Functionalized Bentonite clay-sPEEK based composite membranes for direct methanol fuel cells

Composite membranes comprising functionalized Bentonite (HSO3-BEN)-sulfonated poly(ether ether ketone) (sPEEK) is fabricated as an alternative polymer electrolyte membrane (PEM) for direct methanol fuel cells (DMFCs). K+-Bentonite is functionalized through silane condensation to introduce organo sulfonic acid groups. Ion-exchange capacity, sorption and proton conductivity for the composite membranes have been investigated. These composite membranes are also characterised for their mechanical and thermal properties. DMFCs employing sPEEK-HSO3-BEN composite membrane delivered peak power density of 140 mW cm−2, while peak power density of 71 mW cm−2 is obtained for the DMFC employing pristine sPEEK membrane at 70 °C. The results show that these composite membranes exhibits lower methanol permeability in comparison to pristine sPEEK membrane.