Giant Energy Harvesting via Maxwell Displacement Current Enhancement Using Metal Sheet Interspaced Hetero-Layer Structured Piezo-Composite Nanofiber Device

The limited performance of piezoelectric nanogenerators (PENGs) has hindered their practical applications in self-powered electronics. To address these limitations, this study presents a new design of a PENG that incorporates hetero-layer structured piezo-composite nanofibers with interspaced metal sheets. The hetero-layer structure consists of alternating layers of ferroelectric barium titanate (BT) nanoparticles interfaced with poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) composite nanofibers (P(VDF-TrFE)/BT), and conductive graphite nano-sheets (GNS)-embedded P(VDF-TrFE) composite nanofibers (P(VDF-TrFE)/GNS) mats. The inclusion of interspaced metal sheets in the device configuration enhances the stress concentration effect, thereby effectively distributing the applied mechanical vibrations. Simultaneously, the P(VDF-TrFE)/BT composite nanofibers improve the piezoelectric coefficient (187.86 pC N-1), while the P(VDF-TrFE)/GNS composite nanofibers reduce the internal impedance of the device. These combined enhancements result in an increased Maxwell displacement current and power output. Consequently, the hetero-layer structured PENG exhibits an impressive open circuit voltage (Voc) output of 350 V, a short circuit current (Isc) output of 6 mu A, and a power output of 3.62 W m-2. Moreover, the developed PENG demonstrates extraordinary energy harvesting performance under harsh vibrations caused by human musculoskeletal movements, as well as subtle vibrations from heart pulses, emotional changes, and speech recognition. Additionally, the PENG shows its potential use in wearable self-powered wireless e-health systems. The giant energy harvesting performance hetero-layer structured piezoelectric nanogenerator (HT-PENG) shows promising potential application in self-powered wearable sensors for detecting different physiological signs from human body movement wirelessly.image