Halide Solid Electrolyte Composition for Water-Resistant Ionic Conduction
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Solution Overview
Problem
Halide solid electrolytes used in all-solid-state batteries are highly hygroscopic, leading to instability and making them challenging to implement at an industrial scale despite their high ionic conductivity and electrochemical stability.
Innovation Solution
A halide solid electrolyte material of the formula M3Me1-xInxCl6-yBr y, where M is an alkali metal element and Me is a trivalent element, is developed, with specific stoichiometric proportions of x and y to achieve a stable and high ionic conductivity, and a preparation process involving mixing precursors in a polar solvent and heating to form a solid-state solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If halide solid electrolytes are used to achieve high ionic conductivity and electrochemical stability, then the battery performance is improved, but the material becomes highly hygroscopic and unstable in presence of water
Solution Approach 1:
The patent applies parameter changes by systematically varying the stoichiometric ratios of elements (Li, Y, In, Cl, Br) in the halide solid electrolyte composition. Specifically, it optimizes the In content (x parameter) and halide ratio (y parameter) to achieve the right balance between ionic conductivity and water stability. The patent discovers that specific compositional parameters (x > 0 and x < 0.50, y > 1.0 and y < 3.0) yield the optimal performance, resolving the contradiction between electrochemical stability and hygroscopicity.
Solution Approach 2:
The patent employs composite materials by creating a multi-element halide solid electrolyte system combining Li, Y, In, Cl, and Br in specific proportions. This composite approach allows the material to benefit from the advantageous properties of different elements while mitigating their individual drawbacks. The synergistic combination of these elements in the formula Li3-Y-In-xCl6-yBr-y achieves both high ionic conductivity and improved water stability that cannot be obtained with single-element or simpler composite systems.
2Productivity
If halide solid electrolytes are used to achieve good ionic conductivity above 2 mS/cm, then the battery capacity is improved, but the material becomes unstable in presence of traces of water leading to complicated industrial use
Solution Approach 1:
The patent resolves this contradiction by identifying and optimizing specific compositional parameters that simultaneously achieve high ionic conductivity and water stability. By carefully controlling the stoichiometric ratios (x and y parameters) within defined ranges, the patent produces a material that maintains >2 mS/cm ionic conductivity while exhibiting improved water stability, thereby enabling scalable industrial manufacturing without the complications associated with highly hygroscopic materials.
3Object-affected harmful factors
If specific stoichiometric proportions of x and y are used to achieve stable solid solution, then the water resistance is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent addresses this contradiction by defining broad but constrained ranges for the compositional parameters (x > 0 and x < 0.50, y > 1.0 and y < 3.0) that guarantee the formation of stable solid solutions with improved water resistance. These parameter ranges provide manufacturing flexibility while ensuring consistent performance, reducing the burden of extreme precision requirements compared to narrower compositional windows.
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 solution provides a cost-efficient, stable halide solid electrolyte with improved water resistance and high ionic conductivity, enabling easier industrial-scale implementation while maintaining high electrochemical performance.
Implementation Method 1
Halide solid electrolytes are of particular interest since they display good ionic conductivity (above 2 mS/cm)
Implementation Method 2
heating the resulting mixture at a temperature ranging from 200 °C to 800 °C
Data Source
Figure 1~2
Figure 3
AI summary
The present invention relates to a solid electrolyte material of formula (I) M3Me1-xlnxCl6-yBry wherein M comprises an alkali metal element, in particular including Li, Me is a trivalent element chosen from Y, Al, Sc, La, Ce, Gd, Er and Yb, x is greater than 0 and lower than 0.50, and y is greater than 1.0 and lower than 3.0. The invention further concerns preparations processes for obtaining said solid electrolyte material and a battery wherein at least one of the cathode, the anode and the electrolyte layer comprises said solid electrolyte material.