Salts Induce Enhanced Disintegration of Natural Minerals in Charged Water Microdroplets

Charged water microdroplets have been demonstrated to be microreactors capable of disintegrating hard minerals into nanoparticles (NPs) under ambient conditions. However, the high applied potentials required (∼4–4.5 kV) limit the energy efficiency and industrial applications of the phenomenon. Herein, we demonstrate that when aqueous solutions containing trace concentrations of salts (0.1 ppm) are electrosprayed, the threshold potential for quartz disintegration decreases by up to 85%, leading to the formation of 2–10 nm NPs at voltages as low as 1.5 kV. Systematic variation in salt concentration reveals that enhanced droplet conductivity, surface tension, interfacial charge polarization, and localized electric field amplification collectively facilitate efficient disintegration at lower voltages. The effect of ionic size was systematically investigated through different cations (H + to Cs + ) and anions (F – to I – ), establishing that smaller ions promote stronger field localization and faster charge relaxation dynamics. COMSOL simulations elucidate how ionic additives modulate droplet deformation and cleavage of the mineral lattice. This salt-assisted electrospray route offers a green, energy-efficient, and scalable strategy for the ambient synthesis of mineral-derived nanomaterials.