Matched-Ion Membrane for Redox Flow Battery Crossover

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Solution Overview

Problem

Existing flow battery technologies face challenges with scalability, round trip energy efficiencies, cycle life, and cost due to material and engineering hurdles, limiting their widespread commercial adoption for large-scale energy storage.

Innovation Solution

The use of low-cost battery active materials composed of charged metal ligand coordination compounds, matched in charge sign with the ionomer membrane, to prevent active material crossover and enhance ion transport selectivity in flow batteries, achieving high electrochemical performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If thin membranes are used to achieve high conductivity, then ion transport efficiency is improved, but active material crossover increases

Engineering Contradiction:

Improveion transport efficiencyVSAvoidactive material crossover

Core Design Contradiction:

Use of energy by moving objectVSLoss of substance

Solution Approach 1:

The patent changes the charge sign parameter of the membrane to match the active material, transforming the membrane from a conventional opposite-charge design to a same-charge design. This parameter change enables the membrane to achieve both high ion transport efficiency and low active material crossover simultaneously through electrostatic repulsion of like charges.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the typically harmful effect of charge-based attraction (which causes active material crossover) into a beneficial effect by using same-charge repulsion. The electrostatic repulsion between like-charged membrane and active material prevents crossover while maintaining ion transport, turning what would normally be a problematic attraction mechanism into a protective repulsion mechanism.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Use of energy by moving object

If conventional ionomer membranes are used, then ion transport is enabled, but active material crossover occurs

Engineering Contradiction:

Improveion transportVSAvoidactive material crossover

Core Design Contradiction:

Use of energy by moving objectVSLoss of substance

Solution Approach 1:

The patent fundamentally changes the charge sign parameter of the ionomer membrane from the conventional opposite-charge design to a same-charge design that matches the active material. This parameter change transforms the membrane's interaction with active material from attractive (causing crossover) to repulsive (preventing crossover), while maintaining ion transport functionality.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the typically harmful charge-based attraction between conventional membranes and active material into a beneficial protective mechanism by using same-charge electrostatic repulsion. The repulsive force prevents active material crossover while allowing ion transport, transforming a problematic attraction mechanism into a beneficial barrier mechanism.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Loss of substance

If matched charge sign configuration is used, then active material crossover is prevented, but ion transport selectivity must be optimized

Engineering Contradiction:

Improveactive material crossoverVSAvoidion transport selectivity

Core Design Contradiction:

Loss of substanceVSManufacturing precision

Solution Approach 1:

The patent changes the charge sign parameter to create electrostatic repulsion that prevents active material crossover. This same parameter change inherently provides ion transport selectivity by allowing only counter-ions to pass through the membrane while repelling co-ions, achieving both goals simultaneously through a single parameter optimization.

Inventive Principle:

Principle #35Parameter changes

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

This configuration results in flow batteries with improved round trip current efficiencies, energy densities, and operational stability, enabling cost-effective and scalable energy storage solutions.

Implementation Method 1

negatively charged ionomers are selected to transport positively charged ions between the electrodes of the cell

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 2

the sign of the charge of the metal-ligand coordination compound is chosen to match the sign of the ionomer membrane, so as to induce ionic repulsion between the membrane and active material and prevent active material crossover

Methodology Applied

Scientific EffectElectrostatic repulsion: Ion Repulsion/Attraction

Implementation Method 3

aqueous redox flow batteries comprising matched ionomer membranes... charged metal ligand coordination compounds... first redox active material... second redox active material

Methodology Applied

Scientific EffectRedox reactions: Redox Reactions

Data Source

PatentUS9692077B2Aqueous redox flow batteries comprising matched ionomer membranes

Publication Date: 2017.06.27 LOCKHEED MARTIN ADVANCED ENERGY STORAGE LLC

AI summary

This invention is directed to aqueous redox flow batteries comprising ionically charged redox active materials and ionomer membranes, wherein the charge of the redox active materials is of the same sign as that of the ionomer, so as to confer specific improvements.