A Methanol Concentration Sensor Using Twin Membrane Electrode Assemblies for Direct Methanol Fuel Cells

• Published in: International journal of electrochemical science Vol. 1; no. 4; pp. 160 - 170
• Main Authors: Sun, Wei, Sun, Gongquan, Yang, Weiqian, Yang, Shaohua, Xin, Qin
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2006; Elsevier
• Subjects: Fuel cell; Membrane electrode assembly (MEA); Methanol concentration; Sensor; Methanol concentration; Membrane electrode assembly (MEA); Fuel cell; Sensor
• ISSN: 1452-3981; 1452-3981
• DOI: 10.1016/S1452-3981(23)17146-X

A methanol concentration sensor based on twin Nafion membrane electrode assemblies(MEAs)wasconstructed with anodes face to face eliminating the interference ofoxygen in environment. The signalof the sensor was obtained by electro-oxidation of themethanol crossing over Nafion membranes fromcathodes. During operation, carbon dioxideas a product of methanol oxidation not only was expelledfrom the gaps between twoMEAs, but also permeated across the membranes into the cathodes, whichwas confirmedbyGC in the outflowing stream of the sensor. Electrochemical characterization showsthat the sensor has good response performance with a concentration range up to 5M andthe signalincreases with temperature elevating. The slightly nonlinearity of the workingcurves was mainlycaused by electro-osmotic effect confirmed by electro-osmotic dragcoefficient. Though logarithmtendency degradation with 0.9% hr-1 was observed fromstability test, the performances in terms ofhigh sensitivity to concentration with widemeasuring range and signal recovery characteristics showthat the sensor is promising for direct methanol fuel cells.