This study contributes to advancing research in aluminium alloys employed as fuels for thermites (pyrotechnic compositions formed of metal and metal oxide powders). Aluminium alloys possess certain potential in regulating energy release and enhancing combustion efficiency; in order to explore better formulations for the aluminium alloy fuel thermite, PVDF-coated Al–Si samples with different proportions were prepared here by using the electrostatic spraying method. In this study, we are primarily addressing the energy release limitation problems which are imposed by the oxide layer formation during the combustion of aluminium–silicon alloy powders in air and explore the optimal formulation of aluminium–silicon fuel combined with fluoropolymer oxidants. Leveraging advanced electrostatic spraying technology, various PVDF (polyvinylidene fluoride)-coated Al–Si samples (Al–Si@PVDF) were successfully synthesized. Morphological characterization confirmed the complete encapsulation of Al–Si alloy powders by PVDF, yielding spherical core–shell structures with uniform elemental distribution and favourable microstructural characteristics. Further, by thermal analysis and calorimetry investigation, a two-stage reaction between Al–Si and PVDF was unveiled: an initial PVDF decomposition phase followed by an ignition reaction phase. To comprehensively evaluate the combustion performance of samples with varying proportions, high-speed and infrared cameras were employed for precise observations, enabling a deep dive into the combustion parameters and their disparities under two distinct spatial conditions. Through these combustion performance experiments and post-combustion product analysis, we deduced the micro-combustion process mechanism of Al–Si@PVDF. This works not only that it provides a scientific basis for optimizing the formulation of aluminium–silicon fuels and fluoropolymer oxidants, but also holds positive implications for advancing research and development in aluminium alloy-based metastable intermolecular composites. Last but not least, besides the high combustion rates, low ignition temperatures, stable combustion, and strong exothermic performance were obtained for these thermite composite materials.