Proton exchange membrane fuel cell impact

Proton exchange membranes (PEMs) are one of the key materials in low-temperature fuel cells proton exchange membrane fuel cells (PEMFCs) and direct methanol fuel cells (DMECs). Especially, recent trend in the research and development of low-temperamre fuel cells focuses on PEMFCs for transportation (electric vehicle) applications due to the impact on economy and environment. The most important role of PEMs is to transport protons formed as a product of oxidation reaction of fuels at the anode to the cathode, where oxygen reduction reaction takes place to produce water. In addition to this, there are a number of requirements for PEM materials for the practical fuel cell applications, which include... 

Angelo, M., Bender, G., Dorn, S. et al. 2008. The impacts of repetitive carbon monoxide poisoning on performance and durability of a proton exchange membrane fuel cell. ECS Trans. 16 669-676. 

This chapter is a review focussed on the development of ionomers based on aromatic polysulfones for their application as Polymer Electrolyte Membrane (PEM) in Proton Exchange Membrane Fuel Cells (PEMFC) or in Direct Methanol Fuel Cells (DMFC). Different types of synthesis routes have been discussed in this chapter in order to obtain ionomers based on polysulfones with variation in structural designs. Special attention is given to the impact of the structural design of the ionomer on various properties such as membrane morphology, thermo-mechanical stability and protonic conductivity of the membranes for their utilization as PEMs. 

Du, B. et al.. Impact of cold start and hot stop on the performance and durability of a proton exchange membrane (PEM) fuel cell, in Extended Abstracts of 2006 Fuel Cell Seminar, Honolulu, HI, November 13-18, 2006, p. 61. 

Halseid et al. [24] have tested the ohmic resistance of the cell while introducing 1 and 10 ppm NH3 into the anode stream. It was foimd that the increase in cell resistance after the cell was exposed to NH3 was about 20% in most cases, and made just 5% (1 ppm) and 15% (10 ppm) contribution to the performance losses. Ton exchange" may provide a reasonable explanation for the quick and severe impact of NH3, i.e., NHj would react with protons in the membrane, thus staying in the membrane and causing the decrease in the protonic conductivity of the membrane. In addition, the water content in the membrane phase decreases linearly with increasing NH4 fraction [22]. For PFSA membrane, dehydration will cause catastrophic consequences to the fuel cell performance. 

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