Cellulosic Ion Exchange Membranes With Ionic Liquid Coatings

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Solution Overview

Problem

Existing ion exchange membranes, particularly perfluorinated polymer membranes, are costly and have undesired crossover properties, limiting their effectiveness in applications like fuel cells and batteries.

Innovation Solution

A method involving the application of an ionic liquid with polymerizable and/or crosslinking groups on a cellulosic substrate, followed by polymerization and crosslinking, to produce ion exchange membranes with improved properties, including low diffusivity and high ion conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If perfluorinated polymer membranes are used, then ion conductivity is improved, but cost increases and crossover properties worsen

Engineering Contradiction:

Improveion conductivityVSAvoidcrossover properties

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent combines cellulosic substrate with ionic liquid to create a composite membrane structure. The cellulosic substrate provides mechanical strength and structural stability, while the ionic liquid imparts high ion conductivity and selective transport properties. This composite approach achieves superior ion conductivity without the crossover problems of perfluorinated membranes.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent modifies the physical and chemical parameters of the membrane by controlling the concentration, composition, and processing conditions of the ionic liquid. By adjusting these parameters, the membrane achieves optimal ion conductivity and rejection properties, outperforming conventional perfluorinated membranes in both conductivity and selectivity.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If perfluorinated polymer membranes are used, then ion conductivity is improved, but manufacturing cost increases

Engineering Contradiction:

Improveion conductivityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive perfluorinated polymers with cost-effective cellulosic materials and ionic liquids. The cellulosic substrate is abundant and inexpensive, and the ionic liquid can be applied in thin layers, significantly reducing material costs while maintaining or improving ion conductivity performance.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

By optimizing the ionic liquid concentration and application parameters, the patent achieves high ion conductivity with minimal material usage. The simple dip-coating or spray-coating process requires no complex manufacturing steps, further reducing production costs compared to perfluorinated membrane fabrication.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If conventional ion exchange membranes are used, then ion transport is achieved, but environmental impact increases

Engineering Contradiction:

Improveion transportVSAvoidenvironmental impact

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses ionic liquids, which are inherently environmentally benign substances with low volatility and high stability. Unlike perfluorinated membranes that persist in the environment, ionic liquids can be designed from biodegradable components and do not contribute to environmental pollution, maintaining ion transport functionality while reducing ecological harm.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

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 resulting ion exchange membranes exhibit superior performance in terms of low diffusivity and high ion conductivity, offering a cost-effective and environmentally friendly alternative to conventional membranes.

Implementation Method 1

polymerizing and/or crosslinking said at least one polymerizable and/or crosslinking groups forming a polymer or copolymer layer on the cellulosic substrate

Methodology Applied

Scientific EffectPolymerization: Photopolymerisation

Implementation Method 2

The transport of ions through an ion exchange membrane is driven by convection, diffusion, and migration

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 3

Ion exchangers are materials with which dissolved ions can be replaced by other ions

Methodology Applied

Scientific EffectIon Exchange: Ion Exchange

Data Source

PatentUS20250372685A1Method for preparing an ion exchange membrane

Publication Date: 2025.12.04 TECHNISCHE UNIVERSITAT GRAZ

AI summary

The present invention relates to a method for producing an ion exchange membrane comprising the steps of:a. applying an ionic liquid comprising at least one polymerizable and/or crosslinking group at the cation and/or at the anion on a cellulosic substrate, wherein the cation of the ionic liquid is a heterocyclic aromatic comprising at least one nitrogen as heteroatom, andb. polymerizing and/or crosslinking said at least one polymerizable and/or crosslinking groups forming a polymer or copolymer layer on the cellulosic substrate.