Proton exchange membrane fuel cell functions

Proton Exchange Membrane Fuel Cells (PEMFCs) are being considered as a potential alternative energy conversion device for mobile power applications. Since the electrolyte of a PEM fuel cell can function at low temperatures (typically at 80 °C), PEMFCs are unique from the other commercially viable types of fuel cells. Moreover, the electrolyte membrane and other cell components can be manufactured very thin, allowing for high power production to be achieved within a small volume of space. Thus, the combination of small size and fast start-up makes PEMFCs an excellent candidate for use in mobile power applications, such as laptop computers, cell phones, and automobiles. 

Fang, B., et al., High Pt loading on functionalized multiwall carbon nanotubes as a highly efficient cathode electrocatalyst for proton exchange membrane fuel cells. Journal of Materials Chemistry, 2011. 21(22) p. 8066-8073. 

A. M. Kannan, L. Cindrella, and L. Munukutla. Functionally graded nanopo-rous gas diffusion layer for proton exchange membrane fuel cells under low relative humidity conditions. Electrochimica Acta 53 (2008) 2416-2422. 

P P Po PCHE PCR PCS PDF PDMS Pe PEM PEMFC PET pH Power output Pressure Pressure drop of one SAR step Printed circuit heat-exchanger Printed circuit reactor Process control system Probability density function Poly-dimethylsiloxane Peclet-number Proton exchange membrane Proton exchange membrane fuel cell Poly-ethylene terephthalate Potentia Hydrogenii (measure for acid and base strength)... 

Baker R (2008) Substituted iron phthalocyanines electrocatalytic activity towards 02 reduction in a proton exchange membrane fuel cell cathode environment as a function of temperature. M.A.Sc. diss. The University of British Columbia, Canada... 

Figure 6.16. Impedance plots as a function of pore-former content in the GDL of a H2/02 single cell at a voltage of a 0.7 V and b 0.4 V. (0) 0 mg/cm2, (o) 3 mg/cm2, ( ) 5 mg/cm2, (A) 7 mg/cm2, and (V) 10 mg/cm2 [15]. (Reprinted from Journal of Power Sources, 108(1— 2), Kong CS, Kim DY, Lee HK, Shul YG, Lee TH. Influence of pore-size distribution of diffusion layer on mass-transport problems of proton exchange membrane fuel cells, 185-91, 2002, with permission from Elsevier and the authors.)...

The membranes in polymeric proton-exchange membrane fuel cells (PEMFC) serve as a solid electrolyte. The membrane s conductivity comes about because in the presence of water it swells, a process leading to the dissociation of the acidic functional groups and formation of protons free to move about throughout the membrane. 

So SY, Yoon YJ, Kim TH, Yoon K, Hong YT. Sulfonated poly(arylene ether sulfone)/functionalized silicate hybrid proton conductors for high-temperature proton exchange membrane fuel cells. J Membr Sci 2011 381(l-2) 204-10. 

Hemandez-Femandez P, Montiel M, Ocon P, de la Fuente JLG, Garcia-Rodriguez S, Rojas S, Fierro JLG (2010) Functionalization of multi-walled carbon nanotubes and application as a support for electrocatalysts in proton-exchange membrane fuel cell. Appl Catal B 99... 

Saha MS, Kundu A (2010) Functionalizing carbon nanotubes for proton exchange membrane fuel cells electrode. J Power Sourc 195(19) 6255-6261... 

So as it can not be considered to provide a fuel cell functioning at higher temperatures than 80 or even 100°C for the user s safety, the choice in the type of fuel cell to use in portable devices is limited to low temperature fuel cells such as PEMFC (for Proton Exchange Membrane Fuel Cell or sometimes Polymer Electrolyte Membrane Fuel Cell) and DMFC (for Direct Methanol Fuel Cell). 

Carbon-supported metal nanoparticles are often employed as electrocatalysts in low-temperature, proton-exchange membrane, fuel cells. In the Southampton group, in-situ XRD has been used as a probe for both the composition and particle size as a function... 

Carbon nanotubes (CNTs) have been added to a polymeric matrix to improve their mechanical and other properties [69]. The use of CNTs in PEM must be carried out with caution because the well-known high electrical conductivity may cause short circuiting in proton exchange membrane fuel cells. The jt-n interaction between PBI and the side walls of CNT makes these two different materials compatible. Despite CNT-PBI composite membranes have shown enhancement in mechanical strength, the proton conductivity resulted in some cases compromised [70, 71]. Hence, different authors functionalized the CNTS in order to increase both the proton conductivity and the mechanical properties for hydrogen fed PBI-based HT-PEMFC [72, 73]. In this context,... 

Suryani, Chang C-M, Liu Y-L et al (2011) Polybtmzi-midazole membranes modified with polyelectrolyte-functionalized multiwalled carlxm nanotubes for proton exchange membrane fuel cells. J Mater Chem 21 7480-7486... 

Xue C, Zou J, Sun Z et al (2014) Graphite oxide/ functionalized graphene oxide and polybenzimidazole composite membranes for high temperature proton exchange membrane fuel cells. Int J Hydrogen Eneigy 39 7931-7939... 

FIGURE 8.30 CO surface coverage of the Ft catalyst for 2% CO and 5% CO mixed with hydrogen as a function of temperature. (Reprinted from Journal of Power Sources, 193, Das, S. K., Reis, A., and Berry, K. J., Experimental evaluation of CO poisoning on the performance of a high temperature proton exchange membrane fuel cell, 691-698, Copyright (2009), with permission from Elsevier.)... 

In this present section, statistical information based on two-point and linear path correlation functions, obtained from 2D micrographs of real catalyst layers (CL) of proton exchange membrane fuel cells (PEMFC), is used as initial information for the reconstruction of CL structures. As will be seen, with this information, stochastic replicas of CLs 3D pore networks at two scales can be built (Barbosa et ah, 2011b). Once statistical information is available from real samples, this can be used for a scaling strategy in order to determine the effective transport coefficients. In past sections statistical information was determined from reconstructed structures rather than from real samples. 

Suryani, C.M., Chang, Y.N., Lai, J.Y, and Liu, YL. (2012) Polybenzimidazole (PBl)-functionalized silica nanoparticles modified PBl nanocomposite membranes for proton exchange membrane fuel cells, J. Membr. Sci., 403-404, 1-7. 

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