Authors: Mei Chen Shengjun Wang Zhiqing Zou Ting Yuan Zhilin Li Daniel L Akins Hui Yang
Publish Date: 2010/09/16
Volume: 40, Issue: 12, Pages: 2117-2124
Abstract
The effect of adding fluorinated Vulcan XC72R into the microporous layer MPL of the cathode in a passive micro direct methanol fuel cell μDMFC has been investigated Upon fluorination with fluoroalkyl silane FAS the surface of XC72R becomes more hydrophobic as indicated by contact angle measurements The performance of the membrane electrode assembly MEA is improved significantly when fluorinated Vulcan XC72R is used in MPL of the cathode The maximum power density of a passive μDMFC reached ca 362 mW cm−2 at room temperature and the constantcurrent discharging test exhibits enhanced stability Also observed is a decreased water transport coefficient α calculated from discharging test attributable to the greater hydrophobicity resulting in higher liquid pressure on the cathode which forces more water to flow back to the anode Additionally AC impedance analysis indicates that the improvement in performance results from the decrease of charge transfer resistance of the cathodic reactionWe would like to thank the National Natural Science Foundation of China 20706056 the National “863” HighTech Research Programs of China 2006AA05Z136 2007AA05Z141 2008AA05Z102 and the 100 People Plan Program and the Knowledge Innovation Engineering of the CAS for support of this work Also DLA thanks the National Science Foundation of the USA for support under Cooperative Agreement HRD0833180
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