ZnFe2O4 nanocomposite films for electromagnetic-triboelectric-piezoelectric effect-based hybrid multimodal nanogenerator

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 nanogenerator (PENG), and an electromagnetic nanogenerator (EMG). Polydimethylsiloxane (PDMS) and polyvinylidene 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 nanogenerators 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.