes it difficult to prepare a slurry.

The positive electrode slurry composition may include 10 to 78 wt% of the positive electrode active material, 1 to 50 wt% of the binder, 0.1 to 10 wt% of the alcohol, and the balance water, based on the total weight of the composition, but the present invention is not limited thereto.

In addition, the composition may further include 0.1 to 10% by weight of a conductive material.

The cathode paste composition of the present invention may include the alcohol in an amount of 2 to 45 parts by weight, more preferably 5 to 30 parts by weight, based on 100 parts by weight of the cathode active material and the conductive material in total.

In addition, the cathode slurry composition of the present invention may include 0.1 to 15% by weight of the alcohol and 85 to 99.9% by weight of water, more preferably 0.5 to 10% by weight of the alcohol and 90 to 99.5% by weight of water, and further preferably 1 to 7% by weight of the alcohol and 93 to 99% by weight of water, based on the total weight of the alcohol and the water.

When the content ratio of the alcohol included in the positive electrode slurry composition satisfies the content range, the dispersibility of the positive electrode active material and/or the conductive material may be greatly improved, the surface roughness of the electrode may be reduced, and the curling phenomenon of the electrode may be significantly reduced. In particular, when the electrode is curled during the manufacture of the electrode, cracks may occur on the electrode when the electrode is planarized in the manufacturing process of the battery, or the electrode may be separated from the current collector, which may cause processing difficulty and increased cost. Thus, the improvement of these problems provides great advantages in manufacturing the electrode.

The positive electrode slurry composition of the present invention has very excellent characteristics of greatly improving the dispersibility of the positive electrode active material and/or the conductive material without using any dispersant.

The positive electrode slurry composition of the present invention can be preferably used for manufacturing a positive electrode for a lithium sulfur battery. In this case, a sulfur-carbon composite may be preferably used as the positive electrode active material.

Further, the present invention relates to a positive electrode manufactured by coating the positive electrode slurry composition of the present invention on a current collector.

A current collector known in the related art may be used as the current collector, and the manufacturing method of the positive electrode may also be performed according to a method known in the art.

The positive electrode of the present invention provides a very excellent effect on the energy density of the electrode.

Furthermore, the present invention relates to a battery comprising:

the positive electrode of the invention;

a negative electrode containing lithium metal or a lithium alloy as a negative electrode active material;

a separator disposed between the positive electrode and the negative electrode; and

an electrolyte.

The battery may be a lithium sulfur battery.

As for the positive electrode, the above can be applied as it is.

The negative electrode of the battery according to the present invention may be a negative electrode including lithium metal or a lithium alloy as a negative electrode active material. In this case, an anode known in the related art may be used as the anode without any limitation.

As the lithium alloy used as the negative electrode active material, an alloy of lithium and a metal selected from the group consisting of Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, Ra, Al, and Sn may Be used.

The separator disposed between the cathode and the anode serves to isolate or insulate the cathode and the anode from each other and enable transfer of lithium ions between the cathode and the anode, and may be composed of a porous non-conductive material or an insulating material, but the present invention is not limited thereto. For example, a diaphragm known in the related art may be used herein.

The separator may be a separate member such as a film, and may also be a coating layer added to the positive electrode and/or the negative electrode. For example, the material constituting the separator includes polyolefins such as polyethylene and polypropylene; glass fiber filter paper and ceramic, but the present invention is not limited thereto. In this case, the separator may have a thickness of about 5 μm to about 50 μm, particularly about 5 μm to about 25 μm.

As the electrolyte, an electrolyte known in the related art may be used. For example, an electrolyte of a type including a lithium salt and an organic solvent may be used herein. The electrolyte may be configured such that the electrolyte is impregnated into the anode, the cathode, and the separator.

As the organic solvent contained in the electrolyte, for example, a single solvent or a mixture of two or more organic solvents may be used. When a mixture of two or more organic solvents is used, one or more solvents may be selected from two or more groups of the weak polar solvent group, the strong polar solvent group, and the lithium metal protective solvent group, respectively, and then used. The weakly polar solvent is defined as a solvent having a dielectric constant of less than 15 capable of dissolving a sulfur element in an aryl compound, a bicyclic ether or an acyclic carbonate, and the strongly polar solvent is defined as a solvent having a dielectric constant of more than 15 capable of dissolving lithium polysulfide in a cyclic carbonate, a sulfoxide compound, a lactone compound, a ketone compound, an ester compound, a sulfate compound or a sulfite compound, and the lithium metal protecting solvent is defined as a solvent having a charge/discharge cycle efficiency of 50% or more, such as a saturated ether compound, an unsaturated ether compound, a heterocyclic compound including N, O, S or a combination thereof, which forms a stable Solid Electrolyte Interface (SEI) on lithium metal.

Specific examples of the weakly polar solvent include xylene, dimethoxyethane, 2-methyltetrahydrofuran, diethyl carbonate, dimethyl carbonate, toluene, dimethyl ether, diethyl ether, diglyme, tetraglyme, etc., but the present invention is not limited thereto.

Specific examples of the strongly polar solvent include hexamethylphosphoric triamide, γ -butyrolactone, acetonitrile, ethylene carbonate, propylene carbonate, N-methylpyrrolidone, 3-methyl-2-Oxazolidinones, dimethylformamide, sulfolane, dimethylacetamide, dimethylsulfoxide, dimethyl sulfate, ethylene glycol diacetate, dimethyl sulfite, ethylene glycol sulfite, and the like, but the present invention is not limited thereto.

Specific examples of the lithium metal protecting solvent include tetrahydrofuran, ethylene oxideAlkane, dioxolane, 3, 5-dimethylisoOxazole, furan, 2-methylfuran, 1, 4-dioxane, 4-methyldioxolane, etc., but the present invention is not limited thereto.

In addition to the features of the present invention as described above, the battery may be constructed by applying techniques known in the related art.

[ EXAMPLES OF THE INVENTION ]

Hereinafter, preferred embodiments of the present invention are provided to aid understanding of the present invention. However, it will be understood by those skilled in the art that the detailed description disclosed herein is given by way of illustration of the present invention only, and thus various changes and modifications may be made without departing from the spirit and scope of the present invention. Further, it will be apparent that such changes and modifications fall within the scope of the appended claims.