Enhancing hydrogen desorption in magnesium hydride via nanosized aluminum catalysts synthesized by electrical explosion of wires: Part 2 – The role of formed defect structure

• Electrical explosion of wires (EEW) enables synthesis of MgH2–Al composites with core–shell structures that enhance hydrogen interaction characteristics. • The combination of mechanochemical milling, hydrogenation, and Mg–Al interface formation lowers the desorption activation energy from 161 ± 2 to 109 ± 1 kJ/mol. • A developed network of vacancies, dislocations, and increased microstrains is identified as the key microstructural feature enabling low-temperature hydrogen desorption. • Positron annihilation spectrometry (PAS) is applied to characterize defect structure evolution, connecting material processing to desorption performance.