Waterborne PVDF Electrode Slurry for Adhesion Without NMP
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Solution Overview
Problem
The use of N-methyl-2-pyrrolidone (NMP) as a solvent for polyvinylidene fluoride (PVDF) binders in electrode manufacturing poses health and environmental risks, and alternative solvents fail to maintain the necessary stability, application properties, and interconnectivity of electrode compositions.
Innovation Solution
A slurry composition comprising an electrochemically active material, a fluoropolymer binder dispersed in a liquid medium, and an adhesion promoter, which is free from NMP, ensuring stability, application properties, and interconnectivity of electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If NMP is used as solvent for PVDF binder, then adhesion and interconnectivity are improved, but health and environmental safety deteriorate
Solution Approach 1:
The patent introduces water as an intermediary solvent to replace NMP. The PVDF binder is dispersed in water with the addition of dispersants and adhesion promoters, which mediate between the hydrophobic PVDF and the hydrophilic water medium, enabling non-toxic solvent replacement while maintaining adhesion performance
Solution Approach 2:
The patent changes the fundamental parameter of solvent type from organic (NMP) to aqueous (water-based). This parameter change is achieved by adjusting the dispersion medium and adding specific additives to modify the interfacial properties, thereby eliminating toxicity while preserving functional performance
2Object-affected harmful factors
If alternative organic solvents are used instead of NMP, then health and environmental safety are improved, but stability and application properties deteriorate
Solution Approach 1:
Dispersants and adhesion promoters are introduced as intermediary substances that facilitate stable dispersion of PVDF in water. These additives act as mediators between the binder particles and aqueous medium, preventing aggregation and maintaining colloidal stability without requiring toxic organic solvents
Solution Approach 2:
The patent creates a composite slurry system comprising PVDF binder, water, dispersants, and adhesion promoters. This composite formulation combines multiple components with complementary functions to achieve stable dispersion and good application properties while using non-toxic water as the primary solvent
3Object-affected harmful factors
If waterborne PVDF dispersions are used, then environmental safety is improved, but peel strength deteriorates
Solution Approach 1:
Adhesion promoters are introduced as specialized intermediary agents that specifically target the interface between the electrode coating and current collector. These promoters enhance interfacial bonding in waterborne systems, compensating for the typically weaker adhesion of aqueous dispersions compared to organic solvent systems
Solution Approach 2:
The patent applies local quality enhancement by adding specific adhesion promoters that concentrate their effect at the critical interface region between the electrode material and current collector. This localized improvement in interfacial properties achieves satisfactory peel strength without compromising the overall environmental safety of the waterborne system
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 composition provides stable PVDF dispersions with good application properties, enabling the production of high-quality electrodes with satisfactory peel strength and interconnectivity, suitable for batteries and electrical storage devices.
Implementation Method 1
a binder comprising a polymer comprising a fluoropolymer dispersed in a liquid medium
Implementation Method 2
an adhesion promoter... provide good adhesion between the electrode material particles and the metal foil or mesh
Implementation Method 3
the polyvinylidene fluoride is dissolved in an organic solvent... PVDF binders dissolved in NMP provide superior adhesion and an interconnectivity of all the active ingredients
Data Source
AI summary
The present invention provides a slurry composition comprising a binder comprising a polymer comprising a fluoropolymer dispersed in a liquid medium; an adhesion promoter; and at least one of an electrochemically active material or an electrically conductive agent. The present invention also provides electrodes and electrical storage devices.