Graphene/hbn heterostructures as high-capacity cathodes with high voltage for next-generation aluminum batteries

Abstract

The field of Al batteries immensely demands the development of highly efficient cathode materials which can provide large storage capacities along with maintaining a constant high voltage. In this work, using the first-principles calculations, we have proposed the graphene/hexagonal boron nitride heterostructure (G/hBN) as a suitable cathode material for Al batteries. We have systematically investigated the binding, electronic, and electrochemical properties for the AlCl 4 -Adsorbed/intercalated G/hBN heterostructure in various possibilities, and a necessary comparison has also been executed with the pristine monolayer of graphene and hBN. It is observed that the binding strength of AlCl 4 has significantly improved on the outer surfaces of graphene and hBN and in interlayer spaces of the G/hBN heterostructure compared to monolayer hBN, besides maintaining a similar strong binding as that of monolayer graphene. The lower diffusion barrier (0.01 eV) ensures a faster charge/discharge rate in the G/hBN heterostructure as the Al battery cathode. On systematically observing the incorporation of AlCl 4 in G/hBN through the voltage profile study, it is determined that the G/hBN heterostructure can deliver both a high voltage of 2.14 V as well as a high storage capacity of 183 mA h/g, whereas monolayers of graphene and hBN are either good at delivering higher storage capacity or better net voltage. All of these results motivate us toward the usage of the G/hBN heterostructure as the potential cathode material for the Al battery and provide valuable insights into the exploration of other 2D heterostructures for the highly efficient Al batteries. © 2019 American Chemical Society.