For application in direct methanol fuel cells

a series of SPEEK (sulfonated polyether ether ketone) membranes with different sulfonation degrees were tested

and a novel acid-base composite proton exchange membrane was prepared- SPEEK and chitosan were chosen as acidic and basic polyelectrolytes respectively. The properties of composite membranes

such as proton conductivity

methanol permeability

water uptake

membrane swelling and thermal stability

were tested- Although the proton conductivity reduced to some extent and the methanol permeability wasn’t improved

the water uptake and membrane swelling were significantly improved-Particularly

after chitosan was blended with SPEEK (sulfonation degree=71.4%) at a molar ratio of 1∶5

the prepared composite membrane exhibited comparable performances with Nafion 117

and such membranes are thus promising for application in fuel cells.