Fabrication of Ammonium Dinitramide/Si Energetic Coparticles from Silicon Waste with Enhanced Combustion Heat and Ignition Performance

Abstract

The development of high-energy-density energetic materials from low-cost raw materials remains a formidable scientific challenge. Significantly, photovoltaic silicon waste with exceptional purity and high combustion enthalpy represents an ideal low-cost candidate. This study demonstrates the construction of energetic Ammonium Dinitramide (ADN) /Si coparticles from halogen-free ammonium dinitramide and silicon, offering a sustainable strategy for silicon upcycling and green propellant applications. Multiscale characterization (SEM, XRD, FT-IR, XPS) revealed that nano-silicon formed intimately structured coparticles with ADN, while micro-silicon led to physical mixtures. XRD confirmed well-crystallized ADN and silicon phases without detectable oxidation. XPS and FT-IR confirmed interfacial interactions via Si 2p binding energy shifts (0.1–0.9 eV) and vibrational peak blue shifts (10–20 cm⁻¹). Thermal analysis (DSC/TG-MS-FTIR) indicated a 14–23 °C delay in decomposition onset temperature and a 10–20% increase in apparent activation energy, attributed to partial redox reactions between silicon and NO₂ from ADN decomposition. With 80 mass% ADN loading, nano-silicon coparticles achieved a heat release of 12.58 kJ/g, which is approximately three times that of TNT, along with tunable impact sensitivity (4–11 J) and friction sensitivity (96–240 N). Laser ignition tests confirmed reduced ignition delay and enhanced combustion behavior due to nanoscale reactivity. Furthermore, this coparticle construction strategy is directly applicable to real industrial silicon waste. Real photovoltaic silicon kerf waste can be directly used for composite fabrication after simple pretreatment, whose inherent SiC and Fe-based alloy impurities only reduce the combustion heat by 4.8% to 13.4%, preserving the core energetic performance while exerting a modest beneficial effect on the application safety of the material. This work presents a microstructure-driven strategy for optimizing energy release and safety in silicon-based energetic materials.