Core-Shell Electrode Binder for Peel Strength and Low Internal Resistance
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Solution Overview
Problem
Existing water-dispersed binders for non-aqueous electrolyte rechargeable batteries fail to provide sufficient peel strength between the electrode mixture layer and the current collector, leading to potential detachment during processing and increased internal resistance.
Innovation Solution
A binder with a core-shell structure is developed, comprising a hydrophobic core made of aromatic vinyl, unsaturated carboxylic acid alkyl ester, and (meth)acrylic acid monomers, and a hydrophilic shell made of (meth)acrylic acid, sodium styrene sulfonate, and (meth)acrylonitrile monomers, with a weight ratio of 90-97% hydrophobic core and 3-10% hydrophilic shell, enhancing adhesion and reducing internal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a water-dispersed binder mainly composed of 2-ethylhexyl acrylic acid and styrene is used, then internal resistance is reduced, but peel strength between the electrode mixture layer and current collector is insufficient
Solution Approach 1:
The invention uses a composite binder system combining a water-dispersed binder (for low internal resistance) with a polyvinylidene fluoride-based binder (for high peel strength). This composite approach allows both requirements to be satisfied simultaneously by leveraging the complementary strengths of each binder type.
Solution Approach 2:
The invention changes the chemical composition parameters of the binder system by introducing polyvinylidene fluoride and its copolymers with specific fluorinated monomers. This parameter change enables the binder to achieve both low internal resistance and high adhesion strength through optimized molecular structure and composition ratios.
2Ease of manufacture
If a water-dispersed binder is used, then manufacturing process is simplified, but adhesion between electrode mixture layer and current collector deteriorates
Solution Approach 1:
The invention creates a composite binder system that maintains the ease of water-based processing while adding polyvinylidene fluoride components to improve adhesion. The water-dispersed binder provides manufacturing simplicity, while the fluorinated binder component delivers the required bonding strength.
Solution Approach 2:
The polyvinylidene fluoride-based binder serves multiple functions: it provides strong adhesion to the current collector, maintains water dispersibility for easy manufacturing, and contributes to low internal resistance. This multi-functionality resolves the contradiction between ease of manufacture and adhesion strength.
3Quantity of substance
If electrode mixture layer is made with conventional binder, then production cost is controlled, but reliability during cutting and transport processes deteriorates
Solution Approach 1:
The invention optimizes the composition parameters of the binder system by using polyvinylidene fluoride and its copolymers with specific fluorinated monomers. This parameter optimization enhances electrode integrity and reliability during cutting and transport while maintaining cost-effectiveness through efficient material utilization.
Solution Approach 2:
The enhanced adhesion provided by the polyvinylidene fluoride-based binder acts as a preventive measure that cushions against potential detachment during cutting and high-speed transport. This prior cushioning prevents reliability issues before they occur during subsequent processing steps.
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
The core-shell binder improves adhesion between the electrode mixture layer and the current collector, resulting in reduced internal resistance and enhanced performance of non-aqueous electrolyte rechargeable batteries.
Implementation Method 1
a particle-shaped binder having a core-shell structure including a hydrophobic core and a hydrophilic shell
Implementation Method 2
the peel strength between the electrode mixture layer and the current collector is not sufficient
Data Source
AI summary
A binder for the non-aqueous electrolyte rechargeable battery includes a particle-shaped binder having a core-shell structure including a hydrophobic core and a hydrophilic shell. The hydrophobic core includes at least one selected from among a derivative from an aromatic vinyl monomer, a derivative from an unsaturated carboxylic acid alkyl ester monomer, a derivative from a (meth)acrylic acid monomer, and a derivative from an unsaturated carboxylic acid amide monomer. The hydrophilic shell includes a derivative from a (meth)acrylic acid monomer, a derivative from a sodium styrene sulfonate monomer, and a derivative from a (meth)acrylonitrile monomer. An amount of the hydrophobic core is greater than or equal to about 90 wt % and less than or equal to about 97 wt %, and an amount of the hydrophilic shell is greater than or equal to about 3 wt % and less than or equal to about 10 wt % based on 100 wt % of the binder.