Enhancing hydrogen storage through processable porous composite membranes

Hydrogen (H₂) is a promising energy carrier for decarbonization; however, efficient storage remains a key challenge. Porous materials offer potential for enhanced H₂ densification and may enable the development of next-generation lightweight storage systems. A major limitation of such materials is their fine powder form, which hampers retention and processability. In this study, composite membranes comprising a polymer of intrinsic microporosity (PIM-1) matrix and a polytriphenylamine (PTPA)-based conjugated microporous polymer (CMP) filler were developed. The composites are mechanically robust, forming self-standing membranes that retain stability under high temperatures and humidity. H₂ storage capacities of the membranes showed excess gravimetric uptakes of 1.03 wt% at 1 bar and 1.84 wt% at 50 bar (77 K), with total capacities reaching 3.22 wt% at 100 bar. These values are significantly higher than those of pristine PIM-1, which achieved 0.87 wt%, 1.64 wt%, and 2.89 wt% under the same conditions. Net adsorption isotherms demonstrate the potential of the composites to outperform conventional compression storage up to 10 bar at 77 K. Additionally, the composites exhibit high mass transfer coefficients (3.42 min⁻¹), indicating strong H₂ affinity and faster charging rates compared with the pristine PIM-1 membrane (2.79 min⁻¹).