Sulfide Solid Electrolyte Heat Treatment for Residual Sulfur Removal
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Solution Overview
Problem
The capacity retention of all-solid-state batteries using sulfide solid electrolytes is compromised due to residual elemental sulfur, which is difficult to completely remove using existing methods, leading to decreased battery performance.
Innovation Solution
A method involving heat-treating sulfide solid electrolyte materials in a gas flow capable of forming chemical bonds with elemental sulfur at temperatures above the sulfur's melting point, followed by washing with an organic solvent, to reduce residual sulfur content and enhance battery capacity retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sulfide solid electrolyte materials are synthesized from raw materials, then the electrolyte can be produced, but residual elemental sulfur remains as an impurity that decreases battery capacity retention
Solution Approach 1:
The patent applies preliminary action by heat-treating the sulfide solid electrolyte material before battery assembly to remove residual elemental sulfur. The heat treatment is performed at temperatures above the melting point of sulfur (115°C) but below the decomposition temperature of the electrolyte material, converting residual sulfur into gaseous form that can be evacuated, thereby preventing capacity retention degradation without affecting the electrolyte's functional properties
Solution Approach 2:
The patent utilizes parameter changes by controlling the heat treatment temperature within a specific range (above sulfur's melting point but below electrolyte decomposition temperature). This parameter optimization allows selective removal of elemental sulfur while preserving the sulfide solid electrolyte's structural integrity and ionic conductivity, resolving the contradiction between thorough sulfur removal and material stability
2Reliability
If heat treatment is performed to remove residual sulfur, then battery capacity retention improves, but the processing complexity increases
Solution Approach 1:
The patent applies the extraction principle by separating the sulfur removal function into a distinct heat treatment step performed on the sulfide solid electrolyte material before battery assembly. This extraction approach removes residual elemental sulfur as a separate gaseous byproduct during heat treatment, simplifying the overall process compared to attempting sulfur removal through multiple washing or filtration steps that would increase device complexity
3Loss of substance
If washing with organic solvent is used to remove elemental sulfur, then some sulfur can be removed, but residual sulfur remains that is difficult to completely eliminate
Solution Approach 1:
The patent replaces the mechanical/chemical washing system with a thermal system. Instead of relying on organic solvent washing that cannot completely remove residual sulfur trapped in the electrolyte matrix, the patent uses heat treatment to vaporize and evacuate sulfur, achieving more complete removal (reducing sulfur content to 0.1 wt% or less) without the limitations of solvent penetration and extraction
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
This approach effectively reduces the amount of residual elemental sulfur, thereby improving the capacity retention of all-solid-state batteries by ensuring better chemical stability and reactivity of the sulfide solid electrolytes.
Implementation Method 1
heating the material for a sulfide solid electrolyte in a flow of a gas at a temperature of no less than a melting point of elemental sulfur, the gas being able to form a chemical bond with the elemental sulfur
Implementation Method 2
heating the material for a sulfide solid electrolyte in a flow of a gas at a temperature of no less than a melting point of elemental sulfur
Data Source
AI summary
Provided is a method of producing a sulfide solid electrolyte with which the capacity retention of an all-solid-state battery can be improved.The method of producing a sulfide solid electrolyte comprises synthesizing material for a sulfide solid electrolyte from raw material for an electrolyte; and after said synthesizing, heating the material for a sulfide solid electrolyte in a flow of a gas at a temperature of no less than a melting point of elemental sulfur, the gas being able to form a chemical bond with the elemental sulfur.