P-doping improves the stability of BP-N at ambient conditions

Black phosphorus nitrogen (BP-N) is an attractive high-energy density material. However, high pressure synthesized BP-N will decompose at low pressure and cannot exist under ambient conditions. Finding a method to stabilize it at atmospheric pressure is of great significance for its practical applications. However, unlike cg-N, LP-N, and HLP-N, it is not in ground state on the enthalpy-pressure curve under all pressure, and it exhibits imaginary frequencies in its phonon spectrum under 0 GPa. In our study, we have discovered that P doping can effectively reduce the synthesis pressure of BP-N and maintain its stability under atmospheric conditions. Homogeneous doping within the layers helps maintain the static structural stability of layer, while specific interlayer doping enhances its dynamic stability by eliminating interlayer slipping. the calculated energy density of 12.5% doping is 7.49 kJ/g, which is twice the energy density of TNT. This highlights the significance of doping as an effective approach to achieve stable and high-performance BP-N.