Two-dimensional single-layer PC6 as promising anode materials for Li-ion batteries: The first-principles calculations study

Very recently, single-layer (SL) PC6, which has buckled graphene-like structure and ultrahigh carrier mobility, was reported. In this paper, the properties of SL PC6 as anticathode material for Li-ion batteries have been studied by using the first-principle density functional theory. The most stable binding situation of the Li-atom in the SL PC6 is the P-atomic top position with C atom as the plane two flanks. The Fermi level of SL PC6 moves upward to the conduction band, indicating that SL PC6 transitions from semiconductor to metal after adsorption of the Li atom. At all the concentrations studied, the binding energy of Li atoms adsorbed on SL PC6 are negative, showing that the adsorption process is stable. Li-ions tend to diffuse along path I in SL PC6 and the diffusion path is small. The maximum theoretical specific capacity of SL PC6 as Li-ion batteries is 478.61 and 717.09 mAh/g for single and double side adsorption, respectively. In addition, the average open circuit voltage for single and double side adsorption is respectively 0.23 V and 0.21 V. Our research shows that SL PC6 is an appropriate Li-ion anticathode material.