Search

KR-102962590-B1 - POSITIVE ELECTRODE FOR LITHIUM SECONDARY BATTERY AND LITHIUM SECONDARY COMPRISING THE SAME

KR102962590B1KR 102962590 B1KR102962590 B1KR 102962590B1KR-102962590-B1

Abstract

The present invention relates to a positive electrode for a lithium secondary battery and a lithium secondary battery including the same. More specifically, by adding a certain amount of a metal oxide-based additive to the positive electrode, the discharge capacity and lifespan characteristics of the lithium secondary battery can be improved.

Inventors

  • 조현아
  • 안지현
  • 이창훈

Assignees

  • 주식회사 엘지에너지솔루션

Dates

Publication Date
20260507
Application Date
20211118

Claims (10)

  1. In a positive electrode for a lithium secondary battery comprising a positive electrode active material layer, The above positive active material layer comprises a sulfur-carbon composite which is a positive active material, a binder, and a metal oxide-based additive, wherein The above metal oxide-based additive includes niobium tungsten oxide, and A cathode for a lithium secondary battery, wherein the metal oxide-based additive is included in an amount of 3 to 5 weight percent based on the total weight of the cathode active material layer.
  2. delete
  3. delete
  4. In paragraph 1, The above binder comprises one or more selected from the group consisting of SBR (Styrene-Butadiene Rubber)/CMC (Carboxymethyl Cellulose), poly(vinyl acetate), polyvinyl alcohol, polyethylene oxide, polyvinylpyrrolidone, alkylated polyethylene oxide, cross-linked polyethylene oxide, polyvinyl ether, poly(methyl methacrylate), polyvinylidene fluoride, copolymer of polyhexafluoropropylene and polyvinylidene fluoride, poly(ethyl acrylate), polytetrafluoroethylene, polyvinyl chloride, polyacrylonitrile, polyvinylpyridine, polystyrene, and polyacrylic acid, a positive electrode for a lithium secondary battery.
  5. In paragraph 1, A positive electrode for a lithium secondary battery, wherein the positive active material layer is formed on at least one surface of a positive current collector.
  6. In paragraph 5, The positive current collector comprises stainless steel, aluminum, nickel, titanium, or calcined carbon, for a lithium secondary battery.
  7. delete
  8. A lithium secondary battery comprising the positive electrode, negative electrode, and electrolyte of claim 1.
  9. In paragraph 8, The above lithium secondary battery is a lithium secondary battery, which is a lithium-sulfur secondary battery.
  10. In paragraph 8, The above lithium secondary battery is a lithium secondary battery that is a pouch-type lithium secondary battery.

Description

Positive electrode for lithium secondary battery and lithium secondary battery comprising the same The present invention relates to a positive electrode for a lithium secondary battery and a lithium secondary battery including the same. The demand for rechargeable batteries is increasing due to the rapid recent advancements in the fields of electronic devices and electric vehicles. In particular, driven by the trend toward miniaturization and lightweighting of portable electronic devices, there is a growing demand for rechargeable batteries with high energy density capable of meeting these needs. Among secondary batteries, lithium-sulfur secondary batteries utilize sulfur-based compounds containing sulfur-sulfur bonds as the positive electrode active material, and carbon-based materials in which the insertion and deinsertion of alkali metals such as lithium or metal ions such as lithium ions occur, or materials such as silicon or tin that form alloys with lithium, as the negative electrode active material. Specifically, electrical energy is stored and generated by utilizing an oxidation-reduction reaction in which the sulfur-sulfur bonds break and the oxidation number of sulfur decreases during discharge (a reduction reaction), and the oxidation number of sulfur increases and the sulfur-sulfur bonds are reformed during charging (an oxidation reaction). In particular, sulfur, used as a cathode active material in lithium-sulfur secondary batteries, has a theoretical energy density of 1675 mAh/g, which is about five times higher than that of cathode active materials used in conventional lithium secondary batteries, making it a battery capable of exhibiting high power and high energy density. In addition, sulfur is attracting attention as an energy source for medium-to-large devices, such as electric vehicles, as well as portable electronic devices, due to its advantages of being inexpensive, having abundant reserves for easy supply, and being environmentally friendly. However, the above-mentioned lithium-sulfur secondary battery has a problem in that polysulfides are formed and leached from the cathode during operation, and a shuttle ring phenomenon may occur, which leads to the irreversible loss of the cathode active material and a degradation of the battery's lifespan characteristics. To address the problem of degradation in the lifespan characteristics of such lithium-sulfur secondary batteries, research is being conducted on adding polysulfide adsorbent materials or redox mediators to the cathode, or coating the surface of the separator with polysulfide adsorbent or repulsive materials. For example, Japanese Patent Publication No. 2004-179160 and Korean Patent Publication No. 2015-046861 disclose a cathode for a lithium-sulfur secondary battery containing an inorganic additive, but there are some limitations in improving the battery life characteristics. Therefore, there is a continuing demand for the development of materials that can demonstrate a significant effect on improving the lifespan characteristics of lithium-sulfur secondary batteries. Figure 1 is a graph showing the results of measuring the discharge capacity of lithium-sulfur secondary batteries prepared in Example 1 and Comparative Example 1, respectively. Figure 2 is a graph showing the results of measuring the lifespan characteristics of lithium-sulfur secondary batteries prepared in Example 1 and Comparative Example 1, respectively. Hereinafter, the present invention will be described in more detail to aid in understanding the invention. 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. cathode for lithium secondary batteries The present invention relates to a positive electrode for a lithium secondary battery, wherein the positive electrode comprises a positive electrode active material layer, and the positive electrode active material layer comprises a sulfur-carbon composite which is a positive electrode active material, a binder, and a metal oxide-based additive. Specifically, the positive electrode for a lithium secondary battery according to the present invention may include a positive electrode current collector; and a positive electrode active material layer formed on at least one surface of the current collector. In the positive electrode for a lithium secondary battery according to the present invention, the metal oxide-based additive is included in the positive electrode active material layer to improve the capacity of the positive electrode and improve the lifespan characteristics of the battery. The above metal oxide-based additive can suppress the shuttling phenomenon of polysulfides by promoting the adsorption an