Skin-Inspired Gradient Architecture Enabling Dynamic Hydrogen Blocking in an Extreme Hydrogen Environment

Because hydrogen atoms are tiny and have a low activation energy for diffusion, they can readily penetrate even dense barrier coatings and gradually undermine their protective performance. This study presents a biomimetic gradient coating, inspired by the skin's multilayered defense system. The architecture integrates: (i) a catalytic self-passivating surface layer where in situ formed oxide/hydroxide nanosheets not only block hydrogen but accelerate atomic-to-molecular recombination; (ii) an electronic-reconfigured mid-layer of alternating S-30sccm/CrN heterostructures, creating charge-polarized interfaces for hydrogen trapping sites, and exploiting nanoscale energy fluctuations from lattice distortions to disrupt coherent diffusion pathways, and (iii) a gradient-supporting base layer eliminating shear stress. This multiscale synergy achieves a record zero-permeation breakthrough of 105 h (compared to 298 s for bare substrate), the D_app of 1.899 × 10⁻⁹ cm²·s⁻¹, and the J was 4.664 × 10⁻¹³ mol·cm⁻²·s⁻¹, which were three orders lower than the bare substrate, while retaining 95.77% hydrogen embrittlement resistance. This work establishes a novel paradigm for hydrogen-barrier design in extreme environments.