Sulfonated poly(arylene ether ketone) (SPAEK) block copolymers were synthesized through nucleophilic aromatic substitution polymerization. Compared with a Nation (NRE-212), state-of-the-art proton conducting membrane, the block copolymer membrane showed a well separated phase morphology and high proton conductivity under fully hydrated condition at 80 degrees C. The fuel cell operated with a SPAEK membrane showed a current density of 1617 mA cm(-2) at 0.6 V under 100% relative humidity (RH), whereas a NRE-212 membrane exhibited a current density of 1238 mA cm(-2), which is about 30% lower than newly prepared SPEAK membrane. In addition, the maximum power density of 1160, and 800 mW cm(-2) was observed for SPAEK, NRE-212 membranes, respectively at 80 degrees C under 100% RH condition. The SPEAK membrane exhibited 1.4-folds enhancement in the maximum power density in comparison with NRE-212 membrane. (C) 2016 Elsevier B.V. All rights reserved.