A novel composite membrane of sulfonated poly(ether ether ketone) (SPEEK) and graphene was prepared and investigated in this paper. The scanning electron microscopy images of the composite membrane revealed the presence and the uniformity dispersion of graphene in the SPEEK matrix. The properties of the obtained composite membrane, including the water uptake, swelling ratio, ion exchange capacity (IEC), area resistance, proton conductivity, VO2+ permeability, ion selectivity, single cell performance, chemical stability and mechanical properties are evaluated in detail, compared to the pristine SPEEK membrane and Nafion 117 membrane. Self-discharge test proved that the composite membrane possessed the longest discharge time (61 h above 0.8V). At 80 mA cm(-2), a higher coulombic and energy efficiency for SPEEK/Graphene membrane was obtained, compared with Nafion 117 (96.4% vs 92.8% and 83.8% vs 79.5% respectively). Furthermore, the SPEEK/Graphene composite membrane exhibited high stability in 500 cycle's long time running. (C) 2014 Elsevier Ltd. All rights reserved.