First-principle study of the Nbn+1CnT2 systems as electrode materials for supercapacitors

Abstract

MXene has attracted significant attention as a promising electrode material for energy storage applications. In this study, the energy storage properties of Nbn+1Cn (n = 1 or 2), as a member of the MXene family, are investigated by using the first-principle density-functional theory. Bare Nb2C and Nb3C2 systems show an extremely high theoretical capacitance of Li atoms. It is determined that the surface termination has a considerable impact on the energy storage properties. The F- or O-terminated surfaces promote a charge transfer between the adatom and the surface. However, these terminations obviously reduce the electronic conductivity and the rate performance in the charge/discharge process. Moreover, the F- and OH-functional groups on the Nbn+1Cn surfaces can be removed through metal atom absorption. Our findings can be useful in designing MXene-based electrode materials for energy storage applications.