Fluoroelastomer Composite Electrolyte for Adhesive Flexible Solid-State Cells
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Solution Overview
Problem
Existing sulfide-based solid composite electrolytes face challenges with poor adhesion to current collectors, insufficient flexibility, and complex manufacturing processes while maintaining high ionic conductivity and mechanical properties.
Innovation Solution
A solid composite electrolyte comprising fluoroelastomer and sulfide-based solid ionic conducting inorganic particles, without lithium salts, which includes recurring units of vinylidene difluorides and C2-C8 chloro, bromo, or iodo fluoroolefins, providing excellent adhesion and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sulfide-based solid ionic conducting inorganic particles are dispersed into a polymeric matrix, then high ionic conductivity is achieved, but poor adhesion to current collectors and insufficient flexibility result
Solution Approach 1:
The invention uses a composite material system consisting of sulfide-based solid ionic conducting inorganic particles (such as Li10SnP2S12, Li6PS5Cl, Li7P3S11) dispersed into a polymeric matrix (such as polyacrylonitrile, polyvinylidene fluoride, carboxymethyl cellulose). This composite structure combines the high ionic conductivity of sulfide-based materials with the mechanical flexibility and adhesion properties of polymers, thereby achieving both high ionic conductivity and good adhesion to current collectors simultaneously
Solution Approach 2:
The invention optimizes parameters including the weight ratio of inorganic particles to polymer matrix (typically 90:10 to 50:50), the particle size distribution of sulfide particles (0.1-10 micrometers), and the molecular weight and crosslinking degree of the polymer matrix. These parameter adjustments enable fine-tuning of the balance between ionic conductivity and mechanical adhesion properties
2Reliability
If sulfide-based solid ionic conducting inorganic particles are dispersed into a polymeric matrix, then high ionic conductivity is achieved, but relatively weak flexibility results
Solution Approach 1:
The composite material system combines the rigid high-conductivity sulfide particles with the flexible polymer matrix, where the polymer phase provides chain mobility and elasticity that compensates for the brittleness of inorganic particles, achieving a balance between ionic conductivity and flexibility
Solution Approach 2:
The invention creates local quality differentiation within the composite electrolyte, where sulfide-rich regions provide high ionic conductivity pathways while polymer-rich regions provide flexibility and mechanical compliance. This spatial heterogeneity allows different regions to fulfill different functional requirements
3Ease of manufacture
If conventional polymeric electrolytes are used, then good mechanical properties and easy processability are achieved, but poor solvent compatibility of sulfide materials restricts polymer selection
Solution Approach 1:
The invention modifies the chemical parameters of the polymer matrix by selecting polymers with specific functional groups (nitrile groups in PAN, fluorinated groups in PVDF, carboxyl groups in CMC) that are compatible with sulfide particles. The polymer molecular weight, crystallinity, and crosslinking density are also adjusted to optimize both processability and compatibility with sulfide-based electrolytes
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 electrolyte achieves superior adhesion to current collectors and flexibility, enhancing the performance of solid-state batteries by maintaining high ionic conductivity and mechanical properties.
Implementation Method 1
at least one sulfide-based solid ionic conducting inorganic particle that differs from a lithium salt
Data Source
AI summary
The present invention relates to a solid composite electrolyte comprising a) at least one fluoroelastomer and b) at least one sulfide-based solid ionic conducting inorganic particles that differs from a lithium salt, wherein a) the fluoroelastomer comprises recurring units derived from i) vinylidene difluorides and ii) from 15.0 to 80.0 mol % of at least one C2-C8 chloro and/or bromo and/or iodo fluoroolefin, the mol % being relative to the total moles of recurring units, wherein the solid composite electrolyte does not contain a lithium salt; to a slurry for manufacturing a solid composite electrolyte comprising a) a fluoroelastomer and b) a sulfide-based solid ionic conducting inorganic particle that differs from a lithium salt, and c) at least one non-aqueous solvent, wherein the slurry does not contain a lithium salt; 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 fluoroelastomer and c) at least one non-aqueous solvent.