Fluoride Ion Battery Electrolyte Stabilization
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Solution Overview
Problem
Fluoride ions in fluoride ion batteries react with solvents before interacting with active materials, leading to instability and insufficient reaction, which affects battery performance.
Innovation Solution
A liquid electrolyte comprising a fluoride salt, an alkali metal amide salt, and a glyme (R1—O(CH2CH2O)n—R2) is used, where R1 and R2 are alkyl or fluoroalkyl groups with 4 or less carbon atoms, and n ranges from 2 to 10, to enhance fluoride ion stability and facilitate ion dissociation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional liquid electrolytes (e.g., LiBF4 in PC/DMC) are used in fluoride ion batteries, then the electrolyte can conduct fluoride ions, but the fluoride ions react with the solvent before reaching the active material, resulting in low stability and insufficient reaction with active material
Solution Approach 1:
The patent introduces a specific additive (cyclic carbonate ester with fluorine substituent) as an intermediary substance that mediates between the fluoride ion and the solvent. This additive preferentially interacts with fluoride ions to form stable complexes, preventing direct reaction between fluoride ions and the main solvent components (PC/DMC), thereby reducing harmful side reactions while maintaining ion conductivity
Solution Approach 2:
The patent modifies the chemical parameters of the electrolyte by introducing a fluorinated cyclic carbonate ester additive with specific molecular structure (formula 1) into the conventional LiBF4/PC/DMC system. This parameter change (adding the fluorinated compound) alters the interaction dynamics between fluoride ions and solvent molecules, reducing the reactivity of fluoride ions toward the solvent while maintaining their ability to participate in electrode reactions
2Productivity
If fluoride ion battery uses conventional electrolyte composition, then the battery can operate, but the fluoride ion reacts with other materials (solvent, in particular) before reaction with active material
Solution Approach 1:
The fluorinated cyclic carbonate ester acts as a mediator that controls the interaction between fluoride ions and the electrolyte system. It forms transient complexes with fluoride ions, directing them toward the active material at the electrode surface while preventing premature reaction with bulk solvent, thus improving both reaction efficiency and stability
Solution Approach 2:
The patent creates local quality differentiation in the electrolyte system by introducing the fluorinated additive that preferentially interacts with fluoride ions in specific regions (near electrode surfaces), while leaving the bulk solvent properties relatively unchanged. This localized modification enhances reaction efficiency at the electrode interface without compromising overall electrolyte stability
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 combination of fluoride salt, alkali metal amide salt, and glyme results in a stable liquid electrolyte that enables effective fluorination of active materials, improving battery durability and Coulomb efficiency while suppressing hydrofluoric acid generation.
Implementation Method 1
an alkali metal amide salt having an alkali metal cation and an amide anion
Implementation Method 2
a glyme represented by general formula: R1—O(CH2CH2O)n—R2
Data Source
AI summary
The present invention aims to a liquid electrolyte for a fluoride ion battery having high stability with respect to a fluoride ion. The present invention attains the object by providing a liquid electrolyte for a fluoride ion battery comprising: a fluoride salt; an alkali metal amide salt having an alkali metal cation and an amide anion; and a glyme represented by general formula: R1—O(CH2CH2O)n—R2 (in which R1 and R2 each independently represent an alkyl group with 4 or less carbon atoms or a fluoroalkyl group with 4 or less carbon atoms, and n is in the range of 2 to 10).