Complex Halide Lithium-Ion Conductor for Pressure-Stable Conductivity
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Solution Overview
Problem
Lithium ion conductors used in batteries tend to experience decreased ionic conductivity under pressure, leading to potential interruptions in ion conduction paths due to cracking or deformation, especially in all-solid-state batteries where the organic electrolyte behaves as a liquid at elevated temperatures.
Innovation Solution
A lithium ion conductor comprising a complex halide represented by LiGaX4, where X is one or more halogens, and tetrabutylammonium bis(trifluoromethanesulfonyl)imide (TBATFSI) is used, with a specific ratio of TBATFSI to the total compounds, which enhances ionic conductivity under pressure and allows for room temperature sintering, maintaining conductivity even when subjected to deformation or cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a solid lithium ion conductor is used in a pressurized state, then the battery can maintain structural integrity, but the ionic conductivity decreases due to pressure-induced cracking or deformation
Solution Approach 1:
The patent uses a composite material consisting of LiGaX4 complex halide and TBATFSI organic salt. This composite combines the structural stability of the inorganic complex halide with the flexibility and pressure-resistance of the organic TBATFSI component, creating a material that maintains both structural integrity and ionic conductivity under pressure
Solution Approach 2:
The patent changes the chemical composition parameters by introducing TBATFSI at specific ratios (0.01-30 mol%). This parameter change transforms the material properties, making the lithium ion conductor softer and more resistant to pressure-induced cracking while maintaining high ionic conductivity
2Reliability
If the organic electrolyte behaves as a liquid at elevated temperatures, then the ionic conductivity is improved, but the material loses its solid-state structural stability
Solution Approach 1:
The patent merges the properties of solid complex halide and liquid organic TBATFSI into a unified composite material. The organic TBATFSI component provides liquid-like ionic conductivity at elevated temperatures, while the inorganic LiGaX4 framework maintains solid-state structural stability
Solution Approach 2:
The patent applies local quality by having different components perform different functions: the LiGaX4 complex halide provides structural stability and framework, while the TBATFSI organic salt provides ionic conductivity. This division of functional quality allows the material to exhibit both solid-state stability and liquid-like conductivity
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 lithium ion conductor exhibits high ionic conductivity under pressure, effectively repairing cracks and maintaining ion conduction paths, thereby improving the cycle characteristics and reliability of lithium ion batteries, especially in all-solid-state configurations.
Implementation Method 1
can cause a reaction such as a sintering reaction even at a low temperature of about room temperature
Implementation Method 2
the organic electrolyte behaves as a liquid from a behavior as a solid with an increase in temperature
Data Source
AI summary
The lithium ion conductor of the present disclosure includes a first compound and a second compound, wherein the first compound is a complex halide represented by LiGaX4 (X is one or more halogens), the second compound is tetrabutylammonium bis(trifluoromethanesulfonyl)imide, and the ratio of the second compound to the sum of the first compound and the second compound is more than 0 mol % and 30 mol % or less.