Fuel Cell Lifespan Extension

Proton exchange membrane fuel cell stack design to improve performance and longevity by controlling moisture and temperature levels inside the stack. The stack has a permeable membrane outside the membrane electrode to allow water molecules to pass through when needed to keep the electrode moist. A water circulation system with a pump and temperature control circulates water around the stack. This allows regulating stack cell temperatures and removing/adding water as needed to prevent dry or flooded cells.

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A self-humidifying fuel cell membrane electrode that allows fuel cells to operate without external humidification systems. The electrode design involves adding hydrophilic substances to the catalyst layer and creating a self-humidifying functional layer between the membrane and catalyst. This improves water management by enhancing back-diffusion of water from the cathode. The hydrophilic substances and functional layer provide more ion channels, active sites, and hydrophilicity for the membrane electrode to better handle water generated during cell operation.

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Membrane electrode assembly for fuel cells that prevents dryness and flooding issues to improve fuel cell performance. The assembly has a water management system that distributes water uniformly across the fuel cell to prevent dryness and flooding failures. It does this by having a water distribution layer between the cathode and proton exchange membrane that collects water from the cathode side and distributes it evenly to the membrane. This prevents dryness at the membrane and also prevents water flooding in the cathode side. This helps maintain optimal moisture levels in the membrane for performance and longevity.

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Membrane electrode assembly for fuel cells with improved water management and reduced humidity requirements. The assembly has electrode catalyst layers on either side of a polymer electrolyte membrane. One of the electrode catalyst layers has a section on the inlet side coated with carbon fibers, ionomer, and catalyst particles. The other section on the outlet side has the same composition without the carbon fiber coating. This configuration promotes water retention on the inlet side and water removal on the outlet side, allowing operation at lower humidity levels compared to conventional electrode structures.

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Improving water management in the cathode catalytic layer of proton exchange membrane fuel cells (PEMFCs) to enhance performance and durability. The technique involves creating a three-layer structure with a hydrophilic-hydrophobic gradient in the cathode catalytic layer. The layers are prepared using catalyst slurries with different sulfonated perfluorosulfonic acid resins having varying water contents. A hydrophilic layer close to the membrane is made with a low EW (equivalent weight) resin, a hydrophobic layer near the gas diffusion layer is made with a high EW resin, and an intermediate layer uses a mixture of resins with varying EW. This gradient helps balance water retention and distribution in the cathode catalytic layer for better fuel cell performance and longevity.

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A perfluorosulfonic acid proton exchange membrane design for fuel cells that improves durability by eliminating gaps between the membrane, catalysts, and diffusion layers. The membrane is sandwiched between matched-size diffusion layers and catalysts without gaps. This prevents membrane dehydration and cracking that can occur when gaps dry out during fuel cell operation. The membrane matches the size of the cathode diffusion layer. The left side connects to multiple anode catalysts and the right side connects to multiple cathode catalysts.

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A proton exchange membrane fuel cell membrane electrode structure and fuel cell design that eliminates the need for external humidifiers by utilizing internal water management. The fuel cell has a membrane electrode assembly with catalyst layers, a proton exchange membrane, and clamping frames. Blank areas are provided between the catalyst layers and frame edges. These areas are called anti-diffusion zones and are devoid of catalyst. This allows water produced by the cathode reaction to migrate into the blank zones instead of back-diffusing into the anode area. The blank zones act as internal humidifiers to maintain sufficient moisture levels in the membrane for operation without external humidifiers.

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Designing gas diffusion layers (GDLs) for hydrogen fuel cells that improve efficiency and stability. The GDLs have a porosity gradient along their length to enable uniform oxygen distribution over the fuel cell cathode catalyst layer. This prevents hotspots, water accumulation, and uneven reactions that reduce fuel cell performance.

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A fuel cell system that suppresses deterioration of the electrolyte membrane by incorporating a humidifier with a moisture permeable membrane containing cerium ions. The cerium-containing membrane is placed in the humidifier to provide humidified fuel cell feed gas. The cerium ions diffuse through the membrane into the electrolyte membrane of the fuel cell to neutralize harmful hydroxyl radicals generated by hydrogen peroxide, preventing electrolyte membrane degradation.

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Proton exchange membrane fuel cell water balance system and control method to maintain optimal water content in the fuel cell for better performance. The system has separate air intakes for anode and cathode. It monitors parameters like hydrogen and air pressure, flow rates, and outlet humidity. By adjusting the air intake humidity based on the anode hydrogen humidity and cathode conditions, it balances water levels and prevents dryness or flooding.

