Sulfide Glass Electrolyte Coating for Moisture-Stable Li-Ion Transport
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Solution Overview
Problem
Sulfide glass solid electrolytes are highly sensitive to moisture, leading to hydrolysis and reaction with lithium metal, which increases resistance and reduces the performance of lithium metal batteries, especially during storage, transportation, and assembly processes.
Innovation Solution
A thin metal layer is coated onto the sulfide glass surfaces, which is then converted into a protective compound layer, such as metal oxides, sulfides, nitrides, or halogenides, to prevent moisture reaction and allow lithium ion transport, thereby reducing the requirement for dry conditions and enhancing the stability of the electrolyte.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sulfide glass solid electrolyte is exposed to moisture during storage and assembly, then hydrolysis reaction occurs increasing resistance, but performance of lithium metal battery is reduced
Solution Approach 1:
A thin protective coating layer is applied as an intermediary between the sulfide glass solid electrolyte and moisture in the environment. This coating acts as a barrier that prevents direct contact between moisture and the electrolyte surface, thereby preventing hydrolysis reactions while allowing the electrolyte to maintain its lithium ion conductivity and electrochemical functionality.
Solution Approach 2:
The protective coating is applied in advance before the electrolyte is exposed to moisture during storage, transportation, or assembly. This preliminary protective action prevents the harmful hydrolysis reaction from occurring in the first place, eliminating the need for subsequent removal or replacement of degraded electrolyte.
2Object-affected harmful factors
If thin metal layer is converted to protective compound layer, then moisture protection is achieved, but lithium ion transport capability must be maintained
Solution Approach 1:
The protective coating is designed with specific local properties: it provides dense moisture barrier protection on the outer surface while maintaining lithium ion transport pathways. The coating composition and structure are optimized to have different characteristics at different locations - hydrophobic and impermeable to water on the exterior, yet ion-conductive where it interfaces with the electrolyte.
Solution Approach 2:
The protective coating parameters (thickness, composition, porosity) are carefully controlled to achieve the desired balance. By adjusting these parameters, the coating can provide sufficient moisture protection while maintaining adequate lithium ion conductivity for battery operation.
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 protective compound layer effectively shields the sulfide glass from moisture, enabling higher allowable electrolyte moisture content, reducing the need for stringent dryness in cell components, and maintaining the integrity of lithium metal batteries during assembly and operation.
Implementation Method 1
a thin metal layer may be coated onto the glass surfaces to provide such protection, and removed prior to cell assembly (e.g., by ion etching the metal layer to remove it). In other embodiments a thin metal layer coating may be converted to a thin electrochemically functional and protective compound layer rather than removed prior to cell assembly. The converted protective compound layer may be composed of the metal element of the thin protective metal layer and a non-metal selected from the group consisting of a nonmetal chalcogen, nonmetal halogen, and nonmetal pnictogen.
Implementation Method 2
The converted protective compound layer is electrochemically functional in that it allows for through transport of lithium ions.
Implementation Method 3
Protection of sulfide glass solid electrolyte surfaces against reaction with moisture during sulfide glass solid electrolyte storage, transportation, and cell assembly in a dry room atmosphere can provide important benefits.
Implementation Method 4
a thin metal layer may be coated onto the glass surfaces to provide such protection
Data Source
AI summary
A sulfide glass solid electrolyte sheet can be protected from reaction with moisture by a thin metal layer coating converted to a thin electrochemically functional and protective compound layer. The converted protective compound layer is electrochemically functional in that it allows for through transport of lithium ions.