Driving the Polyvinylidene Fluoride Crystallization via Surface Functionalization of Ferromagnetic Nanoparticles for Liquid-Solid Triboelectric Nanogenerator Enhancement

Abstract

In order to meet the growing demand for sustainable and renewable energy, significant processes have been achieved in the energy harvesting field in recent years. Due to its strong polarity property and superior mechanical characteristics, polyvinylidene fluoride (PVDF) serves as the most attractive material for a liquid-solid triboelectric nanogenerator (LS-TENG). PVDF-based TENG has come a long way thus far. Hence, we developed a high-performance magnetoelectric (ME) nanocomposite membrane made of PVDF and CoFe2O4 nanoparticles for application in the triboelectric layer of the LS-TENG device. Due to the large magnetic anisotropy of CoFe2O4, a strong interaction between the electromagnetic phase and the crystalline phase could well be established. Moreover, a chemical technique is used to introduce 1H,1H,2H,2H-perfluorooctyltriethoxysilane (POTS) with a reasonably extended fluoride chain to increase the dispersion of CoFe2O4 nanoparticles in the PVDF. Thus, the crystalline β phase of the membrane increased to 77.7% with 10 wt.% CoFe2O4 and reached a maximum value of 85.4% with 10 wt.% CoFe2O4@POTS in PVDF matrix, indicating an increase in polarity property and dielectric constant of the nanocomposite membrane. Besides, the CoFe2O4/PVDF-based TENG also delivers a power density of 1.62 W/m2, which is 2.7 higher than the pure PVDF-based TENG. This work demonstrates a novel technique for increasing the β phase of the CoFe2O4/PVDF nanocomposite membrane, which could also improve the LS-TENG output performance for real-life applications in energy harvesting.