Wearable Piezoelectric Nanogenerators Based on Core-Shell Ga-PZT@Ga-Ox Nanorod-Enabled P(VDF-TrFE) Composites

High-output flexible piezoelectric nanogenerators (PENGs) have achieved great progress and are promising applications for harvesting mechanical energy and supplying power to flexible electronics. In this work, unique core-shell structured Ga-PbZrxTi1-xO3 (PZT)@GaOx nanorods were synthesized by a simple mechanical mixing method and then were applied as fillers in a poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) matrix to obtain highly efficient PENGs with excellent energy-harvesting properties. The decoration of gallium nanoparticles on PZT @GaOx nanorods can amplify the local electric field, facilitate the increment of polar beta-phase fraction in P(VDF-TrFE), and strengthen the polarizability of PZT and P(VDF-TrFE). The interfacial interactions of GaOx and P(VDF-TrFE) are also in favor of an increased beta-phase fraction, which results in a remarkable improvement of PENG performance. The optimized Ga-PZT@GaOx/P(VDF-TrFE) PENG delivers a maximum open-circuit voltage of 98.6 V and a short-circuit current of 0.3 mu A with 9.8 mu W instantaneous power under a vertical force of 12 N at a frequency of 30 Hz. Such a PENG exhibits a stable output voltage after 6 000 cycles by the durability test. Moreover, the liquid gallium metal offers a mechanical matching interface between rigid PZT and the soft polymer matrix, which benefits the effective, durable mechanical energy-harvesting capability from the physical activities of elbow joint bending and walking. This research renders a deep association between a liquid metal and piezoelectric ceramics in the field of piezoelectric energy conversion, offering a promising approach toward self-powered smart wearable devices.

Automated summary

This study synthesized unique core-shell structured Ga-PbZrxTi1-xO3 (PZT)@GaOx nanorods, which were used as fillers in a matrix to obtain highly efficient PENGs. The decoration of gallium nanoparticles amplified the local electric field and facilitated the increment of polar beta-phase fraction in P(VDF-TrFE), resulting in improved performance. The interfacial interactions between GaOx and P(VDF-TrFE) also contributed to the enhancement of PENG performance.