Fluoropolymer Composite Electrolyte for Sulfide Adhesion and Conductivity
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Solution Overview
Problem
Existing solid-state batteries face issues with poor solvent compatibility of sulfide materials, insufficient cohesion between polymer and sulfide materials, and low adhesion towards current collectors, leading to reduced ionic conductivity and electrode delamination.
Innovation Solution
A solid composite electrolyte comprising a fluoropolymer with specific recurring units and sulfide-based solid ionic conducting inorganic particles, combined with a non-aqueous solvent, to enhance adhesion and cohesion while maintaining ionic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sulfide-based solid electrolyte particles are dispersed into a polymeric matrix, then high ionic conductivity is achieved, but poor solvent compatibility restricts polymer selection and insufficient cohesion between polymer and sulfide materials occurs
Solution Approach 1:
The patent changes the chemical composition parameters of the polymer matrix by selecting specific fluorinated polymers (PVDF, PTFE, Eton) with particular molecular structures and properties. This parameter change enables the polymer to be compatible with sulfide-based electrolytes while maintaining high ionic conductivity, resolving the contradiction between reliability and adaptability.
Solution Approach 2:
The patent creates a composite material system by dispersing sulfide-based solid electrolyte particles into a fluorinated polymer matrix. This composite structure combines the high ionic conductivity of sulfide materials with the mechanical properties and solvent compatibility of fluorinated polymers, simultaneously achieving both improved reliability and adaptability.
2Reliability
If sulfide-based solid electrolyte particles are dispersed into a polymeric matrix, then high ionic conductivity is achieved, but insufficient cohesion between polymer and sulfide materials occurs
Solution Approach 1:
The patent modifies the surface properties and chemical composition parameters of both the polymer matrix and sulfide particles to enhance interfacial adhesion. By selecting fluorinated polymers with specific functional groups and adjusting particle surface characteristics, the patent achieves strong cohesion while preserving high ionic conductivity.
Solution Approach 2:
The fluorinated polymer acts as an intermediary material between the sulfide-based electrolyte particles and the electrode components. This intermediary provides both mechanical cohesion to hold particles together and chemical compatibility to maintain ionic conductivity, resolving the contradiction between strength and reliability.
3Ease of manufacture
If conventional polymers are used as binders for sulfide-based solid electrolytes, then ease of manufacture is improved, but low adhesion towards current collector occurs leading to electrode delamination
Solution Approach 1:
The patent changes the chemical and physical parameters of the polymer binder by using fluorinated polymers with specific molecular weights, functional groups, and thermal properties. These parameter changes enable the binder to maintain ease of manufacture while achieving strong adhesion to current collectors, preventing electrode delamination.
Solution Approach 2:
The patent applies local quality enhancement by using fluorinated polymers that provide targeted adhesion properties at the electrode-current collector interface while maintaining overall processability. The specific functional groups in the fluorinated polymer create strong local bonding at critical interfaces without compromising manufacturing ease.
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 excellent adhesion to current collectors and enhanced cohesive strength within the electrolyte, improving the performance and stability of solid-state batteries.
Implementation Method 1
excellent adhesion to current collectors and enhanced cohesive strength within the electrolyte
Implementation Method 2
enhanced cohesive strength within the electrolyte
Implementation Method 3
sulfide-based solid ionic conducting inorganic particle
Data Source
AI summary
The present invention relates to a solid composite electrolyte comprising a) at least one fluoropolymer and b) at least one sulfide-based solid ionic conducting inorganic particle, wherein a) the fluoropolymer comprises recurring units derived from i) at least 50.0 mol % of vinylidene difluorides, the mol % being relative to the total moles of recurring units; ii) at least one C2-C8 chloro and/or bromo and/or iodo fluoroolefin; and iii) at least one C2-C8 fluoroolefin, wherein i), ii) and iii) are different from each other; to a slurry for manufacturing a solid composite electrolyte comprising a) at least one fluoropolymer according to the present invention and b) a sulfide-based solid ionic conducting inorganic particle, and c) at least one non-aqueous solvent; to an electrode comprising a solid composite electrolyte according to the present invention, d) at least one electroactive material, and optionally e) at least one conductive agent; and to a solid state battery comprising a positive electrode, a negative electrode and a membrane, at least one among which comprises a solid composite electrolyte according to the present invention. The present invention also relates to a binder solution for a solid state battery comprising a) at least one fluoropolymer according to the present invention and c) at least one non-aqueous solvent.