Sodium Hydrazinidoborane: A Chemical Hydrogen-Storage Material

Herein, we present the successful synthesis and full characterization (by 11B magic-angle-spinning nuclear magnetic resonance spectroscopy, infrared spectroscopy, powder X-ray diffraction) of sodium hydrazinidoborane (NaN2H3BH3, with a hydrogen content of 8.85wt%), a new material for chemical hydrogen storage. Using lab-prepared pure hydrazine borane (N2H4BH3) and commercial sodium hydride as precursors, sodium hydrazinidoborane was synthesized by ball-milling at low temperature (30 degrees C) under an argon atmosphere. Its thermal stability was assessed by thermogravimetric analysis and differential scanning calorimetry. It was found that under heating sodium hydrazinidoborane starts to liberate hydrogen below 60 degrees C. Within the range of 60150 degrees C, the overall mass loss is as high as 7.6wt%. Relative to the parent N2H4BH3, sodium hydrazinidoborane shows improved dehydrogenation properties, further confirmed by dehydrogenation experiments under prolonged heating at constant temperatures of 80, 90, 95, 100, and 110 degrees C. Hence, sodium hydrazinidoborane appears to be more suitable for chemical hydrogen storage than N2H4BH3.