Direct methanol fuel cells membranes

Sanicharane S, Bo A, Sompalli B, Gurau B, Smotkin ES. 2002. In-situ 50 °C ETIR spectroscopy of Pt and PtRu direct methanol fuel cell membrane electrode assembly anodes. J Electrochem Soc 149 A554-A557. 

Woo, Y., Oh, S., Kang, Y., Jung, B. (2003). Synthesis and characterization of sulpho-nated polyimide membranes for direct methanol fuel cell. /. Membrane Science 220, 31.45. 

Wu et al. [106] prepared hybrid direct methanol fuel cell membranes by embedding organophosphorylated titania submicrospheres (OPTi) into a CS polymer matrix. The pristine monodispersed titania submicrospheres of controllable particle size are synthesized through a modified sol-gel method and then phosphorylated by amino trimethylene phosphonic acid (ATMP) via chemical adsorption. Compared to pure CS membrane, the hybrid membranes exhibit increased proton conductivity to an acceptable level of 0.01 S/cm for DMFC application and a reduced methanol permeability of 5 xlO cm /s at a 2 M methanol feed. 

Wu, H., Hou, W., Wang, J., Xiao, L., and Jiang, Z. 2010. Preparation and properties of hybrid direct methanol fuel cell membranes by embedding organophosphorylated titania submicrospheres into a chitosan polymer matrix. J. Power Sources 195 4104-4113. 

Wycisk R, Chisholm J, Lee J, Lin J, Pintauro PN (2006) Direct methanol fuel cell membranes from Nafion-polybenzimidazole blends. J Power Sources 163 9-17... 

Tsai JC, Cheng HP, Kuo JF, Huang YH, Chen CY (2009) Blended Nafion/SPEEK direct methanol fuel cell membranes for reduced methanol permeability. J Power Sources 189 958-965... 

The states of methanol in proton exchange membranes are considered to have a significant influence on the permeability of methanol in direct methanol fuel cell membranes [102]. 

Crosslinked sulfonated poly(phenylene sulfide sulfone nitrile) has been prepared for its potential use for direct methanol fuel cell membrane applications [91]. The monomers and the synthesis are shown in Figure 5.9. 

Tang et al. [30] and Guo et al. [31] found that sulfonated poly[bis(3-methylphenoxy)phosphazene] (denoted as SPB3MPP) (Fig. 7b) offered an attractive combination of good proton conductivity, crosslinkability and low methanol permeability features especially important for direct methanol fuel-cell membranes. UV-crosslinked membranes prepared from SPB3MPP of lEC 1.4 mmol/g exhibited a methanol diffusion coefficient on the order of 1.0 X lO cm /s, which was significantly smaller than that in a Nation... 

Jiang, Z. Jiang, Z. Meng, Y. (2011). Optimization and Synthesis of Plasma Polymerized Proton Exchange Membranes for Direct Methanol Fuel Cells. /. Membrane Sci., Vol. 372, pp. 303-313... 

Recent fuel cell membrane research and development (R D) efforts are summarized with a focus on (1) membranes for high-temperature, low-hmnidity PEMFC operation, (2) low-cost alternatives to PFSA membranes, and (3) direct methanol fuel cell membranes. A listing of fuel cell membrane performance data is given in Tables 29.4-29.6 for each membrane subcategory. The review material is by no means exhaustive, but it is representative of the kinds of fuel cell membranes previously/cmrently under investigation. For different viewpoints on the evolutionary development of various fuel cell membranes, the reader is directed to other review articles in the open hterature (Rikukawa and Sanui, 2000 Li et al., 2003 Haile, 2003 Jannasch, 2003 Savadogo, 2004 Hickner et al., 2004 Hogarth et al., 2005 Smitha et al., 2005). 

P. Piboonsatsanasakul, J. Wootthikanokkhan, S. Thanawan, Preparation and characterizations of direct methanol fuel cell membrane from sulfonated polystyrene/ poly(vinylidene fluoride) blend compatibilized with poly(styrene)-b-poly(methyl methacrytlate) block copolymer, J. Appl. Polym. Sci., 107 (2008) 1325-1336. 

Ren, X. Springer, T. E. and Gottesfeld, S. (1998). Direct Methanol Fuel Cell Transport Properties of the Polymer Electrolyte Membrane and Cell Performance. Vol. 98-27. Proc. 2nd International Symposium on Proton Conducting Membrane Euel Cells. Pennington, NJ Electrochemical Society. 

The electrocatalytic oxidation of methanol has been widely investigated for exploitation in the so-called direct methanol fuel cell (DMFC). The most likely type of DMFC to be commercialized in the near future seems to be the polymer electrolyte membrane DMFC using proton exchange membrane, a special form of low-temperature fuel cell based on PEM technology. In this cell, methanol (a liquid fuel available at low cost, easily handled, stored, and transported) is dissolved in an acid electrolyte and burned directly by air to carbon dioxide. The prominence of the DMFCs with respect to safety, simple device fabrication, and low cost has rendered them promising candidates for applications ranging from portable power sources to secondary cells for prospective electric vehicles. Notwithstanding, DMFCs were... 

Mustain WE, Kepler K, Prakash J. 2007. CoPd, oxygen reduction electrocatalysts for polymer electrolyte membrane and direct methanol fuel cells. Electrochim Acta 52 2102-2108. Nagy Z, You H. 2002. Applications of surface X-ray scattering to electrochemistry problems. Electrochim Acta 47 3037-3055. 

