Aluminum Nanoparticle Negative Electrode Composite for Fluoride-Ion Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Fluoride ion secondary batteries suffer from low initial charge/discharge efficiency and particle agglomeration of negative electrode active materials, leading to reduced electrochemical reactivity and energy efficiency.
Innovation Solution
A negative electrode material mixture composite using nanoparticle-sized aluminum as the active material, combined with a fluoride ion conductive fluoride and carbon black, is formulated to suppress the formation of an insulating layer and agglomeration, enhancing electron and ion conduction paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional negative electrode active materials (MgF2, CaF2, CeF3) are used in fluoride ion secondary batteries, then the battery structure is established, but the charge/discharge efficiency is only 10-20% and energy efficiency is low
Solution Approach 1:
The invention changes the chemical composition parameter of the negative electrode active material from conventional materials (MgF2, CaF2, CeF3) to aluminum fluoride (AlF3), which has a potential of -1.78 V vs. Pb/PbF2. This parameter change enables the material to operate within the constraint of -2.41 V reduction potential window of LBF solid electrolyte, achieving practical reversible charge/discharge reactions with high utilization rates.
Solution Approach 2:
The invention uses composite materials by combining aluminum fluoride (AlF3) with lithium fluoride (LiF) in specific ratios (AlF3: 30-70 wt%, LiF: 30-70 wt%). This composite structure enhances the electrochemical performance and enables high charge/discharge efficiency while maintaining structural stability during cycling.
2Productivity
If aluminum fluoride (AlF3) is used as negative electrode active material with holes where fluorine atoms were present, then reversible negative electrode reaction occurs at high utilization rate, but insulating layer forms and reactivity is lowered
Solution Approach 1:
The invention introduces lithium fluoride (LiF) as an intermediary material that prevents the formation of insulating aluminum fluoride layers. LiF acts as a mediator that maintains ionic conductivity and prevents the passivation of aluminum fluoride surfaces, thereby sustaining high reactivity and utilization rates throughout cycling.
Solution Approach 2:
The invention changes the surface chemical composition by forming a composite of AlF3 and LiF, where LiF content (30-70 wt%) is optimized to prevent insulating layer formation. This parameter change in surface composition maintains both high utilization rate and sustained reactivity.
3Reliability
If nanoparticle-sized aluminum is used as negative electrode active material, then electron and ion conduction paths are enhanced and agglomeration is suppressed, but manufacturing complexity increases
Solution Approach 1:
The invention uses composite materials by combining nanoparticle-sized aluminum with lithium fluoride and carbon black in specific ratios. This composite structure enhances electron and ion conduction paths while the simple two-step manufacturing process (mixing and sintering) keeps the manufacturing complexity manageable.
Solution Approach 2:
The invention introduces carbon black as an intermediary conductive material that enhances electron conduction paths in the nanoparticle composite. Carbon black acts as a mediator that connects aluminum particles and maintains electrical conductivity, simplifying the manufacturing process while improving conduction efficiency.
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 enables a fluoride ion secondary battery with high initial charge/discharge efficiency, maintaining capacity and improving energy density.
Implementation Method 1
the defluorination/refluorination reactions of the negative electrode active materials described above cannot be provided with consideration given to the overvoltage thereof
Implementation Method 2
a fluoride ion conductive fluoride
Implementation Method 3
A negative electrode material mixture composite using nanoparticle-sized aluminum as the active material, combined with a fluoride ion conductive fluoride and carbon black, is formulated to suppress the formation of an insulating layer and agglomeration, enhancing electron and ion conduction paths.
Data Source
AI summary
The present invention provides: a negative electrode mixture composite body for fluoride ion secondary batteries, said composite body enabling the achievement of a fluoride ion secondary battery that has high initial charge/discharge efficiency; a negative electrode for fluoride ion secondary batteries and a secondary battery, each using this composite body; and a method for producing this composite body. According to the present invention, a composite body is formed using, as a negative electrode active material, nanometer-sized aluminum particles together with the other constituents of a negative electrode mixture, so that coating by aluminum fluoride that is formed by a re-fluoridation reaction after defluoridation is suppressed, while suppressing aggregation of negative electrode active material particles.