Electrochemical stability membrane electrode assembly

In the PEFC, the membrane, together with the electrodes, forms the basic electrochemical unit, the membrane electrode assembly (MEA). The first and foremost function of the electrolyte membrane is the transport of protons from anode to cathode. On one hand, the electrodes host the electrochemical reactions within the catalyst layer and provide electronic conductivity, and, on the other hand, they provide pathways for reactant supply to the catalyst and removal of products from the catalyst. The components of the MEA need to be chemically stable for several thousands of hours in the fuel ceU under the prevailing operating and transient conditions. PEFC electrodes are wet-proofed fibrous carbon sheet materials of a few 100 ttm thickness. The functionality of the proton exchange membrane (PEM) extends to requirements of mechanical stability to also ensure effective separation of anode and... 

In general, PFSA membranes are characterized by excellent performance, electrochemical stability, suitable mechanical properties, and allow rapid startup. However, it appears necessary to ameliorate the PFSA membranes and ionomers to improve the operating efficiency of membrane-electrode assemblies of PEM electrolysers at practical current densities useful to reduce capital costs. PESA membranes used in electrochemical devices are essentially based on Nafion however, several alternative PSFA membranes with shorter pendant side chain have been developed by Dow, 3 M, Gore, Asahi Glass, Solvay Specialty Polymers, etc.. 

Hamon, C., Purdy, G., Kim, Y.S., Pivovar, B. and Zelenay, P. (2006) Novel process for improved long-term stability of DMFC membrane-electrode assemblies. Proceedings - Electrochemical Society, vol. P2004-21, pp. 352-362. 

The development of a portable and rugged sensing device requires that the selective recognition element be directly interfaced to the physical transducer. In the case of electrochemical transducers based on artificial BLMs, this entails stabilization of the assembly onto an electrode. The stabilization method must allow the membrane to retain characteristics of molecular mobility and fluidity which are essential for transduction and should provide sufficient ruggedness to permit use over an extended period of time (several months) without severe alteration of the response characteristics of the membrane. 

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