Secondary Battery Electrode Surface Treatment for Low-Resistance Charging
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Solution Overview
Problem
The existing methods for fabricating electrodes for secondary batteries result in increased resistance due to the binder being exposed on the surface, which deteriorates quick charging performance and lifespan characteristics, particularly leading to the formation of lithium dendrite.
Innovation Solution
A method involving coating an electrode slurry on a current collector, drying it to form an electrode active material layer, and then performing a UV-ozone surface treatment to selectively remove the binder layer from the surface, maintaining a sufficient binder content inside the layer for adhesion while minimizing surface resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the electrode slurry is coated and dried to form an electrode active material layer, then the binder distributes uniformly inside the electrode, but the binder is exposed on the surface forming a binder layer that increases resistance
Solution Approach 1:
The invention extracts and removes the harmful binder layer from the surface of the electrode active material layer through surface treatment (such as plasma treatment or solvent washing), while preserving the binder's binding function inside the electrode. This separation eliminates the resistive surface layer while maintaining internal structural integrity.
Solution Approach 2:
The invention creates different binder characteristics in different regions: inside the electrode, the binder maintains its binding function with electrode active material particles, while on the surface, the binder layer is removed to prevent resistance increase. This local differentiation resolves the contradiction between uniform distribution and surface exposure.
2Strength
If the binder is exposed on the surface of the electrode, then the adhesion of electrode active material to current collector is maintained, but the resistance of the electrode increases
Solution Approach 1:
The invention selectively removes the binder layer from the surface while preserving the binder's adhesion function at the interface between the electrode active material layer and current collector. This extraction eliminates the harmful resistive layer while maintaining the necessary mechanical strength.
Solution Approach 2:
The invention creates a gradient structure where the binder concentration is high at the interface with the current collector for adhesion, and low or zero at the surface to minimize resistance. This local quality differentiation resolves the contradiction between adhesion strength and electrical resistance.
3Ease of manufacture
If the binder layer remains on the surface of the electrode, then the fabrication process is simple, but the quick charging performance deteriorates due to resistance increase
Solution Approach 1:
The invention performs surface treatment (such as plasma treatment or solvent washing) as a preliminary step after electrode formation to remove the binder layer from the surface. This preliminary action eliminates the resistive layer before battery assembly, improving quick charging performance without significantly complicating the overall fabrication process.
Solution Approach 2:
The invention changes the surface properties of the electrode by removing the binder layer through surface treatment, thereby altering the electrical resistance parameter. This parameter change enables improved quick charging performance while maintaining a relatively simple fabrication process.
4Stability of the object's composition
If the binder is exposed on the surface of the electrode, then the electrode structure is maintained, but lithium dendrite formation occurs which deteriorates lifespan characteristics
Solution Approach 1:
The invention extracts and removes the binder layer from the surface where it would otherwise promote lithium dendrite formation. This removal eliminates the nucleation sites for dendrites while preserving the internal electrode structure and its binding functionality.
Solution Approach 2:
The invention creates a surface-free binder structure that eliminates the harmful effects of surface-exposed binder on lithium deposition behavior, while maintaining the internal binder structure necessary for electrode integrity. This local quality differentiation prevents dendrite formation without compromising structural stability.
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 enhances the adhesion of the electrode active material layer to the current collector, reduces resistance, and prevents lithium dendrite formation, thereby improving performance under quick charging conditions and extending the battery's lifespan.
Implementation Method 1
The surface treatment may be performed by ultraviolet (UV)-ozone treatment.
Data Source
AI summary
Provided is a fabrication method of an electrode for a secondary battery including coating an electrode slurry containing an electrode active material and a binder on a current collector; drying the current collector on which the electrode slurry is coated to form an electrode active material layer; and surface-treating the electrode active material layer formed on the current collector to remove a binder layer on a surface of the electrode active material layer.