<scp>TPU</scp> ‐ <scp>PAN</scp> Hollow Fiber Membranes With High Elasticity Performance Fabricated for Dynamic Air Humidification

ABSTRACT Efficient water management is critical for the performance and longevity of proton exchange membrane fuel cells (PEMFCs). Pressure fluctuations in the humidifier during dynamic load changes can considerably reduce the lifespan of membrane materials, and traditional strength‐based approaches have inherent limitations in addressing this challenge. In this study, an elasticity‐over‐strength (EOS) design concept is introduced, and a hollow fiber humidification membrane with superior elasticity and stability is fabricated by blending thermoplastic polyurethane (TPU) with polyacrylonitrile (PAN) through nonsolvent‐induced phase separation (NIPS). The optimized T12P8 membrane achieves a water vapor permeation flux of 1280 g m −2 h −1 at 80°C under −10 kPa transmembrane pressure difference, along with an elongation at break of 1090% and high elastic recovery upon unloading. An accelerated 63‐h cyclic durability test confirms its exceptional operational stability. This work not only offers an innovative material solution to the dynamic fatigue challenge in fuel cell humidifiers but also demonstrates the broader potential of elastic design strategies for energy devices operating in highly dynamic environments.