A micro methanol fuel cell operating at near room temperature

We present a bipolar micro direct methanol fuel cell (muDMFC) with high-power density and simple device structure. A proton exchange membrane-electrode assembly was integrated in a Si-based muDMFC with micro channels 750 mum wide and 400 mum deep, fabricated using silicon micromachining. The muDMFC has been characterized at near room temperature, showing a maximum power density of 47.2 mW/cm(2) when 1 M methanol was fed at 60 degreesC. The cell voltage dependence on the current density agrees well with the modified Tafel model, in which regimes of kinetic polarization and ohmic polarization are observed without significant presence of the concentration polarization. (C) 2003 American Institute of Physics.