Hierarchical structure energetic composites: Synergistic lattice and surface confinement for effective energy and safety balance

The pursuit of high energy density materials (HEDMs) with intrinsic safety has long been hindered by the energy-safety trade-off. This study proposed a hierarchical structure strategy integrating lattice stabilization and surface energy dissipation to address this challenge in HNIW. Embedding N 2 O molecules within the explosive lattice by hydrogen bonding effectively improved the oxygen balance of HNIW, resulting in the construction of HNIW/N 2 O host-guest explosives. Concurrently, polyethyleneimine (PEI) and polypyrrole (PPy) were employed for surface coating to further enhance the safety performance of explosives. The lattice-surface modifications synergistically achieved prominent mechanical stimulus buffering (IS>20 J, FS > 140 N) and enhanced phase stability (203 °C). Benefiting from the hierarchical structure, the HNIW/N 2 O@PEI and HNIW/N 2 O@PPy composites exhibited superior comprehensive characteristics including remarkable energy performance, improved safety and combustion properties. The lattice-surface optimization surpassed traditional single-scale modifications in balancing explosive energy and safety, yielding unprecedented performance integration. The work can present a scalable approach for developing next-generation energetic materials, providing valuable design insights for multifunctional material engineering.