Development of a 4-cell air-breathing micro direct methanol fuel cell stack

In this work, we present a 4-cell air-breathing micro direct methanol fuel cell (μDMFC) stack featured with novel n-inlet and n-outlet (NINO) anode flow fields. Compared with the conventional parallel flow field, the NINO flow field with micro structures improves the methanol solution transport efficiency and facilitates the exclusion of CO ₂ gas bubbles accumulated in flow channels. The μDMFC stack patterned with novel NINO flow field is fabricated using silicon-based micro electromechanical system (MEMS) technologies. The polydimethylsiloxane (PDMS) distributors are used not only for the stack packaging but also for the uniform distribution of methanol solution through the connected double-side patterns. Experimental results reveal that the NINO flow fields exhibit higher peak power density than that of the conventional flow field. The NINO structures with different patterns have significant influences not only on the momentum transfer but also on the cell performance. The maximum power output of the μDMFC stack can yield about 80 mW at room temperature, which is significative for portable applications.