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

ABSTRACT 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 cm ² ·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.