KR-20260065310-A - BINDER COMPRISING COPOLYMER COMPOSITION, CATHODE FOR SECONDARY BATTERY COMPRISING THE SAME, AND SECONDARY BATTERY COMPRISING THE CATHODE

KR20260065310AKR 20260065310 AKR20260065310 AKR 20260065310AKR-20260065310-A

Abstract

The present invention relates to a copolymer composition comprising a copolymer and an acid compound, wherein the copolymer comprises an acrylic acid-based monomer unit and a vinyl alcohol-based monomer unit, an anode slurry composition comprising the same, an anode, and a secondary battery.

Inventors

이은송
김창범
박찬수
박지혜
조민기
권현지
김균태
강지수
최지현
권세만

Assignees

주식회사 한솔케미칼

Dates

Publication Date: 20260508
Application Date: 20241101

Claims (13)

copolymer; and Includes acid compounds; and The above copolymer comprises acrylic acid-based monomer units and vinyl alcohol-based monomer units, Copolymer composition.
In paragraph 1, The above copolymer is prepared by copolymerizing and hydrolyzing an acrylate-based monomer and a vinyl acetate-based monomer, Copolymer composition.
In paragraph 1, Based on 100% by weight of the total copolymer weight of the copolymer, the above acrylic acid-based monomer units in an amount of 20% or more and 80% or less by weight; and Comprising 20 weight% or more and 80 weight% or less of the above vinyl alcohol series monomer units, Copolymer composition.
In paragraph 1, The above acrylic acid-based monomer unit is combined with an alkali metal, Copolymer composition.
In paragraph 1, The above acid compound comprises two or more terminal groups capable of bonding to the acrylic acid series monomer unit of the copolymer, the vinyl alcohol series, or a combination thereof. Copolymer composition.
In paragraph 5, The above terminal group comprises one or more oxygen atoms, Copolymer composition.
In paragraph 1, The above acid compound comprises oxalic acid, malonic acid, succinic acid, glutaric acid, sulfuric acid, adipic acid, phthalic acid, lactic acid, glycolic acid, salicylic acid, itaconic acid, fumaric acid, citric acid, isocitric acid, aconitic acid, tricarboxylic acid, agaric acid, trimellitic acid, ethylenetetracarboxylic acid, 3-phosphoglyceric acid, malic acid, phosphoric acid, polyacrylic acid, polymethacrylic acid, polyalcohol, polystyrene sulfonate, polyvinyl phosphate, a polymer containing a carboxylic acid group, a polymer containing an alcohol group, a polymer containing a sulfonic acid group, a polymer containing a phosphate group, or a combination thereof. Copolymer composition.
In paragraph 1, The above acid compound is mixed with the above copolymer and includes an amount such that the pH of the above copolymer composition is 5 or higher and 8 or lower. Copolymer composition.
In paragraph 1, pH 5 or higher, 8 or lower Copolymer composition.
A copolymer composition of any one of claims 1 to 9; and A positive electrode active material; comprising Anode slurry composition.
In Paragraph 10, The above positive active material contains sulfur atoms, Anode slurry composition.
The whole house; and A positive active material layer formed by applying the positive slurry composition of claim 10 onto the above current collector; comprising anode.
including the anode of Clause 12 Secondary battery.

Description

Binder comprising a copolymer composition, a cathode for a secondary battery comprising the binder, and a secondary battery comprising the cathode. The present invention relates to a copolymer composition and an anode slurry composition containing the same, an anode, and a secondary battery. More specifically, it relates to a copolymer composition capable of producing an anode slurry composition capable of suppressing the leaching phenomenon of lithium polysulfide ( Li₂Sx , 1≤x≤8), an anode slurry composition containing the copolymer composition, an anode, and a lithium-sulfur secondary battery. Due to their high energy density, lithium-ion batteries are widely used in the electrical, electronic, telecommunications, and computer industries. Following small lithium-ion batteries for portable electronic devices, their applications are expanding to include high-capacity batteries for hybrid and electric vehicles. Recently, active research and development are being conducted on lithium-sulfur secondary batteries, which use sulfur-based materials with S-S bonds (Sulfur-Sulfur Bonds) as the positive electrode active material and lithium metal as the negative electrode active material. Sulfur, the main material of lithium-sulfur secondary batteries, has the advantages of being very abundant compared to lithium, being non-toxic, and having a low weight per atom. In lithium-sulfur secondary batteries, during discharge, lithium, the negative electrode active material, releases electrons and becomes ionized, undergoing oxidation, while sulfur-based materials, the positive electrode active material, accept electrons and are reduced. Here, the oxidation reaction of lithium is the process in which lithium metal releases electrons and is converted into a lithium cation. In addition, the reduction reaction of sulfur is a process in which S-S bonds accept two electrons and are converted into the form of sulfur anions. Sulfur before discharge has a cyclic S8 structure and is converted into lithium polysulfide (LiS x ) by a reduction reaction. In addition, when lithium polysulfide is completely reduced, lithium sulfide (Li 2 S) is produced. Although lithium-sulfur secondary batteries have advantages in energy storage density, various problems are known in their practical applications, such as the instability of lithium metal, low conductivity of the cathode, sublimation of sulfur-based materials during electrode manufacturing, and loss of sulfur-based materials during repeated charge-discharge cycles. In particular, the leaching of sulfur-based materials from the anode, which occurs when lithium polysulfides generated at the anode during discharge migrate to the lithium metal surface of the cathode during charging and are reduced, is emerging as the biggest obstacle to the commercialization of lithium-sulfur batteries. Lithium polysulfides leach into the electrolyte, causing various problems such as reduced cathode capacity and electrolyte contamination, thereby degrading the performance of lithium-sulfur batteries. To suppress the leaching of these sulfur-based substances, the use of sulfur adsorption additives, surface treatment of the sulfur surface, and the use of carbon nanostructures have been suggested. However, there are still disadvantages, such as increased risk of conductivity degradation and side reactions, loss of active material, rising costs, and complex manufacturing processes. In addition, there was a disadvantage in that the capacity and lifespan characteristics of lithium-sulfur batteries could not be significantly improved. Therefore, in order to secure secondary batteries with excellent characteristics, a new approach is required to suppress the leaching phenomenon of sulfur-based materials such as lithium polysulfide. The operation and effects of the invention will be described in more detail below through specific embodiments. However, these embodiments are merely examples of the invention and do not define the scope of the invention. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention. Therefore, it should be understood that the configuration of the embodiments described in this specification is merely one of the most preferred embodiments of the present invention and does not represent all of the technical ideas of the present invention, and that various equivalents and modifications that can replace them may exist at the time of filing this application. In this specification, singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as “comprising,” “comprising,” or “having” are intended to specify the exi