Abstract: To address low hydrogen storage capacity, compositional heterogeneity, and oxidation vulnerability in traditional titanium-based hydrogen storage alloys (TM), mechanical ball milling was used to introduce Co, Ni, V, Cu, and Mg for modification. Multimodal characterizations,including SEM-EDX for microstructure, XRD for phase analysis, ICP for quantificationand XPS for chemical state identification,were combined with hydrogen storage kinetics and oxygen poisoning tests. Results showed that V significantly enhanced maximum hydrogen storage capacity (w) from 1.70% to 2.15%, Co modification accelerated hydrogen absorption kinetics, increasing 30-min storage from 1.67% to 1.71%. Critically, Co addition improved oxygen poisoning resistance: the decline rate of post-oxidation storage capacity dropped from 41.8% to 1.74%. Microstructural analysis revealed that Co preferentially localized at the surface layer, where it formed a dense oxide barrier. This dual role—sacrificial oxidation of Co instead of active sites and physical inhibition of oxygen diffusion—protected bulk hydrogen storage functionality. These findings highlight element-specific modifications as an effective strategy to optimize both storage capacity and oxidative stability in TM alloys.

Key words: hydrogen storage, titanium-based alloys, metal elements doping, mechanical ball milling, oxygen poisoning resistance