Solid Electrolyte Metallic Additives Conductivity
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Solution Overview
Problem
Solid-state lithium ion rechargeable batteries with solid electrolytes face challenges due to low lithium ion conductivity, leading to high internal resistance and low output current, as the second component in the electrolyte layer lacks lithium ion conductivity and can be unevenly distributed, reducing the contact area and conductivity.
Innovation Solution
Incorporating metallic elements like Zn, Ca, Mg, and Cu within specific ranges into the lithium ion-conducting solid electrolyte to enhance lithium ion conductivity and denseness, thereby reducing internal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid electrolyte is used in a lithium ion rechargeable battery, then the battery size can be reduced and reliability is improved, but the lithium ion conductivity is lower compared to organic electrolytic solutions
Solution Approach 1:
The patent uses a composite solid electrolyte layer containing both a lithium-containing phosphoric acid compound (first component) and a compound containing Mg, Ca, Ba, or Sr (second component). This composite structure combines the high ionic conductance of the NASICON-type structure with the denseness improvement from the second component, achieving both high reliability and acceptable lithium ion conductivity.
Solution Approach 2:
The patent optimizes the content ratio of the second component to the first component within specific ranges (0.1-5 mass% or 1-10 mass%) to balance denseness and lithium ion conductivity. By precisely controlling these compositional parameters, the patent resolves the contradiction between reliability and conductivity.
2Manufacturing precision
If a second component is added to improve denseness of the solid electrolyte layer, then denseness and ionic conductance are improved, but lithium ion conductivity may be reduced when the second component is unevenly distributed
Solution Approach 1:
The patent specifies that the second component should be uniformly distributed throughout the solid electrolyte layer, with particular attention to ensuring adequate contact area between first component pieces. This local quality control ensures that the denseness improvement does not come at the expense of lithium ion conductivity pathways.
3Ease of manufacture
If the contact area between first component pieces is reduced to accommodate uneven distribution of the second component, then manufacturing is simplified, but lithium ion conductivity of the solid electrolyte layer is reduced
Solution Approach 1:
The patent establishes feedback control by specifying minimum contact area requirements between first component pieces and using these criteria to evaluate and control the sintering process. This ensures that manufacturing simplicity does not compromise the essential conductivity requirements.
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 improved lithium ion conductivity and denseness of the solid electrolyte result in lower internal resistance and higher output current for the solid-state lithium ion rechargeable battery.
Implementation Method 1
lithium ion-conducting solid electrolyte contains at least one metallic element selected from the group consisting of Zn, Ca, Mg, and Cu within a predetermined range... significantly improve lithium ion conductivity
Implementation Method 2
improve denseness of the solid electrolyte after sintering
Data Source
AI summary
A lithium ion-conducting solid electrolyte containing at least one metallic element selected from the group made of Zn, Ca, Mg, and Cu within a range of 0.01% by mass to 3.0% by mass, and a solid-state lithium ion rechargeable battery containing this lithium ion-conducting solid electrolyte.