Polyacrylate Electrolyte for Lithium-Air Battery Stability

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Solution Overview

Problem

Current lithium-air batteries face challenges with electrolyte stability, particularly when exposed to discharge products like lithium oxide (Li2O2), leading to degradation and reduced cycle characteristics, especially at high voltages.

Innovation Solution

A polyacrylate electrolyte compound with a specific chemical formula, including a first and second repeating unit, is used, which provides improved stability and ion conductivity, preventing degradation by Li2O2 and maintaining mechanical integrity at high voltages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electrolytes are used in lithium-air batteries, then the battery can operate, but the electrolyte degrades when exposed to discharge products like lithium oxide (Li2O2) leading to reduced stability and cycle characteristics

Engineering Contradiction:
Improveelectrolyte stabilityVSAvoidcycle characteristics
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent modifies the chemical structure of the electrolyte by changing parameters such as incorporating fluorinated groups and specific cyclic carbonate components into the electrolyte composition. This structural modification enhances the electrolyte's resistance to degradation by Li2O2 while maintaining its ionic conductivity and electrochemical stability, thereby improving both reliability and cycle characteristics simultaneously.

Inventive Principle:
Principle #35Parameter changes

2Power

If high voltage operation is achieved in lithium-air batteries, then energy density improves, but electrolyte degradation accelerates leading to reduced lifespan

Engineering Contradiction:
ImprovevoltageVSAvoidlifespan
Core Design Contradiction:
PowerVSDuration of action of moving object

Solution Approach 1:

The patent employs a specially designed electrolyte composition that acts as a sacrificial protective layer, preferentially reacting with or resisting degradation from high-voltage stress and discharge products. This engineered electrolyte formulation maintains stability at high voltages by incorporating robust molecular structures that prevent chain reactions of degradation, thereby extending battery lifespan without sacrificing power output.

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

3Weight of moving object

If lightweight materials are used to achieve high energy density, then the battery weight decreases, but maintaining electrolyte stability becomes more challenging

Engineering Contradiction:
Improvebattery weightVSAvoidelectrolyte stability
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent creates a composite electrolyte system combining multiple components including fluorinated cyclic carbonates, chain carbonates, and lithium salts in optimized ratios. This composite formulation leverages the synergistic effects of different materials to achieve both lightweight characteristics and enhanced stability against Li2O2 degradation, resolving the contradiction between reducing weight and maintaining reliability.

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 polyacrylate electrolyte ensures the lithium-air battery's stability and extends its lifespan by preventing degradation from discharge products, while maintaining excellent mechanical characteristics and ion conductivity.

Implementation Method 1

the first method involves providing anode and cathode materials that exhibit a high electrochemical potential difference... forming an ionically conductive layer that allows an appropriate electrochemical reaction

Methodology Applied
Scientific EffectIonic conduction: Conduction (electrical)

Data Source

PatentEP3171449B1Lithium air battery comprising a polymer electrolyte
Publication Date: 2021.05.19 SAMSUNG ELECTRONICS CO LTD
  • EP3171449B1 patent drawingFigure 1~2
  • EP3171449B1 patent drawingFigure 3A~3B
  • EP3171449B1 patent drawingFigure 4A~4B

AI summary

An alkali metal-air battery including an ionically conductive compound comprising homopolymers or copolymers of acrylic acid and/or acrylic acid derivatives as shown in Formula 1a or Formula 1b, wherein the acrylic acid derivatives may comprise anionic groups of type -SO3M or -SO2NSO2X; M defined as an alkali metal; X defined for example as F, CF3.