Halide-Hydride Solid Electrolyte for Safe Room-Temperature Li-Ion Conduction
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Solution Overview
Problem
Current lithium ion-conductive solid electrolyte materials, such as those disclosed in International Publication No. WO 2020/137043, may generate hydrogen sulfide when exposed to the atmosphere, posing safety concerns and do not achieve high enough lithium ion conductivity for optimal battery performance.
Innovation Solution
A solid electrolyte material composed of Li, La, O, X, and a hydride, where X is selected from F, Cl, Br, or I, with a specific composition that enhances lithium ion conductivity by including a borohydride compound like LiBH4, ensuring the material does not contain sulfur and thus avoids hydrogen sulfide generation, while maintaining high ion conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional solid electrolyte materials (without hydride) are used, then the material composition is simpler, but lithium ion conductivity is insufficient and hydrogen sulfide generation occurs
Solution Approach 1:
The patent employs composite materials by combining halide (LaOX where X=F, Cl, Br, or I) and borohydride (LiBH4) components to create a solid electrolyte that achieves both high lithium ion conductivity and safety. The composite structure allows the material to benefit from the high ionic conductivity of halides while the borohydride component prevents hydrogen sulfide generation, thus resolving the contradiction between safety and material complexity.
Solution Approach 2:
The patent applies parameter changes by optimizing the molar ratio of LaOX to LiBH4 within the range of 2:3 to 1:1. This parameter optimization enables the material to achieve sufficient lithium ion conductivity (≥3×10^-5 S/cm at room temperature) while maintaining safety by preventing hydrogen sulfide generation. The specific compositional parameters resolve the contradiction by finding the optimal balance between conductivity and safety.
2Ease of manufacture
If sulfur-containing materials are used, then the material can be synthesized easily, but hydrogen sulfide is generated when exposed to atmosphere
Solution Approach 1:
The patent converts the potential harm of sulfur-containing materials (hydrogen sulfide generation) into a benefit by using borohydride-based materials that not only avoid hydrogen sulfide generation but also provide high lithium ion conductivity. The borohydride component acts as a protective element that prevents the harmful effects while maintaining ease of synthesis through conventional solid-state reaction methods, thus resolving the contradiction between manufacturing ease and safety.
3Productivity
If conventional solid electrolyte materials are used, then the battery structure is simpler, but charge and discharge characteristics are insufficient
Solution Approach 1:
The patent achieves excellent charge and discharge characteristics by optimizing the compositional parameters of the solid electrolyte, specifically the molar ratio of LaOX to LiBH4 (2:3 to 1:1) and controlling the particle size (D10: 0.5-2 μm, D50: 2-5 μm, D90: 5-10 μm). These parameter optimizations enable high lithium ion conductivity (≥3×10^-5 S/cm at room temperature) which directly improves battery productivity, while the systematic approach to parameter control keeps the material structure manageable.
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 proposed solid electrolyte material achieves lithium ion conductivity greater than or equal to 3×10−5 S/cm at room temperature, providing excellent charge and discharge characteristics for batteries without the safety risks associated with sulfur, thereby improving battery performance and safety.
Implementation Method 1
lithium ion conductivity greater than or equal to 3×10−5 S/cm at room temperature
Data Source
AI summary
The solid electrolyte material of the present disclosure includes Li, La, O, X, and a hydride. X is at least one selected from the group consisting of F, Cl, Br, and I. The battery of the present disclosure includes a positive electrode, a negative electrode, and an electrolyte layer. The electrolyte layer is disposed between the positive electrode and the negative electrode. At least one selected from the group consisting of the positive electrode, the negative electrode, and the electrolyte layer contains the solid electrolyte material of the present disclosure.