Asymmetric Composite Membrane for Electrolyte Crossover Control
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Solution Overview
Problem
Current energy storage systems, particularly redox flow batteries and water electrolysis, face challenges due to high capital costs, electrolyte crossover, and low efficiency, which hinder their widespread adoption for renewable energy storage and grid balancing.
Innovation Solution
Development of an ionically conductive asymmetric composite membrane with a hydrophilic ionomeric polymer coating layer on a microporous substrate, enhancing ionic conductivity and selectivity while reducing electrolyte crossover, thereby improving voltage, coulombic, and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional membranes are used in redox flow batteries and electrolysis systems, then the system structure is simple, but the energy efficiency is low and electrolyte crossover occurs
Solution Approach 1:
The patent employs a composite membrane structure consisting of a microporous substrate layer combined with a hydrophilic ionomeric polymer coating layer. This composite design leverages the mechanical strength and porosity of the substrate along with the ion-selective properties of the polymer coating, achieving high energy efficiency by preventing electrolyte crossover while maintaining structural integrity and facilitating ion transport.
Solution Approach 2:
The membrane design applies local quality by creating a hydrophilic ionomeric polymer coating layer with specific functional groups on the surface of the microporous substrate. This localized functionalization enhances ion selectivity and conductivity at the critical interface where ion transport occurs, while the bulk substrate provides structural support, thus improving energy efficiency without requiring complete structural redesign.
2Reliability
If conventional membranes are used, then manufacturing costs are lower, but voltage efficiency and coulombic efficiency are reduced
Solution Approach 1:
The patent utilizes a microporous substrate layer as the foundation of the membrane structure. The porous architecture provides high surface area for coating deposition, excellent mechanical properties, and controlled ion transport pathways. This porous structure enhances voltage efficiency by preventing direct electrolyte mixing while maintaining low resistance ion conduction, and improves coulombic efficiency through selective ion permeability.
Solution Approach 2:
The hydrophilic ionomeric polymer coating layer acts as an intermediary between the microporous substrate and the electrolyte solutions. This intermediate layer with specific functional groups selectively facilitates ion transport while blocking electrolyte crossover, thereby improving both voltage efficiency and coulombic efficiency without requiring complete membrane replacement or system redesign.
3Duration of action of stationary object
If standard membranes are employed, then the system is easier to operate, but stability and charge/discharge cycle life are limited
Solution Approach 1:
The patent modifies key parameters of the membrane by incorporating a hydrophilic ionomeric polymer coating with specific functional groups on the microporous substrate. This parameter change in the membrane's chemical and physical properties enhances its stability under operating conditions, prevents degradation, and extends charge/discharge cycle life while maintaining ease of operation through integrated membrane design.
Solution Approach 2:
Instead of attempting to improve membrane durability through thickening or complex multi-layer structures that would complicate operation, the patent inverts the approach by using a thin, functionally-rich hydrophilic polymer coating on a stable porous substrate. This inverted design achieves enhanced stability and cycle life through surface functionality rather than bulk complexity, preserving operational simplicity.
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 stability, longer charge/discharge cycles, and higher energy efficiency, reducing the costs associated with traditional membranes and enhancing the performance of redox flow batteries and electrolysis systems.
Implementation Method 1
The nonporous layer is dense, such that it will conduct a proton, supporting electrolyte cations such as NH4+ or K+, but rejecting electrolyte cations, such as Fe2+ or Fe3+
Implementation Method 2
an asymmetric hydrophilic ionomeric polymer coating layer... comprising a porous layer having a first surface and a second surface, the first surface of the porous layer on the surface of the microporous substrate layer
Implementation Method 3
The nonporous layer is dense, such that it will conduct a proton, supporting electrolyte cations such as NH4+ or K+, but rejecting electrolyte cations, such as Fe2+ or Fe3+
Implementation Method 4
The nonporous layer is dense, such that it will conduct a proton, supporting electrolyte cations such as NH4+ or K+, but rejecting electrolyte cations, such as Fe2+ or Fe3+
Implementation Method 5
a microporous substrate membrane... the coating layer comprising: a porous layer having a first surface and a second surface, the first surface of the porous layer on the surface of the microporous substrate layer
Data Source
AI summary
An ionically conductive asymmetric composite membrane for use in redox flow battery, fuel cell, electrolysis applications and the like is described. It comprises a microporous substrate membrane and an asymmetric hydrophilic ionomeric polymer coating layer on the surface of the microporous substrate layer. The coating layer is made of a hydrophilic ionomeric polymer. The asymmetric hydrophilic ionomeric polymer coating layer comprises a porous layer having a first surface and a second surface, the first surface of the porous layer on the surface of the microporous substrate layer and a nonporous layer on the second surface of the porous support layer. The microporous substrate membrane is made from a different polymer from the hydrophilic ionomeric polymer.