<p>Charged droplets, owing to their advantages of non-contact manipulation, rapid response, and precise controllability, have become a frontier research topic. Moreover, nanofluids have been proven to possess superior heat transfer performance. In this study, a needle–ring electrode configuration was employed to pre-charge Al₂O₃–H₂O/ethylene glycol nanofluid droplets. The spreading characteristics of charged droplets impacting on a solid surface were investigated. The effects of applied voltage, base fluid composition, nanoparticle concentration, and Weber number (We) on the spreading and recoiling behaviors of droplets were systematically examined. The results show that, under zero-voltage conditions, the maximum spreading ratio (β_max) increases with increasing ethylene glycol ratio in the base fluid and We, while it decreases with increasing nanoparticle concentration. After applying voltage, the electrostatic repulsion induced by surface charges effectively reduces the surface tension, triggers the electro-wetting effect, and promotes droplet spreading. For solutions with higher water content (H75 and H100), β_max increases by approximately 5–6%, accompanied by noticeable oscillatory behavior. In contrast, for solutions with medium to high ethylene glycol content (H50, H25, and H0), the charge effect is weaker, with an increase of less than 2%. As the nanoparticle concentration increases, the enhancement effect of voltage on spreading gradually diminishes, and the increase tends to saturate when the nanoparticle concentration exceeds 0.3%. Furthermore, after applying voltage, β_max increases at low We, whereas no significant increase is observed at high We.</p>