PDF Publication Title:
Text from PDF Page: 008
Nafion and modified-Nafion membranes for polymer electrolyte fuel cells 291 cell polarization data as a function of varying load cur- rent-density. Figure 7 compares the polarization curves for the Nafion–silica composite and commercial Nafion- 1135 membranes under fully-wet condition (≈ 100%RH) at 60°C under ambient pressure. In all the experiments, the flow rates for both the fuel and the oxidant are fixed so as to preclude any water retention in the cell. Nafion– silica composite membranes with varying silica content show better performance in relation to Nafion mem- branes. The peak power density of 720 mW/cm2 for the PEFC is achieved with Nafion–silica (10 wt.%) compo- site membrane as compared to 550 mW/cm2 for the PEFC with Nafion-1135 membrane under identical operational conditions. Proton conductivity in the Nafion–silica com- posite membrane is attributed to protons that are trans- ferred through hydrogen bonding with water-filled ion pores. However, an excess of silica phase in Nafion matrix reduces the PEFC performance due to electrode flooding in the PEFC. Accordingly, the peak power den- sity for the PEFC with Nafion–silica (15 wt.%) composite membrane is lower in relation to PEFC with Nafion– silica (10 wt.%) composite membrane. Polarization data for PEFCs with Nafion-1135 and Nafion-silica composite membranes under near-dry con- ditions (≤ 18% RH) are shown in figure 8. At these RH values, the humidification of hydrogen gas is inapt to ope- rate PEFCs with pure Nafion membranes as the PEFCs yield a peak power-density of only about 30 mW/cm2 at 100 mA/cm2 primarily due to the poor conductivity of the Nafion membrane. By contrast, under identical condi- tions, PEFCs employing Nafion-silica composite mem- branes perform much better in relation to those with pristine-Nafion membranes. The performance of PEFCs with Nafion–silica composite membranes increases gradu- ally with increasing silica content in the Nafion matrix. A peak power-density of 300 mW/cm2 is achieved at Figure 7. Performance of H2/O2 PEFC with Nafion-1135 and Nafion–silica composite membranes at 100% RH under atmos- pheric pressure operating at 60°C. 1200 mA/cm2 for the PEFC employing a Nafion–silica composite membrane with 15 wt.% silica while operating at 60°C under atmospheric pressure. It is, therefore, quite obvious that PEFC performance is purely related to water-management. In commercial Nafion membranes, the limited availability of water at the anode, electroos- motic drag of water from anode to cathode and insufficient water back-diffusion from cathode to anode cause the membrane to dehydrate. The membrane dehydration is manifested with an increase in ohmic resistance of the cell leading to decreased cell performance. By contrast, in the case of composite Nafion membranes, due to water reten- tion characteristics of the silica, such a problem is obviated. 3.3 Nafion–mesoporous zirconium phosphate composite membranes as electrolytes for PEFCs Synthesis of mesoporous zirconium phosphate (MZP) by co-assembly of a tri-block copolymer, viz. pluronic-F127, as a structure directing agent and a mixture of zirconium butoxide and phosphorous trichloride as inorganic pre- cursors has been recently reported (Sahu et al 2009). Nafion–MZP composite membrane is obtained by em- ploying MZP as surface-functionalized solid-super-acid- proton-conducting medium as well as inorganic filler with high affinity to absorb water and fast proton-transport across the electrolyte membrane even under low relative humidity conditions. The presence of large pores and high internal-surface-area ameliorates the hydrophilic character of the internal pore-surfaces and results in a solid super-acid exhibiting fast proton-conduction. MZP, thus synthesized, is impregnated with the Nafion ionomer to realize a proton-conducting composite membrane. Figure 9 shows the FTIR spectra for the calcined zirconium phosphate with a strong sharp band centred at Figure 8. Performance of H2/O2 PEFC with Nafion-1135 and Nafion–silica composite membranes at 18% RH under atmo- spheric pressure operating at 60°C.PDF Image | Nafion and modified-Nafion membranes for polymer fuel cells
PDF Search Title:
Nafion and modified-Nafion membranes for polymer fuel cellsOriginal File Name Searched:
285.pdfDIY PDF Search: Google It | Yahoo | Bing
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
IT XR Project Redstone NFT Available for Sale: NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Be part of the future with this NFT. Can be bought and sold but only one design NFT exists. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Turbine IT XR Project Redstone Design: NFT for sale... NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Includes all rights to this turbine design, including license for Fluid Handling Block I and II for the turbine assembly and housing. The NFT includes the blueprints (cad/cam), revenue streams, and all future development of the IT XR Project Redstone... More Info
Infinity Turbine ROT Radial Outflow Turbine 24 Design and Worldwide Rights: NFT for sale... NFT for the ROT 24 energy turbine. Be part of the future with this NFT. This design can be bought and sold but only one design NFT exists. You may manufacture the unit, or get the revenues from its sale from Infinity Turbine. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Supercritical CO2 10 Liter Extractor Design and Worldwide Rights: The Infinity Supercritical 10L CO2 extractor is for botanical oil extraction, which is rich in terpenes and can produce shelf ready full spectrum oil. With over 5 years of development, this industry leader mature extractor machine has been sold since 2015 and is part of many profitable businesses. The process can also be used for electrowinning, e-waste recycling, and lithium battery recycling, gold mining electronic wastes, precious metals. CO2 can also be used in a reverse fuel cell with nafion to make a gas-to-liquids fuel, such as methanol, ethanol and butanol or ethylene. Supercritical CO2 has also been used for treating nafion to make it more effective catalyst. This NFT is for the purchase of worldwide rights which includes the design. More Info
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
Infinity Turbine Products: Special for this month, any plans are $10,000 for complete Cad/Cam blueprints. License is for one build. Try before you buy a production license. May pay by Bitcoin or other Crypto. Products Page... More Info
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)