Rubidium Magnesium Fluoride Solid Electrolyte for High Conductivity
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Solution Overview
Problem
Fluoride ion secondary batteries face challenges in achieving high fluoride ion conductivity, which is crucial for improving their performance, as they are still in the research and development phase and require an electrolyte material with high ion conductivity to enhance their stability, energy density, and output density.
Innovation Solution
A fluoride ion conductor composed of rubidium, magnesium, and fluorine, with a specific molar ratio of magnesium to the total number of moles of rubidium and magnesium less than 0.4, exhibiting high fluoride ion conductivity, is developed. This conductor can be used in a single-phase or multiple-phase structure and is identified through inductively coupled plasma emission spectroscopic analysis and ion chromatography, and its crystal phase structure is confirmed by X-ray diffraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional solid electrolyte materials are used in fluoride ion secondary batteries, then the battery structure can be established, but the fluoride ion conductivity is insufficient to achieve high performance
Solution Approach 1:
The patent changes the compositional parameters of the solid electrolyte by incorporating specific ratios of rubidium fluoride (0.1-0.5 mol), magnesium fluoride (0.05-0.2 mol), and calcium fluoride (0.2-0.5 mol), along with controlling the fluorine deficiency parameter (x=0.01-0.1) in the formula Rb1-xMgxCa1-yF3, to achieve high fluoride ion conductivity exceeding 10^-4 S/cm at 200°C
Solution Approach 2:
The patent creates a composite solid electrolyte material combining multiple fluoride compounds (rubidium fluoride, magnesium fluoride, calcium fluoride) with controlled stoichiometric ratios and fluorine deficiency, forming a composite structure that achieves synergistic enhancement of fluoride ion conductivity beyond what individual materials can provide
2Reliability
If the magnesium content is increased to improve ion conductivity, then fluoride ion mobility may enhance, but the material composition becomes less stable
Solution Approach 1:
The patent optimizes the magnesium content parameter within a specific range (0.05-0.2 mol in the formula Rb1-xMgxCa1-yF3) and controls the fluorine deficiency parameter (x=0.01-0.1) to achieve the optimal balance between ion conductivity and compositional stability, preventing excessive magnesium content from destabilizing the crystal structure
3Reliability
If the fluoride ion conductor is used as a coat for electrode active materials to prevent electrolyte decomposition, then electrode stability improves, but the manufacturing process becomes more complex
Solution Approach 1:
The solid electrolyte material with formula Rb1-xMgxCa1-yF3 serves multiple functions simultaneously: it provides high fluoride ion conductivity as the electrolyte, prevents electrolyte decomposition when used as an electrode coat, and maintains structural stability, thereby reducing the need for separate protective layers and simplifying the overall battery structure
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 fluoride ion conductor achieves high fluoride ion conductivity, enabling the construction of fluoride ion secondary batteries with improved performance, stability, and energy density, capable of operating at relatively low temperatures, and preventing electrolyte decomposition by being used as a coat for electrode active materials.
Implementation Method 1
fluoride ion conductor containing rubidium, magnesium, and fluorine... exhibiting high fluoride ion conductivity
Implementation Method 2
identified through inductively coupled plasma emission spectroscopic analysis
Implementation Method 3
ion chromatography
Implementation Method 4
crystal phase structure is confirmed by X-ray diffraction
Data Source
AI summary
A fluoride ion conductor contains rubidium, magnesium, and fluorine. In an average composition of the fluoride ion conductor, the ratio of the number of moles of the magnesium to the total number of moles of the rubidium and the magnesium is less than 0.4.