Low-Sodium Anode Binder Composition for Lower Battery Resistance
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Solution Overview
Problem
Existing non-aqueous secondary battery binders contribute to high internal resistance due to the presence of sodium ions, which solvate and deteriorate the negative electrode active material, particularly graphite, hindering lithium ion insertion and increasing battery resistance.
Innovation Solution
A binder composition for non-aqueous secondary battery negative electrodes is developed, with a controlled sodium ion concentration of 3.0 mg/L or less, using a polymer with specific structural units and an aqueous medium, ensuring minimal sodium ion interference and maintaining electrode integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional binders are used in non-aqueous secondary batteries, then the electrode structure is maintained, but the internal resistance increases due to sodium ion solvation and deterioration of negative electrode active material
Solution Approach 1:
The invention changes the chemical composition parameters of the binder by specifying a polymer with particular structural units (styrene 10-70 mass%, butadiene 5-40 mass%, acrylic acid 5-30 mass%) and controlling the sodium ion concentration to 3.0 mg/L or less. This parameter optimization resolves the contradiction by maintaining electrode stability while minimizing harmful sodium ion effects that increase internal resistance
Solution Approach 2:
The invention uses a composite binder system combining multiple polymer components with specific functional units that work synergistically. The styrene provides structural stability, butadiene enhances flexibility and adhesion, and acrylic acid units contribute to electrolyte compatibility. This composite approach maintains electrode integrity while reducing internal resistance compared to conventional single-component binders
2Ease of manufacture
If sodium ion concentration is not controlled in binder composition, then manufacturing is simpler, but lithium ion insertion is hindered and battery performance deteriorates
Solution Approach 1:
The invention establishes a specific sodium ion concentration parameter (≤3.0 mg/L) as a critical quality threshold. By controlling this parameter during binder preparation, the invention enables lithium ion insertion while maintaining manufacturing feasibility. The specification provides clear guidance for production while resolving the contradiction between manufacturing simplicity and battery performance
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 binder composition results in a non-aqueous secondary battery with reduced internal resistance by preventing sodium ion solvation and maintaining the integrity of the negative electrode, thereby enhancing battery performance.
Implementation Method 1
a polymer having a first structural unit derived from a monomer (a1), the monomer (a1) is a nonionic compound having only one ethylenically unsaturated bond
Implementation Method 2
an aqueous medium, wherein the polymer has a first structural unit derived from a monomer (a1)
Data Source
AI summary
The binder composition for a non-aqueous secondary battery negative electrode contains a polymer and an aqueous medium, the polymer having a first structural unit derived from a monomer (a1), the monomer (a1) being a nonionic compound having only one ethylenically unsaturated bond, and satisfies the following condition (1): In a test solution obtained by diluting the binder composition with water and having a nonvolatile content of 0.4 mass%, the concentration of sodium ions detected using an inductively coupled plasma optical emission analyzer is 3.0 mg/L or less.