Polymerized Ionic Liquid Block Copolymers for Battery Membranes

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Solution Overview

Problem

Current lithium ion batteries face challenges in achieving stable and efficient ion transport, particularly in the presence of aqueous hydroxide, which affects the performance and longevity of lithium ion batteries and fuel cells.

Innovation Solution

Development of block copolymers comprising a first block of styrene or vinylpyridine derivatives and a second block of polymerized ionic liquid with a tethered ionic liquid cation and mobile anion, exhibiting nanophase separation, which enhances hydroxide stability and ion conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional membranes are used in lithium ion batteries, then manufacturing is simpler, but ion transport stability and efficiency deteriorate in the presence of aqueous hydroxide

Engineering Contradiction:
Improveion transport stabilityVSAvoidmembrane structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The membrane is segmented into distinct hydrophobic and hydrophilic blocks within the copolymer structure. The hydrophobic blocks provide structural stability while the hydrophilic blocks create dedicated ion transport channels, allowing the membrane to maintain stability and efficiency in aqueous hydroxide environments without overall structural complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The membrane uses composite copolymer materials combining different functional blocks - hydrophobic segments for structural integrity and hydrophilic segments for ion conduction. This composite approach enables simultaneous achievement of stability and ion transport efficiency without requiring complex multi-layer structures

Inventive Principle:
Principle #40Composite materials

2Reliability

If polymer electrolytes are designed for high ion conductivity, then ion transport efficiency improves, but stability in the presence of aqueous hydroxide deteriorates

Engineering Contradiction:
Improvehydroxide stabilityVSAvoidion transport efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

Different regions of the polymer electrolyte have specialized functions: hydrophobic blocks provide chemical stability against aqueous hydroxide while hydrophilic blocks provide high ion conductivity. This local differentiation allows the material to simultaneously achieve both stability and productivity without compromise

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The polymer electrolyte uses adjustable parameters including block composition ratios, block lengths, and ionic liquid content to optimize both stability and ion transport. By tuning these parameters, the system achieves high ion conductivity while maintaining hydroxide stability through appropriate material selection

Inventive Principle:
Principle #35Parameter changes

3Productivity

If membrane structure is optimized for ion conduction, then ion transport capability improves, but manufacturing complexity increases

Engineering Contradiction:
Improveion conduction capabilityVSAvoidmembrane fabrication ease
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The copolymer membrane structure self-assembles into the desired morphology with hydrophobic and hydrophilic domains during fabrication. This self-organizing behavior eliminates the need for complex post-processing or precise control of assembly conditions, maintaining ease of manufacture while achieving optimized ion conduction pathways

Inventive Principle:
Principle #25Self-service

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 block copolymers demonstrate improved hydroxide stability and ion transport capabilities, leading to enhanced performance in lithium ion batteries and fuel cells by facilitating sustainable hydroxide ion conduction and maintaining conductivity across various temperatures and humidity levels.

Implementation Method 1

wherein said block copolymer exhibits at least one region of nanophase separation

Methodology Applied
Scientific EffectNanophase separation:

Implementation Method 2

said polymer comprising a tethered ionic liquid cation and a mobile anion

Methodology Applied
Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 3

the materials are capable of sustainably transporting hydroxide therethrough

Methodology Applied
Scientific EffectIon transport: Conduction (electrical)

Data Source

PatentEP2969917B1Polymerized ionic liquid block copolymers as battery membranes
Publication Date: 2022.11.02 DREXEL UNIV
  • EP2969917B1 patent drawingFigure 1
  • EP2969917B1 patent drawingFigure 2
  • EP2969917B1 patent drawingFigure 3A~3B

AI summary

The present invention is directed to compositions useful for use in membranes for sustainable transport of hydroxide (e.g., in fuel cells) and compositions useful for use in separators for use in lithium ion batteries, and membranes, separators, and devices derived therefrom.