Structure Engineering in Ion‐Beam Sputtered High‐Entropy Metallic Glass Electrocatalyst for Enhanced Oxygen Evolution

High‐entropy metallic glasses (HEMGs) have emerged as promising candidates for developing high‐performance and cost‐effective electrocatalysts for oxygen evolution reaction (OER), owing to their synergistic combination of superior catalytic activity and exceptional compositional tunability. However, a persistent challenge in HEMG synthesis lies in achieving atomic‐level control over microstructural configurations for targeted enhancement of electrocatalytic efficiency. Here, it is presented that a structurally engineered Cantor HEMG self‐supporting catalytic electrode is fabricated through ion beam sputtering (IBS) technology. The electrode features a micromesh integrated with nano‐cone array architecture comprising FeCoNiCrMn alloy, achieving homogeneous elemental distribution and enhanced high‐entropy synergistic effects. The precisely designed hierarchical structure combines the high electrical conductivity of the 3D nickel framework with the catalytically active HEMG surface, delivering exceptional OER performance in alkaline media. The optimized electrode demonstrates a remarkably low overpotential of 296 mV at a current density of 10 mA cm−2, while maintaining stable operation for 30 h under industrial‐grade conditions. The IBS‐derived nano‐cone configuration effectively increases electrochemical active surface area and promotes bubble detachment. This work highlights the dual benefits of IBS‐enabled structure engineering and entropy‐driven electronic modulation, proposing a design strategy for high‐efficiency water splitting systems through integration of metastable materials and 3D architectures.