Additive Destabilization of Porous Magnesium Borohydride Framework with Core-Shell Structure

Area of Science:

• Materials Science
• Chemical Engineering
• Hydrogen Storage Technologies

Background:

• Designing interfaces with specific thermodynamic and kinetic properties is crucial for efficient hydrogen storage.
• Metal hydrides, like Mg(BH4)2, are promising for hydrogen storage but face challenges in destabilization and oxidation of decomposition products.

Purpose of the Study:

• To synthesize and investigate a core-shell structure of Mg(BH4)2 with MgCl2 additives.
• To understand the correlation between MgCl2 distribution and the dehydrogenation properties of Mg(BH4)2.
• To improve the hydrogen desorption performance and reversibility of Mg(BH4)2.

Main Methods:

• Wet-chemical synthesis of a core-shell structure.
• Systematic investigation of local structure and electronic states.
• Analysis of dehydrogenation properties, including onset temperature, capacity, and activation barrier.

Main Results:

• Achieved significant improvement in hydrogen desorption with MgCl2 decoration.
• Initial hydrogen release commenced at 100 °C, with 9.4 wt% released at 385 °C.
• Reduced activation barrier by 76.4 kJ mol−1 and prevented oxidation of decomposition products.

Conclusions:

• The MgCl2-decorated Mg(BH4)2 core-shell structure enhances hydrogen storage kinetics and thermodynamics.
• The thin MgCl2 layer effectively destabilizes the metal hydride and protects against oxidation, enabling reversibility.