1489
Method to Resolve Transport Distance for Oxygen Diffusion in the Land-Channel Geometry of a PEMFC

Wednesday, October 14, 2015: 17:00
211-B (Phoenix Convention Center)
U. N. Shrivastava (Michigan Technological University) and K. Tajiri (Michigan Technological University)
Abstract

Land-channel geometry is known to cause significant current density distribution in the land-channel direction of a PEMFC. Previously, many modeling studies and a few experimental studies have shown significant variation of current density in the land-channel direction such as [1-2]. There are two prime sources of such variation: (1) non-uniform transport distance for gas diffusion from channel to the catalyst layer, and (2) non-uniform transport distance for product water generated at catalyst layer to the channel. Baker et. al. defined a shape factor f (> 1)  that removes anisotropy originated from land-channel geometry and gas diffusion layer (GDL) properties to provide resultant thickness of fh where h is thickness of a GDL [3].

We present a method to evaluate local transport distance in the land-channel geometry of a PEMFC. A segmented cell is developed to measure current density and high frequency resistance distribution in land-channel direction at sub-millimeter resolution of 350 μm. In this study, 1 mm wide land and channel configuration and GDL without microporous layer is used. Limiting current analysis reported in literature [4] is utilized to measure local limiting current at given resolution and then transport resistances were estimated.

  1. H. Ju. J. of Power Sources, 191, 259 (2009).
  2. U.N. Shrivastava, K. Tajiri. J. of Electrochem. Soc., 162, F722 (2015).
  3. D. R. Baker, D. A. Caulk, K. C. Neyerlin, and M. W. Murphy. J. of Electrochem. Soc., 156, B991 (2009).
  4. J. St-Pierre, B. Wetton, G.-S. Kim, and K. Promislow, J. of Electrochem. Soc., 154, B186 (2007).