Fluorine-Rich Coated Electrode Active Material for Fluoride Ion Batteries
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Solution Overview
Problem
Metal active materials in fluoride ion batteries undergo significant volume changes during charge and discharge, degrading cycle properties, and exhibit low discharge capacity when used in all solid fluoride ion batteries.
Innovation Solution
An electrode active material with a layered structure and a high fluorine concentration coating region is developed, where the coating region has a higher fluorine concentration than the active material region, facilitating intercalation and desorption of fluoride ions and improving discharge capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a metal active material is used in a fluoride ion battery, then the battery can achieve high voltage and energy density, but the metal undergoes significant volume change during charge and discharge due to fluorination and defluorination reactions, which degrades cycle properties
Solution Approach 1:
The patent applies local quality by creating a coating region with high fluorine concentration on the surface of the active material particles, while the interior maintains the original layered structure. This localized modification allows the coating to accommodate volume changes and facilitate ion transport without altering the bulk material's high energy density characteristics, thus resolving the contradiction between energy density and cycle stability
Solution Approach 2:
The patent creates a composite structure consisting of the layered active material core and the fluorine-rich coating shell. This composite design combines the high energy density of the metal-based layered material with the stability and ion conductivity of the fluorine-containing coating, enabling both high energy density and improved cycle properties
2Reliability
If an active material having a layered structure is used in an all solid fluoride ion battery, then the volume change upon charge and discharge is small which improves cycle properties, but the discharge capacity is low
Solution Approach 1:
The patent applies parameter changes by modifying the fluorine concentration parameter in the coating region to be higher than in the interior region. This parameter gradient facilitates fluoride ion intercalation and desorption reactions, significantly improving discharge capacity while the layered structure maintains small volume changes and good cycle properties
3Quantity of substance
If a coating region with high fluorine concentration is added to the active material, then discharge capacity is improved, but the device structure becomes more complex
Solution Approach 1:
The patent applies preliminary action by forming the fluorine-containing coating region on the surface of the active material particles before electrode assembly. This pre-formed coating structure eliminates the need for additional coating steps during electrode manufacturing, improving discharge capacity without significantly increasing device complexity
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 electrode active material achieves excellent discharge capacity and improved cycle properties in all solid fluoride ion batteries, even at high current rates, by effectively utilizing the limited intercalation slots in the active material and maintaining capacity over multiple cycles.
Implementation Method 1
The charge and discharge of the active material having a layered structure proceed along with intercalation and desorption reactions
Implementation Method 2
a coating region positioned in a surface side of the active material region; and a fluorine concentration in the coating region is higher than a fluorine concentration in the active material region
Data Source
AI summary
An object of the present disclosure relates to an electrode active material that has excellent discharge capacity and is used in an all solid fluoride ion battery. The present disclosure achieves the object by providing an electrode active material to be used in an all solid fluoride ion battery, the electrode active material comprising: an active material region that contains an active material component including a layered structure; and a coating region positioned in a surface side of the active material region; and a fluorine concentration in the coating region is higher than a fluorine concentration in the active material region.