Generating Direct Current Electricity from Ionic Droplets by Using Ferroelectric Material

Generation of direct current (DC) electricity, especially from water, is extremely attractive. Here, by utilizing massive inherent polarized charges of a lead zirconate titanate film, a ferroelectric-based droplet electricity generator (FDEG) is proposed to achieve efficient DC electricity generation from ionic droplets. The electrostatic field that originated from the surface charges separates the charges of opposite polarities in the solution. This separation process enables the transportation of positive charges to the lower electrode by droplet fluidity, while negative charges are guided to the upper electrode, forming a unidirectional charge transfer. From impinging NaCl droplets onto the FDEG, we achieve a peak short-circuit current over 1.3 mA, an equivalent charge density of 5.4 mC m–2, and an energy harvesting efficiency of 3.2% from an individual droplet. Our work provides insights into the electricity generation of solid–liquid nanogenerators, offering promising prospects for energy harvesting from ionic solutions.