Polymer Electrolyte Membrane Layers for Gas Barrier and Ion Conductivity
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Solution Overview
Problem
Solid polymer electrolyte membranes in fuel cells face challenges with mechanical durability, hydrogen ion conductivity, and reaction gas barrier ability due to defects or micropores, leading to premature thinning and reduced lifespan.
Innovation Solution
A polymer electrolyte membrane structure comprising multiple ion conductive layers with sulfonic acid and carboxylic acid groups, where the second ion conductive polymer layer is formed by chlorination, nitrilation, and hydrolysis reactions, and heat treatment, to achieve a thickness range of 1% to 80% of the total membrane thickness, enhancing mechanical properties and chemical stability while maintaining ion conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a solid polymer electrolyte membrane is used in fuel cells, then high hydrogen ion conductivity is achieved, but reaction gas permeation occurs through defects or micropores leading to chemical radical formation and structural decomposition
Solution Approach 1:
The patent applies composite materials by combining a base polymer electrolyte membrane with surface-modified layers containing carboxylic acid groups. This composite structure maintains the high hydrogen ion conductivity of the base membrane while the modified surface layers provide enhanced chemical stability and reduced gas permeation, resolving the contradiction between conductivity and reliability.
Solution Approach 2:
The patent implements local quality by modifying only the surface regions of the polymer electrolyte membrane with carboxylic acid-containing groups, while keeping the bulk membrane structure intact. This localized modification provides enhanced chemical stability at the critical gas-liquid interfaces where radical formation occurs, without compromising the overall hydrogen ion conductivity of the membrane.
2Reliability
If the polymer electrolyte membrane is modified to improve chemical stability, then reaction gas barrier ability is enhanced, but mechanical properties may deteriorate
Solution Approach 1:
The patent applies parameter changes by carefully controlling the concentration of carboxylic acid groups, the thickness of modified layers, and the degree of surface modification. These parameter optimizations ensure that the chemical stability is enhanced through surface modification while the mechanical integrity of the membrane is preserved by maintaining appropriate structural parameters.
3Reliability
If multiple ion conductive layers are formed through chlorination, nitrilation, and hydrolysis reactions, then reaction gas barrier ability is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the membrane modification process into distinct sequential stages: chlorination reaction, nitrilation reaction, and hydrolysis reaction. Each stage introduces specific functional groups in a controlled manner, allowing precise control over the final membrane properties while making the complex manufacturing process more manageable and reproducible.
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 mechanical properties, chemical stability, and reaction gas barrier ability, significantly reducing hydrogen and oxygen permeability, thus extending the lifespan of the fuel cell by preventing structural decomposition.
Implementation Method 1
performing a chlorination reaction on at least one surface of the first ion conductive polymer membrane for 5 to 30 minutes such that a second ion conductive polymer membrane including a chlorinated ion conductive polymer layer is formed
Implementation Method 2
performing a nitrilation reaction on the second ion conductive polymer membrane such that a third ion conductive polymer membrane including a nitrilated ion conductive polymer layer is formed
Implementation Method 3
performing a hydrolysis reaction on the third ion conductive polymer membrane such that a fourth ion conductive polymer membrane including a second ion conductive polymer layer is formed
Implementation Method 4
performing heat treatment on the fourth ion conductive polymer membrane at ±10°C around a glass transition temperature of an ion conductive polymer including a carboxylic acid group
Data Source
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AI summary
The polymer electrolyte membrane includes: a first ion conductive polymer layer; and a second ion conductive polymer layer disposed on at least one surface of the first ion conductive polymer layer, wherein the first ion conductive polymer layer comprises a first ion conductive polymer comprising a sulfonic acid group, wherein the second ion conductive polymer layer comprises a second ion conductive polymer comprising a carboxylic acid group, and wherein a thickness of the second ion conductive polymer layer is in a range of 1 % to 80% of a thickness of the polymer electrolyte membrane. Further, disclosed are the method for preparing the same, the membrane-electrode assembly including the same, and the fuel cell including the same.