Energetic properties of copper azide nanoparticles encapsulated within a conductive porous matrix via electrosynthesis

• Copper azide nanoparticles encapsulated in the conductive MOF were electrosynthesized. • Such strategy ensures high security of both the reaction process and azide products. • The energetic films exhibit tailored energy output and electrostatic sensitivity. • DFT calculations prove the electrochemical azidation mechanism. The copper-based azide (CA), as a sustainable alternative to currently-used primary explosives, will play a critical role in the deployment of miniature initiating systems owing to its outstanding blasting power and environmentally benign nature. However, a secure and controlled synthesis still remains challenging for the high-performance CA-based energetic film. Here, a conductive metal-organic framework (MOF) of cuprous 7,7,8,8-tetracyanoquinodimethane (CuTCNQ) is employed as a template for the electrochemical preparation of the CA nanoparticles encapsulated with conductive porous matrix. Impressively, the composition, morphology, energetic characteristics (1090∼2780 J·g -1 ) and electrostatic sensitivity (0.19∼12.3 mJ) of such CA/CuTCNQ energetic films can be easily tuned by carefully adjusting current density and azidation time in order to achieve the tailored energy release in the form of combustion or detonation. Furthermore, density functional theory (DFT) calculations provide valuable insights for the electrochemical azidation mechanism of the CA/CuTCNQ film. This work pioneers a new pathway to develop the CA composite film as an interesting energetic material for advanced initiating applications.