Fluoride-Ion Battery Negative Electrode for Lightweight Charge Collection
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Solution Overview
Problem
Conventional fluoride ion secondary batteries using self-forming negative electrodes with aluminum as the current collector face challenges in achieving practical capacity due to difficulties in aluminum functioning effectively as a current collector.
Innovation Solution
A fluoride ion secondary battery configuration that includes a positive electrode layer capable of fluorination and defluorination, a solid electrolyte layer with a second metal element having lower fluorination and defluorination potentials than the positive electrode elements, and a negative electrode layer using particles of aluminum or aluminum alloys as current collectors with a third metal element having lower potentials, facilitating efficient self-forming reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If aluminum is used as the negative electrode current collector to reduce weight, then energy density per weight is improved, but the battery capacity and reliability deteriorate due to aluminum's inability to function effectively as a current collector
Solution Approach 1:
A thin film current collector layer made of metal oxide or metal fluoride is introduced between the aluminum current collector and the solid electrolyte. This intermediary layer serves as a bridge that enables effective charge transfer while allowing aluminum to maintain its lightweight advantage. The intermediary layer resolves the contradiction by providing the necessary electrical conductivity interface that aluminum alone cannot provide.
2Reliability
If conventional current collector materials are used to ensure reliable charge transfer, then battery capacity is improved, but energy density per weight deteriorates due to the heavier weight of traditional materials
Solution Approach 1:
The invention changes the parameters of the current collector system by using ultra-thin film structures (nanometer to micrometer scale) of metal oxides or metal fluorides. This parameter change in thickness and material composition allows the current collector to achieve both lightweight properties and effective charge transfer functionality, resolving the weight-reliability contradiction.
3Ease of manufacture
If the negative electrode layer structure is simplified to enhance manufacturing ease, then manufacturing precision may deteriorate due to the complexity of forming effective self-forming reactions
Solution Approach 1:
The current collector layer is prepared in advance with specific material composition (metal oxide or metal fluoride) and controlled thickness before assembling the complete battery. This preliminary preparation ensures that the self-forming reactions proceed correctly during battery operation, achieving both manufacturing ease and reaction precision.
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
This configuration enhances the energy density per weight of the battery by effectively utilizing aluminum as a current collector and increasing the battery's capacity through optimized fluorination and defluorination reactions.
Implementation Method 1
a solid electrolyte layer including a first solid electrolyte material, the first solid electrolyte material including a second metal element
Implementation Method 2
a positive electrode layer including at least one element selected from the group consisting of a first metal element, a carbon element, and a sulfur element, the positive electrode layer having capability of fluorination and defluorination
Implementation Method 3
a negative electrode layer including a second solid electrolyte material and at least one, functioning as a current collector, selected from the group consisting of particles of a simple substance of Al and particles of an Al alloy
Data Source
AI summary
A fluoride ion secondary battery includes: a positive electrode layer including an element from the group consisting of a first metal element, a carbon element, and a sulfur element, the positive electrode layer capable of fluorination and defluorination; a solid electrolyte layer including a first solid electrolyte material including a second metal element; and a negative electrode layer including a second solid electrolyte material and at least one, from the group consisting of particles of a simple substance of Al and particles of an Al alloy, the second solid electrolyte material including a third metal element. The second and third metal elements each have lower fluorination potential and defluorination potential than the at least one element included in the positive electrode layer and an aluminum element have, the at least one element being selected from the group consisting of the first metal element, the carbon element, and the sulfur elements.