A high-level research is currently focused on the construction of polymer nanocomposite membranes with high proton conductivity (PC), peak power density (PD), and open circuit voltage (OCV) for polymer electrolyte membrane fuel cells (PEMFC) to substitute the commercial Nafion-211 membrane. The present study deals with the solvent-casting process for producing ZrO2 nanoparticles (1-7 wt %) dispersed on phosphoric acid (PA) doped polyethylene imine and polyvinyl alcohol (PA-PEI/PVA) polymer nanocomposites (PNCs). ZrO2 (5%) dispersed PA-PVA/PEI PNCs showed the highest ion-exchange capacity (IEC) of 2.94 mmol/g-1 at room temperature (RT), and PC of 4.34 10-2 S/cm-1 at 120 & DEG;C. Experiments on the PNCs were carried out at 120 & DEG;C to evaluate their performance and usability in medium-temperature polymer electrolyte membrane fuel cells (MT-PEMFCs). The results indicate a practical and effective route for the fabrication of a composite membrane that has a semi-interpenetration network structure with abundant active protonated groups, and has future prospects and widespread application in MT-PEMFCs.& COPY; 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.