Combustion synthesis of nanoscale magnesium borides with improved hydrogen uptake and release

Technical Report · Wed Feb 25 00:00:00 EST 2026

DOI:https://doi.org/10.2172/3024235· OSTI ID:3024235

The overarching goal of the reported project was to develop reversible metal hydrides that can be dehydrogenated and recharged at relatively low temperatures and pressures. The project complemented the research on reversible metal hydrides for hydrogen storage conducted by the Hydrogen Materials – Advanced Research Consortium (HyMARC). The students involved were trained at both the University of Texas at El Paso (UTEP) and Sandia National Laboratories (SNL). The research objectives were to fabricate nanoscale magnesium boride powders with different B/Mg atomic ratios and to investigate the effects of B/Mg ratio and particle size on the hydrogenation properties of the obtained materials. Magnesium diboride (MgB2) and tetraboride (MgB4) were synthesized by using combustion synthesis and by heating in a tube furnace. The latter method resulted in materials with significantly reduced impurity levels. An effective method for the removal of magnesium oxide impurities was identified. High-energy ball milling produced submicron MgB2 and MgB4 powders. However, hydrogenation experiments at pressures up to 700 bar have not shown any uptake of hydrogen. Thermogravimetric analysis of the decomposition of the obtained MgB2 and MgB4 demonstrated higher thermodynamic stability of the latter. Thus, the boron-rich nature and phase stability of magnesium borides with high B/Mg ratios make them poor candidates for direct hydrogenation. However, the synthesized MgB4 is a promising energetic additive to solid fuels for high-speed air-breathing propulsion as it offers a lower oxidation onset temperature and greater energy density than MgB2.

• Research Organization: The University of Texas at El Paso
• Sponsoring Organization: USDOE Office of Critical Minerals and Energy Innovation (CMEI), Office of Energy Technology (E-Tech). Alternative Fuels and Feedstocks Office
• DOE Contract Number: EE0010429
• OSTI ID: 3024235
• Report Number(s): DOE-UTEP-10429
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
36 MATERIALS SCIENCE
Metal hydrides
metal borides
hydrogen storage
solid fuels and propellants