Effect of Impurity on Direct Methanol Fuel Cell (DMFC) Discontinuous Operation Performance

Effect of impurity on direct methanol fuel cell (DMFC) performance was investigated using single cell under discontinuous operation with constant current mode. Ethanol and Na+ were selected as candidate organic compound and inorganic ion for impurities of methanol, respectively. In the case of the fuel including ethanol, rapid cell voltage drop was observed in the early period in each repetitive run. However, after the rapid cell voltage drop, cell voltage behavior approached to that with reference fuel in each repetitive run, and accumulation of adverse effect with repetition of the run was scarce. Rapid cell voltage drop was approximately proportional to the logarithm of concentration of ethanol. In the case of the fuel including Na+, even though the rapid cell voltage drop was not observed, an adverse effect accumulated with repetition of the run and the decrease of cell voltage gradually increased with repetition of the run.