Sulfonated poly(ether ether ketone) (SPEEK) membranes have been deposited on the both sides of a sulfonic acid functionalized graphene oxide (SGO) paper to form a proton exchange membrane (PEM) with a sandwiched structure. The obtained SPEEK/SGO/SPEEK membrane could exhibit proton conductivity close to Nafion (R) 112 and lower methanol permeability. The use of this SPEEK/SGO/SPEEK membrane greatly improves the performance of the semi-passive direct methanol fuel cell (DMFC). The semi-passive DMFC with the SPEEK/SGO/SPEEK membrane is found to be capable of delivering the peak power density 60% higher than that with the commercial Nafion (R) 112. This, along with its comparable durability to Nafion (R) 112, strongly suggests the great promise of using the SPEEK/SGO/SPEEK membrane as the PEM. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.