Monolithically Integrated Gas Distribution Chamber for Silicon MEMS Fuel Cells

This paper presents a gas distribution chamber for a silicon polymer-electrolyte-membrane fuel cell. The silicon structure contains the mechanical support, gas distribution channels, and hydrogen diffusion layer, all built from the same substrate. An identical structure can be used for the oxygen or air side, in case of forced circulation. The novel fabrication process has been designed for integrability of the different parts and low cost and is based on standard microfabrication techniques. The main advantages of the present design are the monolithic structure, the inclusion of patterned paths for the hydrogen flow, and the creation of solid pillars for the support of the membrane. Experimental results of the usage of the chamber as part of a fuel cell are shown, comparing different designs for the hydrogen path inside the distribution chamber. For the design with a patterned path for hydrogen, a power density of 30 $\hbox{mW/cm}^{2}$ for 4 mL/min of hydrogen flow was measured, whereas in the design without the patterned path, the measured power density was only 15 $\hbox{mW/cm}^{2}$.$\hfill$ [2009-0178]