Fluorination of Vulcan XC-72R for cathodic microporous layer of passive micro direct methanol fuel cell
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- 作者：Mei Chen ; Shengjun Wang ; Zhiqing Zou ; Ting Yuan ; Zhilin Li ; Daniel L. Akins and Hui Yang
- 关键词：Fluorination ; Cathodic microporous layer ; Membrane electrode assembly ; Passive micro direct methanol fuel cell ; Electrochemical impedance
- 刊名：Journal of Applied Electrochemistry
- 出版年：2010
- 出版时间：December 2010
- 年：2010
- 卷：40
- 期：12
- 页码：2117-2124
- 全文大小：589.1 KB
文摘
The effect of adding fluorinated Vulcan XC-72R into the microporous layer (MPL) of the cathode in a passive micro direct methanol fuel cell (μDMFC) has been investigated. Upon fluorination with fluoro-alkyl silane (FAS), the surface of XC-72R becomes more hydrophobic, as indicated by contact angle measurements. The performance of the membrane electrode assembly (MEA) is improved significantly when fluorinated Vulcan XC-72R is used in MPL of the cathode. The maximum power density of a passive μDMFC reached ca. 36.2 mW cm−2 at room temperature, and the constant-current 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, A.C. impedance analysis indicates that the improvement in performance results from the decrease of charge transfer resistance of the cathodic reaction.