Hydrogen storage remains one of the great challenges limiting the widespread availability of hydrogen (H2) PEM fuel cell technology for automobile and unmanned vehicles. The commercial hydrogen fuel cell passenger vehicles on the market run on highly compressed hydrogen. It still remains a challenge to develop sorbent materials for hydrogen storage, that have enhanced gravimetric and volumetric storage capacities, and optimum kinetics in the fuel cell operation regime, that offer a higher performance alternative to compressed gas storage.

HNEI researchers in collaboration with UH Chemistry Department and DOE’s HYMARC Consortium are developing advanced reversible magnesium boride, MgB2, hydrogen storage materials to overcome this challenge. The MgB2/Mg(BH4)2 system is one of the few reversible materials with a gravimetric H2 density (14.7 wt% H2) that is sufficient to meet the requirements of practical on-board PEM fuel cell applications and also possesses thermodynamics (ΔHo = 39 kJ/mol H2,  ΔS = 112 J/K mol H2) that permit reversible H2 release under moderate pressure and temperature. However, overcoming the extremely slow kinetics of the reversible release of hydrogen by this material is a daunting challenge. Hence, cycling between MgB2 and magnesium borohydride, Mg(BH4)2 has only been previously accomplished only at high temperature (~400 ˚C) and under high charging pressure (> 900 bar).

Our team is investigating innovative approaches to vastly improve the kinetics of hydrogenation of bulk MgB2 to Mg(BH4)2 using additives. Our current results demonstrate for the first time hydrogenation of bulk MgB2 to Mg(BH4)2 at low temperatures and pressures of ≤ 300 oC and ≤ 700 bar. This corresponds to a simultaneous reduction of the conditions required for bulk MgB2 direct hydrogenation to Mg(BH4)2 of ≥ 100 ˚C and ≥ 200 bar. Our approach represents an important step forward with potential to significantly increase the hydrogen cycling kinetics of the MgB2/Mg(BH4)2 system to lightweight fuel cell vehicle relevant conditions.

Point Person: Godwin Severa

 

Technical Reports

 

Papers and Proceedings

 

Presentations

 

Patents

  • 2017, G. Severa, C.M. Jensen, C. Sugai, S. Kim, Activated Magnesium Boride Materials: Hydrogen Storage and Electronics Applications, USPTO Application number 62/561,649.