Reactive Vapor-Phase Additives toward Destabilizing γ-Mg(BH 4 ) 2 for Improved Hydrogen Release
[1];
[2];
[3];
[4];
[5];
- National Renewable Energy Laboratory, Golden, Colorado 80401, United States, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
- National Renewable Energy Laboratory, Golden, Colorado 80401, United States
- Sandia National Laboratories, Livermore, California 94550, United States
- Pacific Northwest National Laboratory, Richland, Washington 99354, United States
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States, Department of Chemical and Biological Engineering and Renewable and Sustainable Energy Institute (RASEI), University of Colorado Boulder, Boulder, Colorado 80309, United States
- National Renewable Energy Laboratory, Golden, Colorado 80401, United States, Chemistry Department, Colorado School of Mines, Golden, Colorado 80401, United States
Magnesium borohydride (Mg(BH4)2) is a promising candidate for material-based hydrogen storage due to its high hydrogen gravimetric/volumetric capacities and potential for dehydrogenation reversibility. Currently, slow dehydrogenation kinetics and the formation of intermediate polyboranes deter its application in clean energy technologies. In this study, a novel approach for modifying the physicochemical properties of Mg(BH4)2 is described, which involves the addition of reactive molecules in the vapor phase. This process enables the investigation of a new class of additive molecules for material-based hydrogen storage. The effects of four molecules (BBr3, Al2(CH3)6, TiCl4, and N2H4) with varying degrees of electrophilicity are examined to infer how the chemical reactivity can be used to tune the additive–Mg(BH4)2 interaction and optimize the release of hydrogen at lower temperatures. Control over the amounts of additive exposure to Mg(BH4)2 is shown to prevent degradation of the bulk γ-Mg(BH4)2 crystal structure and loss of hydrogen capacity. Trimethylaluminum provides the most encouraging results on Mg(BH4)2, maintaining 97% of the starting theoretical Mg(BH4)2 hydrogen content and demonstrating hydrogen release at 115 °C. These results firmly establish the efficacy of this approach toward controlling the properties of Mg(BH4)2 and provide a new path forward for additive-based modification of hydrogen storage materials.
- Research Organization:
- National Renewable Energy Lab. (NREL), Golden, CO (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States); Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Biological and Environmental Research (BER); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Transportation Office. Fuel Cell Technologies Office
- Grant/Contract Number:
- AC36-08GO28308; AC02-76SF00515; NA0003525; AC05-76RL01830
- OSTI ID:
- 1842530
- Alternate ID(s):
- OSTI ID: 1844198; OSTI ID: 1845398; OSTI ID: 1846743; OSTI ID: 1855420
- Report Number(s):
- NREL/JA-5900-80159; SAND2022-1516J; PNNL-SA-162167
- Journal Information:
- ACS Applied Energy Materials, Journal Name: ACS Applied Energy Materials Vol. 5 Journal Issue: 2; ISSN 2574-0962
- Publisher:
- American Chemical SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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