Zirconium Fluoride Negative Electrode for Higher-Capacity FIBs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional fluoride ion secondary batteries using aluminum fluoride as a negative electrode material face issues with low ionic conductivity and limited active material content, leading to insufficient battery capacity and coulombic efficiency.
Innovation Solution
Incorporating zirconium fluoride as the negative electrode active material, with specific particle sizes and concentrations, along with metallic zirconium and a fluoride ion-conducting solid electrolyte, to enhance ionic conductivity and coulombic efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aluminum fluoride is used as the negative electrode active material, then the battery can operate with fluoride ion carriers, but the ionic conductivity is low and the active material content cannot be increased sufficiently
Solution Approach 1:
The patent changes the chemical composition parameter from aluminum fluoride to zirconium fluoride, which inherently possesses higher ionic conductivity. This material substitution resolves the contradiction by providing both adequate ionic conductivity and the ability to increase active material content in the negative electrode.
Solution Approach 2:
The patent creates a composite negative electrode structure combining zirconium fluoride particles with a fluoride ion-conducting solid electrolyte matrix. This composite approach maintains high ionic conductivity through the electrolyte while allowing increased loading of zirconium fluoride active material, thus resolving the contradiction between ionic conductivity and active material content.
2Quantity of substance
If the concentration of negative electrode active material is increased to provide large capacity, then the battery capacity increases, but the low ionic conductivity of lithium metal-doped aluminum fluoride prevents sufficient active material loading
Solution Approach 1:
The patent changes the active material from lithium metal-doped aluminum fluoride to zirconium fluoride, which has superior ionic conductivity. This enables the negative electrode to accommodate higher concentrations of active material without compromising ionic conductivity, thus achieving large battery capacity.
Solution Approach 2:
The fluoride ion-conducting solid electrolyte acts as an intermediary that facilitates fluoride ion transport throughout the negative electrode. This intermediary enables high active material loading by providing efficient ion conduction pathways that compensate for the insulating nature of the zirconium fluoride particles themselves.
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 proposed solution results in a fluoride ion secondary battery with increased capacity and improved charging and discharging reversibility, achieving higher coulombic efficiency and extended battery life.
Implementation Method 1
zirconium fluoride has relatively high ionic conductivity
Implementation Method 2
the negative electrode active material may further include metallic zirconium
Data Source
AI summary
Provided is a fluoride ion secondary battery having a capacity larger than that of a conventional one. The fluoride ion secondary battery has a negative electrode including zirconium fluoride as a negative electrode active material. The zirconium fluoride may be in the form of particles with an average particle size of 100 nm or less, and the negative electrode may have a zirconium fluoride content of less than 50 % by mass. The negative electrode active material may further include metallic zirconium, which may be in the form of particles with an average particle size of 75 μm or less. The negative electrode may have a metallic zirconium content of 8% by mass or less.