Development of Cost-Effective sPEEK/Al2O3 Composite Membranes with Enhanced Proton Conductivity and Durability for PEMFCsMuhammad Fahmi Hakim, Nur Hidayati, Cintiya Septa Hasannah, Eri Widianto and Najmudin FaujiE3S Web Conf., 622 (2025) 01013DOI: https://doi.org/10.1051/e3sconf/202562201013