Cathode Slurry Dispersion for All-Solid-State Battery Interface
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Solution Overview
Problem
Conventional methods fail to form a good solid-solid interface in cathode mixture layers of all-solid-state batteries, leading to resistance deterioration after charge/discharge cycles.
Innovation Solution
A method involving dispersing a conductive additive in a solvent, followed by a sulfide solid electrolyte, and then a cathode active material to create a cathode slurry, with the sulfide solid electrolyte dispersed after the conductive additive, to minimize agglomeration and enhance interface formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional dispersing methods are used to form cathode mixture layers, then the coating process can be completed, but agglomeration of cathode active material occurs and poor solid-solid interface is formed
Solution Approach 1:
The dispersing process is divided into three sequential steps with different dispersants for different components: Step 1 uses a first dispersant for conductive additive, Step 2 uses a second dispersant for sulfide solid electrolyte, and Step 3 uses a third dispersant for cathode active material. This segmentation prevents agglomeration by treating each component separately with optimized dispersing conditions, resulting in uniform distribution and good solid-solid interfaces in the cathode mixture layer.
2Productivity
If multiple components are dispersed simultaneously, then the process time is reduced, but agglomeration increases and interface quality deteriorates
Solution Approach 1:
The cathode slurry preparation is segmented into three sequential dispersing steps, each optimized for specific components. This prevents the agglomeration that would occur with simultaneous dispersing while maintaining high productivity through efficient sequential processing. Each step uses specific dispersing conditions tailored to the component being processed.
Solution Approach 2:
Conductive additive is dispersed first to create a uniform base matrix, followed by sulfide solid electrolyte, and finally cathode active material. This preliminary action of establishing a uniform dispersant-conductive additive mixture before adding other components ensures that subsequent materials are evenly distributed, preventing agglomeration and achieving high dispersing uniformity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach suppresses agglomeration, allowing for a good solid-solid interface, which reduces resistance deterioration in all-solid-state batteries.
Implementation Method 1
a first step of dispersing a conductive additive constituted of carbon in a solvent to obtain a first slurry; a second step of dispersing a sulfide solid electrolyte in the first slurry to obtain a second slurry; and a third step of dispersing a cathode active material in the second slurry to obtain a third slurry
Data Source
AI summary
In conventional arts, it is impossible to form a good solid-solid interface in cathode mixture layers of all-solid-state batteries, which significantly deteriorates resistance of the all-solid-state battery after the charge/discharge cycle, which is problematic. A cathode slurry is produced by a method including: a first step of dispersing a conductive additive constituted of carbon in a solvent to obtain a first slurry; a second step of dispersing a sulfide solid electrolyte in the first slurry to obtain a second slurry; and a third step of dispersing a cathode active material in the second slurry to obtain a third slurry, to be used to form a cathode mixture layer. This may suppress agglomeration of the cathode active material as using the conductive additive as a core, and may lower the proportion of agglomerate present in the cathode mixture layer. As a result, a good solid-solid interface may be formed in the cathode mixture layer of the all-solid-state battery, and the resistance increase of the all-solid-state battery after the charge/discharge cycle may be suppressed.