The performance of phosphorus hexarbide monolayer as lithium-ion battery anode materials by boron and sulfur doping

It is very crucial for the further commercialization of batteries to develop promising new anode materials. In this paper, the potential of sulfur- and boron-doped phosphorus hexacarbide (PC₆) materials in lithium-ion batteries was studied based on density functional theory. Sulfur- and boron-doped improved the conductivity of the PC₆, and reduced the lithium ion diffusion barriers on the PC_6.857 S_0.143 and α-PC_5.875 B_0.125 surfaces with values of 0.38 eV and 0.37 eV, respectively, which were lower than that of the pristine PC₆ surface of 0.47 eV. Charge transfer calculations show strong Coulombic interactions of lithium ions with PC_6.857 S_0.143 and α-PC_5.875 B_0.125. The theoretical storage capacities of PC_6.857S_0.143 and α-PC_5.875B_0.125 were 519.77 mA·h/g and 781.56 mA·h/g, respectively. These values were not only superior to conventional two-dimensional (2D) materials such as graphene (372 mA·h/g) and MXene (Ti₃C₂ 447.8 mA·h/g), but also B-doped PC₆ was higher than the pristine PC₆ (717.09 mA·h/g) and N-doped PC₆ (778.72 mA·h/g). Our research suggests that α-PC_5.875B_0.125 is a potential candidate as anode materials for high-performance lithium-ion batteries.