The morphology effect on the selectivity of SPEEK/ENR membranes for direct methanol fuel cell

The objective of this study is to investigate the morphology effect of ENR-50 content on the conductivity and methanol permeability of SPEEK/ENR-50 membranes for DMFC application. Three different ratios (9.5:0.5, 8.5:1.5 and 7.5:2.5) of blended SPEEK/ENR-50 membranes were prepared via solution intercalation method. The cross sectional images of the all SPEEK/ENR-50 membranes studied by SEM shows an existence of ENR-50 droplets in SPEEK matrix which decrease in size with an increasing of ENR-50 content from 1.5 wt% to 2.5 wt%. The study of the performances of the blended membranes shows that the proton conductivity and methanol permeability of the membranes decrease with an increasing of ENR-50 content. However, the proton conductivity of the blended membrane with 0.5 wt% ENR-50 content (9.66×10-3 S cm-1) proven higher than pristine SPEEK but lower than Nafion 117. The barrier performance of all SPEEK/ENR-50 membranes was enhanced compared to the expensive Nafion 117 membrane and pristine SPEEK. Consequently, by incorporating ENR-50 content into SPEEK membrane, the selectivity of the membranes has considerably increased