Oxide Solid Electrolyte Composition for H2S-Free Li-Ion Conduction
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Solution Overview
Problem
Existing solid electrolyte materials, such as sulfide solid electrolytes, generate hydrogen sulfide when exposed to the atmosphere and have lower lithium ion conductivity, limiting their safety and performance in all-solid-state batteries.
Innovation Solution
A solid electrolyte material composed of Li, Ca, Y, Gd, and O, with specific molar ratios and oxygen distribution, enhancing lithium ion conductivity and safety by avoiding sulfur and optimizing elemental composition and structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sulfide solid electrolyte materials are used, then the battery can achieve solid state operation, but hydrogen sulfide is generated when exposed to atmosphere reducing safety
Solution Approach 1:
The patent changes the chemical composition parameters by replacing sulfur-based electrolytes with oxygen-based electrolytes having specific molar ratios. The solid electrolyte uses Li, Ca, Y, Gd, and O with O/(Y+Gd) molar ratio of 0.05-0.50, fundamentally altering the material chemistry to eliminate H2S generation while maintaining solid state battery functionality
Solution Approach 2:
The patent employs a composite solid electrolyte material combining multiple elements (Li, Ca, Y, Gd, O) in specific proportions. This composite approach creates a stable perovskite-type crystal structure that provides both high ionic conductivity and chemical stability, preventing harmful reactions with atmosphere
2Reliability
If conventional solid electrolyte materials are used, then the battery structure is simplified, but lithium ion conductivity is insufficient limiting performance
Solution Approach 1:
The patent optimizes specific compositional parameters including O/(Y+Gd) molar ratio (0.05-0.50) and Li/(Y+Gd) molar ratio (2.0-4.0), along with controlling Ca content at 0.01-0.50 mol. These parameter adjustments maximize lithium ion conductivity by creating optimal crystal lattice structures for ion transport
Solution Approach 2:
The patent introduces oxygen distribution gradients within the solid electrolyte material, where the oxygen content varies between surface and bulk regions. This local compositional variation enhances both surface stability and bulk ionic conductivity, addressing multiple performance requirements simultaneously
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 electrolyte material achieves high lithium ion conductivity (1×10−5 S/cm or more) and improves charge and discharge characteristics, ensuring safety by preventing hydrogen sulfide generation, suitable for both primary and secondary all-solid-state batteries.
Implementation Method 1
a solid electrolyte material having a high lithium ion conductivity
Data Source
AI summary
The solid electrolyte material of the present disclosure is a solid electrolyte material made of Li, Ca, Y, Gd, X, and O, where X is at least one selected from the group consisting of F, Cl, Br, and I; the molar ratio of O to the sum of Y and Gd in the entire solid electrolyte material is greater than 0 and 0.42 or less; and O is present in a surface region of the solid electrolyte material.