Binder Composition for Electrochemical Device Electrodes
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Solution Overview
Problem
Conventional binder compositions for electrochemical device electrodes struggle to achieve a balance between high solid content dispersibility, flexibility, and voltage resistance, particularly with high molecular weight binders that fail to enhance these properties effectively.
Innovation Solution
A binder composition incorporating a water-soluble polymer with a weight-average molecular weight between 1,000 and 50,000, containing a nitrile group-containing monomer unit and an ethylenically unsaturated carboxylic acid monomer unit, which improves solid content dispersibility and enhances flexibility and voltage resistance of the electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a binder with high molecular weight is used, then binding strength is improved, but solid content dispersibility deteriorates
Solution Approach 1:
The invention divides the binder system into two distinct components: a water-soluble polymer (low molecular weight, 1,000-50,000) for dispersibility and a binder polymer (high molecular weight, 100,000-5,000,000) for binding strength. This segmentation allows each component to perform its specialized function without compromising the other, resolving the contradiction between dispersibility and binding strength.
Solution Approach 2:
The invention creates a composite binder system combining two different polymer types with complementary properties. The water-soluble polymer component provides excellent solid content dispersibility, while the binder polymer component provides high binding strength. This composite approach allows simultaneous achievement of both previously conflicting properties.
2Strength
If a binder with high molecular weight is used, then binding strength is improved, but electrode flexibility deteriorates
Solution Approach 1:
The binder system is segmented into two functional components: the water-soluble polymer component (low molecular weight) provides flexibility and processability, while the binder polymer component (high molecular weight) provides binding strength. This segmentation resolves the contradiction between flexibility and binding strength.
Solution Approach 2:
The invention changes the molecular weight parameter of the binder system by using a low molecular weight water-soluble polymer (1,000-50,000) instead of a high molecular weight binder alone. This parameter change improves electrode flexibility while maintaining binding strength through the combined action of both polymer components.
3Strength
If a binder with high molecular weight is used, then binding strength is improved, but voltage resistance deteriorates
Solution Approach 1:
The binder system is divided into two components with distinct functions: the water-soluble polymer component ensures uniform dispersion and coating formation for good voltage resistance, while the binder polymer component provides binding strength. This segmentation resolves the contradiction between voltage resistance and binding strength.
Solution Approach 2:
The invention changes the molecular weight parameter to low (1,000-50,000) for the water-soluble polymer component, which improves voltage resistance by enabling better dispersion and more uniform electrode coating, while maintaining binding strength through the high molecular weight binder polymer component.
Data Source
AI summary
A binder composition contains a water-soluble polymer and water. The water-soluble polymer includes a nitrile group-containing monomer unit and an ethylenically unsaturated carboxylic acid monomer unit, and has a weight-average molecular weight of not less than 1,000 and not more than 50,000.