A model of a membrane-electrode assembly (MEA) with a Sulfonated Poly Ether-Ether Ketone (SPEEK) membrane is presented and compared with Nafion membrane MEA. The model used the specific hydration and proton conductivity curves developed for SPEEK membrane and accounted for feed-gas momentum and mass transfer, electro-potential in both the electrode and electrolyte fields. The model is first used to obtain and compare the polarization curve of the cell in different water activity of the feed gases for both SPEEK and Nafion. Then, Operating parameters like temperature, pressure, and water mass fraction in feed gases were optimized for maximum power density production of SPEEK membrane using response surface method (RSM). The results indicated that the SPEEK MEA could compete with Nafion in the presence of liquid water at a normal operational temperature (80 degrees C) and surpass it at a higher temperature. Optimization results contribute to guidelines for the practical use of the SPEEK membrane in PEMFCs. Outcomes signified that operating at high temperature is only favorable in high pressure and water content of the anode feed gas, due to the high sensitivity of proton conductivity of SPEEK membrane to the water activity. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.