Constructing Continuous Proton Channels through One-Dimensional Confined Nanofillers for High-Performance H2/O2 Fuel Cells

Establishing continuous proton transport pathways alongside robust interfacial interactions remains a critical bottleneck for organic–inorganic composite proton exchange membranes (PEMs). Herein, we report a rationally designed hybrid nanofiller (SUC@PHNTs) that integrates the long-range orientational order of one-dimensional (1D) halloysite nanotubes (HNTs) with the high-density proton-hopping sites of the metal-organic framework UiO-66-(COOH)2 (UC) and zwitterionic surface grafts. Subsequently when dispersed in a sulfonated poly(ether ether ketone) (SPEEK) matrix, this 1D confined architecture bridges discrete UC domains into interconnected, continuous proton-conducting channels, effectively reducing proton transport tortuosity. Specifically, the S/SUC@PHNTs-3.0% membrane delivered 174.72 mS cm–1 (80 °C, 100% RH), corresponding to a 35.21% increase relative to pristine SPEEK. In an H2/O2 single-cell test, the membrane delivered a maximum power density of 793.29 mW cm–2, substantially exceeding that of SPEEK. Moreover, the voltage decay rate over 150 h of continuous operation was merely 0.42 mV h–1, indicative of excellent long-term operational stability. Overall, these results establish that the 1D confined nanofiller design strategy provides a promising technological pathway toward high-performance PEMs.