2004 年 72 巻 2 号 p. 80-83
In direct methanol fuel cells, methanol crossover causes not only a loss of methanol fuel but also a reduction of the open circuit voltage. We have developed a rapid evaluation of methanol crossover through a proton exchange membrane by utilizing a Pt-microdisc electrode. The equipment consisting of a Nation film sandwiched by a pair of PTFE sheets was put into a set of glass cells. The reservoir cell was filled with 0.5 M H2SO4, which contains methanol in various concentrations, and the opposite receiver cell was filled with 20 ml of 0.5 H2SO4, which also included the Pt-microdisc electrode, a counter electrode and a reference electrode. By making contact of the Pt electrode with the membrane, methanol-oxidation current-potential curves were measured to evaluate the crossover. The crossover on the Nation surface was assessed to be 60% of the reservoir methanol concentration. Consequently, the developed equipment quickly and successfully evaluates the methanol crossover.
