A method for in situ fabrication of Al@C nanocomposite energetic additives through pulsed discharge in liquid cyclohexane has been proposed. The obtained Al@C nanocomposites consist of large aluminum nanoparticles (over 100 nm) enveloped by fullerenes and a carbon matrix with smaller aluminum particles (under 100 nm) embedded within. DSC–TGA curves indicate that the heat release of Al@C is higher than that of micron‐sized and nano‐sized aluminum particles. Al@C nanocomposites effectively reduce the ignition delay for liquid fuels. The energy efficiency of this method is much higher than that of continuous arc ablation, with a yield of up to 2.5 mg/min. This method allows for the simple, convenient, and safe fabrication of energetic additives, presenting a promising prospect for large‐scale industrial production.