Boron-Doped Argyrodite Electrolyte for Moisture-Stable Ion Conduction
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Solution Overview
Problem
Sulfide-based solid electrolytes used in all-solid-state batteries are prone to moisture reactions, compromising their stability and ion conductivity, leading to safety and performance issues.
Innovation Solution
Incorporating boron (B) into the solid electrolyte composition, specifically in the range of 10 ppm to 100,000 ppm, to enhance moisture stability and ion conductivity, while maintaining excellent cycle-life characteristics, through a manufacturing process involving mixing, pelletizing, and heat treatment under controlled conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sulfide-based solid electrolytes are used in all-solid-state batteries, then ion conductivity and battery performance are improved, but moisture stability deteriorates due to reactions with moisture
Solution Approach 1:
The patent introduces a protective coating layer comprising at least one of an oxide, nitride, or carbide on the surface of the sulfide-based solid electrolyte. This coating acts as an intermediary barrier that prevents direct contact between the sulfide electrolyte and moisture in the atmosphere, thereby maintaining ion conductivity while improving moisture stability.
Solution Approach 2:
The patent creates a composite structure by combining sulfide-based solid electrolyte with protective coating materials (oxides, nitrides, or carbides). This composite approach allows the internal sulfide structure to maintain high ion conductivity while the external coating provides moisture resistance, resolving the contradiction between conductivity and stability.
2Stability of the object's composition
If protective coatings are applied to improve moisture stability, then water stability is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent specifies precise compositional parameters for the protective coating (comprising oxide, nitride, or carbide) and applies it through a controlled process. By defining specific material composition ranges and application parameters, the patent simplifies the manufacturing process while ensuring consistent moisture protection without excessive 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 boron-doped argyrodite-type solid electrolyte improves moisture stability and ion conductivity, reducing H2S gas generation and maintaining battery performance, with optimal B content between 10 ppm and 100,000 ppm, thereby enhancing the overall efficiency and longevity of all-solid-state batteries.
Implementation Method 1
a sulfur compound represented by Chemical Formula 1 below and contains B in an amount of 10 ppm to 100,000 ppm
Implementation Method 2
heat treating the pellet, wherein, the B-containing compound is H3BO3, Li3BO3, BBr3, BCl3 or a combination thereof. The heat treatment process is carried out at 400° C. to 600° C.
Data Source
AI summary
It relates to a solid electrolyte and an all-solid-state battery containing it, which contains a sulfur compound represented by Chemical Formula 1 below and B in an amount of 10 ppm to 100,000 ppm.Li7-xPS6-xCl1-yBry [Chemical Formula 1](In the Chemical Formula 1, 1<x<2, and 0≤y<1)