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Pore formers

Schwarz G and Savko P 1982 Structural and dipolar properties of the voltage-dependent pore former alamthicin in octanol/dioxane Biophys. J. 39 211-19... [Pg.2847]

The preparation and properties of a novel, commercially viable Li-ion battery based on a gel electrolyte has recently been disclosed by Bellcore (USA) [124]. The technology has, to date, been licensed to six companies and full commercial production is imminent. The polymer membrane is a copolymer based on PVdF copolymerized with hexafluoropropylene (HFP). HFP helps to decrease the crystallinity of the PVdF component, enhancing its ability to absorb liquid. Optimizing the liquid absorption ability, mechanical strength, and processability requires optimized amorphous/crystalline-phase distribution. The PVdF-HFP membrane can absorb plasticizer up to 200 percent of its original volume, especially when a pore former (fumed silica) is added. The liquid electrolyte is typically a solution of LiPF6 in 2 1 ethylene carbonate dimethyl car-... [Pg.517]

The microstructure, properties, and performance of Ni-YSZ anodes depend sensitively on the microscopic characteristics of the raw materials (e.g., particles size and morphology of NiO and YSZ powders). The particle sizes of the starting YSZ powders vary usually from 0.2 to 0.3 pm, whereas those for the NiO powders are 1 pm. The Ni to YSZ volume ratio usually varies from 35 65 to 55 45. For example, the reported Ni to YSZ volume ratios include 34 66 [20, 21], 40 60 [24], 43 57 [22], and 55 45 [23], For a bilayer anode, the functional anode layer in contact with the electrolyte contains 45 to 50 vol% Ni, whereas the anode support layer has 35 to 40 vol% Ni [25, 26], A pore former is usually added to tailor the shrinkage (for the cofiring) and to achieve sufficient porosity (>30 vol%) in the anode or the anode support layer. [Pg.76]

FIGURE 2.6 Fracture strength of Ni-YSZ cermets as a function of porosity. Standard deviation is superimposed on each average value. The starting NiO and YSZ particle sizes for FF1-13 and FF2-13 are both 0.8 pm, for FC1-13 and FC2-40 they are 0.8 and 6 pm, for CF1-13, CF2-13, and CF2-40 they are 8 and 0.8 pm. The suffixes 13 and 40 represent the volume fraction of carbon black pore former added. (From Yu, J.H. et al., J. Power Sources, 163 926-932, 2007. Copyright by Elsevier, reproduced with permission.)... [Pg.83]

The influence of porosity on the electrochemical activity has not been studied much for electrolyte-supported cells because anode pastes for electrolyte-supported cells are made for screen printing, and thus contain significant amounts of organics, which almost guarantees sufficient porosity. In addition, since the anode thickness for electrolyte-supported cells is only on the order of 50 pm, the concentration polarization itself becomes much less of an issue. In fact, Jiang et al. [44] showed that anode overpotential for cermet anodes prepared with extra graphite pore formers... [Pg.98]

For anode-supported cells, the addition of pore former is a must, especially when fine starting materials are used. It was found that the anode porosity is very low when the starting materials are very fine. For example, Huebner et al. [31] found... [Pg.99]

FIGURE 2.21 Change of anode overpotential versus anode thickness for anodes made with and without 20 wt% graphite as pore former in electrolyte-supported cells. (From Jiang, S.P. et al., Solid State Ionics, 132 1-14, 2000. Copyright by Elsevier, reproduced with permission.)... [Pg.100]

FIGURE 2.22 (a) Impedance spectra for symmetrical cells prepared without (square) and with (circle) 40 vol% corn starch as pore former in 3% H20/H2 at 850°C. (From Primdahl, S. et al., Proceedings of the Sixth International Symposium on Solid Oxide Fuel Cells, 99(19) 793-802, 1999. Reproduced by permission of ECS-The Electrochemical Society.) (b) Influence of anode support porosity on the performance of cells at 800°C. (From Zhao, F. and Virkar, A.V., J. Power Sources, 141 79-95, 2005. Copyright by Elsevier, reproduced with permission.)... [Pg.102]

