Microfabrication Procedures Applicable to Micro-Fuel Cell Design and Production

The potential of the extremely high energy densities that may be possible with a hydrogenic fuel cell makes it an attractive alternative as a future microsystem power source. Additionally, the potential for integration of such devices could be enhanced if they were manufactured in a manner that is compatible with standard microelectronic and MEMS applications. A combination of silicon micromaching and direct writing was used to produce a microelectronic PEM fuel cell. The fuel cell was fabricated on a silicon wafer containing inter-digitated microchannels which were synthesized using an STS Systems Inc. deep reactive ion etcher. The anode and cathode composite materials were deposited using the MicroPen™. The MicroPen™ system is a fluid dispensing system that is capable of “writing” lines of materials with virtually any viscosity onto a wide range of potential substrates. Final assembly was accomplished by the application of a Nafion™ cover plate. These techniques were successfully employed to produce a working microelectronic fuel cell in silicon. The electrical characterization of the device demonstrated an open circuit voltage of 250 mV with a short circuit of 10 μA measured at room temperature when the cell was provided with hydrogen and oxygen at 1 ATM.