Tetrahedral Nitrogen Atoms Arrangement in A-Site Cations: A New Approach for Regulating Sensitivity and Energy of Perovskite Energetic Materials

Abstract

Perovskite energetic materials (PEMs) are emerging combinations of oxidants and reductives, which are promising in explosives owing to the advantages of high energy, simple synthesis and low cost. However, the friction sensitivity of the currently reported PEMs is so high that it limits the further application of PEMs. In this work, a tetrahedral nitrogen-atom-arrangement structure, urotropine, is introduced as A-site cation of PEMs, then four urotropine-based PEMs ([C₆H₁₄N₄][M(ClO₄)₃], named TAPs) are successfully constructed experimentally for the first time. The crystal structure, reaction progress, thermal decomposition, sensitivity, and detonation performance of TAPs are characterized. The results indicate that, different from the existing cubic PEMs, the crystal structure of TAPs experiences compression along the c-axis, despite the c-axis length being twice that of the a or b-axes. As expected, the friction sensitivity is remarkably reduced and the detonation performance is significantly improved. Moreover, the hardness of A-site cations is proposed as a key factor affecting the impact sensitivity of PEMs, while C─H···O hydrogen bonds play an important role in regulating friction sensitivity. The emergence of TAPs provides a design concept of high-energy insensitive PEMs and a unique perspective for understanding the mechanical sensitivity of energetic materials.