(444f) Nanoimprinted Electrodes for Micro Fuel Cell Applications

Fuel cells are an attractive alternative to batteries for portable electronic devices. Micro-fuel cells produced using micro- or nanofabrication methods hold promise for being highly efficient and low cost. Most micro-fuel cells include micromachined fuel cell components combined with conventional macro MEAs (membrane electrode assemblies) [1-3]. Previous work has demonstrated the possibility of a completely microfabricated micro-fuel cell [4, 5]. Promising results have been reported for catalyst structures produced via the electrodeposition of Pt and Pd [6]. In an effort to improve the performance of the electrode thin films, this paper describes the use of nanoimprint technologies to fabricate electrodes with increased active surface areas. Nanoimprint is an emerging lithographic technology that has applications for high-throughput patterning of nanostructures. Based on the mechanical embossing principle, the nanoimprint technique can achieve pattern resolutions beyond the limitations set by the light diffraction or beam scattering in other conventional techniques [7-8]. Figure 1 is a representative example of a Pt nanoimprinted catalyst layer printed on top of a current collector electrode which has triangular vias (via dimensions: base 4.3 µm, height 3.74 µm). The width and pitch of the nanoimprinted layers illustrated were 469 nm and 256 nm respectively. These and other catalyst structures were characterized electrochemically using cyclic voltammetry in a half cell three electrode setup in a 0.5 M H2SO4 vs. Ag/AgCl reference electrode. We will present the results of our study including preparation and material selection.

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