Effect of Nafion ionomer and catalyst in cathode layers for the direct formic acid fuel cell with complex capacitance analysis on the ionic resistance

Sunhyung Kim, Jonghee Han, Yongchai Kwon, Kug Seung Lee, Tae Hoon Lim, Suk Woo Nam, Jong Hyun Jang

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

Using platinum (Pt) black and carbon-supported Pt (Pt/C) as cathode catalysts, membrane-electrode assemblies (MEAs) were fabricated with various Nafion ionomer content, and their direct formic acid fuel cell (DFAFC) performances were investigated. In MEAs incorporating Pt black catalysts, the current density at 0.6 V was highest at ionomer/catalyst volume ratio of 1.0, which was consistent with the electrochemical active area (EAS) variation measured by cyclic voltammetry. However, the current density measured at 0.3 V, the cell performance increased with Nafion ionomer content, especially at low ionomer loading, indicating that proton transport rate played an important role. The variation in ionic resistance (Rion) of cathode layers with Nafion ionomer content was experimentally confirmed by using the complex capacitance analysis of impedance data implemented with nitrogen (cathodes)/hydrogen (anodes) atmosphere. For Pt/C, the layer thickness and EAS of cathode were larger than those of MEA cathode using Pt black; and the current densities at 0.6 V were lower than those of Pt black, suggesting that smaller fraction of EAS was utilized.

Original languageEnglish
Pages (from-to)7984-7990
Number of pages7
JournalElectrochimica Acta
Volume56
Issue number23
DOIs
Publication statusPublished - 2011 Sep 30

Keywords

  • Complex capacitance analysis
  • Direct formic acid fuel cells
  • Impedance spectroscopy
  • Ionic resistance
  • Platinum catalyst

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Electrochemistry

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