Supercritical carbon dioxide treated Nafion 212 commercial membranes for direct methanol fuel cells

Supercritical carbon dioxide (Sc-CO₂) thermal treatment to enhance performance of Nafion 212 (NR212) commercial membranes for direct methanol fuel cells (DMFCs) is described. It is shown that the microstructure of NR212 membranes is re-organized after the Sc-CO₂ treatment, and then the performance of NR212 membranes is improved. Specifically the thinner NR212 membranes after the Sc-CO₂ treatments have higher proton conductivity and better capacity of barrier to methanol crossover compared with the thicker Nafion 117 membranes. It is demonstrated that the DMFC performance of the Sc-CO₂ treated NR212 membranes is better than that of Nafion 117 membranes.