Hollow microsphere architecture via electrostatic spraying: Synergistically enhanced safety and combustion efficiency of DNTF/FOX-7@NC energetic composites

3,4-Bis(4′-nitrofurazano-3′-yl)furoxan (DNTF), a high-energy–density material, is severely restricted in practical applications due to its high mechanical sensitivity. This study develops an advanced desensitization strategy for DNTF composite via electrostatic spraying technology. The DNTF/FOX-7@NC (FOX-7, 1,1-diamino-2,2-dinitroethene; NC, nitrocellulose) hollow microsphere structure was formed through controlling the propulsion rate and the FOX-7 content. The composites retain the crystalline features of DNTF and FOX-7, while NC forms a continuous protective surface layer. Subsequently, the influence of FOX-7 content on the safety performance and combustion efficiency of the composites is systematically investigated. Results indicated that DNTF/FOX-7@NC hollow microsphere composites achieved a favorable balance between energy output and safety performance. Specifically, composites (with 38 % FOX-7 content) demonstrate superior thermal stability compared to raw DNTF. Its impact sensitivity increased by 14.7 J compared to raw DNTF (4.9 J), the critical load for friction sensitivity exceeds 360 N, demonstrating superior mechanical safety. Simultaneously, the combustion efficiency of the DNTF/FOX-7@NC hollow microsphere composite is significantly optimized, benefiting from the architecture of the hollow microspheres facilitating heat and mass transfer. This resulted in a 43 % reduction in ignition delay time of composite (from 109.24 s to 61.71 s). This work resolves the energy-safety trade-off in energetic materials via hollow microsphere structural design by electrostatic spray strategy, offering a scalable strategy for next-generation munitions.