MAX‐Derived Photothermal Nanofiber Scaffolds for Synergistic Ion Transport in Sustainable Blue Energy Conversion

Abstract Osmotic energy that harnessed from salinity gradients at river‐sea interfaces represents an abundant renewable source, yet its exploitation is limited by the critical trade‐off between ion selectivity and permeability of ion‐exchange nanofluidic membranes. Herein, a Ti ₂ AlC MAX phase derived photothermal nanofiber scaffolds integrated with 2D MXene nanosheet assembly is designed onto address this challenge. This design emphasized the mechanical robustness and reduced ion transport resistance of MAX phase nanofiber membrane, simultaneously utilized the exceptional cation selectivity of MXene, enabling >90% osmotic power density retention over 30 days. The heterostructure provides interfacial charge asymmetry to induce ionic current rectification that enhancing cation transport and suppressing concentration polarization, reaching a peak power density of 30.6 W m ⁻² for miniaturized systems (0.03 mm ² ) and maintained 0.25 W m ⁻² for large‐area modules (7800 mm ² ). Furthermore, the photothermal response of MTM enabled solar‐driven ion transport acceleration, increasing power output by 55% under illumination without physical contact. This structural‐material synergy thus provided a capable solution between laboratory research and real‐world applications, establishing a viable pathway for sustainable blue energy conversion.