While scientists at Columbia University have used chemical vapor deposition (CVD) to create large sheets of stronger-than-average graphene, a research team at Massachusetts Institute of Technology (MIT) has found ways to weave stronger carbon nanotubes. James Hone and Jeffrey Kysar, professors of mechanical engineering at Columbia University, learned that the enormous strength of graphene is usually achieved in only small patches. The “grain boundaries” for larger sheets were often far weaker than the theoretical strengths of which the material is capable. That strength is phenomenal. Hone explains, “It would take an elephant, balanced on a pencil, to break through a sheet of graphene the thickness of Saran Wrap.” Results of their study were published in the journal Science. The paper’s lead author, Gwan-Hyoung Lee, a postdoctoral fellow in the Hone lab, says, “Our findings clearly correct the mistaken consensus that grain boundaries of graphene are weak. This is great news because graphene offers such a plethora of opportunities both for …
The Layered Look in Batteries
Gurpreet Singh, assistant professor of mechanical and nuclear engineering, and his research team at Kansas State University in Manhattan, Kansas, are working out less expensive, more efficient ways to create nanomaterials and lithium-ion batteries. “We are exploring new methods for quick and cost-effective synthesis of two-dimensional materials for rechargeable battery applications,” Singh said. “We are interested in this research because understanding lithium interaction with single-, double- and multiple-layer-thick materials will eventually allow us to design battery electrodes for practical applications. This includes batteries that show improved capacity, efficiency and longer life.” Researchers grew graphene films on copper and nickel foils in less than 30 minutes by quickly heating them in a furnace in the presence of argon, hydrogen and methane gases – significantly at atmospheric pressure. Not needing to use a vacuum to create these films saves energy, time and cost, according to Singh. Researchers used the films to create the negative electrode of a lithium-ion cell and test the …