Fabrication of Lead-Free PVDF/KNNLTS/MWCNT Piezoelectric Nanogenerator: Role of MWCNT in the Piezoelectric Performance of Nanogenerator for Energy-Harvesting Application

Lead-free polyvinylidene fluoride/potassium sodium niobate doped with lithium, tantalum, and antimony/multiwall carbon nanotube (PVDF/KNNLTS/MWCNT)-based piezoelectric nanocomposite film has been synthesized by drop-casting, in which KNNLTS nanoparticles were synthesized by using a high-energy ball mill and then incorporated into the PVDF matrix together with MWCNT. The nanocomposite films offer an eco-friendly solution to energy-harvesting applications. The objective of this present work demonstrates the role of MWCNT on KNNLTS (0–25 wt%)-based piezoelectric nanogenerators (PENGs). It was observed that the maximum piezoelectric output voltage for PVDF/KNNNLTS/MWCNT with 20wt% KNNLTS was 87.2 V, while the maximum current was 20.3 µA and power density of 145.48 µW/cm². Further, the PENG was utilized to check the potential performance of human body motion. The output voltages for finger tapping, thumb pressing, fist beating, elbow beating, elbow bending, and wrist stretching were 11.4 V, 27.2 V, 24.8 V, 34 V, 37 V, and 55.2 V, respectively. In addition, the converse piezoelectric coefficient was also measured, with average and maximum values of d₃₃^* ~ 28.67 pm/V and 59.92 pm/V, respectively. Moreover, to test the ability to harvest energy, the nanocomposite film was integrated with conventional electronic components like a full-wave bridge rectifier and resistances. The fabricated PENG demonstrated practical applicability by powering a digital thermometer and digital wrist watch, and successfully lit 18 LEDs. In this study, we have analyzed lead-free piezoelectric nanogenerators which might be considered a good option for self-powered wearable and portable electronic gadgets that need a very small power source.