Ultra-high energetic covalent CON polymeric structures from first-principles investigations

CON polymeric structures are promising high-energy-density materials. Six new CON polymeric structures ( P -3 m 1 - C₃O₃N, Cm -C₂O₂N, Cmca –CON₂, Amm 2-CON₃, Amm 2-CON₄ and C 2/ m -CON₅) with the novel 1D chain, 2D layered, and 3D network-like structures have been proposed by the DFT calculations. Except for the CON₅, the rest of five CON compounds can be quenched to ambient pressure. The stable and non-energetic C-C and C-N bond play a crucial role in stabilizing the CON polymeric structure. Notably, the energy densities of two CO-rich CON structures are comparable to that of TNT. Four N-rich structures achieve energy densities of 6.42–8.47 kJ·g⁻¹, which are 1.5–2.0 times of TNT. The detonation pressures, detonation velocities, detonation temperatures, and detonation volumes range from 87.3 to 212.4 GPa, 12.9–18.5 km·s⁻¹, 3797–5363 K and 503–750 L·kg⁻¹, which are 4.6–11.2 times, 1.9–2.7 times, 1.3–1.8 times higher and comparable to that of TNT, respectively. Mechanism analysis reveals that the remarkable energy densities and detonation performances exhibited by CON polymeric structures are associated with their high mass densities, high total bonding ratio, high mass-ratio of product gases, as well as their fully high-energy covalent bond energy release patterns. The study offers valuable insights for the design of novel high-energy-density materials that combine high stability with outstanding energetic properties.