Accelerated durability test of DMFC electrodes by electrochemical potential cycling

Durability of direct methanol fuel cell electrodes was evaluated by electrochemical potential cycling and we observed the degradation phenomena during the performance decay. An individual potential measurement of anode and cathode with built-in reversible hydrogen electrode revealed that the anode and cathode performance contributions are almost of the same order of magnitude to the entire performance loss, although the anode degradation is relatively bigger, due to the dominating effect of ruthenium dissolution, corresponding loss of electrocatalytic activity. On the contrary, it was apparent that the electrochemical active surface area of Pt cathode decreased significantly with potential cycling under methanol crossover condition, which is not clearly reflected on the performance loss due to the initial decrease of interfacial resistance between membrane and cathode catalyst layer. Impedance studies could reinforce the current–voltage polarization by more comprehensive information.