Sulfide Solid Electrolyte Oxide Phase Gradient for Battery Stability
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Solution Overview
Problem
Existing sulfide solid electrolyte materials in batteries are prone to electrolysis at high or low potentials, leading to reduced ionic conductivity and deteriorated charge/discharge characteristics due to weak sulfur binding, and excessive oxygen binding can reduce flexibility and adhesion at the electrode interface.
Innovation Solution
A sulfide solid electrolyte material with a controlled oxide phase formed by oxidation of the sulfide material, where the oxygen-to-sulfur elemental ratio is optimized between 1.28 and 4.06, and the oxide phase is strategically located on the surface, enhancing oxygen binding at the outermost surface while reducing it near the boundary surface, thereby improving ionic conductivity and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxygen binding is increased in sulfide solid electrolyte material to suppress electrolysis, then stability is improved, but flexibility and adhesion at the electrode interface are reduced
Solution Approach 1:
The patent applies local quality by creating distinct oxygen concentration zones within the sulfide solid electrolyte material. The outermost surface layer contains a higher oxygen concentration (oxygen-to-sulfur ratio x) to suppress electrolysis and enhance stability, while the inner layer contains a lower oxygen concentration (oxygen-to-sulfur ratio y) to maintain flexibility and adhesion. This spatial variation in oxygen content allows the material to simultaneously achieve both stability and adhesion properties that cannot be obtained with a uniform composition.
2Reliability
If oxide phase is formed on the surface of sulfide material to improve stability, then electrolysis suppression is enhanced, but ionic conductivity may be reduced
Solution Approach 1:
The patent implements local quality by forming an oxide phase selectively at the outermost surface of the sulfide solid electrolyte material rather than uniformly throughout the bulk material. The oxide phase concentration is controlled to satisfy specific oxygen-to-sulfur ratio conditions (x and y values), creating a gradient where the surface layer provides stability and electrolysis suppression, while the bulk sulfide phase maintains high ionic conductivity. This localized oxide formation resolves the contradiction between stability enhancement and ionic conductivity preservation.
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 optimized sulfide solid electrolyte material effectively suppresses electrolysis, maintains high ionic conductivity, and enhances charge/discharge characteristics by ensuring sufficient oxygen binding at the surface and reducing it near the boundary, thus improving the battery's energy density and operational efficiency.
Implementation Method 1
an oxide phase containing an oxide formed by oxidation of the sulfide material
Implementation Method 2
sufficient oxygen binding at the surface
Implementation Method 3
maintains high ionic conductivity
Data Source
AI summary
A sulfide solid electrolyte material includes a sulfide phase containing a sulfide material and an oxide phase containing an oxide formed by oxidation of the sulfide material. The oxide phase is located on a surface of the sulfide phase. The sulfide solid electrolyte material satisfies conditions: 1.28≤x≤4.06 and x/y≥2.60, where x denotes the oxygen-to-sulfur elemental ratio measured by XPS depth profiling at the outermost surface of the oxide phase; and y denotes the oxygen-to-sulfur elemental ratio measured by XPS depth profiling at a position 32 nm, estimated from the SiO2 sputtering rate, away from the outermost surface of the oxide phase.