KR-20260065415-A - METHOD FOR EVALUATING SUITABILITY OF MATERIALS FOR ALL-SOLID STATE BATTERY

KR20260065415AKR 20260065415 AKR20260065415 AKR 20260065415AKR-20260065415-A

Abstract

The present invention relates to a method for evaluating the compatibility of materials for all-solid-state batteries. By observing the reaction at the interface and the elemental diffusion reaction under three conditions—conditions where only material diffusion exists, conditions where material diffusion and electron transfer exist, and conditions where material diffusion, electron transfer, and ion transfer all exist—the compatibility between materials when applied to actual all-solid-state batteries can be accurately determined, and thereby, combinations of all-solid-state battery materials capable of realizing the desired effect can be screened.

Inventors

조성만
김영중
정혜성
김형철
장용준
김용구
이상헌
최성현
김사흠
최선호
권덕황
정지윤

Assignees

현대자동차주식회사
기아 주식회사
한국과학기술연구원

Dates

Publication Date: 20260508
Application Date: 20241101

Claims (9)

Step (S1) of manufacturing a specimen containing one or more materials to be evaluated; Step (S2) of placing the above specimen between two electrodes and observing interfacial reaction and elemental diffusion phenomena; Step (S3) of placing the above specimen between two electrodes where the movement of lithium ions is blocked, and then applying a constant current to observe interfacial reaction and elemental diffusion phenomena; and A method for evaluating compatibility between materials for an all-solid-state battery, comprising the step (S4) of placing the above specimen between two electrodes including at least one electrode capable of moving lithium ions, and then applying a constant current to observe interfacial reactions and elemental diffusion phenomena.
In paragraph 1, A method for evaluating compatibility between materials for an all-solid-state battery, wherein the above specimen is at least one selected from a compact formed by compressing one or more materials to be evaluated and a sheet formed by mixing one or more materials to be evaluated with a binder.
In paragraph 1, A method for evaluating compatibility between materials for an all-solid-state battery, wherein the electrode used in the above S2 step comprises one or more selected from the group consisting of lithium, stainless steel, aluminum, copper, titanium, indium, silver, gold, platinum, carbon, and alloys thereof.
In paragraph 1, A method for evaluating compatibility between materials for an all-solid-state battery, wherein the electrode used in the above S3 step, which blocks the movement of lithium ions, comprises one or more selected from the group consisting of stainless steel, gold, platinum, and alloys thereof.
In paragraph 1, A method for evaluating compatibility between materials for an all-solid-state battery, wherein the constant current cycling applied in step S3 above is performed at a current density of 10 to 100 mA/ cm² .
In paragraph 1, A method for evaluating compatibility between materials for all-solid-state batteries, wherein the lithium ion-mobile electrode used in the above S4 step is lithium or an alloy containing lithium.
In paragraph 1, A method for evaluating compatibility between materials for an all-solid-state battery, wherein the constant current cycling applied in step S4 above is performed at a current density of 0.1 to 10 mA/ cm² .
In paragraph 1, A method for evaluating compatibility between materials for all-solid-state batteries, wherein the observation of the above interfacial reaction and elemental diffusion phenomena is performed through one or more methods selected from the group consisting of XRD, XPS, SEM-EDS, SIMS, TEM-EDS, and Raman analysis.
In paragraph 1, A method for evaluating compatibility between materials for all-solid-state batteries, wherein if the existence of a secondary phase is confirmed as a result of observing the above-mentioned interfacial reaction and elemental diffusion phenomenon, the compatibility of the material for all-solid-state batteries is determined to be unsuitable.

Description

Method for Evaluating Suitability of Materials for All-Solid State Batteries The present invention relates to an evaluation method capable of evaluating the compatibility between different types of materials that can be used in all-solid-state batteries. Various batteries capable of overcoming the current limitations of lithium-ion batteries are being researched in terms of capacity, stability, output, scaling up, and miniaturization. Among these, all-solid-state batteries refer to batteries in which the liquid electrolyte used in conventional lithium-ion batteries is replaced with a solid. Since they do not use flammable solvents within the battery, there is no risk of ignition or explosion caused by the decomposition reactions of conventional electrolytes, thereby significantly improving safety. Furthermore, because all materials used in all-solid-state batteries are solid, diversification of materials and shapes is easy. Additionally, all-solid-state batteries are attracting the most attention as next-generation batteries because they are advantageous for realizing high-voltage cells and achieving high energy density through a direct stacking method. Meanwhile, in all-solid-state batteries, the interface between the two electrodes and the solid electrolyte layer interposed between the two electrodes is a solid-solid interface, and accordingly, the characteristics of the solid-solid interface are one of the most important components determining the characteristics and performance of the all-solid-state battery. However, the characteristics of the solid-solid interface are observed differently under various conditions and may also vary depending on the various conditions of the cell being fabricated. Therefore, determining the characteristics of the solid-solid interface based on a single criterion does not sufficiently reflect the characteristics of all-solid-state batteries actually in use. Furthermore, since conventional evaluation methods or screening methods for battery materials are all based on lithium-ion batteries, a new method is required that can accurately determine the characteristics of materials used in all-solid-state batteries or the compatibility between one or more materials by appropriately reflecting the characteristics of the solid-solid interface. Figure 1 is a figure showing the XRD analysis results of a compact obtained according to Example 1 of the present invention. Figure 2 is a figure showing the XRD analysis results of a powder compact obtained according to Example 2 of the present invention. Figure 3 is a figure showing the XRD analysis results of a compact obtained according to Example 3 of the present invention. Figure 4 is a figure showing the TEM-EDS analysis results of a powder compact obtained according to Example 4 of the present invention. The present invention will be described in more detail below. 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. Hereinafter, the method for evaluating the compatibility of a material for an all-solid-state battery according to the present invention will be described in detail. Method for evaluating the compatibility of materials for all-solid-state batteries The present invention provides a method for evaluating compatibility between materials for an all-solid-state battery, comprising the steps of: manufacturing a specimen containing one or more materials to be evaluated (S1); placing the specimen between two electrodes and observing an interfacial reaction and an elemental diffusion phenomenon (S2); placing the specimen between two electrodes where the movement of lithium ions is blocked and applying a constant current to observe an interfacial reaction and an elemental diffusion phenomenon (S3); and placing the specimen between two electrodes containing at least one electrode capable of the movement of lithium ions and applying a constant current to observe an interfacial reaction and an elemental diffusion phenomenon (S4). In the case of all-solid-state batteries, electrochemical reactions occur at the interface between solids, and accordingly, the compatibility of materials for all-solid-state batteries can be determined by the characteristics at the interface between solids. However, the characteristics at the interface between solids may vary under various environmental conditions, and in order to accurately evaluate the actual performance of materials for all-solid-state batteries, it is necessary to observe the characteristics of the solid-solid interface under various environments, including the environment in which the battery operates. In this regard, the present invention provides an evaluation method that c