Thin Film Composite Membrane for Alkaline Water Electrolysis
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Solution Overview
Problem
Conventional porous membranes used in alkaline water electrolysis have high gas permeability, leading to safety risks due to gas mixing, while nonporous membranes have high voltage loads and limited mechanical and thermochemical stability, making them unsuitable for efficient hydrogen production.
Innovation Solution
A thin film composite membrane is manufactured using a crosslinked quaternary ammonium polymer selective layer formed through Menshutkin polymerization on a porous support, which reduces gas permeability and enhances mechanical strength, ion conductivity, and thermochemical stability, thereby improving the safety and efficiency of water electrolysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a porous membrane is used to achieve low mass transport resistance and high ion conductivity, then ion conductivity is improved, but gas permeability increases leading to safety risks
Solution Approach 1:
The membrane structure is divided into two distinct regions: a porous support layer that provides mechanical strength and ion conductivity, and a nonporous selective layer that blocks gas permeation. Each layer performs its specific function locally, allowing the membrane as a whole to achieve both high ion conductivity and low gas permeability simultaneously.
Solution Approach 2:
The invention uses a composite membrane structure combining a porous support layer (made of materials like polyolefin or polysulfone) with a nonporous selective layer (made of crosslinked quaternary ammonium polymer). This composite structure integrates the advantages of both porous and nonporous membranes, achieving low mass transport resistance while preventing gas mixing.
2Object-affected harmful factors
If a nonporous membrane is used to reduce gas permeability, then gas permeability is reduced, but mass transport resistance increases leading to high voltage loads
Solution Approach 1:
The membrane structure is divided into two distinct regions: a porous support layer that provides mechanical strength and ion conductivity, and a nonporous selective layer that blocks gas permeation. Each layer performs its specific function locally, allowing the membrane as a whole to achieve both high ion conductivity and low gas permeability simultaneously.
Solution Approach 2:
The invention uses a composite membrane structure combining a porous support layer (made of materials like polyolefin or polysulfone) with a nonporous selective layer (made of crosslinked quaternary ammonium polymer). This composite structure integrates the advantages of both porous and nonporous membranes, achieving low mass transport resistance while preventing gas mixing.
3Strength
If a thick porous membrane structure is used to achieve mechanical strength, then mechanical strength is improved, but area specific resistance increases
Solution Approach 1:
The selective layer is designed as an ultra-thin nonporous film with thickness of 1-10 μm, which minimizes ion transport distance and area specific resistance. The porous support layer provides the necessary mechanical strength, allowing the thin selective layer to function effectively without compromising structural integrity.
Solution Approach 2:
The invention uses a composite membrane structure combining a porous support layer (made of materials like polyolefin or polysulfone) with a nonporous selective layer (made of crosslinked quaternary ammonium polymer). This composite structure integrates the advantages of both porous and nonporous membranes, achieving low mass transport resistance while preventing gas mixing.
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 thin film composite membrane achieves low mass transport resistance, high ion conductivity, and reduced gas permeability, ensuring safe and efficient hydrogen production by stabilizing the alkaline water electrolysis process.
Implementation Method 1
forming a crosslinked quaternary ammonium polymer selective layer on a porous support or inside pores of the porous support through Menshutkin polymerization
Implementation Method 2
migration of hydroxide ions from the cathode to the anode completes the electrical circuit between both electrodes
Implementation Method 3
there is a risk of explosion when a concentration of hydrogen in oxygen increases to 4% or more, the membrane needs to have low permeability to hydrogen and oxygen gases generated at the cathode and the anode, respectively
Data Source
AI summary
The present invention relates to a method for manufacturing a thin film composite membrane for alkaline water electrolysis, and to a thin film composite membrane for alkaline water electrolysis. The present invention can provide a thin film composite membrane, which has excellent water electrolysis performance due to low mass transport resistance and high ion conductivity thereof compared to conventional nonporous membranes and porous membranes, and it is also highly safe by lowering gas permeability and minimizing gas mixing.