Microstructured membrane electrode assembly for direct methanol fuel cell

The concept of microstructured membrane electrode assembly for direct methanol fuel cell featuring a double-catalyst layer and micropatterned interface between the membrane and the catalyst layer was suggested and realized in this work. The doublecatalyst layer, which consists of a dense first layer and a porous second layer, was designed to achieve effective mass transfer in the catalyst layer. The micropatterned interface was generated by forming a micropattern on the membrane surface prior to catalyst coating on the membrane. The introduction of the double-catalyst layer resulted in a power density increase of 18%, and the generation of the micropatterned interface caused an additional power density increase of 23% at 50 C and 0.4 V. The I-V polarization and impedance analysis indicates that mass transfer in the catalyst layer was significantly improved owing to the large pores in the second catalyst layer. The micropatterned interface did not influence the cathode reaction rate; however, it caused a profound increase of the anode reaction rate. (c) 2007 The Electrochemical Society.