Phosphorus doping stabilizes high-energy polymeric nitrogen at ambient pressure

Using first-principles calculations, a research group led by Prof. WANG Xianlong from the Hefei Institutes of Physical Science of the Chinese Academy of Sciences, found that phosphorus doping is an effective way to achieve high-energy polymeric nitrogen with black-phosphorus structure (BP-N) stable at ambient pressure.

The research results were published in Matter and Radiation at Extremes.

Cubic gauche nitrogen with diamond-like structure and BP-N with black phosphorus structure, represented by polymeric all-nitrogen materials, are a class of high-energy density materials composed entirely of N-N single bonds, but their samples synthesized under high-pressure conditions cannot be preserved under ambient pressure, which is one of the important challenges faced in this field.

In this study, researchers found that the low-pressure instability mechanism of BP-N is different from that of cg-N. 

The surface instability of cg-N leads to structural instability, while the bulk of BP-N will decompose into nitrogen chains at low-pressure range. Phosphorus atom doping can suppress the bulk decomposition of BP-N and stabilize BP-N to 0 GPa, achieving dynamical stability through N-P dipole interaction. 

In addition, the researchers calculated the optimal doping concentration and detonation performance of BP-N.

This research result will actively promote the ambient pressure synthesis and large-scale preparation of BP-N.

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