Hydrogel Composite Separator for Low-Resistance Gas Blocking
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Solution Overview
Problem
Existing electrochemical devices, such as water electrolysers and fuel cells, face challenges with separators that compromise between safety and efficiency due to high electrical resistance and limited chemical stability, particularly in alkaline conditions.
Innovation Solution
A separator comprising a porous carrier with a hydrogel made of a metal oxide and an aqueous medium, which provides low gas permeability, high ionic conductivity, and chemical stability, achieved through a process involving a polar organic solvent, polymeric matrix, and metal alkoxide acidic solution, allowing for efficient ion transport and mechanical robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a diaphragm separator is used to prevent gas crossover and ensure safety, then gas crossover is reduced, but electrical cell resistance increases and efficiency decreases
Solution Approach 1:
The separator combines a porous polymer matrix (providing mechanical strength and gas barrier properties) with metal oxide particles (providing high ionic conductivity). This composite structure achieves both low gas crossover and low electrical resistance simultaneously, resolving the contradiction between safety and efficiency.
2Loss of energy
If the diaphragm thickness is reduced to improve efficiency, then electrical cell resistance decreases, but mechanical stability is compromised and gas crossover increases
Solution Approach 1:
The separator uses a porous polymer matrix that provides mechanical strength throughout the structure, allowing the use of thinner separators (50-300 micrometers) without compromising structural integrity. The localized distribution of metal oxide particles within the matrix provides high ionic conductivity in the regions where it is most needed for ion transport.
3Loss of energy
If AEM membranes are used to achieve thin thickness and high ionic conductivity, then efficiency improves, but chemical stability under alkaline conditions deteriorates
Solution Approach 1:
The patent uses conventional, chemically stable porous polymer materials (such as PTFE, polypropylene, or polyester) that are resistant to alkaline conditions. These materials may have lower ionic conductivity than AEMs but provide long-term chemical stability in alkaline electrolyzers, sacrificing some efficiency for durability.
Solution Approach 2:
By combining chemically stable porous polymer matrices with high-conductivity metal oxide particles, the separator achieves a balance between chemical stability in alkaline conditions and high ionic conductivity, resolving the contradiction between reliability and efficiency.
4Loss of energy
If the diaphragm is made more porous to reduce ionic resistance, then efficiency improves, but mechanical stability and gas crossover control are compromised
Solution Approach 1:
The porous polymer matrix provides the necessary porosity for ion transport while maintaining mechanical stability. The metal oxide particles distributed within the matrix enhance ionic conductivity without compromising the structural integrity or gas barrier properties of the polymer framework, allowing high porosity while controlling gas crossover.
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 solution results in a separator with low gas crossover and high ionic conductivity, maintaining stability even in strongly alkaline conditions, enhancing the efficiency and reliability of electrochemical devices while minimizing electrical resistance.
Implementation Method 1
a hydrogel, made of a first metal oxide and an aqueous medium, present within the first of both largest sides and in at least part of the thickness
Implementation Method 2
the porous and hydrophilic material allows for the electrolyte, usually an alkaline solution, to penetrate through the interconnected pores
Implementation Method 3
the separator acts as an electrical barrier to prevent short-circuits between the cathode and the anode
Implementation Method 4
the separator preferably allows hydroxide ions to be transferred from the cathode to the anode
Data Source
AI summary
A separator for an electrochemical device, including: a porous carrier having two, respectively a first and a second, largest parallel sides separated by a thickness, and a hydrogel, made of a first metal oxide and an aqueous medium, present within the first of both largest sides and in at least part of the thickness.