KR-102962595-B1 - POSITIVE ELECTRODE ACTIVE MATERIAL, POSITIVE ELECTRODE AND ALL-SOLID-STATE BATTERY COMPRISING SAME

Abstract

The present invention relates to a positive electrode active material for an all-solid-state battery, a positive electrode including the same, and an all-solid-state battery. More specifically, the positive electrode active material for an all-solid-state battery has a form comprising a core particle containing a positive electrode active material in the form of a secondary particle and an amorphous coating layer formed on the surface of the core particle. Since the porosity of the positive electrode active material itself is minimized, when applied to a positive electrode, the porosity of the positive electrode is reduced, thereby providing an effect of improving the output of the all-solid-state battery.

Inventors

• 강소라
• 권혜진
• 이충현
• 김명수
• 최석인
• 오경배
• 박미희
• 이준호

Assignees

• 주식회사 엘지에너지솔루션

Dates

Publication Date

20260512

Application Date

20250820

Priority Date

20240821

Claims (10)

1. A positive electrode active material for an all-solid-state battery comprising: a core particle; and an amorphous coating layer located on the surface of the core particle, The above core particle is in the form of a secondary particle formed by the aggregation of a plurality of positively active materials having the form of a primary particle, and The above amorphous coating layer comprises a compound including two or more selected from the group consisting of Li, M, and O, wherein M comprises one or more selected from the group consisting of B, Zr, Nb, Ti, Al, W, P, Fe, C, N, Si, S, Co, Ge, Ga, Y, and In, as a positive electrode active material for an all-solid-state battery, The particle size (D50) of the positive electrode active material for the all-solid-state battery is 3 μm to 7.52 μm, and A positive electrode active material for an all-solid-state battery, wherein the span (span, (D90-D10)/D50) of the above-mentioned positive electrode active material is 0.7 or less.
2. In paragraph 1, A positive electrode active material for an all-solid-state battery, wherein the above compound comprises one or more selected from the group consisting of LiO, MO, LiM, and LiMO.
3. In paragraph 1, A positive electrode active material for an all-solid-state battery, wherein the thickness of the amorphous coating layer is 5 nm to 200 nm.
4. delete
5. delete
6. In paragraph 1, The above positive active material comprises a lithium composite metal oxide, a positive active material for an all-solid-state battery.
7. In paragraph 1, A positive electrode active material for an all-solid-state battery, wherein the porosity of the positive electrode active material for an all-solid-state battery is 7% or less.
8. A positive electrode for an all-solid-state battery comprising a positive electrode active material for an all-solid-state battery according to any one of claims 1 to 3, 6 and 7.
9. In paragraph 8, The above-described positive electrode comprises the above-described positive electrode active material, a sulfide-based solid electrolyte, a binder, and a conductive material, for an all-solid-state battery.
10. An all-solid-state battery comprising the positive electrode, the negative electrode, and a sulfide-based solid electrolyte membrane interposed between them according to claim 8.

Description

Positive ELECTRODE ACTIVE MATERIAL, POSITIVE ELECTRODE AND ALL-SOLID-STATE BATTERY COMPRISING SAME The present invention relates to a positive electrode active material for an all-solid-state battery, a positive electrode including the same, and an all-solid-state battery. Various batteries capable of overcoming the current limitations of lithium-ion batteries are being researched in terms of capacity, safety, output, scaling up, and miniaturization. Continuous research is being conducted in academia and industry on representative technologies, such as metal-air batteries, which have a much larger theoretical capacity compared to lithium-ion batteries; all-solid-state batteries, which pose no risk of explosion in terms of safety; supercapacitors in terms of output; NaS batteries or RFBs (redox flow batteries) in terms of scale; and thin-film batteries in terms of miniaturization. All-solid-state batteries refer to batteries in which the liquid electrolyte used in conventional lithium-ion batteries is replaced with a solid electrolyte. Since they do not use flammable solvents within the battery, there is absolutely no ignition or explosion caused by decomposition reactions of conventional electrolytes, thereby significantly improving safety. Furthermore, among all-solid-state batteries, technological development is continuing for sulfide-based all-solid-state batteries, which possess high ionic conductivity of the solid electrolyte and can theoretically achieve a high energy density of over 900 Wh/L. In this context, a sulfide-based all-solid-state battery refers to an all-solid-state battery containing a sulfide-based solid electrolyte. In all-solid-state battery systems, lithium ion conduction does not occur through the liquid electrolyte contained in conventional lithium-ion batteries (LIBs). Therefore, when manufacturing cathodes for sulfide-based all-solid-state batteries, small-diameter sulfide-based solid electrolyte particles must be added to the cathode to increase the contact interface between the cathode active material and the sulfide-based solid electrolyte particles, thereby enhancing lithium ion conduction. Furthermore, to improve energy density, physical contact between the cathode active material, sulfide-based solid electrolyte particles, and other battery components within the cathode must be enhanced, and the porosity of the cathode after rolling must be reduced and maintained throughout the charging and discharging cycles. Furthermore, unlike liquid electrolytes, solid electrolytes lack fluidity and cannot permeate between the cathode active materials; consequently, the pores formed between the cathode active materials remain as dead areas, leading to a decrease in the output of the all-solid-state battery. Accordingly, there is a persistent need for the development of technology that can improve the performance of all-solid-state batteries by further reducing the porosity in the cathode. FIG. 1 is a schematic cross-sectional view showing the interface between a positive active material and a sulfide-based solid electrolyte according to one embodiment of the present invention. Figure 2 is an X-ray diffraction (XRD) graph for a positive electrode active material according to Example 1 of the present invention. Hereinafter, the present invention will be described in more detail to aid in understanding the invention. Terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention. As used in this specification, the term “anode active material” refers to a material that generates electrical energy through a chemical reaction at the anode of a battery, and is synonymous with the anode active material. To distinguish between a material contained in a core particle and a material comprising a core particle and an amorphous coating layer, the material contained in the core particle is referred to as the anode active material, and the material comprising a core particle and an amorphous coating layer is referred to as the anode active material. The term “primary particle” as used in this specification means a single particle. The primary particle is a primary particle of the anode active material. As used in this specification, the term “secondary particle” refers to a polyp formed by the aggregation of a plurality of primary particles. The secondary particle is a secondary particle of the anode active material. Cathode active material for all-solid-state batteries The present invention relates to a positive electrode active material for an all-solid-state battery. The positive electrode active material for an all-solid-state battery according to the present invention comprises: a core particle; and