Sulfur-Doped Garnet Electrolyte for Solid State Battery Conductivity
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Solution Overview
Problem
Conventional solid state electrolytes have low conductivity due to grain boundary hindrance, limiting the migration rate of lithium ions and failing to meet practical requirements for energy density and safety in lithium batteries.
Innovation Solution
A sulfur-doped oxide solid state electrolyte with a garnet type crystal structure, where sulfur is added as a dopant to replace oxygen, improving lithium ion diffusion and conductivity within a specific molar percentage range (5 mol % to 35 mol %) to enhance the electrolyte's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solid state electrolyte is used to replace liquid state electrolyte, then safety problems are improved and energy density is increased, but grain boundary hindrance limits lithium ion migration rate resulting in low conductivity
Solution Approach 1:
The patent changes the chemical composition parameters of the solid state electrolyte by introducing sulfur doping at specific concentrations (5-35 mol% based on oxygen content). This parameter change modifies the crystal structure and electronic properties, enabling improved lithium ion conductivity while maintaining the solid state safety advantages. The sulfur doping creates additional conduction pathways and reduces grain boundary resistance.
Solution Approach 2:
The patent creates a composite solid state electrolyte system by combining traditional oxide materials with sulfur dopants. This composite approach leverages the structural stability of the base oxide material while the sulfur component provides enhanced ionic conduction pathways, resolving the contradiction between safety (solid state) and conductivity (ion migration rate).
2Manufacturing precision
If sulfur is added as dopant to improve lithium ion diffusion and conductivity, then conductivity is improved, but chemical stability must be maintained within specific molar percentage range
Solution Approach 1:
The patent precisely controls the sulfur content parameter within the range of 5-35 mol% based on oxygen content. This parameter optimization ensures that sufficient sulfur is present to enhance conductivity through increased lithium ion migration, while maintaining the chemical stability of the garnet-type crystal structure. The specific range prevents excessive sulfur that would compromise structural integrity.
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 sulfur-doped oxide solid state electrolyte achieves improved lithium ion migration rates and conductivity while maintaining chemical stability, effectively addressing the limitations of conventional solid state electrolytes and enhancing the energy density and safety of lithium batteries.
Implementation Method 1
improving lithium ion diffusion and conductivity within a specific molar percentage range
Data Source
AI summary
A solid state electrolyte having a garnet type crystal structure is provided. The chemical composition of the solid state electrolyte includes lithium, lanthanum, zirconium, oxygen, and sulfur. The content of sulfur in the solid state electrolyte is between 5 mol % and 35 mol % based on the content of oxygen in the solid state electrolyte. A solid state battery including a positive electrode layer, a negative electrode layer, and a solid state electrolyte layer is also provided. The solid state electrolyte layer is disposed between the positive electrode layer and the negative electrode layer. The solid state electrolyte layer includes the solid state electrolyte.