ZnFe<sub>2</sub>O<sub>4</sub> nanocomposite films for electromagnetic-triboelectric-piezoelectric effect-based hybrid multimodal nanogenerator

Abstract

Hybridizing the pre-existing energy harvesting techniques in a single device is in focus nowadays to improve the electrical output of energy harvesting device. This work uses a versatile nanocomposite films comprises cuboctahedron zinc ferrite nanoparticles (CZF NPs) and polymer matrix as energy harvesting layers to implement a hybrid multimodal nanogenerator (HNG) of a triboelectric nanogenerator (TENG), a piezoelectric nano -generator (PENG), and an electromagnetic nanogenerator (EMG). Polydimethylsiloxane (PDMS) and poly-vinylidene fluoride (PVDF) were used as polymer matrix materials of two different nanocomposite films. With embedded multi-spiral coil structuring, CZF NPs @PDMS composite film works for the EMG and the TENG. Furthermore, ferroelectric CZF NPs @PVDF composite film produces piezoelectric output by pushing force, serving as the PENG. Our HNG provides an efficient multimodal energy harvesting as the integrated nano -generators generate high output power with not only high output voltage, but also low internal electrical impedance with three different working modes including non-contact mode, contact-separation mode, and non -separation mode in response to the external mechanical pushing force and its release. We believe that these techniques can realize the commercial application of flexible hybrid nanogenerators.