Copolymer Cathode Binder Using Water to Replace NMP Solvents
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Solution Overview
Problem
Existing lithium-ion battery binders, such as PVDF and aqueous alternatives like CMC and SBR, face challenges in providing adequate adhesion, electrochemical stability, and environmental safety, particularly in cathodes, leading to high production costs and environmental risks.
Innovation Solution
A binder composition comprising a copolymer with structural units derived from carboxylic acid, amide, and nitrile group-containing monomers, used in an aqueous dispersion medium, enhances adhesion and electrochemical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PVDF binder is used in lithium-ion batteries, then electrochemical stability and adhesion are improved, but environmental safety deteriorates due to toxicity and flammability of NMP solvent
Solution Approach 1:
The invention changes the chemical composition parameters of the binder by introducing a copolymer with specific functional groups (carboxylic acid, amide, nitrile) in defined ratios, enabling the binder to achieve both electrochemical stability and environmental safety by replacing toxic NMP with water as solvent
Solution Approach 2:
The invention uses a composite binder system comprising a copolymer made from multiple monomers (acrylic acid, methacrylic acid, acrylamide, methacrylamide, acrylonitrile, methacrylonitrile) combined in specific proportions, creating a material that combines the advantages of different functional groups to achieve both performance and environmental safety
2Object-affected harmful factors
If aqueous binders like CMC and SBR are used to replace PVDF, then environmental safety is improved, but adhesion capability and electrochemical stability deteriorate
Solution Approach 1:
The invention modifies the binder's chemical structure by incorporating multiple functional groups (carboxylic acid for chelation, amide for polarity, nitrile for coordination) in optimized ratios, transforming weak aqueous binders into high-performance eco-friendly alternatives with superior adhesion
Solution Approach 2:
The invention creates different functional zones within the binder molecule by incorporating specific functional groups at controlled proportions, where carboxylic acid groups provide chelation at particle surfaces, amide groups enhance polarity and adhesion, and nitrile groups contribute to coordination and stability
3Object-affected harmful factors
If NMP recovery system is implemented, then environmental safety is improved, but manufacturing cost increases due to capital investment
Solution Approach 1:
The invention extracts and eliminates the problematic NMP solvent from the battery manufacturing process entirely, replacing it with water as the dispersion medium, thereby removing the need for expensive NMP recovery systems while maintaining binder functionality
Solution Approach 2:
The invention adopts water, a cheap and readily available solvent, as the dispersion medium instead of expensive NMP, eliminating the need for costly recovery infrastructure while achieving the same or better environmental 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 improves cathode adhesion and electrochemical performance, reducing production costs and environmental impact by using water-based solvents and maintaining high stability.
Implementation Method 1
The binder provides a good electrochemical stability, holds together the electrode active materials and adheres them to the current collector in the fabrication of electrodes
Implementation Method 2
a binder composition comprising a copolymer and a dispersion medium, wherein the copolymer comprises a structural unit (a) derived from a carboxylic acid group-containing monomer
Data Source
AI summary
An aqueous binder composition for a positive electrode of a secondary battery electrode, comprising a copolymer and a dispersion medium, wherein the copolymer comprises a structural unit (a) derived from a carboxylic acid group-containing monomer, a structural unit (b) derived from an amide group-containing monomer and a structural unit (c) derived from a nitrile group-containing monomer, with an improved binding capability. In addition, battery cells comprising the cathode prepared using the binder composition disclosed herein exhibits exceptional electrochemical performance.