The presence of a small amount of water vapor (up to pH20/pH2 = -0.03) in fuel reduces anode overpotential. For anode-supported cells, the use of pore formers is important to tailor the shrinkage during cofiring and to create adequate porosity for better performance. The difference in cell power output could differ by as much as 100% for cells as porosity changes from -30 to -50%. [Pg.121]

The introduction of such a layer can dramatically improve the fuel cell performance. For example, in the SOFC with bilayered anode shown in Figure 6.4, the area-specific polarization resistance for a full cell was reduced to 0.48 Hem2 at 800°C from a value of 1.07 Qcm2 with no anode functional layer [24], Use of an immiscible metal oxide phase (Sn()2) as a sacrificial pore former phase has also been demonstrated as a method to introduce different amounts of porosity in a bilayered anode support, and high electrochemical performance was reported for a cell produced from that anode support (0.54 W/cm2 at 650°C) [25], Use of a separate CFL and current collector layer to improve cathode performance has also been frequently reported (see for example reference [23]). [Pg.248]

Combustion CVD (CCVD) has also been developed and employed in the deposition of functionally and porosity graded LSM-GDC/LSM-LSC-GDC/LSC-GDC cathodes on a YSZ electrolyte with a NiO-GDC anode also deposited by CCVD. Reasonable performances of 0.48 W/cm2 peak power density and 0.11 Qcm2 electrode RP at 800°C were recorded for the cell [101]. CCVD has also been utilized to deposit anode layers with Sn02 as a sacrificial pore former layer [25] and to deposit an SSC-SDC cathode layer, resulting in a low RP of 0.195 Qcm2 at 600°C at OCV [102],... [Pg.265]

Unfortunately, cell performance is not proportional to catalyst layer porosity. In order to achieve maximum fuel cell performance, the CL should have an optimal porosity [24]. With higher catalyst layer porosity, the mass transfer rate increases, while the electron and proton transport rates decrease. Gamburzev and Appleby [25] documented fuel cell performance with pore formers in the CL and found that optimum pore-former content was about 33%. [Pg.69]

Zhao, J., He, X., Wang, L., Tian, J., Wan, C., and Jiang, C. Addition of NH4HCO3 as pore-former in membrane electrode assembly for PEMFC. International Journal... [Pg.105]

A similar study was performed by Jian-hua et al. [137], who used (NH4)2S04 as the pore former due to its high solubility in water. After fuel cell testing was performed, it was observed that the pore former improved the performance of the cell at higher current densities (>0.9 A cm" ), indicating that control of the pore distribution in the MPL and DL was critical to enhancing the efficiency of the fuel cell system. [Pg.244]

In the hydrated ionomer membrane, liquid-like water acts as the pore former, pore filler, and proton shuffle. The wafer disfribufion and the random network morphology of aqueous pafhways determine proton conduction at... [Pg.350]

The shape of the pores in the porous oxide matrix can be controlled quite effectively through the shape of the pore formers that are used. Figure 13 shows... [Pg.617]

Sustained release coating materials with degradable domains (pore formers)... [Pg.158]

Epoxides can co-polymerize with CO2 to give aliphatic polycarbonates. The co-polymerization is one of the most promising methods to utilize GO2 as a Cl feedstock. The product polycarbonates have many potential applications because of their unique properties. For example, poly(propylene carbonate) (PPG) decomposes completely at 300 °G in any environment to leave a very small amount of ash. This feature makes it applicable to pore former for mesoporous carbon composites. Poly(cyclohexene carbonate) (PGG) has glass-transition temperature (Tg) of 115°G, higher than 35-40 °G of PPG, endowing the materials with properties very similar to polystyrene. ... [Pg.609]

Brogden, K. A. (2005). Antimicrobial peptides Pore formers or metabolic inhibitors in bacteria Nat. Rev. Microbiol. 3, 238-250. [Pg.245]


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See also in sourсe #XX -- [ Pg.116 , Pg.121 ]

See also in sourсe #XX -- [ Pg.469 ]

See also in sourсe #XX -- [ Pg.137 ]




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Former

Poly Pore-former

Synthetic pore formers

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