Influence of High Aspect Ratio Lead‐Free Piezoelectric Fillers in Designing Flexible Fibrous Nanogenerators: Demonstration of Significant High Output Voltage

Abstract

Engineering a flexible, cost‐effective piezoelectric energy harvester with a higher piezoelectric performance, i.e., higher voltage and power density, is a great technical challenge nowadays. Herein, the same target is set to demonstrate a unique nanogenerator comprising nanorods (aspect ratio of ≈8.5) of lead‐free potassium sodium niobate (KNN) and poly(vinylidene fluoride) (PVDF) where further poling process is fully omitted. The unique dimension of the synthesized rods with minimal loading (only 3%) bestows, somewhat surprisingly, a negative effect on beta nucleation but subdues this effect by the significant contribution toward the piezoelectric response by self‐orienting the dipoles at the electrospinning process by itself. Thus, the approach resolves the unmet task of complicacy in poling both the molecular and ionic dipoles at the same electric field in a subsequent poling of the finally formed nanocomposite. The nanodevice shows a higher open‐circuit output voltage of ≈17.5 V, an output current of ≈0.522 μA, and a current density of ≈0.13 μA cm−2 under repeated finger tapping and can power a light‐emitting diode (LED) of 2 V practically. The study opens a new route for excellent flexible piezoelectric nanogenerators for promising application in an enormous arena of self‐powering portable and wearable electronic gadgets.