Sulfide Composite Electrolyte for Conductivity and Mechanical Strength
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current solid-state batteries face challenges with sulfide-based composite electrolytes due to high solvent reactivity, poor solvent compatibility, and reduced ionic conductivity caused by non-conductive binders, limiting their application in high-power devices like electric vehicles.
Innovation Solution
A solid composite electrolyte comprising polymers derived from vinylidene fluoride, alkylene carbonate, acrylonitrile, silane, fluorosilane, acrylate, and caprolactone, combined with high loadings of sulfide-based solid ionic conducting inorganic particles and lithium salts, along with a polar aprotic solvent, to enhance processability and ionic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If sulfide-based inorganic electrolytes are used to achieve high ionic conductivity, then ionic conductivity is improved, but mechanical properties deteriorate due to brittleness
Solution Approach 1:
The patent employs composite materials by combining sulfide-based inorganic electrolyte particles with an organic polymer matrix. The inorganic particles (e.g., Li10SnP2S12, Li6PS5Cl) provide high ionic conductivity pathways, while the polymer matrix (e.g., PVDF, PAN, PMMA) imparts mechanical flexibility and processability. This composite structure allows the electrolyte to achieve both high ionic conductivity (>10^-4 S/cm at room temperature) and adequate mechanical strength for practical battery applications.
2Use of energy by moving object
If oxide-based inorganic electrolytes are used to achieve high ionic conductivity, then ionic conductivity is improved, but grain boundary conductivity deteriorates due to hindered Li-ion transport
Solution Approach 1:
The patent changes the material parameter from oxide-based to sulfide-based inorganic electrolytes. Sulfide-based materials (e.g., Li10SnP2S12, Li6PS5Cl) inherently exhibit lower grain boundary resistance and better Li-ion transport across grain boundaries compared to oxide-based materials. This parameter change enables achieving high bulk conductivity (>10^-4 S/cm) while maintaining good grain boundary conductivity, eliminating the need for complex sintering processes.
3Strength
If solid polymer electrolytes are used to achieve good mechanical properties, then mechanical properties are improved, but ionic conductivity deteriorates due to crystallinity
Solution Approach 1:
The patent creates a composite electrolyte system where the organic polymer matrix provides mechanical properties and flexibility, while dispersed sulfide-based inorganic particles provide high ionic conductivity pathways. The inorganic particles act as conductive fillers within the polymer matrix, creating percolation networks that enable high ionic conductivity (>10^-4 S/cm) while the polymer continuous phase maintains mechanical integrity and processability.
4Productivity
If hot pressing is used to reduce sintering duration for oxide-based electrolytes, then productivity is improved, but device complexity increases due to specialized equipment requirements
Solution Approach 1:
The patent changes the material system from oxide-based to sulfide-based inorganic electrolytes, which have lower sintering temperatures and better cold pressability. Sulfide-based particles can be densified and sintered at lower temperatures (e.g., <1000°C) and shorter durations using conventional equipment, eliminating the need for specialized hot pressing equipment while achieving high density and good grain boundary contact. This parameter change simplifies the manufacturing process and reduces equipment complexity.
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 proposed electrolyte achieves improved ionic conductivity and mechanical properties, enabling better performance and easier processability, thus addressing the limitations of existing sulfide-based composite electrolytes.
Implementation Method 1
at least one sulfide-based solid ionic conducting inorganic particle... for improving ionic conductivity
Data Source
AI summary
The present invention relates to a solid composite electrolyte comprising i) at least one polymer; ii) at least one sulfide-based solid ionic conducting inorganic particle; and iii) at least one lithium salt, wherein the i) at least one polymer is selected from the group consisting of (co)polymers having recurring units derived from vinylidene fluoride (VDF), alkylene carbonate, acrylonitrile, silane, fluorosilane, acrylate, caprolactone and blends thereof, and wherein an amount of the ii) at least one sulfide-based solid ionic conducting inorganic particle is from 40.0 to 98.0% by weight (wt %), preferably from 60.0 to 97.0 wt %, and more preferably from 70.0 to 96.0 wt %, based on the total weight of the solid composite electrolyte. The invention also relates to a slurry for manufacturing a solid composite electrolyte comprising i) at least one polymer, ii) at least one sulfide-based solid ionic conducting inorganic particle, iii) at least one lithium salt, and iv) at least one polar aprotic solvent, to a solid state battery comprising the solid composite electrolyte and to use of the solid composite electrolyte in an electrolyte or an electrode of a solid state battery for improving ionic conductivity and mechanical properties.