Highly sulfonated poly(ether ether ketone) (PEEK) polymer is hydrogenated and then readily grafted on GO to provide nanohybrid material GO-g-SPEEK. The material shows good enough properties for the preparation of proton exchange membranes. First, the GO-g-SPEEK membrane has much more water uptake but less water swelling compared with Nafion((R)), and an excellent proton conductivity of 0.219 Scm(-1) at 90 degrees C. Then, it demonstrates a peak power density of 112 mWcm(-2) when utilized in a H-2/air fuel cell at circumstance temperature. Further, blending of the materials with Nation leads to composite membranes of GO-g-SPEEK/Nafion, which has a close proton conductivity to that of GO-g-SPEEK but far higher cell performances. Of the composite membranes, GO-g-SPEEK/Nafion-33 reveals cell performance of 182 mWcm(-2) at 25 degrees C and 213 mWcm(-2) at 60 degrees C. These results indicate that Nation might serve only as an enhancer of compatibility between membrane and Nafion-supported catalyst phase in the membrane electrode assembly, and therefore suggest that the GO-g-SPEEK may be a promising membrane material for the application in proton exchange membrane fuel cells. (C) 2018 Elsevier Ltd. All rights reserved.