Electrode Active Material Layer with Surface Binder Gradient
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In solid-state batteries, the conventional electrode active material layers often experience peeling when a solid electrolyte layer is formed by coating with a solid electrolyte slurry, due to insufficient binder spread between the layers.
Innovation Solution
An electrode active material layer is developed with a binder area fraction ratio of 55% or more on the solid electrolyte layer side compared to the current collector side, achieved by drying a preparatory electrode active material layer at a low temperature followed by further drying at a higher temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a solid electrolyte layer is formed by coating a conventional electrode active material layer with a solid electrolyte slurry, then the production cost is reduced, but peeling occurs between the electrode active material layer and the solid electrolyte layer
Solution Approach 1:
The invention changes the binder content parameter in the electrode active material layer, specifically setting the binder area fraction on the solid electrolyte layer side to be 5 area% or more. This parameter adjustment ensures sufficient binder presence to anchor the solid electrolyte layer, preventing peeling while maintaining the cost-effective coating method
Solution Approach 2:
The invention applies local quality by creating a non-uniform binder distribution within the electrode active material layer, with higher binder concentration specifically at the surface facing the solid electrolyte layer. This localized binder enrichment provides targeted adhesion strength where it is most needed for preventing peeling, while allowing other regions to maintain their original composition
2Reliability
If the binder area fraction on the solid electrolyte layer side is increased to prevent peeling, then the adhesion between layers is improved, but the electrode active material content may be reduced
Solution Approach 1:
The invention concentrates binder material specifically at the surface region that contacts the solid electrolyte layer, rather than uniformly distributing it throughout the entire electrode active material layer. This localized approach ensures strong adhesion at the critical interface while minimizing the overall binder content, thereby preserving maximum electrode active material quantity
Solution Approach 2:
The invention applies partial action by providing binder only where it is most needed - at the surface interface with the solid electrolyte layer - rather than uniformly throughout the entire layer. The binder area fraction of 5 area% or more on the solid electrolyte layer side provides sufficient adhesion strength without requiring excessive binder content in the bulk material
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 ensures sufficient binder spread on the electrode active material layer, preventing peeling and enabling successful formation of the solid electrolyte layer, thereby enhancing the reliability and performance of solid-state batteries.
Implementation Method 1
drying the preparatory electrode active material layer at a temperature lower than 100° C.; and further drying the preparatory electrode active material layer dried at the temperature lower than 100° C. at a temperature of 140° C. or higher
Data Source
AI summary
An electrode active material layer in the present disclosure contains an electrode active material and a binder, and the ratio of a binder area fraction of a solid electrolyte layer side to a binder area fraction of a current collector side is 55 area % or more. A solid-state battery in the present disclosure includes a current collector, the electrode active material layer in the present disclosure, and a solid electrolyte layer, in this order. A method in the present disclosure for producing the electrode active material layer includes (a) providing an electrode composite material slurry containing the binder and others, (b) forming a preparatory electrode active material layer by coating the current collector with the slurry, (c) drying the preparatory electrode active material layer at a temperature lower than 100° C., and (d) further drying the dried preparatory electrode active material layer at a temperature of 140° C. or higher.