Bismuth-Bonded Polymer Electrolyte Membrane for Flow Batteries

Solution Overview

Problem

Current polymer electrolyte membranes in flow batteries face challenges with ion conductivity, mechanical strength, and crossover prevention, particularly due to limitations in bismuth cation content and distribution, which affect battery efficiency and capacity.

Innovation Solution

A polymer electrolyte membrane is developed with a bismuth cation content of 0.2 to 0.5 equivalents forming ionic bonds with sulfonate anions, using a bismuth salt and ion conducting polymer, enhancing ion conductivity and mechanical strength while preventing crossover by controlling ion channel size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If bismuth cation content is increased to improve ion conductivity, then ion conductivity is improved, but mechanical strength deteriorates due to excessive salt content

Engineering Contradiction:

Core Design Contradiction:

Use of energy by moving objectVSStrength

Solution Approach 1:

The patent optimizes the bismuth cation content to a specific range (0.1 to 0.5 equivalents per sulfonate anion) to achieve the best balance between ion conductivity and mechanical strength. This parameter optimization prevents both insufficient ion conductivity and excessive salt content that would weaken the membrane

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite structure combining ion-exchange resin particles with a polymer matrix. The bismuth cations are introduced into this composite structure through ion exchange, creating a multi-component system that achieves both good ion conductivity and mechanical strength through the synergistic combination of different materials

Inventive Principle:

Principle #40Composite materials

2Reliability

If bismuth cation content is increased to prevent crossover, then crossover prevention is improved, but mechanical strength deteriorates due to excessive salt content

Engineering Contradiction:

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent optimizes the bismuth cation content to a specific range (0.1 to 0.5 equivalents per sulfonate anion) to achieve the best balance between crossover prevention and mechanical strength. This parameter optimization ensures sufficient ions for crossover prevention while avoiding excessive salt content that would weaken the membrane

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite structure combining ion-exchange resin particles with a polymer matrix. The bismuth cations are introduced into this composite structure through ion exchange, creating a multi-component system that achieves both good crossover prevention and mechanical strength through the synergistic combination of different materials

Inventive Principle:

Principle #40Composite materials

3Use of energy by moving object

If uniform distribution of bismuth cations is achieved to improve ion conductivity, then ion conductivity is improved, but manufacturing complexity increases

Engineering Contradiction:

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent uses pre-sulfonated ion-exchange resin particles that have been prepared in advance with sulfonate groups. These particles are then mixed with the polymer matrix and processed, allowing the bismuth cations to be uniformly distributed through ion exchange during manufacturing. This preliminary preparation simplifies the manufacturing process compared to attempting to introduce bismuth cations directly into non-sulfonated polymers

Inventive Principle:

Principle #10Preliminary action

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 membrane exhibits improved ion conductivity, mechanical strength, and reduced crossover, leading to enhanced battery capacity and efficiency, as demonstrated by experimental results showing lower capacity decrease and higher voltage efficiency compared to comparative examples.

Implementation Method 1

a bismuth cation content of 0.2 to 0.5 equivalents forming ionic bonds with sulfonate anions

Methodology Applied

Scientific EffectIonic bonding: Chemical Bonding

Implementation Method 2

an ion conducting polymer having an ion conducting functional group represented by the following Chemical Formula 1: -SO3-

Methodology Applied

Scientific EffectIon exchange: Ion Exchange

Data Source

PatentEP3579250B1Polymer electrolyte membrane, electrochemical cell and flow cell each comprising same, composition for polymer electrolyte membrane, and method for preparing polymer electrolyte membrane

Publication Date: 2022.11.30

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AI summary

The present specification relates to a polymer electrolyte membrane having an ionic bond of a sulfonate anion and a bismuth cation, an electrochemical battery and a flow battery including the same, a composition for a polymer electrolyte membrane, and a method for preparing a polymer electrolyte membrane.