An air-breathing silicon-based micro direct methanol fuel cell with a capillary-based water drawn out structure

This paper presents a capillary-based cathode structure for air-breathing micro direct methanol fuel cell (muDMFC). An array of capillaries with hydrophilic surface is designed on the ribs of cathode window to draw out excessive water from the cathode. Microfabrication techniques, including double-side lithography and ICP, are used to fabricate anode and cathode plates of the muDMFC on the same silicon wafer simultaneously. Both muDMFCs, one with capillary-based water drawn out structure and the regular one without, are assembled and characterized. Experimental results show that the muDMFC achieves a power density of 2.35 mW/cm², 10% larger than that of the regular one, of which the power density is about 2.1 mW/cm². The capillary-based water drawn out structure on the cathode draws water out in evidence.