Presenter 1: Amir Farokh (PhD student, Bernhardt group, AIBN)

Title: Hydrogenated defective graphene and functionalized graphene nano-ribbons for anode materials of rechargeable batteries

Abstract: Selection of a suitable anode material along with a suitable charge transfer agent is an important issue for producing a rechargeable battery with good performance. Sodium (Na) and calcium (Ca) have been considered as charge transfer agents for some time, due to their cheaper price compared with lithium. However, they have low binding energy over graphene-based materials. In the first topic, we have considered hydrogenated defected graphene, which increased the binding energy of both Na and Ca. According to our results, a single layer of the proposed material has a capacity of 360.8 and 547.0 mAhg-1, respectively. We have also considered the adsorption of Na and Ca over the functionalized edge of graphene nano-ribbons. This study is very important due to the occurrence of lots of functionalized edge terminating with hydrogen and oxygen in reduced graphene oxide. According to our results, Na and Ca can bind strongly around carbonyl and carboxyl groups at the edge of the graphene nano-ribbons. Moreover, up to nearly 4 adatoms can bind around those groups at the edge. These results suggest Na and Ca will bind over the edge of reduced graphene oxide, making them suitable for rechargeable batteries.


Presenter 2: Yalong Jiao (PhD student, Du group, QUT)

Title: First-principles prediction of spin-polarized multiple Dirac rings in Manganese Fluoride

Abstract: Spin-polarized materials with Dirac features have sparked great scientific interest due to their potential applications in spintronics. But such type of structures is very rare and none has been fabricated. In this talk, I will present the already experimentally synthesized Manganese Fluoride (MnF3) as a novel spin-polarized Dirac material by using first-principles calculations. MnF3 exhibits multiple Dirac cones in one spin orientation, while it behaves like a large gap semiconductor in the other spin channel. The estimated Fermi velocity for each cone is of the same order of magnitude as that in graphene. The 3D band structure further reveals that MnF3 possesses rings of Dirac nodes in the Brillouin zone. Such a spin-polarized multiple Dirac ring feature is reported for the first time in an experimentally realized material. Moreover, similar band dispersions can be also found in other transition metal fluorides (e.g. CoF3, CrF3 and FeF3). This work highlights a new single-spin Dirac material with promising applications in spintronics and information technologies.