Search

KR-102963226-B1 - High energy density electrochemical device

KR102963226B1KR 102963226 B1KR102963226 B1KR 102963226B1KR-102963226-B1

Abstract

The present invention relates to an electrochemical device capable of simultaneously satisfying high energy density of 400 Wh/kg or more, excellent lifespan characteristics, and stability. The electrochemical device according to the present invention comprises a positive electrode; a negative electrode current collector, or a negative electrode comprising a negative electrode current collector and lithium metal; and an electrolyte. The positive electrode comprises a positive electrode current collector; and a positive electrode active material layer formed on the positive electrode current collector, comprising a porous binder scaffold and positive electrode active material particles.

Inventors

  • 이창규
  • 김창현
  • 최근호
  • 김정환
  • 조석규
  • 조형민

Assignees

  • 주식회사 유뱃

Dates

Publication Date
20260512
Application Date
20240125
Priority Date
20230125

Claims (20)

  1. An electrochemical device comprising: a positive electrode; a negative electrode current collector, or a negative electrode comprising a negative electrode current collector and lithium metal; and an electrolyte, having an energy density of 400 Wh/kg or more, The above anode comprises an anode current collector; and an anode active material layer formed on the anode current collector, comprising a porous binder scaffold and anode active material particles. An electrochemical device comprising an anode active material layer comprising 50 weight percent or more with respect to the total weight of the electrochemical device.
  2. In Article 1, An electrochemical device having an energy density of 450 Wh/kg to 650 Wh/kg.
  3. In Article 1, An electrochemical device that further includes a separator.
  4. delete
  5. In Article 1, An electrochemical device comprising a positive active material layer in an amount of 60 to 85 weight% relative to the total weight of the electrochemical device.
  6. In Article 1, An electrochemical device comprising 80 to 99 weight percent of positive active material particles based on the total weight of the positive active material layer.
  7. In Article 1, The above-mentioned anode is an electrochemical device in which the anode active material layer thickness is 50 to 2,000 μm and the anode is a thick-film type anode.
  8. In Article 1, The above-mentioned positive electrode is an electrochemical device having a thick-film type positive electrode with a positive active material layer capacity of 4 to 150 mAh/ cm² formed on one surface of a positive current collector.
  9. In Article 1, The above-mentioned anode is an electrochemical device in which the anode is a thick-film type anode with an anode active material layer composite density (g/cc) of 3.3 to 3.8.
  10. In Article 1, The electrochemical device is one in which the positive active material layer has positive active material particles evenly dispersed therein and a porous binder scaffold exists in the empty spaces between the particles.
  11. In Article 10, An electrochemical device comprising 0.01 to 40 parts by weight of a porous binder scaffold per 100 parts by weight of the above positive active material particles.
  12. In Article 10 The above-described porous binder scaffold further comprises a conductive material, in an electrochemical device.
  13. In Article 10, The electrochemical device wherein the positive active material layer further comprises a metal salt.
  14. In Paragraph 13, An electrochemical device comprising 0.01 to 50 parts by weight of a metal salt per 100 parts by weight of the above positive active material particles.
  15. In Paragraph 13, The above-mentioned metal salt is contained in or adsorbed on the surface of at least one of a porous binder scaffold and a positive active material particle, in an electrochemical device.
  16. In Paragraph 13, The above metal salt is an electrochemical element in which the metal salt is a sulfonyl group-containing metal salt selected from the following chemical formula 1 or chemical formula 2. [Chemical Formula 1] [Chemical Formula 2] In the above chemical formulas 1 and 2, n is 1 or 2 and; A is an n-valent cation; R1 to R3 are each independently a fluoro(C1-C7)alkyl or fluoro group.
  17. In Paragraph 16 The above A is an electrochemical element, wherein A is lithium, sodium, zinc, copper, aluminum, silver, gold, cesium, indium, magnesium, or calcium.
  18. An electrochemical device comprising: a positive electrode; a negative electrode current collector, or a negative electrode comprising a negative electrode current collector and lithium metal; and a liquid electrolyte, having an energy density of 400 Wh/kg or more, The above anode comprises an anode current collector; and an anode active material layer formed on the anode current collector, comprising anode active material particles, a binder, and a conductive material; and When the cross-section of the above positive active material layer is analyzed by X-ray CT imaging, with respect to the average concentration of conductive material ( C0 ) of the positive active material layer, the concentration of conductive material of the first active material layer ( C1 ) corresponding to the point 1/3 in the thickness direction of the positive active material layer from the interface between the positive current collector and the positive active material layer, the concentration of conductive material of the second active material layer ( C2 ) corresponding to the point 2/3 in the thickness direction of the positive active material layer from the point 1/3 in the thickness direction of the positive active material layer, and the concentration of conductive material of the third active material layer ( C3 ) from the point 2/3 in the thickness direction of the positive active material layer to the surface are 10% or less, and An electrochemical device comprising an anode active material layer comprising 50 weight percent or more with respect to the total weight of the electrochemical device.
  19. In Paragraph 1 or Paragraph 18, A half cell manufactured with the above anode is an electrochemical device having a discharge capacity retention rate of 80% or more at 0.3 C relative to the discharge capacity at 0.1 C.
  20. In Article 1, The above electrolyte is an electrochemical device, which is a liquid electrolyte, a solid electrolyte, or a combination thereof.

