Halogen-Doped Sulfide Ceramic Electrolytes for Higher Conductivity
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Solution Overview
Problem
Lithium-rich sulfide solid electrolytes for batteries are costly and have limitations in conductivity, while existing compositions like Li3PS4 require improvements in chemical and electrochemical stability and conductivity.
Innovation Solution
Development of novel compounds with the formula (Li3P1+xS4)1-y(LiX)y, where 0<x<0.2 and 0≤y≤0.3, incorporating halogen atoms, which exhibit enhanced conductivity and stability, prepared by mixing P2S5 and Li2S precursors with phosphorus, followed by mechanical grinding or heating, resulting in crystalline or partially crystalline forms with specific XRD peak ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium-rich sulfide solid electrolytes are used to improve conductivity, then ionic conductivity is improved, but manufacturing cost increases
Solution Approach 1:
The patent modifies the chemical composition parameters of Li3PS4 by controlling the Li2S to P2S5 molar ratio during synthesis. By adjusting this ratio to fall within 2.0-3.0, the patent achieves improved ionic conductivity without requiring excessive lithium content, thus avoiding the high costs associated with lithium-rich materials while maintaining enhanced conductivity performance.
2Ease of manufacture
If Li3PS4 composition is used as base, then manufacturing simplicity is maintained, but conductivity and stability are insufficient
Solution Approach 1:
The patent maintains the simplicity of Li3PS4-based manufacturing by using the same precursor materials (Li2S and P2S5) and synthesis approach. However, it optimizes the molar ratio parameter of Li2S to P2S5 within 2.0-3.0, which transforms the base composition to achieve superior conductivity and stability while preserving the ease of manufacture associated with the Li3PS4 system.
3Stability of the object's composition
If existing sulfide electrolytes are used, then ductility is achieved, but chemical and electrochemical stability are limited
Solution Approach 1:
The patent optimizes the compositional parameters by controlling the Li2S/P2S5 molar ratio within 2.0-3.0 during synthesis. This parameter optimization enhances the chemical and electrochemical stability of the sulfide electrolyte while preserving the ductility characteristic inherent to sulfide-based materials, achieving a balanced improvement in both stability and adaptability.
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 new compounds demonstrate improved lithium ion conductivity, reduced activation energy, and enhanced stability, making them suitable for all-solid-state batteries with higher energy density and lower irreversible capacity compared to Li3PS4.
Implementation Method 1
processing the mixture thus obtained... heating in particular... heating is conducted at a temperature lower than 300° C., typically at a temperature of between 175 and 225° C.
Implementation Method 2
sulfide solid electrolytes have reached a sufficient stage of development... with their high ionic conductivity... measurements of conductivity have shown that this compositional domain allows conductivity to be improved
Implementation Method 3
analysis of structure by XRD conducted on this compositional domain... the compounds of formula (I) display an X-ray diffraction peak (XRD) at 2θ=19.1°+/−0.25 obtained with the copper K(alpha) line
Data Source
AI summary
The present invention relates to sulfide solid electrolytes having improved conductivity, a process for the preparation thereof, and electrochemical elements and batteries containing same.