Layered Cathode Structure for All-Solid-State Battery Adhesion
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Solution Overview
Problem
All-solid-state batteries using sulfide-based solid electrolytes face challenges with incomplete adhesion between electrodes and solid electrolytes due to non-uniform surface leveling caused by linear conductive materials like single-walled carbon nanotubes, and migration issues with point-shaped conductive materials like carbon black during the drying process.
Innovation Solution
A cathode structure comprising multiple layers of granular powder with different shaped conductive materials, where the inner layer includes linear conductive materials like single-walled carbon nanotubes and the outer layer includes point-shaped conductive materials like carbon black, enhancing electrical conductivity and adhesion by forming a uniform surface during sheeting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If linear conductive materials like single-walled carbon nanotubes are used in the granular powder, then electrical conductivity is improved, but surface uniformity deteriorates due to non-uniform surface leveling
Solution Approach 1:
The granular powder is segmented into an inner core layer and an outer layer with different conductive material compositions. The inner layer contains linear conductive materials for high conductivity, while the outer layer contains point-shaped conductive materials for surface uniformity, resolving the contradiction between conductivity and surface quality
Solution Approach 2:
Different regions of the granular powder are assigned different qualities: the inner layer prioritizes electrical conductivity with linear conductive materials, while the outer layer prioritizes surface uniformity with point-shaped conductive materials, allowing each region to fulfill its specific function
2Manufacturing precision
If point-shaped conductive materials like carbon black are used in the granular powder, then surface uniformity is improved, but electrical conductivity deteriorates due to material migration during drying
Solution Approach 1:
The granular powder is divided into inner and outer layers where point-shaped conductive materials are concentrated in the outer layer to provide surface uniformity, while linear conductive materials in the inner layer ensure overall electrical conductivity, preventing the trade-off between these two properties
Solution Approach 2:
The granular powder is pre-formed with a core-shell structure before electrode fabrication, where the conductive material distribution is already optimized with linear materials in the core and point-shaped materials in the shell, preventing migration issues during subsequent drying processes
3Device complexity
If a single-layer granular powder structure is used, then device complexity is reduced, but adhesion to solid electrolyte deteriorates due to non-uniform surface
Solution Approach 1:
The granular powder is segmented into functionally distinct inner and outer layers, where the outer layer specifically addresses adhesion to solid electrolyte through uniform surface morphology provided by point-shaped conductive materials, while maintaining overall structural simplicity
Solution Approach 2:
The surface layer of the granular powder is specifically designed with point-shaped conductive materials to provide uniform morphology for good adhesion to solid electrolyte, while the inner layer maintains high conductivity, allowing localized optimization without complex overall structure
Data Source
AI summary
A cathode for an all-solid-state battery in which a granule layer is composed of multiple layers having different types of particles to provide a uniform surface flatness during sheeting of the granular powder while increasing electrical conductivity of granular powder, resulting in excellent adhesion to the solid electrolyte, a method of preparing the same, and an all-solid-state battery including the cathode are provided. The cathode for an all-solid-state battery includes: a metal current collector; an inner granular powder layer that is located on one surface of the metal current collector and includes an active material, a conductive material, and a binder in the form of a granular powder; and an outer granular powder layer that is stacked on a surface of the inner granular powder layer and includes the active material, a conductive material, and the binder in the form of a granular powder, wherein the conductive material included in the inner granular powder layer and the conductive material included in the outer granular powder layer have different shapes from each other.