Shen M, Roy S, Kuhlmann JW, Scott K, Lovell K, Horsfall JA. 2004. Grafted polymer electrolyte membrane for direct methanol fuel cells. J Memb Sci 251 121-130. 

Wang Y, Li L, Hu L, Zhuang L, Lu J, Xu B. 2003. A feasibility analysis for alkaline membrane direct methanol fuel cell Thermodynamic disadvantages versus kinetic advantages. Electrochem Commun 5 662. 

There are six different types of fuel cells (Table 1.6) (1) alkaline fuel cell (AFC), (2) direct methanol fuel cell (DMFC), (3) molten carbonate fuel cell (MCFC), (4) phosphoric acid fuel cell (PAFC), (5) proton exchange membrane fuel cell (PEMFC), and (6) the solid oxide fuel cell (SOFC). They all differ in applications, operating temperatures, cost, and efficiency. 

Direct methanol fuel cells use sulfuric acid or a polymer membrane as an electrolyte and have an OT of 80 to 130°C. 

This survey focuses on recent developments in catalysts for phosphoric acid fuel cells (PAFC), proton-exchange membrane fuel cells (PEMFC), and the direct methanol fuel cell (DMFC). In PAFC, operating at 160-220°C, orthophosphoric acid is used as the electrolyte, the anode catalyst is Pt and the cathode can be a bimetallic system like Pt/Cr/Co. For this purpose, a bimetallic colloidal precursor of the composition Pt50Co30Cr20 (size 3.8 nm) was prepared by the co-reduction of the corresponding metal salts [184-186], From XRD analysis, the bimetallic particles were found alloyed in an ordered fct-structure. The elecbocatalytic performance in a standard half-cell was compared with an industrial standard catalyst (bimetallic crystallites of 5.7 nm size) manufactured by co-precipitation and subsequent annealing to 900°C. The advantage of the bimetallic colloid catalysts lies in its improved durability, which is essential for PAFC applicabons. After 22 h it was found that the potential had decayed by less than 10 mV [187],... 

In addition to these smaller applications, fuel cells can be used in portable generators, such as those used to provide electricity for portable equipment. Thousands of portable fuel cell systems have been developed and operated worldwide, ranging from 1 watt to 1.5 kilowatts in power. The two primary technologies for portable applications are polymer electrolyte membrane (PEM) and direct methanol fuel cell (DMFC) designs. 

All fuel cells for use in vehicles are based on proton-exchange-membrane fuel cell (PEMFC) technology. The methanol fuel-processor fuel cell (FPFC) vehicle comprises an on-board fuel processor with downstream PEMFC. On-board methanol reforming was a development focus of industry for a number of years until around 2002. Direct-methanol fuel cells (DMFC) are no longer considered for the propulsion of commercial vehicles in the industry (see also Chapter 13). 

Direct-methanol fuel cell Proton- conducting polymer membrane H+ (proton) 80-100... 

Direct-methanol fuel cells (DMFCs) have attracted considerable attention for certain mobile and portable applications, because of their high specific energy density, low poison emissions, easy fuel handling, and miniaturization [129,130], However, the methanol permeation through electrolyte membranes (usually called methanol cross-over) in DMFCs still is one of the critical problems hindering the commercialization [131,132], Nafion , a... 

The effect of annealing temperatures (65 - 250 °C) and blend composition of Nafion 117, solution-cast Nafion , poly(vinyl alcohol) (PVA) and Nafion /PVAblend membranes for application to the direct methanol fuel cell is reported in [148], These authors have found that a Nafion /PVAblend membrane at 5 wt% PVA (annealed at 230 °C) show a similar proton conductivity of that found to Nafion 117, but with a three times lower methanol permeability compared to Nafion 117. They also found that for Nafion /PVA (50 wt% PVA) blend membranes, the methanol permeability decreases by approximately one order of magnitude, whilst the proton conductivity remained relatively constant, with increasing annealing temperature. The Nafion /PVA blend membrane at 5 wt% PVA and 230 °C annealing temperature had a similar proton conductivity, but three times lower methanol permeability compared to unannealed Nafion 117 (benchmark in PEM fuel cells). 

R. X. Liu, and E. S. Smotkin, Array membrane electrode assemblies for high throughput screening of direct methanol fuel cell anode catalysts, J. Electroanal. Chem. 535, 49-55 (2002). 

Scott, K., Taama, W. M. and Argyropoulos, R 2000. Performance of the direct methanol fuel cell with radiation-grafted polymer membranes. Journal of Membrane Science 171 119-130. 

Hatanaka, T., Hasegawa, N., Kamiya, A., Kawasumi, M., Morimoto, Y. and Kawahara, K. 2002. Cell performances of direct methanol fuel cells with grafted membranes. Fuel 81 2173-2176. 

Ren, X., Henderson, W. and Gottesfeld, S. 1997. Electro-osmotic drag of water in ionomeric membranes—New measurements employing a direct methanol fuel cell. Journal of the Electrochemical Society 144 L267-L270. 

Carter, R., Wycisk, R., Yoo, H. and Pintauro, P. N. 2002. Blended polyphosphazene/polyacrylonitrile membranes for direct methanol fuel cells. Electrochemical and Solid-State Letters 5 A195-A197. 

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