|A lithium-coated fullerene (buckyball) as a potential material for hydrogen storage. Yellow represents lithium atoms, and black represents carbon atoms. Click to enlarge.|
Researchers at Virginia Commonwealth University have described a potential new hydrogen storage system for vehicular applications based on lithium-coated buckyballs. The new material promises a gravimetric storage density of 13 wt.%&mdash
As reported in the 6 July online edition of the Journal of the American Chemical Society, the team designed a theoretical buckyball—fullerene containing 60 carbon atoms—in which Li atoms are capped onto the pentagonal faces of the fullerene. Each lithium atom can bond with five hydrogen molecules, resulting in a storage of 60 hydrogen molecules per buckyball.
We are going to face an energy crisis at some point in the future. It’s not a question of if, but when. We need an energy source that is abundant, cost effective and renewable, burns clean and does not pollute. Today, approximately 75 percent of the oil currently available is used for transportation alone. Any solution to the energy crisis has to take into account the amount of energy we spend on transportation.
The biggest hurdle in a hydrogen economy is to find materials to store hydrogen. The storage materials in question need to have the ability to store hydrogen and allow us to take it out, which means the system must be reversible and operate under moderate temperatures and pressures.—Puru Jena, lead author
Theoretical and experimental work by other researchers has proposed using titanium-coated buckyballs for hydrogen storage. However, those researchers observed that the titanium atoms had a tendency to react with each other and form clusters on the surface of the buckyball. Once clustering takes place, the properties of the buckyball are no longer effective for storing hydrogen in large quantities.
The Department of Energy is targeting storage with a total system gravimetric storage density of 9 wt.% and volumetric density of 70 grams/liter.
The material that we have designed is capable of storing hydrogen at a gravimetric density of 13 weight percent – so it exceeds the industry target. Also, the volumetric density is approximately twice that of liquid hydrogen. This theoretical work has promise, provided one can make it in large enough quantities.—Puru Jena
Jena is currently collaborating with scientists who will conduct experiments to prove that hydrogen can be stored in the lithium buckyballs. Furthermore, these investigators will determine the necessary temperature and pressure conditions for storage and removal of hydrogen from the lithium buckyballs, and how to produce these materials in large quantities.
This research was supported by a grant from the US Department of Energy. Jena collaborated with Qiang Sun, Ph.D., who is affiliated with the INEST Group, Research Center at Phillip Morris USA; Qian Wang, Ph.D, a research associate professor at VCU; and Manuel Marquez, Ph.D., with the Research Center at Phillip Morris.
“First-Principles Study of Hydrogen Storage on Li12C60”; Qiang Sun, Puru Jena, Qian Wang, and Manuel Marquez; J. Am. Chem. Soc., ASAP Article 10.1021/ja058330c S0002-7863(05)08330-7