Composite MgF2 Negative Electrode Material for Higher Fluoride-Ion Capacity
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Solution Overview
Problem
Fluoride-ion batteries using magnesium materials as negative electrode active materials face challenges in achieving sufficient battery capacity due to slow fluoride ion diffusion within magnesium fluoride, limiting the effective reaction to the surface of the particles.
Innovation Solution
A composite fluoride material represented by the formula Mg1−xMIIIxF2+x is introduced, where MIII is a trivalent metal, enhancing fluoride ion diffusion by creating new pathways through excess fluoride ions in the interstices, thereby improving battery capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If magnesium fluoride is used as negative electrode active material, then the battery structure is simple and material is available, but fluoride ion diffusion is slow and battery capacity is insufficient
Solution Approach 1:
The patent uses composite materials by combining magnesium fluoride with trivalent metal fluorides (AlF3, GaF3, ScF3, YF3, or lanthanoid fluorides) to form a composite negative electrode active material. This composite structure allows the material to maintain the structural stability of MgF2 while incorporating the beneficial properties of trivalent metal fluorides that enhance fluoride ion diffusion, thereby resolving the contradiction between material availability and battery capacity.
Solution Approach 2:
The patent changes the chemical composition parameters by introducing trivalent metal ions (M3+) into the magnesium fluoride lattice, forming Mg1−xMIIIxF2+x where x is 0.01 to 0.4. This parameter change optimizes the crystal structure to create more diffusion pathways for fluoride ions, increasing the effective capacity while maintaining the base MgF2 structure that ensures material availability and structural stability.
2Stability of the object's composition
If magnesium fluoride is used as negative electrode active material, then material stability is maintained, but fluoride ion diffusion is limited to surface regions
Solution Approach 1:
The patent modifies the compositional parameters of MgF2 by incorporating trivalent metal fluorides at controlled concentrations (x = 0.01 to 0.4), which alters the crystal lattice structure to create additional diffusion pathways. This parameter optimization maintains the structural stability of the base MgF2 while significantly enhancing fluoride ion diffusion speed throughout the bulk material, not just at the surface.
Solution Approach 2:
By creating a composite material system where trivalent metal fluoride components are integrated into the MgF2 lattice, the patent achieves a synergistic effect: the MgF2 provides structural stability and framework, while the trivalent metal fluoride domains create fast diffusion channels for fluoride ions, enabling both stability and high diffusion speed simultaneously.
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 composite fluoride material significantly enhances battery capacity by allowing fluoride ion diffusion beyond the surface, resulting in improved charge-discharge performance.
Implementation Method 1
enhancing fluoride ion diffusion by creating new pathways through excess fluoride ions in the interstices
Implementation Method 2
applying mechanical impact to the raw materials to cause them to react
Data Source
AI summary
An object of the present disclosure is to provide a negative electrode active material for a fluoride-ion battery capable of improving battery capacity, and a method for manufacturing thereof. The negative electrode active material for a fluoride-ion battery of the present disclosure is represented by the following formula (1): Mg1−xMIIIxF2+x (1), wherein, MIII is a trivalent metal, and x is greater than 0 and less than 0.5. The method for the present disclosure for manufacturing a negative electrode active material comprises the following steps: providing raw materials comprising a magnesium fluoride and a fluoride of the trivalent metal, and applying mechanical impact to the raw materials to cause them to react.