University College London Team's "Science Advances": Study on Enhancing Proton Exchange Membrane Fuel Cell Performance with Nanofiber Membranes

Proton exchange membrane fuel cells (PEMFCs) are sustainable and highly efficient energy technologies. The membrane electrode assembly (MEA), as their core component, determines the overall performance of the battery, while the proton exchange membrane (PEM) plays a critical role in proton conduction, gas separation, and efficiency. Current PEM manufacturing primarily relies on solution casting methods, which suffer from issues such as uneven thickness and difficulty in controlling the microstructure. Although polymer modification techniques have been explored, performance and long-term stability in practical applications still need improvement. High-temperature PEMFCs (HT-PEMFCs), operating at elevated temperatures (120°–200°C), offer advantages such as no need for complex water management, tolerance to impure hydrogen fuel, and the ability to integrate waste heat, making them an ideal choice for energy applications. However, a key issue with phosphoric acid (PA)-doped PEMs is PA leaching, which leads to degradation of the catalyst layer and reduced efficiency.

Recently, a team from University College London developed a nanofiber membrane system with synergistic structural and interfacial enhancements. Their findings were published in Science Advances (IF=12.5, citation: Sci. Adv. 11, eadw5747 (2025)) under the title “Nanofiber membranes for enhanced performance and optimization of proton exchange membrane fuel cells.” Through nanofiber structure and surface engineering, the team balanced proton conductivity, mechanical strength, and electrochemical performance in the membrane. Notably, the sandwich-structured nanofiber membrane (SSNFM) demonstrated outstanding performance, achieving a peak power density of 942 mW cm⁻² after 100 hours of accelerated stress testing, significantly surpassing the 520 mW cm⁻² of conventional commercial membranes. Electrochemical characterization revealed a proton conductivity of 40.4 mS cm⁻¹, higher than the 17.5 mS cm⁻¹ of commercial membranes.

The study employed multi-scale analytical methods, including X-ray computed tomography and multiphase simulations, to reveal improvements in membrane performance, catalyst layer stability, and three-phase boundary formation facilitated by the nanofiber membrane, thereby promoting efficient charge and mass transport. The team also conducted electrochemical evaluations of surface-modified porous PBI NFM and SSNFM MEAs (at 160°C, anode: H₂ 100 ml min⁻¹, cathode: O₂ 100 ml min⁻¹), which showed excellent performance in terms of open-circuit voltage (OCV) variation, polarization curves, and accelerated stress testing (AST) stability. The membrane design strategy proposed in this research provides an important solution for enhancing the performance of fuel cells in sustainable energy applications.