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KR-20260064440-A - CARBON-SULFUR COMPOSITE FOR THERMAL BATTERY CATHODE MATERIAL AND METHOD FOR MANUFACTURING THE SAME

KR20260064440AKR 20260064440 AKR20260064440 AKR 20260064440AKR-20260064440-A

Abstract

The present invention relates to a carbon-sulfur composite for a thermal battery cathode material and a method for manufacturing the same. Specifically, the invention relates to a method for manufacturing a carbon-sulfur composite having excellent heat resistance and electrochemical performance by pulverizing polyacrylonitrile and sulfur and heat-treating them under specific conditions. Polyacrylonitrile and sulfur were mixed into a powder with a uniform particle size distribution using a ball mill method, and a carbon-sulfur composite was manufactured by subjecting the mixture to sequential steps of a first heat treatment and a second heat treatment. The manufactured carbon-sulfur composite can be applied as a cathode material for a thermal battery, and the manufactured thermal battery can operate stably even in a high-temperature environment.

Inventors

  • 박상백
  • 김도훈

Assignees

  • 국방과학연구소

Dates

Publication Date
20260507
Application Date
20250228
Priority Date
20241030

Claims (15)

  1. A mixed powder preparation step of mixing and pulverizing polyacrylonitrile and sulfur using a ball mill method; and A first heat treatment step of heat-treating the above mixed powder in an inert gas atmosphere at a temperature of 100 to 200 ℃; and A method for manufacturing a carbon-sulfur composite for a thermal battery cathode material, comprising: a second heat treatment step of increasing the temperature to 300 to 500 ℃ after the first heat treatment step to perform a second heat treatment.
  2. In Article 1, A method for manufacturing a carbon-sulfur composite for a thermal battery cathode material, wherein the molecular weight of the polyacrylonitrile is 10,000 to 300,000 g/mol.
  3. In Article 1, A method for manufacturing a carbon-sulfur composite for a thermal battery cathode material, wherein the polyacrylonitrile and sulfur are mixed in a weight ratio of 1:2 to 8.
  4. In Article 1, A method for manufacturing a carbon-sulfur composite for a thermal battery cathode material, wherein the average particle size of the above-mentioned mixed powder is 20 to 100 μm.
  5. In Article 1, A method for manufacturing a carbon-sulfur composite for a thermal battery cathode material, wherein the above ball milling method uses one or more methods selected from the group consisting of a planetary ball mill, a vibratory ball mill, a high-energy ball mill, a drum ball mill, a magnetic ball mill, an attrition ball mill, and a cryogenic ball mill.
  6. In Paragraph 5, A method for manufacturing a carbon-sulfur composite for a thermal battery cathode material, wherein the above ball mill method uses ceramic balls with a diameter of 1 to 20 mm.
  7. In Paragraph 6, A method for manufacturing a carbon-sulfur composite for a thermal battery cathode material, wherein the ceramic balls used are one or more selected from the group consisting of zirconia ( ZrO2 ) balls, silicon carbide (SiC) balls, silicon nitride ( Si3N4 ) balls, and alumina ( Al2O3 ) balls.
  8. In Article 1, The above ball mill method is a method for manufacturing a carbon-sulfur composite for a thermal battery cathode material, wherein the ball-to-powder ratio (BPR), which is the ratio of the mass of the balls to the mass of the mixed powder, is 3 to 20:1.
  9. In Article 1, A method for manufacturing a carbon-sulfur composite for a thermal battery cathode material, wherein the above ball mill method is performed at a rotational speed of 200 to 1500 rpm.
  10. A carbon-sulfur composite for a thermal battery cathode material comprising polyacrylonitrile and sulfur, wherein sulfur is chemically bonded within a polyacrylonitrile-derived carbon matrix by pulverization and heat treatment, and the 5% weight loss temperature (Td 5% ) is 400°C or higher.
  11. In Article 10, The carbon-sulfur composite for a thermal battery cathode material described above is a carbon-sulfur composite for a thermal battery cathode material having a sulfur content of 30 wt% or more.
  12. In Article 10, A carbon-sulfur composite for a thermal battery cathode material, wherein the D 10 (particle size in which, when the total number of particles of the carbon-sulfur composite is set to 100% in the cumulative particle size distribution of the carbon-sulfur composite, 10% of the smallest particles are smaller than or equal to the particle size) of the carbon-sulfur composite for a thermal battery cathode material is 0.1 to 3 μm.
  13. In Article 10, A carbon-sulfur composite for a thermal battery cathode material, wherein the D 50 (particle size in which, when the total number of particles in the particle size cumulative distribution is 100%, 50% of the smallest particles are smaller than or equal to the particle size) of the carbon-sulfur composite for a thermal battery cathode material is 3 to 20 μm.
  14. A cathode material comprising a carbon-sulfur composite for a thermal battery cathode material selected from any one of claims 10 to 13.
  15. A thermal battery comprising a cathode material comprising a carbon-sulfur composite for a thermal battery cathode material selected from any one of claims 10 to 13.

