KR-20260065571-A - positive electrode active material for secondary battery, method of preparing the same and secondary battery including the same

KR20260065571AKR 20260065571 AKR20260065571 AKR 20260065571AKR-20260065571-A

Abstract

One embodiment of the present invention provides a positive electrode active material for a secondary battery comprising: a composite transition metal oxide particle capable of intercalation/deintercalation of lithium or sodium; a catalyst coating layer located on the particle and comprising a metal fluoride; and a carbon coating layer located on the particle and comprising carbon nanotubes; a method for manufacturing the same, a positive electrode comprising the same, and a secondary battery.

Inventors

김다모아
이동욱
서유경
은혜지

Assignees

주식회사 에코프로비엠

Dates

Publication Date: 20260508
Application Date: 20251030
Priority Date: 20241031

Claims (13)

Composite transition metal oxide particles capable of intercalation/deintercalation of lithium or sodium; A catalyst coating layer located on the above particles and comprising a metal fluoride; and A positive electrode active material for a secondary battery comprising a carbon coating layer located on the above particles and containing carbon nanotubes.
In paragraph 1, The above catalyst coating layer is a positive electrode active material for a secondary battery, wherein the weight ratio (M2 x2 O y2 / M1 x1 F y1 ) of a metal oxide represented by the following chemical formula 2 to a metal fluoride represented by the following chemical formula 1 is 0 to 0.2: [Chemical Formula 1] M1 x1 F y1 [Chemical Formula 2] M2 x2 O y2 In the above chemical formulas 1 and 2, M1 is at least one metal selected from the group consisting of Co, Mg, Al, Zr, Ba, Ce, Ca, and K, and M2 is the same metal as M1, and 0<x1≤3, 0<x2≤3, 0<y1≤4, 0<y2≤4.
In paragraph 1, The above metal fluoride is a positive active material for a secondary battery comprising at least one selected from the group consisting of CoF₂ , MgF₂ , AlF₃ , ZrF₄ , BaF₂ , CeF₃ , CaF₂ , and KF.
In paragraph 1, The above catalyst coating layer comprises 0.05 to 4 weight percent of the metal fluoride based on the total weight of the positive electrode active material, for a secondary battery positive electrode active material.
In paragraph 1, A positive electrode active material for a secondary battery, wherein at least a portion of the carbon coating layer is located on the catalyst coating layer.
In paragraph 1, The carbon coating layer comprises 0.5 to 2 weight percent of the carbon nanotubes based on the total weight of the positive electrode active material, for a secondary battery positive electrode active material.
In paragraph 1, The above-mentioned complex transition metal oxide is, A lithium composite transition metal oxide comprising at least one selected from lithium nickel-cobalt-aluminum oxide and lithium nickel-cobalt-manganese oxide; or A positive electrode active material for a secondary battery, comprising at least one sodium composite transition metal oxide selected from sodium nickel iron-manganese oxide and sodium nickel-copper iron-manganese oxide.
a) a step of mixing lithium or sodium composite transition metal oxide particles with metal fluoride and calcining to form a catalyst coating layer containing metal fluoride; and b) a step of forming a carbon coating layer containing carbon nanotubes by chemically vaporizing (CVD) a carbon source on lithium or sodium composite transition metal oxide particles on which the catalyst coating layer is formed; a method for manufacturing a positive electrode active material for a secondary battery.
In paragraph 8, The step of forming the catalyst coating layer a) above is, A method for manufacturing a positive electrode active material for a secondary battery, wherein the material is calcined at 300 to 500°C in an inert atmosphere for 1 to 7 hours.
In paragraph 8, The step of forming the carbon coating layer b) above is, A method for manufacturing a positive electrode active material for a secondary battery, wherein a gaseous carbon source is introduced at a rate of 1 to 100 sccm and carbon nanotubes are produced by decomposing at 500 to 700°C for 1 to 30 minutes.
In paragraph 8, The step of forming the carbon coating layer b) above is, A method for manufacturing a positive electrode active material for a secondary battery, wherein the carbon nanotubes are grown on the surface of the catalyst coating layer using the metal fluoride as a medium.
A positive electrode for a secondary battery comprising a positive electrode active material according to claim 1.
A secondary battery comprising a positive electrode according to Clause 12.

