A series of sulfonated poly(p-phenylene-co-aryl ether ketone) (SPP-co-PAEK) membranes are successfully prepared from 2,5-dichloro-3'-sulfobenzophenone and 2,2'-bis[4-(4-chlorobenzoyl)] phenoxyl perfluoropropane through Ni(0)-catalyzed copolymerization for polymer electrolyte membrane fuel cell (PEFC) applications. The obtained SPP-co-PAEKs have fairly high reduced viscosities and give ductile and transparent membranes with good mechanical strength. All the membranes exhibit comparable or even better proton conductivities than that of Nafion 112 in the full hydrate state. In addition, the membranes showed almost isotropic proton conductive behavior with a sigma(perpendicular to)/sigma(parallel to) values in the range of 0.85-0.92. Fuel cell operation using SPP-co-PAEK(3/1) (IEC = 2.0 meq g(-1), thickness of 38 mu m, feed gases: H-2/air) exhibited rather good performances: open circuit voltage of 0.94 V. cell voltage at 1.0 A cm(-2) of 0.61 V. and output at 1.7 A cm(-2) of 0.85W cm(-2) under 90 degrees C and 82/68% relative humidity condition. The results suggested that these SPP-co-PAEK membranes are promising candidates for PEFC applications. (c) 2012 Elsevier B.V. All rights reserved.