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.

► Supercritical carbon dioxide treatment was used to enhance performance of NR212. ► The microstructure of NR212 membranes was reorganized after the Sc-CO2 treatment. ► The treated NR212 membranes showed higher proton conductivity than Nafion 117. ► The treated NR212 membranes showed lower methanol permeability than Nafion 117. ► DMFC performance of the treated NR212 membranes was better than Nafion 117.