Mesoporous Cobalt Difluoride Synchronizes Aluminum Oxidation and Perchlorate Decomposition for Enhanced Oxygen Transfer in Energetic Composites

Abstract

Solid propellants with high energy output and stable combustion are essential for advanced micro-propulsion systems, whereas traditional formulations suffer from the self-passivating barrier of metal fuels and uncontrolled oxygen release from oxidizers. In this work, CoF2 is introduced as a multifunctional additive to simultaneously enhance the reactivity of micron-sized Al and regulate decomposition kinetics of KClO4. The CoF2 derived from a perovskite NH4CoF3 precursor features a hierarchical nanoparticle/microcube architecture that provides abundant active sites while ensuring storage stability. Notably, CoF2 not only induces multiphase fluorination to etch the Al2O3 passivation shell of Al particle, enabling low-temperature solid-state oxidation, but also catalyzes KClO4 decomposition, lowering its temperature by more than 100 °C and establishing new pathway with facile initiation yet controlled progression. These dual effects synchronize oxygen release and consumption thermally and kinetically, establishing coupled redox reactions with efficient oxygen transfer. Consequently, the ternary Al/KClO4/CoF2 system achieves ultrahigh heat releases (3.57 kJ·g−1 vs. 0.14 kJ·g−1 for Al/KClO4). Furthermore, CoF2 transforms violent Al/KClO4 deflagration into sustained combustion with enhanced pressure output, providing a design strategy for advanced combustion catalysts.