Acid-Base Polymer Blend Membranes for Low-Resistance Ion Separation
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Solution Overview
Problem
Current redox flow batteries face challenges with halogen-containing membranes, which are environmentally harmful and costly, and require high ion conductivity, low electrical resistance, and reduced electrolyte crossover, especially in strongly basic or acidic electrolytes like lignin-based systems.
Innovation Solution
Development of a halogen-free acid-base polymer blend membrane with a high molar ratio of acidic to basic groups, specifically sulfonated poly(ether ether ketone) and meta-polybenzimidazole, impregnated on a support structure for use in redox flow batteries, fuel cells, and electrodialysis cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If halogen-containing polymers (e.g., fluorinated polymers) are used for cell membranes, then good electrochemical properties and mechanical stability are achieved, but environmental harm and high cost occur
Solution Approach 1:
The patent changes the chemical composition parameters by using sulfonated poly(ether ether ketone) with specific degree of sulfonation (30-80%) combined with polybenzimidazole in controlled ratios, achieving halogen-free membranes with comparable electrochemical performance to traditional fluorinated membranes
Solution Approach 2:
The patent creates composite polymer blend membranes combining sulfonated poly(ether ether ketone) and polybenzimidazole, where the synergistic interaction between the two polymers provides both good electrochemical properties and environmental compatibility without halogen content
2Reliability
If conventional membranes are used, then separation function is achieved, but high electrical resistance and low ion conductivity occur
Solution Approach 1:
The patent introduces local ionic clusters and channels within the membrane structure through the specific arrangement of sulfonate groups and benzimidazole rings, creating localized high-conductivity pathways that maintain separation function while reducing overall electrical resistance
Solution Approach 2:
The patent utilizes the inherent porous structure of the polymer blend membrane, where the phase separation between sulfonated poly(ether ether ketone) and polybenzimidazole creates interconnected pores that facilitate ion transport, reducing electrical resistance while maintaining separation capability
3Loss of energy
If membrane thickness is reduced to lower resistance, then ion conductivity improves, but mechanical stability and chemical stability deteriorate
Solution Approach 1:
The patent employs the composite structure of sulfonated poly(ether ether ketone) and polybenzimidazole where polybenzimidazole provides robust mechanical strength and chemical stability, allowing the membrane to be made thinner for reduced resistance without sacrificing structural integrity
Solution Approach 2:
The patent optimizes the thickness parameter within a specific range (10-50 μm) and adjusts the composition ratio and crosslinking degree to achieve the optimal balance between low resistance and sufficient mechanical stability, demonstrating that thinner membranes can maintain strength through compositional optimization
4Ease of manufacture
If acid-base polymer blend is used to reduce cost and improve environmentality, then processing properties improve, but manufacturing precision and consistency may deteriorate
Solution Approach 1:
The patent establishes specific parameter ranges for the polymer blend composition (e.g., sulfonated poly(ether ether ketone) content, degree of sulfonation, molecular weight) and processing conditions (solvent type, casting temperature, humidity control) to ensure manufacturing precision and membrane consistency while maintaining ease of processing
Solution Approach 2:
The patent implements quality control mechanisms including real-time monitoring of membrane thickness, composition uniformity, and performance parameters during manufacturing, with feedback loops to adjust processing parameters and maintain consistent product quality
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 low electrical resistance, high ion conductivity, and reduced water uptake, leading to improved cycle stability and Coulomb efficiency, while being environmentally friendly and cost-effective.
Implementation Method 1
The main tasks of the cell membrane are the separation of the two positively and negatively charged electrolytes and the selective conduction of cations through the membrane, which is necessary for the conduction of electrons via the external circuit.
Implementation Method 2
These chemical compounds are present as reaction partners in a solvent in dissolved form and circulate as electrolytes in two separate circuits, between which the ion exchange takes place through a membrane.
Data Source
AI summary
The present disclosure relates to an acid-base polymer blend membrane comprising at least one first polymer exhibiting acidic groups (A) and at least one second polymer exhibiting basic groups (B), wherein the molar ratio of acidic groups A / basic groups B in the acid-base polymer blend membrane is at least 1 / 0.25. Furthermore, the present disclosure relates to a cell membrane comprising a support structure and an acid-base polymer blend membrane, wherein the acid-base polymer blend membrane is impregnated on the support structure. Said cell membrane can be used in an electrodialysis cell, in a fuel cell, in a PEM electrolyzer, or in a redox flow battery, preferably in a redox flow battery.