Ultrathin proton-conducting sandwich membrane with low methanol permeability based on perfluorosulfonic acid polymer and phosphosilicate

An ultra-thin, free-standing proton-conductive membrane of Nafion®/Phosphosilicate/Nafion® (NPN) with a sandwich structure has been prepared. The NPN membrane of thickness 960 nm shows extremely low methanol permeability of 1 × 10−8 cm2 s−1, and area specific resistance (ASR) smaller than 0.2 Ω cm2.