Fluoride-ion battery, negative electrode active material for fluoride-ion battery, and method for manufacturing negative electrode active material for fluoride-ion battery
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Solution Overview
Problem
Fluoride-ion batteries face challenges in achieving high charge and discharge capacities.
Innovation Solution
A fluoride-ion battery design incorporating a negative electrode active material layer composed of metallic magnesium, magnesium fluoride, and calcium barium fluoride, with a specific mass ratio of metallic magnesium to magnesium fluoride, and applying mechanical impact to enhance the XRD half-width ratio, facilitating efficient fluoride-ion diffusion and reaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional negative electrode materials are used in fluoride-ion batteries, then the battery structure is simple, but the charge and discharge capacities are low
Solution Approach 1:
The patent employs a composite negative electrode material comprising magnesium fluoride (MgF2) and metallic magnesium (Mg) in a specific mass ratio range (0.01 to 0.5). This composite structure combines the advantages of both materials: MgF2 provides stable fluoride ion insertion/extraction, while metallic Mg enhances electron conductivity and facilitates two-stage reactions, thereby achieving high charge and discharge capacities (100 mAh/g or more) without excessive structural complexity
Solution Approach 2:
The patent optimizes the mass ratio parameter of metallic Mg to MgF2 within the range of 0.01 to 0.5 to achieve optimal performance. Additionally, it controls the crystallinity of MgF2 by adjusting the FWHM ratio (full width at half maximum) to be 1.5 or greater, which affects ion diffusion pathways and reaction kinetics, thereby maximizing charge/discharge capacities through precise parameter control
2Speed
If magnesium fluoride with high crystallinity is used, then the material structure is stable, but the fluoride-ion diffusion efficiency is reduced
Solution Approach 1:
The patent controls the crystallinity of MgF2 by adjusting the FWHM ratio (full width at half maximum of XRD peaks) to be 1.5 or greater. This parameter optimization creates an intermediate crystalline state that balances structural stability with sufficient ion diffusion pathways, enabling fast fluoride-ion transport while maintaining material integrity during cycling
Solution Approach 2:
The composite structure of MgF2 and metallic Mg creates synergistic effects where the metallic Mg phase provides highly conductive pathways for both electrons and fluoride ions, compensating for the relatively slow ion diffusion in crystalline MgF2, thereby achieving high diffusion rates without sacrificing the structural stability of MgF2
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 battery achieves high charge and discharge capacities, with specific capacities exceeding 100 mAh/g, due to the two-stage reaction mechanism and improved crystallinity of the active materials.
Implementation Method 1
the above object can be achieved by the following means... charge and discharge capacities are 100 mAh/g or more... due to the two-stage reaction mechanism
Implementation Method 2
A method for manufacturing the negative electrode active material according to Aspect 5, comprising applying mechanical impact to magnesium fluoride to change a ratio of a first FWHM
Implementation Method 3
the mechanical impact is applied by a ball mill
Implementation Method 4
Fluoride-ion batteries using fluoride ions as carriers... facilitating efficient fluoride-ion diffusion and reaction
Implementation Method 5
negative electrode active material layer contains metallic magnesium, magnesium fluoride... due to the two-stage reaction mechanism
Implementation Method 6
due to the two-stage reaction mechanism and improved crystallinity of the active materials
Data Source
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AI summary
An object of the present disclosure is to provide a fluoride-ion battery capable of achieving high charge and discharge capacities. The fluoride-ion battery of the present disclosure comprises a positive electrode active material layer, a negative electrode active material layer, and an electrolyte layer formed between the positive electrode active material layer and the negative electrode active material layer. In the fluoride-ion battery of the present disclosure, the negative electrode active material layer contains metallic magnesium, magnesium fluoride, and calcium barium fluoride, wherein a mass ratio of metallic magnesium to magnesium fluoride is 0.1 to 10.0.