Composite Membrane Fabrication via Electrospinning for Alkaline Fuel Cells

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Solution Overview

Problem

Alkaline anion-exchange membrane fuel cells face challenges due to the lower mobility of hydroxide anions, which affects ionic conduction, and the use of high ion-exchange capacity polymers exacerbates brittleness and poor mechanical strength, particularly in the dry and fully hydrated states.

Innovation Solution

A method of fabricating composite membranes through electrospinning charged and uncharged polymers, where a dual fiber mat is formed and processed to create a composite membrane with enhanced mechanical strength and conductivity by softening and flowing the fibers to fill void spaces, potentially using perfluorosulfonic acid (PFSA) and polyvinylidene difluoride (PVDF) or polyphenylsulfone (PPSU) polymers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high ion-exchange capacity polymers are used to compensate for lower hydroxide anion mobility, then ionic conduction is improved, but mechanical strength and brittleness worsen

Engineering Contradiction:

Improveionic conductionVSAvoidmechanical strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent employs composite membranes combining PFSA (perfluorosulfonic acid) polymer with uncharged polymer matrices (PVDF or PPSU). This composite structure allows the PFSA component to provide high ionic conduction through its ion-exchange capacity, while the uncharged polymer matrix contributes mechanical strength and structural stability, thereby resolving the contradiction between improved ionic conduction and maintained mechanical strength.

Inventive Principle:

Principle #40Composite materials

2Reliability

If high ion-exchange capacity polymers are used to compensate for lower hydroxide anion mobility, then ionic conduction is improved, but brittleness increases

Engineering Contradiction:

Improveionic conductionVSAvoidbrittleness

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The composite membrane structure integrates PFSA polymer phases responsible for ion transport with flexible uncharged polymer matrices (PVDF or PPSU). The uncharged matrix acts as a flexible backbone that reduces brittleness while the dispersed PFSA domains maintain high ionic conduction pathways, thus achieving both improved ionic conduction and reduced brittleness simultaneously.

Inventive Principle:

Principle #40Composite materials

3Strength

If composite membranes are fabricated through electrospinning and processing to fill void spaces, then mechanical strength is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvemechanical strengthVSAvoidmanufacturing process

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The electrospinning process is used to pre-form fibrous mats with controlled porosity and fiber orientation before the final membrane assembly. This preliminary structuring creates a scaffold that inherently provides mechanical strength, reducing the need for additional reinforcement steps and simplifying the overall manufacturing process despite the initial complexity of electrospinning.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent utilizes thermal processing and solvent treatment to induce phase transitions in the electrospun fibrous mats. By controlling the thermal and solvent environments, the fibers undergo transitions that enhance their mechanical properties and fill void spaces, achieving improved mechanical strength through controlled physical transformations rather than complex chemical processing.

Inventive Principle:

Principle #36Phase transitions

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 composite membranes exhibit improved proton conductivity and dimensional stability, addressing the limitations of alkaline anion-exchange membranes by enhancing mechanical strength and maintaining high proton conductivity even at low humidity and high temperatures.

Implementation Method 1

electrospinning, separately and simultaneously, the first solution and the second solution to form a dual fiber mat

Methodology Applied

Scientific EffectElectrospinning: Electrohydrodynamics

Implementation Method 2

processing the dual fiber mat to form the composite membrane

Methodology Applied

Scientific EffectSoftening and flowing: Melting

Implementation Method 3

exposing the dual fiber mat to solvent vapor to soften and flow at least one of the first polymer fibers and the second polymer fibers to fill void space

Methodology Applied

Scientific EffectSolvent vapor exposure: Solvation

Data Source

PatentUS10141593B2Composite membranes, methods of making same, and applications of same

Publication Date: 2018.11.27 VANDERBILT UNIV

AI summary

A method of fabricating a composite membrane, includes the steps of: forming a first solution comprising a charged polymer and a first uncharged polymer having a repeat unit of a formula of:where each of X and Y is a non-hydroxyl group; forming a second solution comprising a second uncharged polymer; electrospinning, separately and simultaneously, the first solution and the second solution to form a dual fiber mat; and processing the dual fiber mat to form the composite membrane.