Characteristics of hot-pressing condition on the MEAs in a polymer electrolyte fuel cell

  • Seok-Hee Park, Korea Institute of Energy Research, Korea
  • Seong-Kwan Ryu, Korea Institute of Energy Research, Korea
  • Young-Gi Yoon, Korea Institute of Energy Research, Korea
  • Changsoo Kim, Korea Institute of Energy Research, Korea
  • For the preparation of membrane electrode assembly (MEA) by the catalyst coated membrane (CCM) method, the catalyst ink was applied to PET film by continuous type coater using doctor-blade. This is more effective to attach the electrode tightly onto the polymer electrolyte membrane than other conventional methods like spraying, brushing and screen-printing. The catalyst layer was transferred onto the membrane at 140 ºC and various pressures by the decal method to make the CCM. Two gas diffusion layers were placed on the anode and cathode side of the CCM. From the viewpoint of mass transport and water management, applying micro porous layer and/or hydrophobicity to GDL is critical. Surface and cross-sectional views of MEAs were examined by scanning electron microscopy to confirm the thickness and uniformity. Performance of the single cell was evaluated by measuring I-V curves using a fuel cell test station. The results showed that the performance of a cell is significantly influenced by hot-pressing pressure due to the change of porosity and pore size distribution. In case of thin and compressed catalyst layer, it is very important to select proper GDL under various humidifying operation conditions. Electrochemical characteristics of MEAs were investigated by impedance spectroscopy and cyclic voltammeter. Impedance spectroscopy results revealed that the CCM has a smaller contact resistance and charge transfer resistance as compared with conventional methods.