Hydrogen has attracted ever-growing attention due to its high societal impact in green energy technologies, such as green hydrogen production, storage, and green steels manufacturing for CO2 reduction. Parallel to the tremendous amount of effort being put for understanding hydrogen embrittlement in metallic materials for hydrogen storage and transportation, developing efficient hydrogen production and proton-conducting oxide electrolytes as well as mixed proton-electron conductors for the components in fuel cells and electrolyzers is also sharing a large scientific and economic weight.  

In this talk, we demonstrate the fundamental process of hydrogen incorporation and transport in perovskite oxide SrTiO3 with pre-engineered dislocations. Dislocations (see Figure 1a,b: with a density up to ~1014/m2 inside a plastic zone larger than 1 mm2) were mechanically introduced at room temperature using in-house developed Brinell indentation scratching technique [1]. Exposing the reference (with a dislocation density of ~1010/m2) and dislocation-rich regions to hydrogen (deuterium) at 400 °C for 1h, followed by secondary ion mass spectrometry (SIMS) measurements, leads to ~100 times higher hydrogen incorporation (see Figure 1c) in dislocation-rich region to a depth of 1 μm. The result suggests dislocations can act as effective diffusion path for efficient hydrogen transport, paving the road for efficient design of proton-conducting oxide electrolytes. This finding may also hold great potential for the emerging hydrogen-defects interactions and dislocation engineering in oxides [2]. 

References
[1] X. Fang, O. Preuß, P. Breckner, J. Zhang, W. Lu, Engineering dislocation‐rich plastic zones in ceramics via room‐temperature scratching, J. Am. Ceram. Soc., 106 (2023) 4540-4545.
[2] X. Fang, A. Nakamura, J. Rödel, Deform to perform: Dislocation-tuned properties of ceramics, ACerS Bulletin 102(5) (2023) 24-29.