Revolutionary Metal Hydride Nanosheets Boost Hydrogen Storage Capacity by 50 Times

Scientists from Lawrence Livermore National Laboratory (LLNL), Sandia National Laboratories, the Indian Institute of Technology Gandhinagar and Lawrence Berkeley National Laboratory have recently developed 34 nm ultrathin nanosheets of a metal hydride that boosts hydrogen storage capacity. They published their research paper in Small.

The material was produced via solvent-free mechanical exfoliation in zirconia, resulting in a material that is just 1112 atomic layers thick and can hydrogenate to a capacity of around 50 times that of the bulk material. This study demonstrates that mechanochemical exfoliation of magnesium diboride in zirconia produces 34 nm ultrathin MgB2 nanosheets (multilayers) with high yield.

High-pressure hydrogenation of these multilayers at 70 MPa and 330 °C followed by dehydrogenation at 390 °C reveals a hydrogen capacity of 5.1 wt%, which is 50 times larger than the capacity of bulk MgB2 under the same conditions. This enhancement is attributed to defective sites created by ball-milling and incomplete Mg surface coverage in MgB2 multilayers, which disrupts the stable boron–boron ring structure.

Sustainable Energy Storage Systems

Sustainable energy storage systems are needed to counteract the erratic nature of renewable energy sources. Technologies based on hydrogen provide potential long-term approaches to lowering greenhouse gas emissions. With hydrogen having the highest energy density of any fuel, it is thought to be a practical option for marine, air, and land vehicles.

However, complex metal hydrides are a class of hydrogen storage materials that have been exposed to extremely high pressures and temperatures due to their large absolute storage capacity for hydrogen. The scientists overcame this difficulty by nano-sizing which enhances surface area available for hydrogen reactions and reduces necessary depth of hydrogenation resulting in an increase in volumetric energy density surpassing compressed hydrogen gas.

Metal Hydride Nanosheets: The Future of Hydrogen Storage?

Metal hydride nanosheets could revolutionize the way we store hydrogen for energy applications. The partially exfoliated magnesium diboride multilayers have a 5.1 wt% capacity for storing hydrogen, which is approximately 50 times larger than the capacity of bulk MgB2 under the same conditions. Additionally, incomplete Mg surface coverage in MgB2 multilayers helps disrupt the stable boron–boron ring structure.

Furthermore, density functional theory calculations indicate that balance of Mg on the MgB2 nanosheet surface changes as it hydrogenates. This research provides promising new direction for 2D metal boride/borohydride research with potential to achieve high-capacity reversible hydrogen storage at more moderate pressures and temperatures.

Conclusion

Metal hydride nanosheets could revolutionize the way we store and use energy from renewable sources. The partially exfoliated magnesium diboride multilayers have a 5.1 wt% capacity for storing hydrogen, which is approximately 50 times larger than the capacity of bulk MgB2 under the same conditions. Additionally, density functional theory calculations indicate that balance of Mg on the MgB2 nanosheet surface changes as it hydrogenates.

This research provides promising new direction for 2D metal boride/borohydride research with potential to achieve high-capacity reversible hydrogen storage at more moderate pressures and temperatures. If successfully implemented, this technology could prove invaluable in providing efficient and sustainable energy solutions that reduce our dependence on fossil fuels.