Thin Anion Exchange Membranes With Composite Support for Flow Batteries
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Solution Overview
Problem
Existing redox flow batteries face challenges in developing anion exchange membranes with low resistance, high chemical stability, and long useful life, particularly for applications requiring thin membranes that are susceptible to dimensional changes and defects.
Innovation Solution
The development of an anion exchange membrane with a thickness of less than 100 μm, featuring a cross-linked polymerization product integrated into a microporous substrate, which provides low resistance, low diffusivity, and high co-ion transport number, while maintaining mechanical stability and chemical stability through the use of cationic functional monomers and a solvent-free polymerization process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the membrane thickness is reduced to less than 100 μm to lower resistance and improve conductance, then electrical performance is improved, but mechanical stability and chemical stability deteriorate due to susceptibility to dimensional changes and defects
Solution Approach 1:
The patent employs a composite membrane structure consisting of a microporous substrate reinforced with a cross-linked polymer network. The microporous substrate provides mechanical strength and dimensional stability, while the cross-linked polymer layer provides ion exchange functionality and chemical stability. This composite approach allows the membrane to achieve low resistance through thin design while maintaining reliability through the reinforcing substrate structure.
Solution Approach 2:
The patent applies different material properties to different regions of the membrane structure. The microporous substrate region provides mechanical support and structural integrity, while the cross-linked polymer region provides ion exchange capability and chemical stability. This local differentiation of material functions allows the thin membrane to simultaneously achieve low electrical resistance and high mechanical stability.
2Use of energy by moving object
If the membrane thickness is reduced to less than 100 μm to improve ion conductivity, then electrical performance is improved, but chemical stability deteriorates
Solution Approach 1:
The composite structure combines a chemically stable microporous substrate with a cross-linked polymer layer that provides both ion exchange functionality and chemical resistance. The cross-linking creates a stable three-dimensional network that maintains chemical stability even in the thin membrane configuration, while the microporous substrate provides additional chemical inertness and structural support.
Solution Approach 2:
The patent changes the chemical structure of the polymer by introducing cross-links, which fundamentally alters the polymer's chemical stability properties. The cross-linked network structure resists chemical degradation and maintains stability in the thin membrane form, enabling high ion conductivity without sacrificing chemical durability.
3Ease of manufacture
If conventional polymerization processes are used to create the membrane, then manufacturing is simpler, but the membrane exhibits higher resistance and lower co-ion transport number
Solution Approach 1:
The patent changes the polymerization parameters by conducting the reaction in a solvent-free system and using specific cross-linking agents. This alters the polymer network structure to achieve higher cross-link density and more uniform distribution of ionic groups, resulting in lower resistance and improved co-ion transport number while maintaining manufacturing feasibility through a streamlined single-step process.
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 membrane achieves low resistance, high conductance, and extended useful life, enabling efficient operation in redox flow batteries with improved energy efficiency and longevity, suitable for applications in HVDC transmission and automotive energy storage.
Implementation Method 1
The anion exchange membrane may be configured to be ionically conductive between the first electrolyte and the second electrolyte
Implementation Method 2
The anion exchange membrane may have a steady state diffusivity of less than 0.4 ppm/hr/cm2 with respect to at least one of the first cation species and the second cation species
Data Source
AI summary
A flow battery having at least one rechargeable cell is disclosed. The at least one rechargeable cell can include an anolyte compartment, a catholyte compartment, and an anion exchange membrane positioned between the anolyte and catholyte compartments. The anion exchange membrane can have a thickness of less than 100 μm and a steady state diffusivity of less than 0.4 ppm/hr/cm2 with respect to a cation species in an electrolyte of the rechargeable cell. A method of facilitating use of a flow battery including providing the anion exchange membrane is also disclosed. A method of facilitating storage of an electric charge comprising providing the flow battery is also disclosed. A method of producing an anion exchange membrane is also disclosed.