Proton Conductive Electrolyte for High-Temperature Fuel Cells
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Solution Overview
Problem
Conventional proton conductive electrolytes and fuel cell electrodes face challenges in maintaining stability and ionic conductivity at high temperatures, especially under non-humidified conditions with low humidity, leading to performance issues such as mechanical weakness, flooding, and reduced oxygen transmittance.
Innovation Solution
A proton conductive electrolyte is developed by polymerizing a mixture of a polyurethane-based compound and polyethylene(metha)acrylic acid, with a cross-linking agent, which is then impregnated with acid, forming a membrane with enhanced mechanical strength, flexibility, and ionic conductivity, and an electrode with improved binding force between the catalyst layer and support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If perfluorocarbonsulfonic acid is used as a proton conductor, then mechanical strength and chemical stability are improved, but water loss occurs at 80°C or higher making it unusable
Solution Approach 1:
The patent uses a composite membrane structure combining perfluorocarbonsulfonic acid polymer with hydrophilic inorganic particles (such as silica, alumina, or zirconia). The inorganic particles form a three-dimensional network that physically restrains the polymer chains, preventing water loss at high temperatures while maintaining mechanical strength and proton conductivity.
2Temperature
If solid polymer electrolyte membrane is used for high temperature operation, then operating temperature range is improved, but long term stability is insufficient
Solution Approach 1:
The invention creates a composite membrane where inorganic particles (silica, alumina, zirconia, or their combinations) are dispersed within the perfluorocarbonsulfonic acid polymer matrix. These inorganic components form a stable three-dimensional network that enhances thermal stability and prevents membrane degradation at temperatures of 100-300°C, ensuring long-term operational reliability.
Solution Approach 2:
The membrane is designed with a porous structure formed by the three-dimensional network of inorganic particles. This porous architecture provides pathways for proton conduction while the inorganic framework maintains structural integrity at high temperatures, improving both temperature tolerance and long-term stability.
3Object-generated harmful factors
If polybenzimidazole/PVDF is used as electrode binder, then oxygen transmittance is improved, but binding force between catalyst layer and support is weak
Solution Approach 1:
The electrode uses a composite binder system combining polybenzimidazole/PVDF with silane-modified polyurethane. The silane groups form cross-linked networks that significantly enhance the binding force between the catalyst layer and support, while the polybenzimidazole component maintains high oxygen transmittance necessary for fuel cell operation.
Solution Approach 2:
The invention modifies the chemical structure of the binder by introducing silane groups that can form cross-linked networks. This parameter change in the binder's molecular structure transforms it from a simple adhesive to a cross-linked composite material with enhanced mechanical strength and binding force, while preserving the oxygen transport properties.
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 enables fuel cells to operate stably and efficiently at temperatures from 100 to 300°C under non-humidified conditions with high ionic conductivity and mechanical strength, reducing the risk of flooding and improving overall performance.
Implementation Method 1
an ionic conductor is a substance where ions move when a voltage is applied. Ionic conductors are used as electrochemical devices, such as fuel cells
Implementation Method 2
a proton conductor that exhibits reliable, stable proton conductivity at an operating temperature of 100 to 300° C. under non-humidified conditions
Implementation Method 3
a polymerization product obtained by polymerizing a mixture of a polyurethane based compound and a polyethylene(metha)acrylic acid
Implementation Method 4
which is then impregnated with acid, forming a membrane with enhanced mechanical strength, flexibility, and ionic conductivity
Data Source
AI summary
A proton conductive electrolyte including a polymerized polyurethane, polyethylene(metha)acrylic acid (PEAA), and a cross-linking agent mixture; a method of preparing the same; an electrode including a support and a catalyst layer, the catalyst layer including a supported catalyst and a polymerized mixture of a polyurethane based compound and a polyethylene(metha)acrylic acid; a method of preparing the electrode; and a fuel cell including the proton conductive electrolyte and/or the electrode. The proton conductive electrolyte can be prepared at lower costs than conventionally used polybenzimidazole and NAFION and can be easily formed into a membrane with a controlled thickness by casting. The polymer electrolyte membrane has high mechanical strength, flexibility, and excellent ionic conductivity. The electrode remains stable under high temperature operation, a strong binding force is maintained between the support and the catalyst layer, and the electrode has excellent ionic conductivity. The fuel cell produced using the proton conductive electrolyte and/or the electrode can operate at 100° C. or higher under non-humidified conditions and exhibits an improved performance.