Description

Carbon-sulfur composite for thermal battery cathode material and method for manufacturing the same The present invention relates to a carbon-sulfur composite for a thermal battery cathode material and a method for manufacturing the same. Thermal batteries are primary batteries that operate at high temperatures and require high heat resistance and excellent energy storage performance. In particular, since reliable power must be supplied in extreme environments such as missiles, aerospace, and defense industries, the thermal stability of electrode and electrolyte materials is a critical requirement. Conventional sulfur (S)-based electrodes offer high theoretical capacity but are prone to evaporation and leaching at high temperatures, making them difficult to apply to thermal batteries. To address this, carbon-sulfur composites in which sulfur is immobilized within a carbon matrix are being studied; however, performance degradation caused by sulfur evaporation and leaching in high-temperature environments remains a challenge that needs to be resolved. Accordingly, there is a need to develop technologies that improve the heat resistance of carbon-sulfur composites and enhance sulfur immobilization. FIG. 1 is a schematic diagram of a method for manufacturing a carbon-sulfur composite for a thermal battery cathode material according to one embodiment of the present invention. Figure 2 shows SEM and EDS mapping images of the mixed powder of Example 1 of the present invention. Figure 3 shows SEM and EDS mapping images of the carbon-sulfur composite of Comparative Example 1 of the present invention. Figure 4 shows SEM and EDS mapping images of the carbon-sulfur composite of Comparative Example 4 of the present invention. Figure 5 shows SEM and EDS mapping images of the carbon-sulfur composite of Comparative Example 5 of the present invention. Figure 6 shows the thermogravimetric analysis of the carbon-sulfur composites of Comparative Examples 4 and 5 of the present invention. Figure 7 shows the thermogravimetric analysis of the carbon-sulfur composite of Example 1 of the present invention. Figure 8 shows the thermogravimetric analysis of the carbon-sulfur composite of Comparative Example 1 of the present invention. FIG. 9 shows the thermogravimetric analysis of carbon-sulfur composites of Comparative Examples 1 to 4 of the present invention. FIG. 10 shows the thermogravimetric analysis of carbon-sulfur composites of Comparative Examples 5 to 8 of the present invention. FIG. 11 shows the thermogravimetric analysis of carbon-sulfur composites of Examples 1 to 3 of the present invention. FIG. 12 shows the X-ray diffraction (XRD) analysis of the carbon-sulfur composites of Examples 1 to 3 of the present invention. Figure 13 shows the results of Raman analysis of the carbon-sulfur composites of Examples 1 to 3 of the present invention. Figure 14 shows the elemental content analysis of carbon-sulfur composites of Examples 1 to 3 of the present invention. FIG. 15 shows the structure of a thermal battery according to one embodiment of the present invention. Figure 16 shows the pulse discharge curve of the thermal battery of Example 1 of the present invention. Figure 17 shows the internal resistance of the thermal battery of Example 1 of the present invention. The present invention will be described in more detail below. However, the following specific examples or embodiments are merely references for the detailed explanation of the present invention and are not limited thereto, and the present invention may be implemented in various forms. Furthermore, unless otherwise defined, all technical and scientific terms have the same meaning as generally understood by one of the art to which the present invention pertains. The terms used in the description of the present invention are merely for the purpose of effectively describing specific embodiments and are not intended to limit the present invention. Additionally, the singular form used in the specification and the appended claims may be intended to include the plural form unless specifically indicated otherwise in the context. Furthermore, when it is stated that a part "includes" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. Furthermore, unless otherwise specifically defined in the present invention, when a layer or member is described as being located “on” another layer or member, this includes not only cases where a layer or member is in contact with another layer or member, but also cases where another layer or member exists between two layers or two members. Additionally, terms used herein such as “about,” “substantially,” etc., are used to mean at or near the stated value when inherent manufacturing and material tolerances are presented in the said sense, and are used to prevent unscrupulous infringers from unfairly exploiting the disclosed content in which precise o