Description

High energy density electrochemical device The present invention relates to an electrochemical device having high energy density, more specifically, to a lithium metal battery and a negative electrode-free lithium battery having high energy density. Recently, as the required energy density of batteries has increased rapidly, the development of high-capacity lithium batteries has become urgent. To this end, research has been proposed on replacing conventional anode materials, such as graphite or silicon, with lithium metal or on anode-free batteries; however, changing the anode material alone is insufficient to satisfy the increasingly high performance requirements of batteries. Consequently, in addition to changing the anode material, active research is underway on thick-film cathodes, in which the thickness of the cathode active material layer is increased by increasing the density and loading of the cathode active material. However, as the thickness of the cathode active material layer increases, it becomes difficult to secure stable battery performance and lifespan characteristics, so there is practically a limit to increasing the thickness. For example, such thick-film cathodes have a fundamental problem in that the cathode material is unevenly distributed. This causes uneven lithium ion flow characteristics and leads to uneven charge/discharge characteristics and polarization phenomena along the thickness direction. Furthermore, there is a problem of degraded battery performance due to the increased travel distance of lithium ions resulting from the increased thickness of the cathode. In addition, the non-uniform flow characteristics of lithium ions exacerbate the problem of dendrite formation on the lithium metal surface, which shortens the battery's lifespan and reduces its stability. Figure 1 is the result of SEM analysis of the anode surface prepared in Comparative Example 1. Figure 2 is the result of SEM analysis of the anode surface prepared in Example 1. Figure 3 is the result of SEM analysis of the cross-section of the anode prepared in Comparative Example 1. Figure 4 is the result of SEM analysis of the cross-section of the anode prepared in Example 1. FIG. 5 is a graph showing the distribution of conductive material in the anode thickness direction based on the X-ray CT analysis results of the anode cross-sections prepared in (a) Comparative Example 1 and (b) Example 1. Figure 6 is a graph showing the distribution of conductive material content (vol%) in the first active material layer, the second active material layer, and the third active material layer according to the X-ray CT scan results. Unless otherwise defined in this specification, all technical and scientific terms have the same meaning as generally understood by those skilled in the art to which the present invention pertains. The terms used in the description herein are merely for the purpose of effectively describing specific embodiments and are not intended to limit the present invention. The singular form used in this specification is intended to include the plural form unless specifically indicated otherwise in the context. In the present specification and the appended claims, when a part such as a film (layer), region, or component is said to be on or above another part, it includes not only cases where it is directly above in contact with another part, but also cases where another film (layer), other region, or other component is interposed therein. Additionally, numerical ranges used herein include lower and upper limits and all values within the range, increments logically derived from the form and width of the defined range, all of which are limited values, and all possible combinations of upper and lower limits of numerical ranges defined in different forms. Unless otherwise specifically defined in this specification, values outside the numerical range that may occur due to experimental error or rounding are also included in the defined numerical range. The term “comprising” in this specification is an open description having an equivalent meaning to expressions such as “comprising,” “containing,” “having,” or “characterizing,” and does not exclude elements, materials, or processes not additionally listed. The term “porous binder scaffold” in this specification refers to a network structure uniformly formed in three dimensions by a binder, wherein the binder forms a framework and pores are richly developed within the framework. The pores preferably have an open pore structure, and the porous network structure formed by the binder can serve as a support in which the positive active material and the conductive material can be evenly distributed. The pores may have a diameter of 0.1 μm to 50 μm, and specifically, may have a diameter of 0.5 μm to 10 μm. More specifically, the porous binder scaffold may be a support comprising fibers formed by the self-assembly of an organic binder and a conductive material as a unit structu