Polymer electrolyte membrane dimensionality

Jiao K, Li X (2009) Three-dimensional multiphase modeling of cold start processes in polymer electrolyte membrane fuel cells. Electrochim Acta 54 6876-6891 Bar-On I, Kirchain R, Roth R (2002) Technical cost analysis for PEM fuel cells. J Power Sources 109 71-75... 

Coupled Proton and Water Transport in Polymer Electrolyte Membranes 137 Table 4.1 Non-dimensional quantities and associated reference values. 

Chang, P., Kim, G.S., Promislow, K., and Wetton, B. (2007) Reduced dimensional computational models of polymer electrolyte membrane fuel cell stacks. 

Polymers are nsed in fnel cells. Those of particular interest are the polymer electrolyte membrane (PEM) and the phosphoric acid fuel cell (PAFC) designs. The latter design contains the liquid phosphoric acid in a Teflon bonded silicon carbide matrix. In March 2005 Ticona reported that it had bnilt the first fnel cell prototype made solely with engineering thermoplastics. They claimed that this approach rednced the cost of the fuel by at least 50% when compared with fuel cells fabricated from other materials. The 17-cell unit contains injection moulded bipolar plates of Vectra liquid crystal polymer and end plates of Fortron polyphenylene sulfide (PPS). These two materials remain dimensionally stable at temperatures up to 200 "C. The Vectra LCP bipolar plates contain 85% powdered carbon and are made in a cycle time of 30 seconds. 

Interfacial failure during DMFC operation seems to be closely related to water swelling of the ionomer. Typically, the dimensional change of the polymer electrolyte membrane (PEM) under hydration is greater than that of the electrode. As a result, mechanical stress at the membrane-electrode interface is likely to initiate local delamination, which then expands further over the time of DMFC operation. Good correlation between membrane water uptake and the gain in cell resistance was demonstrated (Kim and Pivovar 2005). 

G. Inoue, Y. Matsukuma, and M. Minemoto. Evaluation of the thickness of membrane and gas diffusion layer with simplified two-dimensional reaction and flow analysis of polymer electrolyte fuel cell. Journal of Power Sources 154... 

Futerko, P., Hsing, I-M. (2000). Two-dimensional finite-element method study of the resistance of membranes in polymer electrolyte fuel cells. Electrochimica Acta 45,... 

Exciting research is underway to improve the performance and longevity of batteries, fuel cells, and solar cells. Much of this research is directed at enhancing the chemistry in these systems through the use of polymer electrolytes, nanoparticle catalysts, and various membrane supports. Additionally, considerable effort is being put into the construction of three-dimensional microbatteries, see also Electrochemistry AIaterials Science Solar Cells. 

Novel MEEP-type polyphosphazene-silicate hybrid network membranes (Tg —38 to 67 °C), exhibiting high ionic conductivities with lithium bis(trifluoromethane-sulfonyl)imide (LiTFSI) as the salt, have been prepared as candidates for dimensionally stable solid polymer electrolytes by a designed sequence of steps starting from [NPCl2] and involving the incorporation and hydrolysis of triethoxysilane groups (Scheme 15). ... 

---