Sulfonated poly(ether ether ketone)/amino-acid functionalized titania hybrid proton conductive membranes

► Amino acid-, amino-, carboxylic- and phenyl-functionalized titania were prepared. ► SPEEK/functionalized titania submicrosphere hybrid membranes were fabricated. ► Amino acid groups served as a “buffer” against the environmental fluctuations. ► Membrane mechanical strength and methanol barriering ability were improved. ► SPEEK/amino acid-titania membrane showed the highest proton conductivity.