Carbon Nanotube Thin Film based Fuel Cell to Reach DOE Targets

R. Palanisamy, M.E. Itkis, E. Bekyarova, R.C. Haddon
Carbon Solutions Inc, US

Keywords: fuel cell, catalyst support, SWNTs, thin film, gas diffusion electrode

Summary:

We demonstrate a prototype polymer electrolyte membrane fuel cell (PEMFC) that reaches the technical targets set by DOE for 2015. We show that the Pt required for automotive fuel cells can be reduced by an order of magnitude by utilizing the Pt supported on a thin film of single walled carbon nanotubes (SWNTs). By optimizing the spatial distribution of Pt nano-particles in the catalyst support layer (CSL) we are able to pack more Pt in the active region and reach high power output (1 W/sq.cm) with high mass activity (0.54 A/mgPt). The mass activity of Pt depends on the formation of an efficient triple phase interface for electrons, protons and the reactant gas. Toward this direction we have shown that thin films of carbon nanotubes with ultralow Pt show better Pt mass activity compared to thick commercial carbon black CSL. In order to maintain the efficient triple phase interface it is essential to optimize both the thickness of CSL and the required Pt loading. Here we show that with the optimum thickness and Pt loading, a SWNT-CSL with an efficient triple phase interface is able to realize high power output and high Pt mass activity.