Pushing the Limits of Energy Performance in Micron-Sized Thermite: Core–Shell Assembled Liquid Metal-Modified Al@Fe2O3 Thermites

Thermites are a class of significant energetic materials widely used in aerospace propulsion, explosion, pyrotechnics, thermal batteries, and power generation. Although nanothermites exhibit fast reaction rates and high energy density, micron-sized thermites remain of practical importance over nanothermites due to their low electrostatic discharge (ESD) sensitivity, lower cost, and smaller dead mass. Herein, we develop micron-sized core–shell gallium-based liquid metal-modified Al@Fe2O3 (GLM-Al@Fe2O3), which exhibits high energy density and low laser ignition energy. At an equivalence ratio of 1.3, the differential scanning calorimetry results show that the total heat release of GLM-Al@Fe2O3 reaches 2555 J·g–1, which is much higher than that of the control sample (1424 J·g–1) prepared by a similar process. The density of GLM-Al@Fe2O3 (φ = 1.3) was characterized by a gas pycnometer analyzer, and its volumetric energy density could reach 9.96 kJ·cm–3. Laser-ignited combustion performance of GLM-Al@Fe2O3 was markedly reinforced in terms of the decreased ignition energy. Additionally, the ESD ignition threshold of GLM-Al@Fe2O3 is higher than 1 J, which revealed that the as-prepared GLM-Al@Fe2O3 was insensitive to electrostatic discharge. The facile and efficient strategy in this work provides inspiration to enhance the energy output performance and maintain the ESD safety of micron-sized thermites, which could show great potential in various civilian and military applications.