The U.S. Department of Energy is searching for ways to make storing energy with hydrogen a practical possibility, and they set up some goals for onboard automotive hydrogen storage systems with a driving range of 300 miles or more: the Department had hoped that by 2017, a research team could pack in 5.5 percent hydrogen by weight, and that by 2020, it could be stretched to 7.5 percent. Li’s team has already crossed that threshold, with a hydrogen storage density of 9.5 percent hydrogen by weight. The team has also demonstrated the potential to reach an even higher density, a future research goal.
“Just like paper origami, which can make complicated 3-D structures from 2-D paper, graphene origami allows us to design and fabricate carbon nanostructures that are not naturally existing but have desirable properties,” said Li, an Associate Professor of Mechanical Engineering, a member of the Maryland NanoCenter and the University of Maryland Energy Research Center (UMERC), and a Keystone professor in the A. James Clark School of Engineering. Forming a graphene nanocage: (a) Patterned graphene is suitably hydrogenated (by bonding hydrogen atoms to the carbon atoms of planar graphene, thus warping it) and then folded (b-f) into a nanocage via electric-ﬁeld assistance. (Credit: Shuze Zhu and Teng Li/ACS Nano) “In this paper, we show that graphene nanocages can be used for hydrogen storage with extraordinary capacity, holding the promise to exceed the year 2020 goal of the U.S. Department of Energy on hydrogen storage,” Li explained to KurzweilAI in an email interview.
“Paper origami has existed for more than a millennium. Such a concept has been explored to enable the formation of complicated 3D structures from 2D building blocks in recent years, such as micro-robots and actuators. In these developments, the building block materials are still bulk materials, with a final resulting 3D structure of size on the order of millimeters. “The graphene origami we demonstrate in this paper uses the thinnest yet strongest materials ever made (one atom thick), leading to a nanocage on the order of several nanometers. Another unique feature of [Hydrogenation-assisted graphene origami] HAGO that does not exist in conventional origami is that programmable opening and closing of HAGO-enabled nanostructures can be controlled via an external electric field.