Description

Positive electrode active material for secondary battery, method of preparing the same and secondary battery including the same The present invention relates to a positive electrode active material for a secondary battery, a method for manufacturing the same, and a secondary battery including the same. Rechargeable batteries have been widely used as energy storage devices in various fields of electronic technology. Recently, the demand for lithium-ion rechargeable batteries has surged, and sodium-ion rechargeable batteries are also attracting attention as a replacement for lithium, an expensive metal. As the application range of lithium-ion secondary batteries expands from small electronic devices to electric vehicles and power storage, there is a growing demand for cathode materials for secondary batteries that possess high safety, long lifespan, high energy density, and high power characteristics. Lithium metal compounds are primarily used as cathode active materials for lithium secondary batteries, and examples of lithium metal oxides being studied include LiCoO2 , LiMn2O4 , LiNiO2 , LiNi1 - xyCoxMnyO2 (0<x+y< 1 ), and LiMnO2 . Sodium-ion secondary batteries are one of the next-generation materials with high potential for application as secondary batteries because they have an operating principle of intercalation/deintercalation reactions similar to that of lithium-ion secondary batteries. However, they show lower performance in terms of capacity, lifespan, and rate characteristics compared to lithium-ion secondary batteries, making commercialization difficult. Therefore, the development of high-performance cathode active materials is required for the commercialization of sodium-ion secondary batteries. Layered transition metal oxides, which have a simple structure, excellent electrochemical performance, and are easy to synthesize, are typically used as positive electrode active materials for sodium-ion secondary batteries. Layered transition metal oxides are typically classified into O3-type and P2-type depending on their crystal structure. Positive electrode active materials based on the O3-type structure exhibit a composition such as Na x (TM) O2 (2/3 < x ≤ 1), while positive electrode active materials based on the P2-type structure have a composition such as Na x (TM) O2 (x ≤ 2/3). Previously, a method of simply mixing carbon nanotubes through a post-processing step was used to compensate for the low electrical and thermal conductivity of lithium or sodium metal oxides. However, this method failed to achieve the expected performance improvement due to dispersibility issues between carbon nanotubes and lithium or sodium metal oxides. In other words, the clumping of carbon nanotubes intensifies the non-uniform distribution of particles, which carries the problem of potentially leading to non-uniform electrochemical performance across different electrode regions of batteries composed of lithium or sodium metal oxides. In addition, in conventional methods for manufacturing electrodes for secondary batteries, separate additives or solvents were used to uniformly mix carbon nanotubes using a wet method to prepare an anode slurry. However, when manufacturing electrodes using a wet method, a heat treatment process at high temperatures is essential, requiring recovery processes for solvent drying and recycling, and furthermore, there was a risk of damage to the metal oxide. Accordingly, there is a growing need for the development of electrodes manufactured using a dry method. Figure 1a shows the results of particle surface SEM analysis of the cathode active material with a catalyst coating layer formed in Examples 1-1, 1-3, and Comparative Examples 1 and 4. Figure 1b shows the results of EDS analysis of the particle surface prepared in Example 1-1 and Comparative Example 4. Figures 2a and 2b are the results of particle surface SEM analysis of the cathode active materials with carbon nanotubes formed on their surfaces, prepared in Examples 1-1 and 1-3 and Comparative Examples 2 and 4, respectively. Figure 3 is the result of a cross-sectional SEM analysis of the active material layer in the dry cathode for a sodium secondary battery prepared in Example 1-1 and Comparative Example 1. The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Unless otherwise defined, all terms used in this specification (including technical and scientific terms) may be used in a meaning that is commonly unders