KR-20260064547-A - Fabrication Method of Negative Electrode Active Material for All Solid-State Battery

KR20260064547AKR 20260064547 AKR20260064547 AKR 20260064547AKR-20260064547-A

Abstract

The method for manufacturing a negative electrode active material according to the present invention is a method for manufacturing a negative electrode active material for an all-solid-state battery, and more specifically, comprises: a spheroidization step of manufacturing spheroidized natural graphite through mechanical processing; and an oxidation step of heat-treating the spheroidized natural graphite.

Inventors

안기홍
유정현
이경묵

Assignees

(주)포스코퓨처엠

Dates

Publication Date: 20260507
Application Date: 20251023
Priority Date: 20241031

Claims (12)

A spheroidization step for manufacturing spheroidized natural graphite through mechanical processing; and A method for manufacturing a negative electrode active material for an all-solid-state battery, comprising an oxidation step of heat-treating the spherical natural graphite.
In Article 1, A method for manufacturing a negative electrode active material for an all-solid-state battery, wherein, in the oxidation step above, the spherical natural graphite has a bare surface of natural graphite.
In Article 1, A method for manufacturing a negative electrode active material for an all-solid-state battery, wherein the above mechanical processing is a rotary processing using an airflow.
In Article 1, A method for manufacturing a negative electrode active material for an all-solid-state battery, wherein the cumulative volume median diameter of the spherical natural graphite is 7.5 μm or less.
In Article 1, A method for manufacturing a negative electrode active material for an all-solid-state battery, wherein the BET specific surface area of the spherical natural graphite is 3.0 to 6.0 m²/g.
In Article 1, A method for manufacturing a negative electrode active material for an all-solid-state battery, wherein the above heat treatment is performed in an oxygen-containing atmosphere or an inert atmosphere.
In Article 1, A method for manufacturing a negative electrode active material for an all-solid-state battery, wherein the above heat treatment is performed in a temperature range in which the absolute value of the derivative is 0.01 to 0.20 (%/℃), based on the derivative of the thermogravimetric analysis graph of the spherical natural graphite.
In Article 1, A method for manufacturing a negative electrode active material for an all-solid-state battery, wherein the above heat treatment is performed at 500 to 700°C.
In Article 1, A method for manufacturing a negative electrode active material for an all-solid-state battery, wherein the above heat treatment is performed for 0.5 to 5 hours.
In Article 1, A method for manufacturing a negative electrode active material for an all-solid-state battery, wherein the above heat treatment is performed in a rotary furnace.
In Article 1, A method for manufacturing a negative electrode active material for a solid-state battery, wherein the above-mentioned solid-state battery is a sulfide-based solid-state battery.
A step of manufacturing a natural graphite-based active material, which is a cathode active material, by a manufacturing method according to any one of claims 1 to 11; and A step of manufacturing a cathode by applying a cathode slurry containing the above-mentioned natural graphite-based active material, solid electrolyte, and solvent to at least one surface of a cathode current collector, and drying and calendering; A method for manufacturing a negative electrode for an all-solid-state battery comprising

Description

Fabrication Method of Negative Electrode Active Material for All Solid-State Battery The present invention relates to a method for manufacturing a negative electrode active material for a sulfide-based all-solid-state battery, and more specifically, to a method for manufacturing 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, th