Construction mechanisms of a new generation of high-energy all- and high-nitrogen materials under extreme conditions: Ab initio molecular dynamics simulations from pentazole compounds

Abstract

State-of-the-art ab initio molecular dynamics (AIMD) simulations were performed to reveal the construction mechanisms of a new generation of high-energy all- and high-nitrogen materials under the extreme conditions of high temperature coupling of high pressure. The results indicate that there are two successive stages in the decomposition process for (N5-)2DABTT2+: (i) competition between distortion of cyclo-N5- and initial decomposition pathway of dehydrogenation of DABTT2+ cation; (ii) subsequent competition between ring-opening and protonation of N5-, as well as complex global decomposition reactions. Higher temperature or higher pressure accelerates the competition between distortion of cyclo-N5- and initial decomposition, and higher pressure makes distortion of cyclo-N5- dominant. N5- tends to protonate to form pentazole at 300 K, while there exists fierce competition between ring-opening of N5- and protonation of N5- at 1000 K, and higher pressure accelerates the competition and makes ring-opening of N5- dominant. Higher temperature or higher pressure leads to the earlier appearance of the largest nitrogen-rich cluster, and increasing either temperature or pressure could improve N content in the largest cluster. All- and high-nitrogen species N4, N6, HN5 and H2N6 were formed and crystal predictions were conducted. Our findings reveal the construction mechanisms of high-energy all-nitrogen materials with clean and pollution-free products under extreme conditions, which are of significance for the breakthrough of energy bottleneck in the preparation of all-nitrogen materials under conventional conditions, and provide an engineering solution for sustainable future of nature.