MEMS-based direct methanol fuel cells and their stacks using a common electrolyte sandwiched by reinforced microcolumn electrodes

We present a MEMS-based portable Direct Methanol Fuel Cell (micro-DFMC), featured by a platinum sputtered microcolumn electrode and a built-in fuel chamber containing a limited amount of methanol fuel. Also presented is a micro-DMFC stack structure having a common electrolyte sandwiched by the microcolumn electrodes. Microcolumn electrode (ME16) generates the power density (3.2 times) higher than the planar electrode (PE16). The increased window frame reduces the normalized standard power deviation (standard deviation over the average power). The normalized deviation of 0.11 in ME4 cell has been reduced to 0.01 in ME16 cell due to the increased window frames. The maximum power density of 4-cell stack is 15.7 times higher than that of the single cell. 4-cell stack produces the power capacity of 20.3 mWh/g during 980 min operation at the voltage of 450 mV with the load resistance of 800/spl Omega/.