KR-20260065019-A - Method for Preparing an Aqueous Electrode Slurry Composition

Abstract

The present invention relates to a method for preparing an aqueous electrode slurry composition, and more specifically, comprises: (a) a step of mixing an acrylic acid-based polymer and an aqueous solvent and then performing a first mixing process; and (b) a step of mixing a lithium-titanium oxide (LTO) negative electrode active material and a conductive material into the mixture obtained from step (a) and then performing a second mixing process; wherein the second mixing process is a mixing process by high rotation energy dispersion mixing or rotation shear mixing. According to the method for manufacturing an aqueous electrode slurry composition according to the present invention, a high pH can be stabilized without the addition of a separate acidity regulator, and at the same time, the electrode peeling phenomenon can be improved with a small amount of binder. Furthermore, an aqueous electrode slurry composition for a lithium-ion secondary battery can be manufactured having improved dispersibility compared to conventional general LTO electrode slurries, thereby enabling the manufacture of an electrode having more uniform dispersibility and higher density than conventional aqueous negative electrodes.

Inventors

• 김수진
• 김동현
• 신창년
• 고현석
• 신현진
• 디키수산토
• 김성겸
• 김수선

Assignees

• 주식회사 럼플리어

Dates

Publication Date

20260508

Application Date

20241031

Claims (9)

1. (a) a step of mixing an acrylic acid-based polymer and an aqueous solvent and then performing a primary mixing process; and (b) a step of mixing a lithium-titanium oxide (LTO) negative electrode active material and a conductive material into the mixture obtained from step (a) above, and then performing a secondary mixing process; wherein A method for preparing an aqueous electrode slurry composition, wherein the above secondary mixing process is a mixing process by high rotation energy dispersion mixing or rotation shear mixing.
2. In Article 1, A method for preparing an aqueous electrode slurry composition characterized in that the above acrylic acid-based polymer is polyacrylic acid (PAA).
3. In Article 1, A method for preparing an aqueous electrode slurry composition, characterized in that the above acrylic acid-based polymer is included in an amount of 0.5 to 15 weight% relative to the total weight of the electrode slurry composition.
4. In Article 1, A method for preparing an aqueous electrode slurry composition, characterized in that the above-mentioned first mixing process is a mixing process using a PD mixer (Planetary Disperser Mixer).
5. In Article 1, A method for preparing an aqueous electrode slurry composition, characterized in that the lithium-titanium oxide negative electrode active material is included in an amount of 75 to 98 weight% relative to the total weight of the electrode slurry composition.
6. In Article 1, A method for preparing an aqueous electrode slurry composition, characterized in that the conductive material is included in an amount of 1 to 10 weight percent relative to the total weight of the electrode slurry composition.
7. A water-based electrode slurry composition for a lithium-ion secondary battery manufactured by the method of any one of claims 1 to 6.
8. A negative electrode for a lithium-ion secondary battery manufactured by coating, drying, and pressing the aqueous electrode slurry composition of claim 7 onto a current collector.
9. A lithium-ion secondary battery characterized by comprising a cathode manufactured using an aqueous cathode slurry composition comprising the cathode of claim 8 and a lithium iron phosphate ( LiFePO4 ) cathode active material.

Description

Method for Preparing an Aqueous Electrode Slurry Composition This research was conducted under the Daegu Institute of Machinery and Materials' Next-Generation Battery-Centered Energy Enterprise Support Project. [Aknowlegdement] This research was supported by a grant from Next-Generation Battery Energy Company Support Project funded by DAEGU MECHATRONICS & MATERIALS INSTITUE. The present invention relates to a method for manufacturing an aqueous electrode slurry composition for a lithium-ion secondary battery that can improve electrode peeling while stabilizing pH. The process of forming a battery electrode plate by coating a negative electrode or a negative electrode active material onto a current collector is called the electrode manufacturing process. In the above electrode manufacturing process, a mixing process is generally essential to form a slurry by mixing electrode active material, conductive material, binder, solvent, etc. The reason for forming the mixture containing the active material into a slurry is that the slurry state is easy to coat onto the electrode support and is relatively easy to work with. Therefore, to maximize battery performance, the dispersibility of the mixture slurry containing the active material must be very high, and to this end, the mixing method must also be optimized according to the material. Meanwhile, most existing electrode slurries for lithium-ion secondary batteries are organic slurries using NMP (N-Methyl-2-pyrrolidone) as a solvent. However, in line with recent environmental issues and carbon reduction policies, companies are taking various approaches to reduce NMP usage. Among them, some companies are introducing NMP recovery and purification facilities, but significant solutions remain regarding high operating costs and the need to reuse NMP. Accordingly, in the conventional preparation of organic electrode slurries, distilled water There is growing interest in an eco-friendly method for manufacturing water-based mixing slurries that can reduce costs and the use of harmful organic solvents. In the case of negative electrodes for lithium-ion secondary batteries, conventionally, electrodes using a water-based mixing method applied to natural graphite or artificial graphite were generally used, but recently, negative electrodes using lithium-titanium oxide (LTO) are being developed and applied to address battery fire safety and low-temperature usability issues. However, since it is a lithium-based oxide, when water-based mixing is performed, the pH of the slurry rises above 10, and when manufacturing the electrode, severe delamination occurs with the aluminum current collector mainly used for LTO electrodes during the drying process, resulting in a problem where the electrode itself is not formed. To solve the above problem , boric acid ( H₃BO₃ , pH adjusters such as boric acid or phosphoric acid ( H₃PO₄ , orthophosphoric acid) have been added, but boric acid ( H₃BO₃ ) has the disadvantage of corroding commonly used tank or pipe materials such as SUS304 and SUS316 , which limits the surface treatment of manufacturing equipment and manufacturing processes. In the case of phosphoric acid ( H₃PO₄ ), although it improves electrode delamination and enhances adhesion, there are many problems with usage limitations due to its corrosiveness and numerous precautions regarding harm to the human body. Figure 1 shows photographic data of electrode slurry composition samples of the embodiment, comparative example 2, and comparative example 3 of the present invention. FIG. 1 is a graph showing the results of measuring battery capacity performance for batteries (coin cells) manufactured using the electrode slurry compositions of the embodiment, comparative example 2, and comparative example 3 of the present invention. The present invention is capable of various modifications and may have various embodiments; specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the present invention. In describing the present invention, detailed descriptions of related prior art are omitted if it is determined that such detailed descriptions may obscure the essence of the present invention. The terms used in this application are used merely to describe specific embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, terms such as "comprising" or "having" are intended to specify the presence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features,