Crosslinked Ionomer Membranes for Fuel Cell Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current alkaline exchange membrane (AEM) and proton exchange membrane (PEM) fuel cells face challenges in stability and mechanical durability due to excessive swelling and leaching of polymer chains, which affects ion conductivity and mechanical strength, especially under alkaline conditions and electrochemical reactions.
Innovation Solution
A novel method of crosslinking ionomers is introduced, where a first type of functional groups forms crosslinking bonds between ionomer chains, and a second type of functional groups includes ion conducting functional groups, stabilizing the catalyst layers and membranes. This method involves preparing a catalyst dispersion with polymer precursors having non-cationic and anion-conductive functional groups, depositing it on a substrate, and crosslinking these groups to form a stable catalyst layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymer chains are used in alkaline exchange membranes, then ion conductivity is achieved, but excessive swelling and leaching occur under alkaline conditions, reducing mechanical durability and stability
Solution Approach 1:
The patent applies composite materials by combining polymer chains with crosslinking agents to create a hybrid structure. The crosslinked ionomer membrane integrates the ion conductivity of polymer chains with the structural stability of crosslinked networks, preventing excessive swelling and leaching while maintaining reliability under alkaline conditions
Solution Approach 2:
The patent changes the chemical structure parameters of the ionomer by introducing crosslinking bonds between polymer chains. This modifies the physical and chemical properties of the membrane, reducing swelling and leaching behavior while maintaining ion conductivity, thus resolving the contradiction between reliability and compositional stability
2Reliability
If polymer chains are used in alkaline exchange membranes, then ion conductivity is achieved, but mechanical strength decreases due to leaching, affecting mechanical durability
Solution Approach 1:
The crosslinked ionomer creates a composite structure where polymer chains provide ion conductivity pathways while crosslinking points provide mechanical reinforcement. This composite architecture maintains ion conductivity through the polymer network while the crosslinked structure prevents chain leaching and preserves mechanical strength
Solution Approach 2:
The patent segments the polymer structure into discrete crosslinked units connected by polymer chains. This segmentation creates a network where individual chains are anchored at multiple points, maintaining ion transport pathways while preventing overall structural degradation and mechanical strength loss
3Productivity
If catalyst layers are applied to membranes, then electrochemical activity is enhanced, but structural stabilization is needed to prevent degradation under electrochemical reactions
Solution Approach 1:
The catalyst-coated membrane forms a composite structure where the catalyst layer is chemically bonded to the crosslinked ionomer substrate. The crosslinked structure provides structural stabilization that prevents membrane degradation under electrochemical reactions, while the catalyst layer maintains enhanced electrochemical activity for improved productivity
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 crosslinked membranes and catalyst layers exhibit improved stability, mechanical durability, and ion conductivity, enhancing the performance and longevity of fuel cells by preventing excessive swelling and leaching, while allowing independent optimization of layer strength and conductivity.
Implementation Method 1
crosslinking at least one of the non-cationic functional groups and/or the anion-conductive groups to stabilize the catalyst layer
Implementation Method 2
depositing the catalyst dispersion on a functional substrate and evaporating the solvent to form a catalyst layer
Data Source
AI summary
Methods of making alkaline exchange catalytic electrodes for electrochemical devices are provided, as well as fuel cells, electrolyzers and dual reversible devices with provided electrodes and/or membrane-electrode assemblies. Methods comprise preparing a catalyst dispersion by mixing catalyst nanoparticles and polymer precursor dispersion in a solvent. The polymer precursor(s) comprise multiple types of monomer units with multiple types of functional groups that include non-cationic functional group(s) and anion-conductive functional group(s). Consecutively, the catalyst dispersion is deposited on a functional substrate and the solvent is evaporated to form a catalyst layer, and then the non-cationic functional group(s) and/or the anion-conductive group(s) are crosslinked to stabilize the catalyst layer. Membrane-electrode assemblies may be formed by the provided methods, and used in various types of electrochemical devices.