Can Borophenes with Dirac Cone Be Promising Electrodes for Supercapacitors

Borophene and related materials are of great scientific interest for their unique properties nowadays. In this work, we studied the band structures and capacitive properties of eight borophene related sheets, in which seven have Dirac cone at their Fermi levels as graphene. The results indicate that the carries in these sheets have favorable or even higher Fermi velocity compared with that of graphene. These materials have much larger differential quantum capacitance, surface storage charge and integrated quantum capacitance than graphene, which make them promising for use as electrodes superior to graphene in supercapacitors. Further studies indicate that these sheets are energetically and mechanically stable although some of them are mechanically anisotropic. Ab initio molecular dynamics simulations conducted at 400 K only exclude one sheet as good electrode. Additionally, Work functions of these materials are computed for building heterojunctions for future applications.