Constructing continuous proton transport channels with hybridized nanofibers for high performance sulfonated polyimide-based proton exchange membranes

This study presents a novel strategy for developing high-performance proton exchange membranes (PEMs) by innovatively integrating sulfonated halloysite nanotube (SHNT)-loaded polyvinyl alcohol (PVA) nanofibers into a sulfonated polyimide (SPI) matrix. The fabrication process employed electrospinning of SHNT-dispersed PVA solution to produce axially aligned PVA@SHNT nanofibers, which were subsequently homogeneously dispersed in the SPI matrix via solution casting. The resulting composite membranes exhibited notable properties. The optimized SPI-PVA@6SHNT membrane demonstrated significant improvements in mechanical strength and dense, uniform morphology. The synergistic effect of microphase separation induced by PVA nanofibers and the hollow structure of SHNT significantly enhanced water uptake, reaching 71.5%. The composite membrane achieved effective proton conductivity through dual proton transport mechanisms: vehicular transport facilitated by increased water content and hopping conduction through hydrogen-bonded networks among PVA, SHNT and SPI. When assembled into membrane electrode assemblies (MEAs), the SPI-PVA@6SHNT membrane delivered strong fuel cell performance, achieving maximum power densities of 334.1 mW cm −2 at 100% relative humidity (RH) and 301.4 mW cm −2 at 75% RH with H 2 -air atmosphere, demonstrating effective humidity tolerance. This nanofiber-mediated modification strategy offers a promising approach for developing advanced PEMs with balanced proton conductivity, mechanical robustness, and operational stability.