  Due to its unique physical and chemical properties, graphene is being
considered as a promising material for energy conversion and storage
applications. Introduction of functional groups and dopants on/in graphene is a
useful strategy for tuning its properties. In order to fully exploit its
potential, atomic-level understanding of its interaction with species of
importance for such applications is required. We present a DFT study of the
interaction of sodium atoms with epoxy-graphene and analyze how this
interaction is affected upon doping with boron and nitrogen. We demonstrate how
the dopants, combined with oxygen-containing groups alter the reactivity of
graphene towards Na. Dopants act as attractors of epoxy groups, enhancing the
sodium adsorption on doped oxygen-functionalized graphene when compared to the
case of non-doped epoxy-graphene. Furthermore, by considering thermodynamics of
the Na interaction with doped epoxy-graphene it has been concluded that such
materials are good candidates for Na storage applications. Therefore, we
suggest that controlled oxidation of doped carbon materials could lead to the
development of advanced anode materials for rechargeable Na-ion batteries.
