Novel Flexible Proton-Conducting Gelatin-Based Green Membranes for Fuel Cell Applications and Flexible Electronics

Natural polymers, such as gelatin, offer a sustainable, green, and versatile alternative for developing proton exchange membranes in low-temperature fuel cell applications. They provide a balance of biocompatibility, flexibility, and ionic conductivity. In this work, gelatin-based composite membranes are reported. The membranes were fabricated and modified with various additives, including ionic liquids (ILs), polyethylene glycol (PEG), and glycerol, to enhance their electrochemical and mechanical properties. The proton conductivity of the pure gelatin membrane was relatively low at 1.0368 × 10−4 Scm−1; however, the incorporation of IL ([DEMA][OMs]) significantly improved it, with the gelatin/0.2 g IL membrane achieving the highest conductivity of 4.181 × 10−4 Scm−1. The introduction of PEG and glycerol also contributed to enhanced conductivity and flexibility. The water uptake analysis revealed that IL-containing membranes exhibited superior hydration properties, with the highest water uptake recorded for the gelatin/0.2 g glycerol/0.2 g IL membrane, which was found to be very high (906.55%). The results showed that the combination of IL and PEG provided enhanced proton transport and mechanical stability (as examined visually), making these membranes promising candidates for fuel cell applications. Therefore, this study underscores the importance of bio-based materials by utilizing gelatin as a sustainable, biodegradable polymer, supporting the transition toward greener energy materials. The findings demonstrate that modifying gelatin with conductivity-enhancing and plasticizing agents can significantly improve its performance, paving the way for bio-based proton exchange membranes with improved efficiency and durability.