Aromatic Polyamide Binder for Stable High-Voltage Battery Cathodes
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Solution Overview
Problem
Existing lithium secondary battery binders face issues with dispersibility, adhesiveness, flexibility, and stability, leading to electrode separation and reduced cycle characteristics, particularly under high voltage and exposure to bases, which deteriorate battery performance.
Innovation Solution
A polyamide polymer binder with aromatic rings is used, which reduces swelling in electrolyte solutions, maintains electrochemical stability, and prevents harmful gas generation, enhancing electrode stability and lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the amount of binder is decreased to increase energy density, then energy density is improved, but dispersibility and adhesiveness of electrode active material deteriorate
Solution Approach 1:
The invention changes the chemical composition parameters of the binder by introducing specific functional groups (carboxylic acid groups with specific content ranges) into the polymer structure. This allows the binder to achieve superior dispersibility and adhesiveness at lower concentrations, thereby resolving the contradiction between energy density and electrode material dispersion/adhesion.
Solution Approach 2:
The invention creates a composite binder system combining specific polymer components with controlled functional group content. This composite approach enables the binder to simultaneously provide excellent dispersibility, adhesiveness, and flexibility while maintaining low binder content for high energy density.
2Stability of the object's composition
If PVDF binder is used to maintain electrode structure, then electrode structure stability is improved, but dispersibility of conductive agent and flexibility of electrode plate deteriorate
Solution Approach 1:
The invention modifies the binder's chemical parameters by incorporating specific functional groups (carboxylic acid groups) that enhance interaction with conductive agents and provide flexibility, while maintaining the structural stability function. This resolves the contradiction between structure stability and conductive agent dispersibility/flexibility.
3Stability of the object's composition
If PVDF binder is exposed to basic conditions for long period, then electrode structure is maintained, but HF gas is generated causing stability deterioration
Solution Approach 1:
The invention addresses the harmful effect of HF gas generation by selecting binder components that are inherently resistant to base-induced decomposition. The specific polymer structure with controlled functional group content prevents the harmful chemical reaction while maintaining binder functionality, effectively converting a potentially harmful situation into a safe operation.
Solution Approach 2:
The invention changes the chemical composition parameters of the binder to use base-resistant polymer components, eliminating the generation of HF gas under basic conditions while maintaining electrode structure stability during long-term operation.
4Reliability
If non-fluorine-based binder is used to improve dispersibility of conductive agent and flexibility, then dispersibility and flexibility are improved, but adhesiveness deteriorates
Solution Approach 1:
The invention optimizes the chemical composition parameters by incorporating specific functional groups (carboxylic acid groups) that provide strong adhesive properties through chemical bonding, while maintaining the dispersibility and flexibility benefits of non-fluorine-based polymer structures.
Solution Approach 2:
The invention creates a composite binder system that combines non-fluorine-based polymer components with specific functional groups, achieving a balance of dispersibility, flexibility, and adhesiveness that overcomes the limitations of individual components.
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 polyamide polymer binder improves electrode stability by reducing volume expansion and maintaining electrochemical stability, thereby extending battery lifespan and preventing harmful gas generation.
Implementation Method 1
undergoes less swelling in an organic electrolyte solution
Implementation Method 2
has excellent electrochemical stability due to small change even under high voltage
Implementation Method 3
does not generate harmful gases even after long-term exposure to bases
Data Source
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AI summary
The present invention relates to: a binder comprising a polyamide polymer containing a monomer unit including an aromatic ring; a positive electrode slurry comprising same; a positive electrode; and a secondary battery.