Fluorinated Nitrile Mediator for PFPE Electrolyte Conductivity

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Solution Overview

Problem

Nonaqueous electrolytes containing perfluoropolyether (PFPE) face challenges with low solubility of alkali metal salts and low electrical conductivity due to low polarity, which limits the proportion of PFPE that can be added, and also have insufficient flame retardancy.

Innovation Solution

Incorporating a fluorinated nitrile compound that interacts with PFPE, enhancing solubility and compatibility, allowing for higher PFPE content without impairing conductivity, and improving flame retardancy by homogeneously mixing with PFPE.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If perfluoropolyether (PFPE) is added to nonaqueous electrolyte, then flame retardancy is improved, but electrical conductivity deteriorates due to low polarity and low solubility of alkali metal salts

Engineering Contradiction:

Improveflame retardancyVSAvoidelectrical conductivity

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

A fluorinated nitrile compound is introduced as an intermediary substance between PFPE and the electrolyte system. This intermediary improves the solubility of alkali metal salts in PFPE and enhances compatibility between PFPE and polar organic solvents, allowing higher PFPE content (5% or more by volume) while maintaining electrical conductivity above 100 μS/cm

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the chemical composition parameters by adding fluorinated nitrile compound to modify the electrolyte system. This parameter change enables PFPE to be mixed in larger proportions while maintaining both electrical conductivity and flame retardancy properties

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If perfluoropolyether (PFPE) is added to nonaqueous electrolyte, then flame retardancy is improved, but homogeneity deteriorates due to low compatibility with polar organic solvents

Engineering Contradiction:

Improveflame retardancyVSAvoidhomogeneity

Core Design Contradiction:

Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The fluorinated nitrile compound acts as a mediator that improves compatibility between PFPE and polar organic solvents. This intermediary enables homogeneous mixing of PFPE with the electrolyte components, preventing phase separation and maintaining composition stability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention creates a composite electrolyte system combining PFPE, fluorinated nitrile compound, and polar organic solvents. This composite approach leverages the complementary properties of each component to achieve both homogeneity and flame retardancy

Inventive Principle:

Principle #40Composite materials

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 PFPE and fluorinated nitrile in the nonaqueous electrolyte increases solubility and electrical conductivity while enhancing flame retardancy, leading to improved battery performance and safety.

Implementation Method 1

a specific nitrile compound containing fluorine atoms (hereafter referred to as a fluorinated nitrile) is used. Both the fluorinated nitrile and PFPE contain fluorine atoms and, therefore interact with each other.

Methodology Applied

Scientific EffectMolecular interaction:

Data Source

PatentUS11196087B2Nonaqueous electrolyte containing perfluoropolyether and nitrile compound, and secondary battery including the same

Publication Date: 2021.12.07 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A nonaqueous electrolyte includes a nonaqueous solvent and an alkali metal salt dissolved in the nonaqueous solvent. The nonaqueous solvent contains a perfluoropolyether and a nitrile compound represented by a formula Rf—CN, where Rf represents a hydrocarbon group which has a carbon number of 2 to 4 and in which at least one hydrogen atom is substituted with fluorine.