Polybenzimidazoles acid-doped

Savadogo, O. and Xing, B., Hydrogen/oxygen polymer electrolyte membrane fuel cell (PEMFC) based on acid-doped polybenzimidazole (PBI), J. New Mater. Electrochem. Syst., 3, 345, 2000. 

Wainright, J.S. et ah. Acid-doped polybenzimidazoles a new polymer electrolyte, J. 

Samms, S.R., Wasmus, S., and Savinell, R.F., Thermal stability of proton conducting acid doped polybenzimidazole in simulated fuel cell environments, J. Electrochem. Soc., 143, 1225, 1996. 

Li, Q., Hjuler, H.A., and Bjerrum, N.J., Phosphoric acid doped polybenzimidazole membranes physiochemical characterization and fuel cell applications, J. Appl. Electrochem., 31, 773, 2001. 

A. Schechter and R.F. Savinell. Imidazole and 1-methyl imidazole in phosphoric acid doped polybenzimidazole, electrolyte for fuel cells. Solid State Ionics 147, 181-187 2002. 

R.H. He, Q.F. Li, G. Xiao, and N.J. Bjerrum. Proton conductivity of phosphoric acid doped polybenzimidazole and its composites with inorganic proton conductors. Journal of Membrane Science 226, 169-184 2003. 

B.Z. Xing and O. Savadogo. The effect of acid doping on the conductivity of polybenzimidazole (PBI). Journal of New Materials for Electrochemical Systems 2, 95-101 1999. 

J.T. Wang, R.F. Savinell, J. Wainright, M. Lift, and H. Yu. A H-2/0-2 fuel cell using acid doped polybenzimidazole as polymer electrolyte. Electrochimica Acta A, 193-197 1996. 

Wainright JS, Wang JT, Weng D, Savinell RF, Litt M (1995) Acid-doped polybenzimidazoles—a new polymer electrolyte. J Electrochem Soc 142 L121-L123... 

Figure 10.8 Chemical structure of (a) polybenzimidazole (PBI) and (b) phosphoric acid-doped PBI.

To prepare new and inexpensive membranes, various trials have been made 196 sulfonated aromatic polyether membrane such as polyether ketones (PEEK),197 sulfonated polysulfone198 and membranes from sulfonated polyphenylene sulfide,199 phosphoric acid-doped polybenzimidazole, (PBI),200 polybenzimidazole having sulfonic acid groups,201 polybenzimidazole with phosphonic acid groups,202 a blend membrane of polybenzimidazole and sulfonated polysulfone,203 sulfonated phosphazene polymer.204... 

C. Hasiotis, L. Qingfeng, V Deimede, J.K. Kallitsis, C.G. Kontoyannis and N.J. Bjerrum, Development and characterization of acid doped polybenzimidazole/ sulfonated polysulfone bend polymer electrolytes for fuel cells, J. Electmchem. Soc., 2001, 148, A513-A519. 

Figure 17.3.16 Results for oxidation of formic acid (dotted curves) and methanol (solid curves) at a fuel-cell anode (Pt/Ru) with phosphoric-acid-doped polybenzimidazole polymer electrolyte, 170°C. (a) current density and (b) mass signal for CO2 at a scan rate of 1 mV/s. [From M. Weber, J.-T. Wang, S. Wasmus, and R. F. Savinell, J. Electrochem. Soc., 143, L158 (1996), reprinted by permission of the publisher. The Electrochemical Society, Inc.]...

Polybenzimidazole films doped with phosphoric acid have also been investigated for direct methanol fuel cells. These membranes, however, only display the requisite conductivities at high temperatures and have only been demonstrated in vapor feed systems operated at 150-200 C. Thus, although these novel membrane applications have been demonstrated to have decreased methanol permeability in fuel cells, none of the systems have been successful in being applied to low temperature liquid-feed direct methanol fuel cells. 

Normal PEFC operating temperatures using PFSA or polyaryl membranes are in the range of 80 °C with new developments aiming at temperatures up to 120 °C [3, 4]. Higher operating temperatures up to 180 °C can be achieved with phosphoric acid doped polybenzimidazole membranes [5]. 

In the search for PEMs with lower alcohol permeability than Nafion and other perfuorinated membranes, without degradation of the proton conductivity, a number of new polymeric membranes were synthetized and characterized, such as sulfonated polyimides, poly(arylene ether)s, polysulfones, poly(vinyl alcohol), polystyrenes, and acid-doped polybenzimidazoles. A comprehensive discussion of the properties of these alternative membranes is given in Chap. 6, along with those of Nafion and Nafion composites. 

Wang J-T, Wainright JS, Savinell RF, Lilt M (1996) A direct methanol fuel cell using acid-doped polybenzimidazole as polymCT electrolyte. J Appl Electrochem 26 751-756... 

Bouchet R, Siebeit E (1999) Protrai conduction in acid doped polybenzimidazole. Solid State Ion 118 287-299... 

Nores-Pondal FJ, Buera MP, Corti HR (2010) Thermal properties of phosphoric acid-doped polybenzimidazole membranes in water and methanol-water mixtures. J Power Sources 195 6389-6397... 

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