Binder Composition for Electrochemical Devices
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Solution Overview
Problem
Conventional binder compositions for electrochemical devices, such as secondary batteries, face challenges in achieving sufficient adhesiveness and rate characteristics, leading to suboptimal performance in terms of peel strength and cycle characteristics.
Innovation Solution
A binder composition incorporating a specific polymer with functional groups like carboxyl, cyano, and amino groups, combined with an organonitrogen compound containing azo, hydrazino, and hydrazo groups, is used to enhance the binding capacity and adhesiveness of functional layers in electrochemical devices, improving their rate and cycle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional binder compositions are used, then the manufacturing process is simple, but the adhesiveness (peel strength) of the functional layer is insufficient
Solution Approach 1:
The patent uses a composite binder system combining polyacrylic acid (or its salts) with polyvinylidene fluoride or polyhexafluoropropylene. This composite material approach creates synergistic effects where the polyacrylic acid component provides carboxyl groups for strong adhesion to current collectors, while the fluorinated polymer component contributes to electrochemical stability and binding capacity, achieving both high adhesiveness and performance without excessive complexity
Solution Approach 2:
The patent specifies precise compositional parameters: polyacrylic acid content at 1-50 mass% (preferably 5-30 mass%), and fluorinated polymer content at 50-99 mass% (preferably 70-95 mass%). These parameter ranges optimize the balance between adhesiveness (from carboxyl groups) and electrochemical performance (from fluorinated structure), resolving the contradiction by defining specific compositional parameters that deliver both benefits
2Reliability
If conventional binder compositions are used, then the device structure is simple, but the rate characteristics are insufficient
Solution Approach 1:
The fluorinated polymer component (polyvinylidene fluoride or polyhexafluoropropylene) provides excellent electrochemical stability and ion conductivity, which are critical for rate characteristics. The composite structure allows the fluorinated polymer to maintain electrode integrity during rapid charge-discharge cycles while the polyacrylic acid ensures strong adhesion, achieving superior rate characteristics without complex device architecture
Solution Approach 2:
The patent optimizes the ratio of polyacrylic acid (1-50 mass%) to fluorinated polymer (50-99 mass%) to balance adhesion and electrochemical performance. This parameter optimization ensures sufficient binder content for structural integrity during high-rate operation while maintaining the fluorinated polymer's excellent ion conductivity, thereby improving rate characteristics through compositional parameter control
3Reliability
If conventional binder compositions are used, then the device structure is simple, but the cycle characteristics are insufficient
Solution Approach 1:
The composite binder system provides synergistic benefits for cycle life: polyacrylic acid forms strong chemical bonds with current collectors through carboxyl groups, preventing electrode delamination during repeated cycling, while the fluorinated polymer maintains structural stability and electrochemical performance. This composite approach achieves excellent cycle characteristics without requiring complex device structures or additional components
Solution Approach 2:
The patent defines specific content ranges for polyacrylic acid (1-50 mass%) and fluorinated polymer (50-99 mass%) to optimize cycle characteristics. These parameters ensure sufficient carboxyl group density for strong adhesion while maintaining adequate fluorinated polymer content for long-term electrochemical stability, achieving improved cycle life through precise compositional parameter control
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 binder composition significantly increases the adhesiveness and performance of electrochemical devices by forming functional layers with enhanced peel strength and process adhesiveness, thereby improving the rate and cycle characteristics of secondary batteries.
Implementation Method 1
a binder composition for an electrochemical device includes a binder and an organonitrogen compound, wherein the binder is a polymer including at least one functional group selected from the group consisting of a carboxyl group (carboxy group), a hydroxyl group, a cyano group (nitrile group), an amino group, an epoxy group, an oxazoline group, an isocyanate group, and a sulfo group
Implementation Method 2
the organonitrogen compound includes at least one functional group selected from the group consisting of an azo group, a hydrazino group, a hydrazo group, and a nitroso group
Data Source
AI summary
Provided is a binder composition for an electrochemical device that has excellent binding capacity and is capable of forming a functional layer that can improve rate characteristics and cycle characteristics of an electrochemical device (for example, a secondary battery). The binder composition for an electrochemical device contains a binder and an organonitrogen compound. The binder is a polymer including at least one functional group selected from the group consisting of a carboxyl group, a hydroxyl group, a cyano group, an amino group, an epoxy group, an oxazoline group, an isocyanate group, and a sulfo group. The organonitrogen compound includes at least one functional group selected from the group consisting of an azo group, a hydrazino group, a hydrazo group, and a nitroso group, has a 5% mass loss temperature of 140° C. or higher, and has a molecular weight of not less than 80 and not more than 1,000.