Ion-Exchange Membrane Composition for Redox Flow Battery Efficiency

Solution Overview

Problem

Existing separation membranes for redox flow batteries face challenges in achieving both high current efficiency and voltage efficiency, as they either allow excessive permeation of redox active materials, leading to reduced charge storage, or permit proton permeation, increasing resistance and reducing voltage efficiency.

Innovation Solution

The use of a side-chain heteroaromatic resin with specific structural units in the ion-exchange membrane, combined with a cation-exchangeable resin, balances the permeation of redox active materials and protons, enhancing both current and voltage efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the separation membrane suppresses permeation of redox active materials, then current efficiency is improved, but voltage efficiency deteriorates due to increased resistance

Engineering Contradiction:

Improvecurrent efficiencyVSAvoidvoltage efficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies local quality by creating distinct regions within the membrane with different ion-exchange properties. The first region has a first ion-exchange resin with specific properties optimized for blocking redox active materials, while the second region has a second ion-exchange resin with different properties optimized for proton conduction. This spatial differentiation of functional properties allows the membrane to simultaneously achieve high current efficiency in one region and high voltage efficiency in another region, resolving the contradiction between these two efficiency parameters.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the membrane into multiple distinct regions, each with specialized functions. Rather than using a homogeneous membrane structure, it divides the membrane into a first region and a second region with different resin compositions and properties. This segmentation allows independent optimization of each region for its specific function - one region for redox active material blocking and another for proton transport - thereby resolving the trade-off between current and voltage efficiency.

Inventive Principle:

Principle #1Segmentation

2Loss of energy

If the separation membrane allows proton permeation, then voltage efficiency is improved, but current efficiency deteriorates due to increased resistance to redox active material transport

Engineering Contradiction:

Improvevoltage efficiencyVSAvoidcurrent efficiency

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent applies local quality by creating distinct regions within the membrane with different ion-exchange properties. The first region has a first ion-exchange resin with specific properties optimized for blocking redox active materials, while the second region has a second ion-exchange resin with different properties optimized for proton conduction. This spatial differentiation of functional properties allows the membrane to simultaneously achieve high current efficiency in one region and high voltage efficiency in another region, resolving the contradiction between these two efficiency parameters.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the membrane into multiple distinct regions, each with specialized functions. Rather than using a homogeneous membrane structure, it divides the membrane into a first region and a second region with different resin compositions and properties. This segmentation allows independent optimization of each region for its specific function - one region for redox active material blocking and another for proton transport - thereby resolving the trade-off between current and voltage efficiency.

Inventive Principle:

Principle #1Segmentation

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 proposed membrane design achieves a well-balanced current and voltage efficiency, resulting in a higher power efficiency for redox flow batteries.

Implementation Method 1

the present invention relates to an ion-exchange membrane, a membrane electrode assembly, a cell for redox flow battery, and a redox flow battery

Methodology Applied

Scientific EffectIon exchange: Ion Exchange

Implementation Method 2

such a separation membrane is demanded to suppress permeation of the redox active materials as much as possible because permeation of the redox active materials leads to neutralization of any charge stored and thus a reduction in current efficiency

Methodology Applied

Scientific EffectPermeation: Permeation

Data Source

PatentUS20250273719A1Ion-exchange membrane, membrane electrode assembly, cell for redox flow battery, and redox flow battery

Publication Date: 2025.08.28 ASAHI KASEI KOGYO KABUSHIKI KAISHA

AI summary

An ion-exchange membrane comprisinga resin composition comprisinga side-chain heteroaromatic resin having a structural unit represented by the following general formula 1:wherein,R1, R2, and R3 are each optionally the same or different, and are each a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms,R4 is a direct bond, a substituted or unsubstituted divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 10 carbon atoms, andHc is a substituted or unsubstituted heteroaromatic group having 4 to 30 carbon atoms, the group having at least one nitrogen atom in a heteroaromatic ring structure and containing a five-membered ring and/or six-membered ring structure, anda cation-exchangeable resin.