Search

KR-20260065020-A - positive electrode active material for sodium secondary battery, method for preparing the same and sodium secondary battery including the same

KR20260065020AKR 20260065020 AKR20260065020 AKR 20260065020AKR-20260065020-A

Abstract

The present invention provides a method for manufacturing a positive electrode active material for a sodium secondary battery, comprising: a) a step of preparing a metal oxide precursor by roasting a metal hydroxide compound; and b) a step of preparing a sodium composite transition metal oxide by mixing the metal oxide precursor, a calcium compound, and a sodium compound and heat-treating them.

Inventors

  • 전예진
  • 이동욱
  • 김다모아

Assignees

  • 주식회사 에코프로비엠

Dates

Publication Date
20260508
Application Date
20241031

Claims (7)

  1. a) a step of preparing a metal oxide precursor by roasting a metal hydroxide compound; and b) A method for manufacturing a positive electrode active material for a sodium secondary battery, comprising the step of mixing the metal oxide precursor, calcium compound, and sodium compound and heat-treating to produce a sodium composite transition metal oxide.
  2. In paragraph 1, A method for manufacturing a positive electrode active material for a sodium secondary battery, wherein step a) above involves heat treatment at 700 to 900°C for 2 to 20 hours in an oxidizing atmosphere or an air atmosphere.
  3. In paragraph 1, Step b) above involves mixing a calcium compound in an amount of 0.005 to 0.1 equivalents of Ca/M (M = all metals excluding Na and Ca), and mixing a sodium compound in an amount of 0.8 to 1.2 equivalents of Na/M (M = all metals excluding Na and Ca). A method for manufacturing a positive electrode active material for a sodium secondary battery, wherein the material is heat-treated at 700 to 1,100°C for 2 to 20 hours in an oxidizing atmosphere or an air atmosphere.
  4. In paragraph 1, A method for manufacturing a positive electrode active material for a sodium secondary battery, wherein step b) above involves mixing the metal oxide precursor, the calcium compound, and the sodium compound by a dry method.
  5. A positive active material for a sodium secondary battery manufactured by the method for manufacturing a positive active material of claim 1.
  6. A cathode for a sodium secondary battery comprising a positive active material according to paragraph 5.
  7. Sodium secondary battery using a positive electrode according to Paragraph 6.

Description

Positive electrode active material for sodium secondary battery, method for preparing the same and sodium secondary battery including the same The present invention relates to a positive electrode active material for a sodium secondary battery, a method for manufacturing the same, and a sodium secondary battery comprising the same. With the surging demand for lithium-ion rechargeable batteries, which are widely used as energy storage devices in various electronic technology fields, sodium-ion rechargeable batteries are attracting attention as a replacement for lithium, an expensive metal. Sodium-ion secondary batteries are one of the next-generation materials with high potential for application as secondary batteries because they have an insertion/extraction reaction operating principle similar to that of lithium-ion secondary batteries. However, they show lower performance in terms of capacity, lifespan, and rate characteristics compared to lithium-ion secondary batteries, making commercialization difficult. Therefore, the development of high-performance cathode active materials is required for commercialization. Layered transition metal oxides are typically used as cathode active materials for sodium-ion secondary batteries because they have a simple structure, excellent electrochemical performance, and are easy to synthesize. Layered transition metal oxides are generally classified into O3-type and P2-type based on their crystal structure; cathode active materials based on the O3-type structure exhibit a composition such as Na x (TM) O2 (2/3 < x < 1.2), while cathode active materials based on the P2-type structure have a composition of Na x (TM) O2 (x ≤ 2/3). Although O3-type layered oxides have a higher energy density compared to P2-type layered oxide particles, they have disadvantages such as reduced cycle stability due to larger structural changes during the charge-discharge process, which makes commercial application difficult. Figure 1 is a surface SEM image of the (roasted) oxide precursor and the cathode active material prepared in Comparative Example 1, Comparative Example 2, Example 1, and Comparative Example 3. The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Unless otherwise defined, all terms used in this specification (including technical and scientific terms) may be used in a meaning that is commonly understood by those skilled in the art to which the present invention pertains. Throughout the specification, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. Furthermore, the singular form includes the plural form unless specifically stated otherwise in the text. One embodiment of the present invention provides a method for manufacturing a positive electrode active material for a sodium secondary battery, comprising: a) a step of preparing a metal oxide precursor by roasting a metal hydroxide compound; and b) a step of preparing a sodium composite transition metal oxide by mixing the metal oxide precursor, a calcium compound, and a sodium compound and heat-treating them. Specifically, in the present invention, by using an oxidative roasting precursor, reactivity with sodium (Na) can be improved during the manufacture of the cathode active material, and the roasted cathode active material is formed with a low specific surface area, which can reduce side reactions with the electrolyte during battery activation and improve the problem of capacity reduction. As in one embodiment, step a) may be heat treatment at 700 to 900°C for 2 to 20 hours in an oxidizing atmosphere or an air atmosphere. Specifically, the roasting heat treatment temperature may be optimized to 700 to 900°C to have a Me₂O₃ oxide precursor structure, and the effect of increasing the size and sphericity of the prepared oxide precursor primary particles may be obtained, for example, by roasting at 750 to 850°C, preferably 800°C, for 2 to 10 hours, 2 to 8 hours, or 4 to 8 hours in an air atmosphere. The above metal hydroxide precursor may include a compound represented by the following chemical formula 1. [Chemical Formula 1] [M x TM 1-x ](OH) 2 In the above chemical formula 1, TM may be at least one selected from Ni, Fe, Mn and Co, and M may be at least one selected from P, Sr, Ba, Ti, Zr, Al, W, Ce, Hf, Ta, Cr, F, Mg, Cr, V, Fe, Zn, Si, Y, Ga, Sn, Mo, Ge, Nd, B