High-Performance Triboelectric Nanogenerator Based on Electrospun Polyvinylidene Fluoride-Silver Nanowire Composite Nanofibers

Abstract: We describe the preparation of ferroelectric polymer-metallic nanowire composite nanofiber triboelectric layers for use in high-performance triboelectric nanogenerators (TENGs). The electrospun polyvinylidene fluoride (PVDF)-silver nanowire (AgNW) composite and nylon nanofibers were utilized in the TENGs as the top and bottom triboelectric layers, respectively. The electrospinning process facilitated uniaxial stretching of the polymer chains, which enhanced the formation of the highly oriented crystalline β-phase that forms the most polar crystalline phase of PVDF. The addition of AgNWs further promoted β-phase crystal formation by introducing electrostatic interactions between the surface charges of the nanowires and the dipoles of the PVDF chains. The extent of β-phase formation and the resulting variations in the surface charge potential upon the addition of nanowires were systematically analyzed using x-ray diffraction (XRD) and Kelvin probe force microscopy (KPFM) techniques. The ability of trapping the induced tribo-charges increased upon the addition of nanowires to the PVDF matrix. The enhanced surface charge potential and the charge trapping capabilities of the PVDF-AgNW composite nanofibers significantly enhanced the TENG output performances. Finally, the mechanical stability of the electrospun nanofibers was dramatically enhanced while maintaining the TENG performances by applying thermal welding near the melting temperature of PVDF.