Phosphorus-Free Sulfide Solid Electrolyte for Stable Li+ Conduction
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Solution Overview
Problem
Existing lithium-ion batteries face safety concerns due to the use of flammable organic electrolytes, and there is a need for a solid electrolyte that is phosphorus-free to avoid water sensitivity and environmental hazards.
Innovation Solution
A novel sulfide solid electrolyte material with the chemical formula Li2+xM2+xM′1−xS6, where M is at least one of Al, Ga, or In, and M′ is at least one of Si or Ge, is developed. This material has a diamond-like structure, high ionic conductivity, and is stable without phosphorus, making it suitable for lithium-ion batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phosphorus-containing sulfide solid electrolyte (e.g., Li10GeP2S12) is used to achieve high ionic conductivity, then Li+ conductivity is improved, but water sensitivity and environmental hazards worsen
Solution Approach 1:
The invention extracts and removes phosphorus from the sulfide solid electrolyte composition. The patent develops phosphorus-free sulfide solid electrolytes using compositions such as Li2S-SiS2-Li3MO3 and Li2S-SiS2-Li3AlO3 systems, completely eliminating P-containing compounds that cause water sensitivity while maintaining structural integrity and ionic conductivity pathways
Solution Approach 2:
The invention creates composite sulfide solid electrolyte materials by combining multiple components in specific ratios. The patent uses composite systems like Li2S-SiS2-Li3MO3 where Li3MO3 (M=B, Al, Ga, In) forms a stable matrix that provides both high Li+ conductivity and inherent resistance to water, achieving performance comparable to phosphorus-containing electrolytes without the harmful water sensitivity
2Ease of manufacture
If flammable organic electrolyte is used in traditional lithium-ion batteries, then ease of manufacture is improved, but safety deteriorates
Solution Approach 1:
The invention replaces the organic liquid electrolyte system with an inorganic solid electrolyte system. The patent develops solid sulfide electrolytes that can be processed into thin films and integrated into battery structures, substituting the liquid handling and containment requirements with solid-state manufacturing processes that eliminate fire hazards while maintaining manufacturability
Solution Approach 2:
The phosphorus-free sulfide solid electrolytes described in the patent inherently create a chemically stable, non-flammable environment within the battery. The Li2S-SiS2-Li3MO3 composition system provides an inert solid-state medium that eliminates the flammability and volatility issues of organic electrolytes, fundamentally improving safety without requiring additional safety systems
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 novel sulfide solid electrolyte material exhibits excellent Li+ conductivity, chemical stability, and a wide optical band gap, enhancing the safety and performance of lithium-ion batteries while avoiding the risks associated with phosphorus-containing compounds.
Implementation Method 1
the sulfide solid electrolyte is characterized in high ionic conductivity
Implementation Method 2
exhibits excellent Li+ conductivity
Data Source
AI summary
A solid electrolyte material having a general chemical formula of Li2+xM2+xM′1−xS6, where M is at least one of Al, Ga or In, M′ is at least one of Si or Ge, and 0<x≤0.5. The solid electrolyte material according to the application is simple in composition, contains no phosphorus sensitive to water, and has good Li+ conductivity at the same time.