Silica targeted filled in Nafion membrane is in-situ sulfonated (s-WR-Nafion membrane) to improve the proton conductivity at high-temperature and low relative humidity (RH). The silica introduction as water sorbent in the membrane can both stabilize water balance for polymer electrolyte membrane fuel cells (PEMFCs) and prevent the formation of the water crystalline phase in membrane-electrode assemblies (MEAs) in course of sub-zero temperature operation (so-called cold start) owing to chemical water adsorption. On the other hand, water presence in MEAs provides required operating humidity when temperature increases. Due to the synergistic effect of the targeted filled silica and the efficient -SO3H based proton conductive channel, high temperature proton conductivity of the Nafion membrane is therefore significantly improved at low RH. Particularly, proton conductivity of the s-WR-Nafion membrane is raised to 0.07 S/cm at 110 degrees C and 60% RH. At the same time, mechanical, oxidative and thermal stabilities of the s-WR-Nafion membrane are not decayed due to the integrity of the original structure of Nafion (R). As a result, the maximum output power of the s-WR-Nafion membrane-based fuel cell is ca. 65% higher than that of the pristine Nafion (R) membrane at 110 degrees C and 20% RH. Above all, the s-WR-Nafion membrane exhibit promising application potential for high-temperature PEMFC. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.