KR-20260067174-A - METHOD FOR ANALYZING COATING OR DOPING ELEMENTS OF POSITIVE ELECTRODE ACTIVE MATERIAL

Abstract

The present invention relates to a method for measuring the content of a coating or doping material in a single analysis, regardless of the type of coating or doping material of the positive electrode active material. According to the present invention, the content of the coating or doping material of the positive electrode active material can be measured with high precision by improving the ionization rate of the coating or doping material of the positive electrode active material.

Inventors

• 김종현
• 이지영
• 유승수

Assignees

• 주식회사 엘지에너지솔루션

Dates

Publication Date

20260512

Application Date

20241105

Claims (8)

1. A method for analyzing coating or doping elements of a positive electrode active material, Step of placing the positive active material into a closed Teflon tube and measuring its weight; A step of mixing hydrochloric acid, hydrogen peroxide, and hydrofluoric acid in the above tube and reacting them at room temperature; Microwave processing step; A step of cooling the pretreated tube to room temperature and then adding an internal standard substance to dilute it with ultrapure water; and A method for analyzing coating or doping elements of a positive electrode active material, comprising the step of analyzing by ICP-OES.
2. In paragraph 1, A method for analyzing a coating or doping element of a positive electrode active material, wherein the positive electrode active material comprises aluminum, which is a coating or doping element satisfying Equation 1 in the XPS depth profile measurement results: [Mathematical Formula 1] Al max -Al 4000s ≤ 7 In mathematical formula 1, Al max is the content at which the aluminum content (at.%) reaches its maximum during an etching interval of 4000 seconds, and Al 4000s is the aluminum content (at.%) at 4000 seconds of etching.
3. In paragraph 1, A method for analyzing the coating or doping elements of an anode active material, wherein the above hydrochloric acid, hydrogen peroxide, and hydrofluoric acid are mixed in a volume ratio of 1 to 3:0.1 to 1:0.05 to 0.5.
4. In paragraph 1, A method for analyzing the coating or doping elements of an anode active material, wherein the microwave treatment step comprises treating with microwaves at 200 to 300°C and 120 to 199 bar for 10 to 60 minutes.
5. In paragraph 1, A method for analyzing the coating or doping elements of an anode active material, wherein the above microwave processing conditions are as follows:
6. In paragraph 1, A method for analyzing a coating or doping element of an anode active material, wherein the coating or doping element further comprises one or more of Y, Ti, Zr, and W.
7. In paragraph 1, A method for analyzing a coating or doping element of a positive electrode active material, wherein the recovery rate of the coating or doping element from the positive electrode active material is 95% or higher.
8. A system for analyzing the coating or doping elements of an anode active material, comprising the method according to claim 1.

Description

Method for analyzing coating or doping elements of positive electrode active material The present invention relates to a method for measuring the content of a coating or doping material in a single analysis, regardless of the type of coating or doping material of the positive electrode active material. In the development and quality control of cathode active materials, the content of coating and doping components is managed as a key factor. To measure the content of coating and doping components, ICP-OES analysis is performed after pretreatment of the cathode material using acid and heat. During the pretreatment process, it is important to select an appropriate type and amount of acid and a temperature range so that all components being measured can be ionized. Conventional acid pretreatment methods used disposable polypropylene (PP) Corning tubes to heat up to 130°C on a hot plate and performed pretreatment in an open system to boil and evaporate the acid, thereby measuring the aluminum (Al) content in a state where pressurization was not possible. However, when analyzing any cathode material using this pretreatment method, there are cases where the ICP-OES measurement value of aluminum relative to the input amount is measured to be low, ranging from 20% to 80%, and the analysis is inconsistent. Inconsistent analysis results indicate that the aluminum was not sufficiently ionized. Therefore, it is necessary to develop a pretreatment method that sufficiently ionizes aluminum so that the measured value is 90% or more of the input amount. Figure 1 is a graph showing the XPS analysis results. Figure 2 is a schematic representation of an example of a filtering process. Figure 3 is a graph showing the results of the ICP-OES analysis. Figure 4 is a photograph showing the surface shape of the particle. The present invention is capable of various modifications and may have various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention. In the case of cathode active materials with issues regarding aluminum measurement values, a separate analysis step had to be performed because the conventional ICP-OES analysis method, which involves hot plate heating pretreatment, could not analyze aluminum. This invention aims to solve the problem that the conventional analysis method results in a low recovery rate of aluminum contained in any cathode active material and inconsistent content measurements. The term "recovery rate" in the present invention may be replaced with "ionization rate." Hereinafter, a method for analyzing the coating or doping elements of an anode active material according to an embodiment of the present invention will be described in more detail. Specifically, the present invention comprises the steps of: placing a positive electrode active material into a closed Teflon tube and measuring its weight; mixing hydrochloric acid, hydrogen peroxide, and hydrofluoric acid in the tube and reacting them at room temperature; treating with a microwave (Microwave Digestion System, MDS); cooling the pretreated tube to room temperature and adding an internal standard substance to dilute it with ultrapure water; and analyzing it using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). Conventional ICP-OES pretreatment methods use disposable polypropylene for hot plate heating and open tubes that can be heated up to a maximum of 130°C and cannot apply pressure. Since heat is transferred from the outside of the tube in this pretreatment method, it is difficult to transfer heat uniformly to the center of the contents inside the tube, which can affect the ionization rate of the analyte. In the present invention, aluminum oxides that are difficult to ionize, including aluminum, can be ionized by using a closed Teflon tube. Using a Teflon tube allows for multiple uses, heating up to 300°C, and pressurization up to 199 bar using N₂ gas, etc. According to one embodiment, the present invention may use a mixed acid comprising hydrochloric acid, hydrogen peroxide, and hydrofluoric acid in a volume ratio of 1 to 3:0.1 to 1:0.05 to 0.5 or 2 to 3:0.3 to 0.8:0.05 to 0.3. According to an embodiment of the present invention, the method includes the step of adding a mixed acid to a positive electrode active material and then performing microwave treatment. Specifically, for example, the microwave treatment step may be performed at 200 to 300°C, 220 to 280°C, or 240 to 260°C, and at 120 to 199 bar, for example, 120 to 180 bar, or 130 to 160 bar, for 10 to 60 minutes, for example, 20 to 40 minutes. Any cathode active material for which the aluminum content cannot be analyzed by conventional analytical methods has the charact