Search

KR-20260065521-A - Negative Electrode Active Material for All Solid-State Battery

KR20260065521AKR 20260065521 AKR20260065521 AKR 20260065521AKR-20260065521-A

Abstract

The negative electrode active material according to the present invention is a negative electrode active material for an all-solid-state battery and comprises particulate natural graphite such that when the pressure increases from 200 kgf/㎠ to 600 kgf/㎠, the ratio ΔD/ΔP of the increase in pellet density ΔD (mg/㎤) according to the increase in pressure ΔP (kgf/㎠) is 0.50 (mg/㎤)(kgf/㎠) -1 or greater.

Inventors

  • 안기홍
  • 최호선
  • 이경묵

Assignees

  • (주)포스코퓨처엠

Dates

Publication Date
20260508
Application Date
20251023
Priority Date
20241031

Claims (18)

  1. A negative electrode active material for an all-solid-state battery comprising particulate natural graphite, wherein when the pressure increases from 200 kgf/cm² to 600 kgf/cm², the ratio ΔD/ΔP of the increase in pellet density according to the increase in pressure ΔP (kgf/cm²) is 0.50 (mg/cm²)·(kgf/cm²) - 1 or greater.
  2. In Article 1, The above natural graphite is a negative electrode active material for an all-solid-state battery, in which natural graphite crystals are interlocked and assembled in a particulate form.
  3. In Paragraph 2, The above-mentioned particulate natural graphite is a negative electrode active material for an all-solid-state battery having a surface of natural graphite.
  4. In Article 1, A negative electrode active material for an all-solid-state battery having a pellet density of 1.40 x 10³ mg/cm³ or more at a pressure of 600 kgf/cm².
  5. In Article 1, A negative electrode active material for an all-solid-state battery having a pellet density of 1.60 x 10³ mg/cm³ or more at a pressure of 1200 kgf/cm².
  6. In Article 1, A negative electrode active material for an all-solid-state battery, wherein the ratio S BET / D 50 , obtained by dividing the BET specific surface area S BET in m²/g units of the above natural graphite by the cumulative volume median diameter D 50 in μm units, is 1.00 or greater.
  7. In Article 1, A negative electrode active material for an all-solid-state battery, wherein the tap density of the above-mentioned natural graphite is 0.95 g/cm³ or less.
  8. In Article 1, A negative electrode active material for an all-solid-state battery, wherein the cumulative volume median diameter D 50 of the above natural graphite is 1.0 to 7.5 μm.
  9. In Article 1, A negative electrode active material for an all-solid-state battery, wherein the linseed oil absorption amount of the above natural graphite is 40 to 60 ml/100g.
  10. In Article 1, A negative electrode active material for an all-solid-state battery, wherein the degree of sphericity of the above natural graphite is 0.85 to 0.93.
  11. In Article 1, The above-mentioned all-solid-state battery is a sulfide-based all-solid-state battery, a negative electrode active material for an all-solid-state battery.
  12. An electrode material for an all-solid-state battery comprising a natural graphite-based active material and a non-natural graphite-based active material, which are negative electrode active materials according to any one of claims 1 to 11.
  13. In Paragraph 12, The above-mentioned non-natural graphite-based active material is an electrode material for an all-solid-state battery comprising a silicon-based active material.
  14. In Paragraph 13, The above electrode material is an electrode material for an all-solid-state battery that further comprises a solid electrolyte.
  15. A negative electrode slurry for an all-solid-state battery comprising a natural graphite-based active material which is a negative electrode active material according to any one of claims 1 to 11, a solid electrolyte, a binder, and a solvent.
  16. In Paragraph 15, The above-mentioned cathode slurry is a cathode slurry for an all-solid-state battery, further comprising a non-natural graphite-based active material.
  17. The whole house and A negative electrode for an all-solid-state battery comprising a negative electrode active material layer located on at least one surface of the current collector and comprising a natural graphite-based active material, a non-natural graphite-based active material, a solid electrolyte, and a binder, which are negative electrode active materials according to any one of claims 1 to 11.
  18. An all-solid-state battery comprising a cathode, an anode, and a solid electrolyte membrane interposed between the cathode and the anode according to claim 17.

