Sulfur-Free Solid Electrolyte Composition for Li-Ion Conductivity
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Solution Overview
Problem
Existing lithium ion-conductive solid electrolyte materials do not achieve high lithium ion conductivity and are prone to safety issues due to the presence of sulfur, which can generate hydrogen sulfide when exposed to the atmosphere.
Innovation Solution
A solid electrolyte material composed of Li, La, and I, represented by the compositional formula Li a La b OI c, where 0 < a, 0 < b, and c = 3.0, with specific ranges for a and b to enhance ion conductivity, and devoid of sulfur to ensure safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing lithium ion-conductive solid electrolyte materials are used, then lithium ion conductivity is insufficient, but if sulfur-containing materials are used to improve conductivity, then safety deteriorates due to hydrogen sulfide generation
Solution Approach 1:
The patent extracts and removes sulfur from the solid electrolyte composition entirely, replacing it with iodine-based compounds (Li3YI6, Li2YI5, Li4YI7). This extraction eliminates the source of hydrogen sulfide generation while maintaining lithium ion conductivity through the iodine-containing perovskite structure, directly resolving the contradiction between conductivity and safety.
Solution Approach 2:
The patent changes the chemical composition parameters by introducing iodine (I) as the halogen element instead of sulfur, and optimizes the stoichiometric ratios (a, b, c values in the formula LiaLbXc) to achieve high lithium ion conductivity. The specific parameter range 0.5 ≤ a ≤ 2.3 and 0.7 ≤ b ≤ 1.5 with c = 3.0 ensures optimal conductivity without sulfur-containing compounds, thus preventing hydrogen sulfide generation.
2Reliability
If high lithium ion conductivity is pursued, then material composition must be optimized, but this increases manufacturing complexity
Solution Approach 1:
The patent applies local quality by focusing optimization on specific compositional regions - the perovskite structure with formula LiaLbXc where X is iodine. By confining the complexity to well-defined stoichiometric ranges (0.5 ≤ a ≤ 2.3, 0.7 ≤ b ≤ 1.5, c = 3.0) and specific crystal structures, the patent achieves high conductivity without excessive manufacturing complexity, as the optimization is localized to compositional parameters rather than requiring complex multi-component 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 material achieves high lithium ion conductivity of greater than or equal to 5 × 10 -5< S/cm at room temperature and prevents the generation of hydrogen sulfide, offering improved safety and performance in all-solid-state batteries.
Implementation Method 1
lithium ion-conductive solid electrolyte material
Data Source
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AI summary
The solid electrolyte material of the present disclosure consists of Li, La, O, and I. The battery 1000 of the present disclosure includes a positive electrode 201, a negative electrode 203, and an electrolyte layer 202. The electrolyte layer 202 is disposed between the positive electrode 201 and the negative electrode 203. At least one selected from the group consisting of the positive electrode 201, the negative electrode 203, and the electrolyte layer 202 contains the solid electrolyte material of the present disclosure.