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Fuel cell design to reduce humidification requirements and improve water retention for better performance and durability. The design involves optimizing the contact angle of the fuel cell layers to promote self-humidification. The catalytic layer has a lower contact angle than the gas diffusion layer, and the diffusion layer has a lower contact angle than the polar plate. This gradient distribution improves water retention by making the hydrophilicity of the catalytic layer greater than the diffusion layer, and the diffusion layer greater than the plate. This reduces the need for external humidification equipment and improves fuel cell operation in dry conditions.

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Fuel cell cathode gas diffusion layer with improved water management for higher performance and durability under varying humidity conditions. The layer has three components: a base carbon paper, an intermediate layer made of a mixture of single-walled and multi-walled carbon nanotubes, and a hydrophobic microporous layer. The intermediate layer provides water retention and transmission properties, enabling self-humidification under low humidity and preventing flooding under high humidity. The composition of the intermediate layer is 25-90% single-walled carbon nanotubes and 75-10% multi-walled carbon nanotubes. The overall layer has porosity of 58-70%, aperture sizes of 50 nm to 1 um, and resistivity of 4-20 mΩ·cm.

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Improving the durability and conductivity of fuel cell membranes by adding a nanofiber antioxidant, cerium hydrogen phosphate (CeHPO4), to the membrane. The antioxidant scavenges destructive radicals produced in the fuel cell to protect the membrane without reducing proton conductivity like conventional antioxidants. The nanofiber form provides high dispersibility in the membrane. The membranes with dispersed CeHPO4 show improved proton conductivity and durability in fuel cells.

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Open cathode fuel cell system with self-humidifying proton exchange membrane (PEM) that eliminates the need for external humidifiers. The cell stack has an open cathode design and uses a modified PEM with hygroscopic fillers like carbon nanotubes. The fillers improve water retention in the membrane at low humidity. This allows the fuel cell to operate without external humidification. The fillers also enhance conductivity compared to pure PEM. The open cathode design allows oxygen to flow freely to the cathode without humidification. The cathode flow field is optimized to efficiently distribute oxygen and water to maintain membrane hydration.

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Designing gas diffusion layers (GDLs) for fuel cells that improve efficiency and stability by providing custom porosity gradients. The GDLs have non-uniform porosity along the oxygen flow direction to distribute oxygen evenly over the catalyst layer. This reduces hotspots and water accumulation that can decrease fuel cell efficiency.

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Improving the durability and lifespan of fuel cells by avoiding stack deterioration due to mixed potential and reverse currents when the fuel cell is restarted after being stopped. The fuel cell deterioration avoidance method involves selectively recirculating air and hydrogen, controlling anode hydrogen pressure, and managing cooling water temperature based on diagnostic criteria like open circuit decay time and current distribution deviation. This prevents degradation by avoiding conditions prone to mixed potential and reverse currents when restarting the fuel cell.

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Membrane electrode assembly (MEA) for polymer electrolyte fuel cells that prevents reverse voltage. The MEA has a design where the anode catalyst layer is on the microporous layer (MPL) instead of directly on the polymer electrolyte membrane. An oxygen evolution reaction (OER) catalyst layer is formed on the MPL and anode side. This prevents deactivation of the OER catalyst due to carbon oxidation during reverse voltage operation. The MEA also allows removing carbon from the anode catalyst layer for improved durability and performance stability over time. The OER catalyst layer prevents water electrolysis and carbon oxidation at the interface during reverse voltage.

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Fuel cell system that enhances fuel cell lifetime by controlling hydrogen partial pressure in the cell membrane. The system calculates the optimal target hydrogen partial pressure based on the catalyst location in the membrane. A controller adjusts the gas supply to achieve the target. This reduces chemical degradation of the membrane. The catalyst suppresses hydrogen peroxide formation when hydrogen is over-rich. By limiting hydrogen partial pressure, the catalyst location maximizes the suppression effect.

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Moisture management in fuel cells to improve reliability and reduce size. The membrane electrode assembly has a catalyst-free area before and/or after the active catalyst coated area. This catalyst-free area is designed to absorb moisture from the fuel cell reactions. By concentrating the moisture absorption closer to the individual fuel cell units, it reduces the need for external humidifiers and complex plumbing. The membrane can absorb and distribute moisture internally to maintain optimal humidity for the membrane without relying on external humidifiers.

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An electrode for a polymer electrolyte membrane fuel cell that contains an antioxidant to improve the durability of the fuel cell. The antioxidant is cerium hydrogen phosphate dispersed as nanofibers. Adding this antioxidant to the catalyst layer of the fuel cell electrode helps protect the membrane from chemical degradation during operation. The antioxidant scavenges radicals that can attack and degrade the electrolyte membrane, thereby minimizing performance loss over time.

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