New roles of metal-organic frameworks: Fuels for aluminum-free energetic thermites with low ignition temperatures, high peak pressures and high activity

Aluminum-based thermites are widely used in gas generators, propulsions, explosives, and welding because these materials can release a large amount of stored energy on combustion. However, one of the biggest problems in the traditional aluminum-based thermite systems is excessive oxidation of the aluminum particle before combustion, resulting in a decrease of the active aluminum content. Here, we report a new-concept aluminum-free thermites based on an energetic metal-organic framework [Cu(atrz)3(NO3)2]n (MOF(Cu), atrz = 4,4′-azo-1,2,4-triazole) as a fuel. Compared with the traditional aluminum-based thermites, these new thermites exhibit superior performances such as low electrostatic discharge sensitivities, low ignition temperatures, high heats of reaction, high peak pressures, high activity, and production of very few solid residues. It is anticipated that this work will open a new field for the application of MOFs, while laying the groundwork for the development of new energetic materials.