Fuel cells scheme with proton membrane

SCHEME 14.16 Phenol synthesis with in situ generated in a proton-exchange membrane fuel cell Reproduced with permission from Ref. [22]. Copyright (2006) WILEY-VCH Verlag GmbH Co. KGaA, Weinheim). 

Perfluorinated sulfonamide monomers were prepared by DesMarteau. A typical synthetic scheme is given in Fig. 16 [39,40]. The temperature dependency and humidity dependency of proton conductivity of the sulfonamide copolymer with TFE were examined, and the properties were proved to be similar to those of a sulfonic acid type membrane [41-43]. Fuel cell performance was dependent upon membrane thickness and/or lEC, and there do not seem to be large differences depending on the species of the ion-exchange groups. Synthesis of a short side chain type sulfonimide monomer is also reported (see Fig. 17 [44]). 

General scheme of an oxygen-hydrogen fuel cell with a proton membrane electrolyte. 

Poly(2,5-benzimidazole) (ABPBI, see Scheme 7.6) has reeently been reviewed for fuel cell applications [55]. Compared with PBI, higher molecular weight ABPBI was aehieved, resulting in better mechanieal properties. Proton conduetiv-ity of H PO -doped ABPBI membranes ranged from 0.01 to 0.05 S cm above 100°C under dry conditions, and increased with the doping level. 

Kim et al. studied the effect of sulfonated multiwalled carbon nanotubes (s-MWNTs)/SPES composite membranes on the membrane properties, including the proton conductivity, WU, mechanical properties, and methanol for direct methanol fuel cells (DMFCs) [57], The s-MWNTs were prepared by the oxidation of MWNTs with H2SO4 and HNO3, followed by treatment of MWNTs-COOH with SOCI2, and finally the reaction of MWNTs-COCl with aminomethanesulfonic acid (Scheme 4.23). 

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