Composite Fluoride Solid Electrolyte for Low-Temperature Ion Conductivity
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Solution Overview
Problem
Fluoride ion batteries face low ion conductivity at low temperatures due to the low conductivity of solid electrolytes, limiting their operational effectiveness.
Innovation Solution
A solid electrolyte material comprising a metal composite fluoride with lanthanoid and alkali earth metals, heat-treated in the presence of a fluorine-containing material, exhibiting a specific infrared absorption ratio and high whiteness level, which enhances fluoride ion conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a solid electrolyte material is used in a fluoride ion battery, then the battery achieves high energy density, but the ion conductivity becomes low at low temperatures
Solution Approach 1:
The patent changes the chemical composition parameters of the solid electrolyte by incorporating specific ratios of lanthanoid metals (La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) and alkaline earth metals (Ca, Sr, Ba, Ra) in the formula Ln1-x-yMxMy-1F3-z, where 0 < x ≤ 0.5, 0 < y ≤ 0.5, and 0 < z ≤ 1. This compositional parameter optimization enables the material to maintain high ion conductivity across a wide temperature range while preserving the high energy density characteristics of fluoride ion batteries
2Reliability
If a metal composite fluoride with lanthanoid and alkaline earth metals is synthesized, then the infrared absorption ratio indicates high ion conductivity, but the manufacturing process becomes complex
Solution Approach 1:
The patent employs a multi-step synthesis approach where precursors are first prepared with controlled metal ratios, then subjected to sequential heat treatments at specific temperatures (e.g., 900-1100°C for initial sintering, followed by fluorine-containing atmosphere treatment). This preliminary structuring of the synthesis process ensures consistent infrared absorption characteristics (A3200/A420 ≤ 0.10) and high ion conductivity while making the complex manufacturing more controllable and reproducible
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 material achieves high ion conductivity for fluoride ions at 25°C, exceeding 10^-7 S/cm, improving battery performance across temperature ranges.
Implementation Method 1
The metal composite fluoride has, in an infrared absorption spectrum thereof, the ratio of the maximal value of the absorption in a wave number range of 3,150 cm−1 or greater and 3,250 cm−1 or smaller to the maximal value of the absorption in a wave number range of 400 cm−1 or greater and 450 cm−1 or smaller, that is 0.10 or smaller
Implementation Method 2
heat-treating the first metal composite fluoride in the presence of a fluorine-containing material to obtain a second metal composite fluoride
Data Source
AI summary
Provided is a solid electrolyte material for a fluoride ion battery. The solid electrolyte material includes: a metal composite fluoride containing: a lanthanoid metal; an alkali earth metal; and fluorine. The metal composite fluoride has, in an infrared absorption spectrum thereof, a ratio of a maximal value of absorption in a wave number range of 3,150 cm−1 or greater and 3,250 cm−1 or smaller to a maximal value of absorption in a wave number range of 400 cm−1 or greater and 450 cm−1 or smaller, that is 0.10 or smaller.