Sulfide Solid Electrolyte Battery Positive Electrode Coating
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Solution Overview
Problem
The partial peeling off of the reaction suppressing layer on the surface of positive electrode active material particles during the manufacturing process of all-solid batteries leads to increased interface resistance, deteriorating battery performance.
Innovation Solution
A positive electrode active material particle is developed with concave and convex portions on its surface, which prevents the peeling off of the reaction suppressing layer, even under mechanical stress, by forming an aggregate of primary particles and coating a reaction suppressing layer with inorganic materials like Zr, W, or Ti.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reaction suppressing layer is coated on the surface of positive electrode active material particles, then the reaction between active material and sulfide-based solid electrolyte is suppressed, but the coating layer peels off during manufacturing process, increasing interface resistance
Solution Approach 1:
Concave and convex portions are formed on the surface of the positive electrode active material particles before coating the reaction suppressing layer. This preliminary surface modification creates mechanical interlocking features that prevent coating layer peeling during subsequent manufacturing processes, thereby maintaining coating integrity and reducing interface resistance.
Solution Approach 2:
The surface of the positive electrode active material particles is modified to include concave and convex portions with specific curvature characteristics. These curved surface features enhance the adhesion of the reaction suppressing layer by creating mechanical interlocking, preventing peeling while maintaining the protective function of the coating.
2Device complexity
If the positive electrode active material particles are mixed with sulfide-based solid electrolyte, then the battery assembly is simplified, but interface resistance increases due to reaction between active material and electrolyte
Solution Approach 1:
A reaction suppressing layer is introduced as an intermediary between the positive electrode active material and the sulfide-based solid electrolyte. This intermediate layer prevents direct harmful reactions between the active material and electrolyte while maintaining ionic conductivity, thereby reducing interface resistance and enabling simplified battery assembly.
Solution Approach 2:
The reaction suppressing layer is applied locally on the surface of the positive electrode active material particles rather than throughout the entire particle. This localized coating provides protection at the critical interface regions where contact with the sulfide-based solid electrolyte occurs, preventing harmful reactions while maintaining overall battery structure simplicity.
Data Source
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AI summary
In a battery production process, a positive electrode active material having a reaction-suppressing layer that does not easily peel off formed on the surface thereof, and a positive electrode and an all-solid-state battery that use said material are provided. The present invention involves positive electrode active material particles for an all-solid-state battery containing sulfide-based solid electrolyte. The positive electrode active material particles are an aggregate containing two or more particles. The surface of the aggregate is coated with a reaction-suppressing layer for suppressing reactions with the sulfide-based solid electrolyte.