Quantitatively Profiling the Evolution of Hydrogen Storage and Defect Healing Processes in Palladium at the Nanoscale

Area of Science:

• Materials Science
• Nanotechnology
• Analytical Chemistry

Background:

• Detecting light elements (atomic number Z < 10) is challenging due to weak electron and photon interactions.
• Characterizing hydrogen storage materials requires sensitive methods for low Z elements.

Purpose of the Study:

• Introduce a direct thermal absorbance measurement platform for scanning electron microscopy (ZEM).
• Demonstrate ZEM's sensitivity to low Z materials, including hydrogen (Z=1) and vacancies (Z=0).
• Explore ZEM's potential in characterizing hydrogen storage in Palladium (Pd).

Main Methods:

• Developed a direct thermal absorbance measurement platform integrated with scanning electron microscopy (ZEM).
• Applied ZEM to characterize hydrogen storage in Pd, analyzing hydrogen distribution and defects.
• Investigated multiple hydrogen charging-discharging cycles using ZEM's nondestructive detection.

Main Results:

• ZEM revealed inhomogeneous hydrogen storage in Pd, concentrating on grain boundaries and defects.
• Hydrogenation created significant defect density and subsurface voids.
• Observed two distinct hydrogen uptake phenomena and defect healing processes during cycling.
• Established causality between hydrogenation and defect formation, quantifying hydrogen-defect correlations.

Conclusions:

• ZEM is a powerful, nondestructive technique for characterizing light elements and compounds.
• The study uncovered rich phenomena in hydrogen storage materials, highlighting ZEM's potential for advanced material characterization.