Sulfide Solid Electrolyte Glass for High-Output Batteries
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Solution Overview
Problem
Current sulfide solid electrolyte materials, such as Li4P2S6-based amorphous substances, have low Li ion conductivity and stability issues, particularly when exposed to water, limiting their application in high-output batteries.
Innovation Solution
A sulfide solid electrolyte glass with a P2S4- structure ratio of 50% or more, characterized by a glass transition point and absence of specific X-ray diffraction peaks, is developed using elemental phosphorus and sulfur, allowing for high amorphous nature and stability, and synthesized through mechanical milling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional Li4P2S6-based amorphous substances are used, then the battery can achieve high output potential, but the Li ion conductivity is low and stability is poor especially when exposed to water
Solution Approach 1:
The patent changes the chemical composition parameters by introducing P2S4 structure (containing P-P bonds) into the Li4P2S6-based amorphous substance. This compositional parameter change transforms the material's properties, achieving both high Li ion conductivity (10^-3 to 10^-2 S/cm) and improved water stability, resolving the contradiction between reliability and water resistance.
Solution Approach 2:
The patent creates a composite amorphous substance combining Li4P2S6 with P2S4-containing compounds (such as Li2S-P2S4 or Li2S-P4S3). This composite approach integrates the high conductivity potential of Li4P2S6 with the structural stability and water resistance of P2S4 networks, simultaneously improving both reliability and water resistance.
2Power
If Li4P2S6-based amorphous substances are used for high output battery, then the energy density can be improved, but the Li ion conductivity remains low
Solution Approach 1:
The patent modifies the compositional parameters by incorporating P2S4 structures with P-P bonds into the Li4P2S6 matrix. This parameter change creates a dual-network structure that provides both high Li ion conductivity (10^-3 to 10^-2 S/cm) and high Li content, enabling the battery to achieve both high output and high reliability.
Solution Approach 2:
The P2S4-containing compounds act as an intermediary phase between Li4P2S6 molecules, creating a percolation network that facilitates Li ion transport. This intermediary structure enables high Li ion conductivity while maintaining the high energy density required for high output batteries.
3Reliability
If amorphous structure is maintained for high conductivity, then the material shows glass transition point, but water stability is compromised
Solution Approach 1:
The patent creates a composite amorphous material combining Li4P2S6 with P2S4-containing compounds. The P2S4 forms a stable amorphous network structure with P-P bonds that maintains the glass transition point (confirming amorphous nature) while providing enhanced water stability, thus preserving both high conductivity and compositional stability.
Solution Approach 2:
The patent introduces P2S4 clusters with P-P bonds at specific local regions within the Li4P2S6 amorphous matrix. These local P2S4 domains provide water stability and structural rigidity, while the overall amorphous structure is maintained, preserving high Li ion conductivity through the glass transition characteristic.
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 resulting sulfide solid electrolyte glass exhibits high Li ion conductivity and stability, enabling the creation of high-output lithium solid state batteries with improved water resistance and performance.
Implementation Method 1
synthesized through mechanical milling
Implementation Method 2
high Li ion conductivity
Data Source
Figure 1~3
Figure 4
Figure 5A~5B
AI summary
An object of the present invention is to provide a sulfide solid electrolyte glass with high Li ion conductivity. The present invention achieves the above-mentioned object by providing a sulfide solid electrolyte glass comprising Li4P2S6, characterized by having a glass transition point.