Argyrodite Solid Electrolyte Composition for High-Voltage Stability
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Solution Overview
Problem
Sulfide-based solid electrolytes used in all-solid-state secondary batteries have poor oxidation stability at high potentials, limiting their safety and performance.
Innovation Solution
A solid electrolyte with an argyrodite crystal structure, represented by Formula 1, is prepared by mixing phosphorus, sulfur, bromine, and a halogen precursor, and heat-treated to achieve improved oxidation stability and ionic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sulfide-based solid electrolyte is used, then ion conductivity is improved, but oxidation stability at high potentials deteriorates
Solution Approach 1:
The patent creates a composite solid electrolyte material by combining multiple elements within the argyrodite crystal structure framework. The dual halogen-substituted argyrodite structure integrates chloride, bromide, and/or iodide ions along with various metal cations to form a composite material that simultaneously provides high ionic conductivity pathways and enhanced electrochemical stability, resolving the contradiction between conductivity and stability
2Object-affected harmful factors
If all-solid-state battery is used instead of liquid electrolyte, then safety is improved, but oxidation stability at high potentials deteriorates
Solution Approach 1:
The patent optimizes the chemical composition parameters of the solid electrolyte by controlling the ratios of dual halogen elements and incorporating specific metal elements to achieve the desired balance between safety and oxidation stability. The compositional parameters are tuned to enable operation at high potentials (≥3.0V vs. Li/Li+) while maintaining the inherent safety advantages of solid-state batteries.
Solution Approach 2:
The patent applies local quality modification by specifically substituting halogen elements at certain lattice positions within the argyrodite structure and incorporating metal elements at designated sites. This localized compositional adjustment enhances oxidation stability at the cathode interface without compromising the overall safety and ionic conductivity of the solid electrolyte material.
3Use of energy by moving object
If high voltage operation is implemented, then energy density is improved, but cycle characteristics deteriorate
Solution Approach 1:
The patent modifies the chemical composition parameters of the solid electrolyte to enable high voltage operation (≥3.0V vs. Li/Li+) while maintaining long cycle life. The dual halogen substitution and metal element incorporation create a stable crystal structure that resists degradation during cycling, allowing the battery to maintain high energy density over extended periods.
Solution Approach 2:
The patent uses the argyrodite-based solid electrolyte as a stable, replaceable component that enables high voltage operation without requiring complex protective coatings or additional stabilization layers. The inherent stability of the dual halogen-substituted argyrodite structure provides long-lasting performance.
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 provides enhanced ion conductivity and stability at high voltages, improving the safety and cycle characteristics of electrochemical batteries.
Implementation Method 1
a solid electrolyte layer between the cathode layer and the anode layer
Implementation Method 2
heat-treating the solid electrolyte precursor at a temperature of about 200° C. to about 1000° C. to prepare the solid electrolyte
Data Source
AI summary
A solid electrolyte includes a compound having an argyrodite crystal structure represented by Formula 1,LiaMxPSbBrcXd. Formula 1wherein Formula 1,M is Fe, Mg, Ca, Ag, Cu, Zr, Zn, or a combination thereof;X is Cl; and0≤x<1, 5≤(a+x)<7, 5≤a≤6, 4≤b≤6 and 0<(c+d)≤2.