Generating Direct Current Electricity from Ionic Droplets by Using Ferroelectric Material

Generation of direct current (DC) electricity, especiallyfromwater, is extremely attractive. Here, by utilizing massive inherentpolarized charges of a lead zirconate titanate film, a ferroelectric-baseddroplet electricity generator (FDEG) is proposed to achieve efficientDC electricity generation from ionic droplets. The electrostatic fieldthat originated from the surface charges separates the charges ofopposite polarities in the solution. This separation process enablesthe 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 dropletsonto the FDEG, we achieve a peak short-circuit current over 1.3 mA,an equivalent charge density of 5.4 mC m(-2), andan energy harvesting efficiency of 3.2% from an individual droplet.Our work provides insights into the electricity generation of solid-liquidnanogenerators, offering promising prospects for energy harvestingfrom ionic solutions.