High-Performance Water Management Film for Durable and Recyclable Electrochemical Hydrogen Compressors

Water management remains a central obstacle in electrochemical hydrogen compressors (EHCs), where anode-side membrane dehydration under low-humidity conditions compromises both the performance and long-term stability. Here, we report a water management film (WMF) that directly regulates internal water distribution to overcome this intrinsic limitation. The WMF is fabricated through a scalable vacuum filtration process using oxidized multiwalled carbon nanotubes (O-MWCNTs), carbon nanofibers (CNFs), and poly(vinylidene fluoride) (PVDF), forming a porous architecture ∼20 μm thick. The introduction of oxygen-containing functional groups on O-MWCNTs enhances hydrophilicity, facilitating a current density of 2.9 A·cm–2 at 0.3 V under 50% RH and achieving 1 MPa in 100 s. The intertwined O-MWCNT/CNF network, coupled with hydrogen bonding of the PVDF matrix, imparts excellent mechanical robustness, including a tensile strength of 63.5 MPa and cycling stability over 200 cycles. This anode-side strategy establishes a scalable pathway for resolving internal water imbalance in EHCs, advancing the reliability of next-generation membrane-based energy technologies.