Description

Negative Electrode Active Material for All Solid-State Battery The present invention relates to a negative electrode active material for an all-solid-state battery, and more specifically, to a natural graphite-based negative electrode active material for an all-solid-state battery. All-solid-state batteries are rechargeable batteries that use a solid electrolyte instead of a liquid electrolyte. By fundamentally eliminating leakage and flammability issues, they are relatively safe from risks of thermal runaway and explosion caused by temperature rise or internal short circuits. Due to these advantages, including not only superior safety but also improved productivity resulting from process simplification and high integration, industrial interest in all-solid-state batteries is rapidly increasing. In all-solid-state batteries, the interface between the electrode and the solid electrolyte is the boundary where ions move and electrochemical reactions occur. Consequently, if the contact between the electrode and the solid electrolyte is insufficient and results in high interfacial resistance, the number of active sites where electrochemical reactions take place is reduced. This acts as a major factor degrading the battery's reversible capacity, output characteristics, and cycle life characteristics. Preferred embodiments of the present invention are described below. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. In addition, embodiments of the present invention are provided to more fully explain the present invention to those with average knowledge in the relevant technical field. In describing the embodiments of the present invention, if it is determined that a detailed description of known technology related to the present invention may unnecessarily obscure the essence of the present invention, such detailed description will be omitted. Furthermore, the terms described below are defined considering their functions in the present invention, and these may vary depending on the intentions or conventions of the user or operator. Therefore, such definitions should be based on the content throughout this specification. The terms used in the detailed description are merely for describing the embodiments of the present invention and should not be limited in any way. Unless explicitly stated otherwise, expressions in the singular form include the meaning of the plural form. In this description, expressions such as “include” or “equipped” are intended to refer to certain characteristics, numbers, steps, actions, elements, parts or combinations thereof, and should not be interpreted to exclude the existence or possibility of one or more other characteristics, numbers, steps, actions, elements, parts or combinations thereof other than those described. Unless otherwise specifically defined in the specification of the present invention, % units mean weight %. The present invention will be described in detail below through each embodiment or example of the invention. It should be noted that each embodiment or example described in this specification is not limited to a single embodiment or example, but may also be combined with other embodiments or examples. Accordingly, the citation of claims within the scope of the intellectual property rights is merely an example of an embodiment, and the technical concept of the present invention should not be interpreted as being limited only to a combination with the cited claims; rather, combinations with various claims are also included within the scope of the technical concept of the present invention. cathode active material A negative electrode active material according to one embodiment of the present invention is a negative electrode active material for an all-solid-state battery and comprises particulate natural graphite such that when the pressure increases from 200 kgf/㎠ to 600 kgf/㎠, the ratio ΔD/ΔP of the increase in pellet density ΔD (mg/㎤) according to the increase in pressure ΔP (kgf/㎠) is 0.50 (mg/㎤)·(kgf/㎠) - 1 or greater. The pressure is the pressure applied to particulate natural graphite in a powdered state to measure the pellet density. The increase in pellet density refers to the increase in density between the pellet density of particulate natural graphite at a pressure of 200 kgf/㎠ and the pellet density of particulate natural graphite at a pressure of 600 kgf/㎠. The aforementioned ΔD/ΔP may be an indicator of the softness of particulate natural graphite. Particulate natural graphite having a ΔD/ΔP value of 0.50 (mg/cm²/cm³kgf) or higher can have its particles deformed due to excellent softness, allowing the solid electrolyte and the cathode to adhere stably and preventing the formation of fine gaps between the cathode and the solid electrolyte, thereby increasing the interfacial contact area between the solid electrolyte and the catho