PVDF Electrode Slurry Composition Using Adhesion Promoters Without NMP
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Solution Overview
Problem
The use of N-methyl-2-pyrrolidone (NMP) as a solvent in polyvinylidene fluoride (PVDF) binder compositions for electrodes in electrical storage devices poses health and environmental risks, and replacing it with alternative solvents is challenging due to PVDF's limited solubility in other organic solvents, leading to stability and interconnectivity issues in electrode formulations.
Innovation Solution
A slurry composition comprising an electrochemically active material, a fluoropolymer binder dispersed in a liquid medium, and an adhesion promoter, which uses organic solvents like 1,2,3-triacetoxypropane to achieve stable and interconnected electrode films without NMP, ensuring compatibility with manufacturing practices and maintaining desired properties.
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 issues arise
Solution Approach 1:
The patent introduces water as an intermediary solvent to replace NMP. The fluoropolymer is first dissolved in water to form a dispersion, which then serves as a binder medium. This intermediary approach allows achieving adhesion and interconnectivity without using the harmful NMP solvent, thus resolving the contradiction between reliability and harmful factors.
Solution Approach 2:
The patent changes the fundamental parameter of solvent type from organic (NMP) to aqueous (water-based). By modifying the solvent parameter, the patent eliminates the health and environmental issues associated with NMP while maintaining the functional requirements for adhesion and interconnectivity through proper formulation of the waterborne dispersion.
2Object-affected harmful factors
If alternative organic solvents are used to replace NMP, then health and environmental issues are reduced, but PVDF solubility and dispersion stability deteriorate
Solution Approach 1:
The patent uses water as an intermediary medium to achieve stable PVDF dispersion. By formulating a waterborne PVDF dispersion with appropriate stabilizers and surfactants, the patent achieves both reduced toxicity and improved dispersion stability, resolving the contradiction between harmful factors and composition stability.
Solution Approach 2:
The patent employs composite formulation by combining PVDF with water and additional components such as surfactants and stabilizers. This composite approach creates a stable waterborne dispersion that maintains PVDF's functional properties while eliminating the need for toxic organic solvents, thus resolving the contradiction between toxicity and stability.
3Object-affected harmful factors
If waterborne PVDF dispersions are used, then environmental issues are reduced, but peel strength decreases
Solution Approach 1:
The patent optimizes parameters of the waterborne dispersion formulation, including polymer molecular weight, dispersion concentration, and curing conditions. By adjusting these parameters, the patent achieves both environmental friendliness and sufficient peel strength, resolving the contradiction between harmful factors and strength.
Solution Approach 2:
The patent incorporates adhesion promoters and surfactants in the preliminary formulation stage to enhance the adhesive properties of the waterborne dispersion. This preliminary action ensures that even though water is used as solvent, the final coating achieves adequate peel strength, thus resolving the contradiction between environmental issues and strength.
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 solution provides stable PVDF dispersions with improved application properties and interconnectivity, enhancing the quality and peel strength of electrodes while avoiding the drawbacks associated with NMP, thus supporting the production of high-quality electrodes 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
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.