Garnet Oxide Electrolyte Composition With High Li-Ion Conductivity
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Solution Overview
Problem
The preparation of raw materials and firing methods for producing garnet-type oxide with Li, Zr, and La must be rigorously controlled to stabilize the cubic system, making the process complex and difficult to manage.
Innovation Solution
An oxide with a garnet-type crystal structure including Li, La, and Zr, where the crystal structure belongs to the space group I4 1 /acd, with a Li occupancy of 8a sites ranging from 30% to 95% and 16e sites occupancy of 60% or less, is developed. This oxide can be produced through a simpler method, and optional Sr can be included to enhance stability and ion conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rigorous control of raw material preparation and firing method is applied to stabilize the cubic system, then the stability of the oxide is improved, but the manufacturing complexity increases
Solution Approach 1:
The invention changes the crystal system parameter from cubic to tetragonal (space group I41/acd), which fundamentally alters the stability mechanism. This parameter change allows the oxide to achieve stability without requiring rigorous control of raw material preparation and firing methods, thus resolving the contradiction between stability and manufacturing complexity
Solution Approach 2:
Instead of attempting to stabilize the conventional cubic system through rigorous process control, the invention inverts the approach by deliberately adopting a tetragonal crystal system that inherently provides stability through its unique Li occupancy configuration (8a sites: 30-95%, 16e sites: 60% or less), thereby simplifying the manufacturing process while maintaining stability
2Ease of manufacture
If conventional tetragonal LLZ is used, then the manufacturing process is simpler, but the ion conductivity is lower
Solution Approach 1:
The invention applies local quality by specifically controlling the Li occupancy at different crystallographic sites (8a sites: 30-95%, 16e sites: 60% or less) within the tetragonal structure. This localized control of Li distribution at specific sites enhances ion conductivity while maintaining the simplicity of the tetragonal manufacturing process, resolving the contradiction between ease of manufacture and ion conductivity
Solution Approach 2:
The invention creates a composite-like structure within the tetragonal LLZ by optimizing the combination of Li occupancies at 8a and 16e sites, effectively combining the manufacturing simplicity of tetragonal systems with the high ion conductivity characteristics typically associated with cubic 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 simplified production method allows for the easy fabrication of an oxide with high ion conductivity, achieving ion conductivity of 10 -4 S/cm or higher at room temperature, which is 100 times greater than that of conventional tetragonal LLZ, while maintaining stability and ease of production.
Implementation Method 1
an oxide which has a garnet-type crystal structure including Li, Zr, and La exhibits high chemical stability and a lithium ion-conductive property
Data Source
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AI summary
Provided are an oxide which can be produced by a simple method, an electrolyte composition, and an electricity storage device. The oxide has a garnet-type crystal structure including Li, La, and Zr. The crystal structure belongs to the space group I41/acd and has an Li occupancy rate at the 8a site of 30-95% and an Li occupancy rate at the 16e site of 60% or less (excluding 0%). The oxide can contain Sr. The electrolyte composition and the electricity storage device include the oxide.