Layered Perovskite Fluoride Battery Active Material
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Solution Overview
Problem
Metal active materials for fluoride ion batteries exhibit low cycle properties due to significant changes in crystal structure during fluoridation and defluoridation reactions, leading to increased resistance and reduced durability.
Innovation Solution
A fluoride ion battery active material with a layered perovskite structure, represented by An+1BnO3n+1−αFx, where A includes alkaline earth and rare earth elements, and B comprises transition metals, facilitating intercalation and desorption reactions rather than fluoridation and defluoridation, thereby maintaining structural integrity and enhancing cycle properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If metal active materials are used for fluoride ion batteries, then the battery capacity can be increased, but the cycle property deteriorates due to significant crystal structure changes during fluoridation and defluoridation reactions
Solution Approach 1:
The invention changes the fundamental reaction mechanism parameter from fluoridation/defluoridation (metal + fluoride ↔ metal fluoride) to intercalation/desorption (host lattice ↔ intercalated fluoride). This parameter change transforms the reaction from one causing significant structural changes to one maintaining structural integrity, thereby improving cycle property while preserving capacity
Solution Approach 2:
The invention uses composite materials with a host lattice structure (such as layered structures or porous frameworks) that can accommodate fluoride ions through intercalation and desorption. The host lattice acts as a stable matrix that prevents structural degradation, combining the high capacity benefits of metal-based materials with the structural stability needed for good cycle properties
2Productivity
If conventional metal active materials undergo fluoridation and defluoridation reactions, then charge and discharge can proceed, but resistance increases and durability reduces due to crystal structure changes
Solution Approach 1:
The invention separates the functions of charge storage and structural stability by using a host lattice structure that remains stable while accommodating reversible fluoride intercalation and desorption. The host lattice segments the system into a stable framework and mobile fluoride ions, allowing charge-discharge reactions without compromising overall structural integrity
Solution Approach 2:
The host lattice structure acts as an intermediary that mediates between the fluoride ions and the external circuit. Instead of direct fluoridation/defluoridation of metal atoms, the host lattice provides a stable interface for reversible fluoride insertion and extraction, reducing resistance and improving durability
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 active material with a layered perovskite structure and specific composition achieves improved cycle and rate properties by minimizing structural changes during ion intercalation and desorption, resulting in higher capacity retention and efficiency compared to conventional materials.
Implementation Method 1
intercalation and desorption of a fluoride ion occur for the reason of having the layered perovskite structure
Implementation Method 2
intercalation and desorption of a fluoride ion occur for the reason of having the layered perovskite structure
Data Source
AI summary
The main object of the present invention is to provide an active material that has a favorable cycle property. The present invention achieves the object by providing an active material to be used for a fluoride ion battery comprising a crystal phase having a layered perovskite structure, and represented by An+1BnO3n+1−αFx (A is composed of at least one of an alkaline earth metal element and a rare earth element; B is composed of at least one of Mn, Co, Ti, Cr, Fe, Cu, Zn, V, Ni, Zr, Nb, Mo, Ru, Pd, W, Re, Bi, and Sb; “n” is 1 or 2; “α” satisfies 0≤α≤2; and “x” satisfies 0≤x≤2.2).