Enhancement of Durability and Performance in Direct Methanol Fuel Cell by A Microporous Layer with Ultra-Small Pores

摘要

In this work, we modified the anode MPL structure design for MEA operated with high MeOH concentration feedstock with an aim to reduce MeOH crossover and, as a consequence, to enhance stability during continuous operation. The results showed that twice reduced voltage decay rate of MEA during continuous operation in constant current mode(3A) compared with commercial GDL-based MEA was done by creating ultra-small(<5 urn) and uniform distributed pores in MPL. Extra-small pore was created by applying high pressure as well as high temperature to MPL during the fabrication process. The enhancement of power density at low temperature (40°C) with lowering MeOH crossover compared with commercial GDL based MEA was also demonstrated. The maximum power density of 105 mW/cm~2 at low temperature(40°C) and 140 mW/cm~2 at high temperature(60°C) under high MeOH concentration feedstock was achieved with ultra-small pores MPL as anode diffusion media. Furthermore, the durability test of DMFC after 1000hr operation demonstrates that the DMFC with extra-small pore MPL as anode diffusion media exhibits very good stability. The voltage decay was smaller than 20% compared with the initial voltage.