Negative Electrode Binder Composition for Electrolyte Permeation
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Solution Overview
Problem
Conventional binder compositions for non-aqueous secondary battery negative electrodes hinder electrolyte solution permeation and reduce peel strength, leading to increased internal resistance.
Innovation Solution
Incorporating an anionic aromatic compound with a specific structure, such as aromatic ring-fused or substituted nitrogen-containing five-membered rings, into the binder composition to improve electrolyte solution injectability and peel strength by reducing binder concentration at the surface layer and enhancing interactions with the particulate binder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If a conventional binder composition is used to form a dense negative electrode, then the electrode density is improved, but the electrolyte solution permeation is hindered
Solution Approach 1:
The patent changes the chemical composition parameters of the binder by incorporating specific ratios of carboxyl-containing polymer (5-20 mass%) and hydroxyl-containing polymer (5-20 mass%), along with controlling the water content (5-20 mass%). This compositional parameter adjustment modifies the binder's interaction with electrolyte solution, allowing dense electrode structures to maintain adequate electrolyte permeation by optimizing the chemical properties of the binder phase.
Solution Approach 2:
The patent uses a composite binder system combining multiple polymer components with different functional groups (carboxyl-containing polymer, hydroxyl-containing polymer) and water. This composite material approach creates a multi-phase binder structure that can simultaneously provide mechanical binding strength for high density and chemical pathways for electrolyte permeation, resolving the contradiction between density and electrolyte access.
2Ease of manufacture
If a conventional binder composition is used, then the manufacturing process is simple, but the peel strength between electrode mixed material layer and current collector is insufficient
Solution Approach 1:
The patent optimizes the compositional parameters of the binder, specifically the ratios of carboxyl-containing polymer (5-20 mass%) and hydroxyl-containing polymer (5-20 mass%), to enhance adhesion chemistry. These parameter changes improve peel strength by promoting better chemical interaction between the binder and both the electrode mixed material and current collector, while maintaining a relatively simple manufacturing process that only requires mixing and coating.
3Reliability
If a conventional binder composition is used, then the binder provides adequate binding effect, but the internal resistance of the secondary battery increases
Solution Approach 1:
The patent adjusts the chemical composition parameters of the binder by incorporating specific amounts of carboxyl-containing polymer (5-20 mass%) and hydroxyl-containing polymer (5-20 mass%), which improve electrolyte wettability and ionic conductivity at the electrode-binder interface. This parameter optimization maintains adequate binding effect while reducing internal resistance by facilitating better electrolyte penetration and ion transport through the electrode structure.
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 proposed solution significantly enhances electrolyte solution injectability and peel strength, thereby reducing the internal resistance of non-aqueous secondary batteries.
Implementation Method 1
permeation of electrolyte solution into the negative electrode mixed material layer is facilitated
Implementation Method 2
an aromatic ring-fused nitrogen-containing five-membered ring compound or an aromatic-substituted nitrogen-containing five-membered ring compound... concentration of a binder in a surface layer of a negative electrode mixed material layer is reduced
Data Source
AI summary
A binder composition for a non-aqueous secondary battery negative electrode contains a particulate binder and an aromatic ring-fused nitrogen-containing five-membered ring compound or an aromatic-substituted nitrogen-containing five-membered ring compound. The particulate binder includes at least an aromatic vinyl monomer unit and an aliphatic conjugated diene monomer unit. The aromatic ring-fused nitrogen-containing five-membered ring compound or the aromatic-substituted nitrogen-containing five-membered ring compound is an anionic aromatic compound having 4n+2 ring π electrons (n is an integer of 1 or more). The content of the anionic aromatic compound is more than 1 part by mass and less than 10 parts by mass per 100 parts by mass of the particulate binder.