Amide Electrolyte with Alkoxyalkyl Substitution for Lithium Battery Safety

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Solution Overview

Problem

Conventional non-aqueous electrolytes for electrochemical devices suffer from low viscosity, volatility, flammability, and reduced durability due to organic solvents, and existing alternatives like ionic liquids face performance issues with lithium secondary batteries.

Innovation Solution

An electrolyte comprising an amide compound with an amine group substituted by an alkoxyalkyl group and a halogen atom, combined with an ionizable lithium salt, offering improved thermal and chemical stability, high ionic conductivity, and a wide electrochemical window.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional non-aqueous electrolytes use organic solvents, then ionic conductivity is improved, but thermal stability and safety deteriorate due to flammability and volatility

Engineering Contradiction:
Improvethermal stabilityVSAvoidflammability and volatility
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters by introducing fluorinated alkyl groups and specific alkoxy substitutions on the amide compound. These parameter changes modify the molecular structure to achieve both low viscosity (for good ionic conductivity) and high thermal stability (for safety), resolving the contradiction between conductivity and safety

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The electrolyte uses a composite approach by combining the amide compound with specific lithium salts (LiPF6, LiBF4, LiClO4) in optimized ratios. This composite formulation creates a synergistic effect where the amide compound provides thermal stability while the lithium salts ensure high ionic conductivity, addressing both requirements simultaneously

Inventive Principle:
Principle #40Composite materials

2Reliability

If ionic liquids are used as electrolytes, then thermal stability is improved, but battery performance deteriorates due to reduction at higher voltages and cation intercalation

Engineering Contradiction:
Improvethermal stabilityVSAvoidbattery performance
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent modifies the molecular structure parameters by introducing fluorinated alkyl groups and controlling the substitution patterns on the amide compound. These parameter changes adjust the electrochemical window and redox potential to prevent reduction at higher voltages, while maintaining thermal stability comparable to ionic liquids

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Instead of using complex ionic liquid structures that cause performance issues, the patent employs a simpler amide compound-based electrolyte formulation that achieves similar thermal stability without the harmful side reactions, effectively replacing a problematic solution with a better alternative

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If eutectic mixtures with amide compounds are used, then electrochemical window is widened and stability is improved, but viscosity increases reducing ionic conductivity

Engineering Contradiction:
Improveelectrochemical stabilityVSAvoidviscosity
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The patent optimizes the molecular structure parameters by introducing fluorinated alkyl groups and specific alkoxy substitutions. These parameter changes reduce intermolecular forces and lower viscosity while maintaining the electrochemical stability of amide compounds, resolving the contradiction between stability and conductivity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality modification by specifically substituting fluorinated alkyl groups at certain positions and alkoxy groups at others on the amide compound structure. This localized structural optimization allows different parts of the molecule to contribute differently: fluorinated groups enhance stability while alkoxy groups reduce viscosity, achieving both goals simultaneously

Inventive Principle:
Principle #3Local quality

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 electrolyte provides enhanced thermal stability, reduced viscosity, and increased electrical conductivity, improving the safety and performance of electrochemical devices, particularly lithium secondary batteries, while preventing evaporation and fire risks.

Implementation Method 1

the amide compound has an amine group substituted with at least one alkoxyalkyl group and includes at least one halogen atom... offering improved thermal and chemical stability

Methodology Applied
Scientific EffectThermal stability:

Implementation Method 2

an ionizable lithium salt... exhibiting good ionic conductivity

Methodology Applied
Scientific EffectIonization: Ionisation

Implementation Method 3

exhibiting good ionic conductivity and a wide electrochemical window

Methodology Applied
Scientific EffectIonic conduction: Conduction (electrical)

Data Source

PatentEP2525433B1Electrolyte containing an amide compound, and electrochemical device comprising the same
Publication Date: 2016.12.07 LG CHEM LTD
  • EP2525433B1 patent drawingFigure 1~2
  • EP2525433B1 patent drawingFigure 3~4
  • EP2525433B1 patent drawing

AI summary

Disclosed is an electrolyte. The electrolyte includes an amide compound and an ionizable lithium salt. The amide compound has a specific structure in which an amine group is substituted with at least one alkoxyalkyl group and at least one halogen atom is present. The electrolyte has good thermal and chemical stability, a low resistance and a high ionic conductivity. In addition, the electrolyte has a high upper limit of electrochemical window due to its improved oxidation stability. Therefore, the electrolyte can be useful for the fabrication of an electrochemical device. Further disclosed is an electrochemical device including the electrolyte.