Clean Technology 2009
K.-J. Kim, R. Bernas, G.H. Miley, N. Luo, X. Yang
University of Illinois, US
fuel cell, Borohydride, catalysis, electrode
As part of the development of a portable fuel cell using direct sodium Borohydride fuel, deposition methods of the catalysis on the diffusion layer have been studied. In earlier studies catalyst deposition onto a porous carbon cloth diffusion layer were studied. Undesirable tendency for pore clogging due to sodium metaborate formation in the small pores where the high reaction and low flow rate cause high concentration of this reaction product during the operation is observed. As one alternative, a nickel substrate based diffusion layer with larger pore size is under evaluation. The revision of catalyst deposition method is needed for the application of nickel substrate. We evaluated three diffusion layer materials including open weave carbon cloth, Nickel Micro Fiber felt (NMF), and a nickel foam, and employed a new catalyst deposition to realize maximum uniform surface coverage. The catalyst coated diffusion layers were then tested in a test cell. The results of these initial tests indicating a significant increase in cell power is obtained with nickel foam compared to nickel felt and even more increase compared with carbon cloth substrate. The run time test results of catalysis coated Ni felt-foam and carbon cloth diffusion layers will be presented.